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									    Public Health Risk
    Management Plan
                Guide
Surface and Groundwater Sources
             Version 1, Ref S1.1




                June 2001
                Published in June 2001 by
                    Ministry of Health
           PO Box 5013, Wellington, New Zealand

                ISBN: 0-478-26152-7 (Booklet)
                ISBN: 0-478-26153-5 (Internet)

This document is available on the Ministry of Health‟s Web site:
                   http://www.moh.govt.nz
Contents


Introduction                                                           1

Risk Summary                                                           2

Risk Information Table                                                 3

Contingency Plans                                                    15

PHRMP Performance Assessment                                         19

Appendix (S1.1): Source Protection Zones (SPZ)                       20




Ref S1.1                 Public Health Risk Management Plan Guide:   iii
Version 1, June 2001             Surface and groundwater sources
Introduction
Raw water is groundwater, surface water or rainwater that has not received any treatment
to make it suitable for drinking. This Guide is concerned with groundwater and surface
water; rainwater is covered in Guide S1.2.

The quality of the raw water must be good enough to produce a safe and acceptable
drinking-water when treated, and it must come from a source that can consistently provide
sufficient required quantity. In many cases it can be better to protect the quality of the raw
water than to treat it after it has become contaminated.

Contaminated and poorly managed water sources can contain chemical, microbiological or
radiological hazards which can lead to sickness.

This Guide considers four methods for managing risks to raw water quality:
     regulation of activities by law (Resource Management Act 1991 – RMA)
     increasing people’s awareness of the effects their activities have on the drinking-
      water supply
     increasing awareness of natural activities and processes, so that the risks to raw
      water quality they create can be managed
     co-operation and communication with landowners whose activities can affect raw
      water quality; being aware of planned activities that might affect water quality.

These methods require water suppliers to work alongside regional and district councils and
unitary authorities.

The RMA can be used to manage some risks to raw water quality arising from land use
activities. However, there are a number of risks that are not easy to manage using the
RMA and interpretation of it differs among regional and district councils so that risk
management is sometimes unsatisfactory.

Law changes have not been suggested as a way of managing raw water quality, although
these may be necessary if water suppliers are to have the information and the powers they
need to manage their supplies effectively.

Raw water quality has effects on many other supply elements, especially treatment
processes. This Guide is therefore linked to a number of other Guides: those dealing with
abstraction from the source (P1 series), pre-treatment processes (P4 series) and the various
treatment processes (P5, P6, P7 and P8 series).




Ref S1.1                            Public Health Risk Management Plan Guide:              1
Version 1, June 2001                        Surface and groundwater sources
Risk Summary
A range of events can affect raw water quality. These have with varying levels of risk.
The most important preventive measures that can be put in place to deal with them are:
     monitoring to decide if and where contamination of the water is occurring; this is
      best done when contamination is most likely
     knowing where the catchment (surface water) or re-charge zone (groundwater) of
      your source is and the nature of the land in this area
     identifying source protection zones for your source, so that possible contamination
      sources that need to be managed can be identified (source protection zones are
      discussed in the Appendix to this document)
     collection of all available information about possible sources of contamination –
      identifying gaps in information is an important part of this Guide.




2        Public Health Risk Management Plan Guide:                              Ref S1.1
         Surface and Groundwater Sources                            Version 1, June 2001
Risk Information Table
This table does not provide a guide to the level of risk of each event because the level of
risk is too dependent on the nature of each individual source. The following factors will
help in estimating the level of risk for each event for your supply.
     An activity that is absent does not present a risk.
     In general, the closer an activity is to where you draw water from the source, the
      greater the chance of contamination (so long as the separation is not great).
     Continuing contamination is more likely, and the risk therefore higher, if there is
      already evidence of contamination.
     Activities leading to germs getting into the water generally create a greater risk to
      public health than those leading to chemical hazards.

Reliable information about water quality is essential for the proper management of a water
supply. Knowledgeable and skilled staff are also essential for minimising the public health
risks associated with water supplies. Please read the staff training guide (G1) and the
monitoring guides (G2). While we haven’t pointed out every detail of how these
documents are linked with the present document, the links are many and are important.




Ref S1.1                             Public Health Risk Management Plan Guide:          3
Version 1, June 2001                         Surface and groundwater sources
Abbreviations: DWSNZ – Drinking-Water Standards for New Zealand; MAV – Maximum acceptable value – see
DWSNZ:2000. Council – unitary authority, regional council, or district council depending on the area concerned.

         Causes                Preventive measures                   Checking preventive measures               Corrective action

                                                                    What to check       Signs that action
                                                                                           is needed

Event: SOURCE WATER RECEIVES DISCHARGE OR LEACHATE FROM A CONTAMINATED SITE (including sheep dips,
offal and carcass pits)
Possible hazards: Germs; chemical determinands (depending on nature of site).

S1.1.1                       Identify the source catchment        Concentrations in      Elevated             Gather more
                              or recharge zone, and source          the source water        levels of             information
   Contaminated
                              protection zones I, II and III        of all contaminants     contaminants          about
    sites close enough
                              (see Appendix).                       of concern              in source             catchment or
    to source water to
                                                                    identified for the      water.                recharge zone.
    potentially affect       Obtain all information                contaminated
    its quality.              available about known                 sites.                 Reticulated          Approach
                              contaminated sites in the                                     water not             council for
   Poor
                              catchment or recharge zone.                                   compliant with        information
    understanding of
                                                                                            DWSNZ:                about
    catchment or             Once all contaminated sites                                   2000.                 contaminated
    recharge zone.            have been identified, establish                                                     sites.
                              a strategy to:                                               Lack of
   Poor identification
                                                                                                            
    of source                 – develop a list of possible                                  knowledge of
                                                                                            catchment/
                                                                                                                  Arrange for
                                                                                                                  council to
    protection zones.           contaminants                                                recharge              establish
   No knowledge of           – monitor water quality for                                   zone, and             strategy to deal
    the contaminant‟s           evidence of health-                                         contaminated          with the effects
    existence.                  significant contaminants1,                                  sites in the          of any
                                and request the council to                                  area.                 contaminated
   Possible effects of         oversee site clean-up                                                             sites.
    sites not
    recognised when           – develop a plan with the                                                          Consider
    source                      council using monitoring                                                          treatment
    development                 and site inspection to                                                            options or
    consent was                 provide early-warning of                                                          development of
    obtained.                   source contamination                                                              a new source.

   New contaminated          – work with the council to
    site.                       identify and carry out
                                measures that can be put
                                in place to control the
                                spread of contaminants.
                             Arrange for water supplier to
                              be informed of new discharge
                              consent applications in the
                              source protection zone.




4           Public Health Risk Management Plan Guide:                                                          Ref S1.1
            Surface and Groundwater Sources                                                        Version 1, June 2001
         Causes                 Preventive measures                     Checking preventive measures                Corrective action

                                                                       What to check        Signs that action
                                                                                               is needed

Event: SOURCE WATER RECEIVES DISCHARGE FROM DOMESTIC OR INDUSTRIAL PROCESSES, EITHER DIRECTLY
OR INDIRECTLY (excluding septic tanks)
Possible hazards: Germs; chemical determinands (depending on the nature of the discharge).

S1.1.2                       Develop an understanding of             Any determinand,        Elevated             Obtain more
                              the extent of the source                 microbiological or       levels of             information
   Non-permitted or
                              catchment or recharge zone.              chemical which           contaminants          about
    permitted
              2               Identify source protection               might possibly be        in source             catchment or
    activities within
                              Zones I, II and III.                     present in the           water.                recharge zone.
    the source
                                                                       discharge.
    protection zone.         Obtain information about non-                                    Reticulated          Approach
                              permitted activities in the                                       water not             councils for
   Poor
                              catchment or recharge zone                                        compliant with        information
    understanding of
                              from the council.                                                 DWSNZ:                concerning non-
    catchment or
                                                                                                2000.                 permitted
    recharge zone.           Obtain a list of permitted                                                              activities in the
                              activities that are potential                                    Lack of
   No, or incomplete,
                                                                                                knowledge of
                                                                                                                      area.
                              causes of contamination.
    knowledge of
                                                                                                catchment/           Establish
    activities in the        Obtain information about                                          recharge              strategy to deal
    catchment or              permitted activities in the                                       zone, and             with the effects
    recharge zone.            catchment or recharge zone                                        sources of            of any discharge
                              by survey if not available
   Insufficient                                                                                contamination         (eg, deep
                              elsewhere.                                                        in the area.          abstraction).
    consideration of
    potential impact of      Once all discharges are                                                                Consider
    activities when           identified, liaise with council to                                                      treatment
    consents granted.         establish a strategy to:                                                                options or
   Council plan              – develop a list of possible                                                            development of
    classes activity as          contaminants with distance                                                           a new source.
    permitted, and               from abstraction point
    hence consent
    conditions do not         – monitor water quality for
    exist.                       evidence of health-
                                 significant contaminants,1
   Possible effects of          and request that the
    sites not                    council arrange for
    recognised when              reduction of contaminant
    source                       loading (if necessary)
    development
    consent was
                              – obtain monitoring results
                                 from consent holders
    obtained.
   Conditions of the
                              – develop a plan with the
                                 council using monitoring
    consent are not
                                 and site inspection to
    followed.
                                 provide “early-warning” of
                                 source contamination
                              – work with the council to
                                 identify and carry out
                                 measures that can be put
                                 in place to control the
                                 spread of contaminants.
                             Ensure water supplier is
                              informed of new discharge
                              consent applications in the
                              source protection zone.

1   The monitoring plan should take into account seasonal changes, as lower flows can lead to lead to higher contaminant
    concentrations. Situations in which contamination is most likely to occur should be identified so that monitoring can be suitably
    timed.
2   Permitted activities are defined in regional and district plans. These are activities for which no resource consent is required,
    and because of this, councils often hold very little information that would help in managing them. The risks they create are often
    from non-point sources of contamination, rather than point sources.




Ref S1.1                                             Public Health Risk Management Plan Guide:                                       5
Version 1, June 2001                                         Surface and groundwater sources
         Causes                 Preventive measures                  Checking preventive measures               Corrective action

                                                                    What to check         Signs that action
                                                                                             is needed

Event: SOURCE WATER RECEIVES DISCHARGE FROM MINING OPERATIONS
Possible hazards: Metal determinands (depending on the ore).

S1.1.3                                                                   See S1.1.2.
Non-permitted or
permitted activities2
within the source
protection zone.
(See S1.1.2.)

Event: SOURCE WATER RECEIVES LEACHATE FROM LANDFILL SITE
Possible hazards: Germs; chemical determinands.

S1.1.4                                                                   See S1.1.2.
   Non-permitted
    activity within the
    source protection
    zone.
   Poor
    understanding of
    catchment or
    recharge zone.
   No, or incomplete,
    knowledge of
    activities in the
    catchment or
    recharge zone.
   Insufficient
    consideration of
    potential impact of
    activities when
    consents granted.
   Poorly constructed
    landfill.
   Landfill liner is
    damaged.
   Inappropriate use
    of landfill (eg,
    wrong type of
    waste dumped).
   Possible effects of
    sites not
    recognised when
    source
    development
    consent was
    obtained.
   Conditions of the
    consent are not
    followed.

Event: SOURCE WATER RECEIVES WASTE ORIGINALLY DISCHARGED TO LAND
Possible hazards: Germs; chemical determinands.

S1.1.5                                                                   See S1.1.2.
Non-permitted or
permitted activities2
within the source
protection zone.
(See S1.1.2.)

2   Permitted activities are defined in regional and district plans. These are activities for which no resource consent is required,
    and because of this, councils often hold very little information that would help in managing them. The risks they create are often
    from non-point sources of contamination, rather than point sources.




6            Public Health Risk Management Plan Guide:                                                            Ref S1.1
             Surface and Groundwater Sources                                                          Version 1, June 2001
         Causes                 Preventive measures                   Checking preventive measures                   Corrective action

                                                                     What to check        Signs that action
                                                                                             is needed

Event: SOURCE WATER RECEIVES SPILLAGE, OR LEAKAGE, ARISING FROM THE STORAGE OR USE OF HAZARDOUS
SUBSTANCES
Possible hazards: Germs; chemical determinands (depending on the nature of substances in use).

S1.1.6                                                                    See S1.1.2.
Non-permitted or
                     2
permitted activities
that use hazardous
substances within the
source protection zone.
(See S1.1.2.)

Event: SOURCE WATER RECEIVES SEPTIC TANK DISCHARGES
Possible hazards: Germs; chemical determinands (predominantly nitrate and nitrite).

S1.1.7                       Develop an understanding of           Microbiological         Elevated                Get more
Septic tanks within the       the extent of the source               quality of source        levels of                information
source protection zone.       catchment or recharge zone.            water.                   nitrate, nitrite         about
                              Identify source protection                                      or E. coli in            catchment or
(See S1.1.2.)                 Zones I, II and III.                  Nitrate.                 source water.            recharge zone.
                             Obtain information about the          Nitrite.                Reticulated             Approach
                              number and location of septic                                   water not                council for
                              tank discharges in the                                          compliant with           information
                              catchment or recharge zone.                                     DWSNZ:                   concerning
                                                                                              2000.                    discharge
                             Liaise with councils to identify                                                         consents for
                              all septic tank disposal fields                                Lack of                  septic tanks in
                              located within source                                           knowledge of             the area.
                              protection Zone II.                                             catchment/
                                                                                              recharge                Establish
                             Request that the council                                        zone, and                strategy to deal
                              decline new applications for                                    sources of               with the effects
                              septic tank installation within                                 contamination            of any septic
                              source protection Zone II.                                      in the area.             tanks that are
                             Once the location of septic                                    No information
                                                                                                                       affecting the
                              tank discharges are known,                                                               source.
                                                                                              to allow
                              establish a strategy to:                                        establishment           Consider
                              – monitor water quality for                                     of satisfactory          treatment
                                 evidence of health-                                          separation               options
                                 significant contaminants1                                    between                  (particularly
                                                                                              bores/wells              disinfection –
                              – develop a plan with the                                       and tanks.               see P7 Guide
                                 council using monitoring                                                              series) or
                                 and site inspection to                                                                development of
                                 provide „early-warning‟ of                                                            a new source.
                                 source contamination
                              – in collaboration with
                                 councils, provide public
                                 information on
                                 recommended
                                 maintenance and use of
                                 septic tank systems
                              – identify and carry out
                                 measures that can be put
                                 in place to control
                                 contamination from the
                                 existing discharges.

1   The monitoring plan should take into account seasonal changes, as lower flows can lead to lead to higher contaminant
    concentrations. Situations in which contamination is most likely to occur should be identified so that monitoring can be suitably
    timed.
2   Permitted activities are defined in regional and district plans. These are activities for which no resource consent is required,
    and because of this, councils often hold very little information that would help in managing them. The risks they create are often
    from non-point sources of contamination, rather than point sources.




Ref S1.1                                            Public Health Risk Management Plan Guide:                                            7
Version 1, June 2001                                        Surface and groundwater sources
         Causes                 Preventive measures                  Checking preventive measures                 Corrective action

                                                                    What to check        Signs that action
                                                                                            is needed

Event: SOURCE WATER RECEIVES RUN-OFF FROM URBAN OR SEALED SURFACES
Possible hazards: Germs; chemical determinands.

S1.1.8                       Develop an understanding of          Any determinand,        Elevated              Get more
                              the extent of the source              microbiological or       levels of              information
   Urban or industrial
                              catchment or recharge zone.           chemical which           contaminants           about
    area within source
                              Identify source protection            might possibly           in source              catchment or
    protection zone.
                              Zones I, II and III.                  arise from               water.                 recharge zone.
   Poor                                                            activities in the
                             Obtain information about all          catchment.              Treated water         Identify areas
    understanding of
                              sources of urban and                                           not compliant          where land use
    catchment or
                              industrial run-off and its                                     with DWSNZ:            is likely to affect
    recharge zone.
                              treatment and disposal in the                                  2000.                  run-off.
   Poor identification       catchment or recharge zone.
                                                                                            Lack of               Establish
    of areas where
                             Once the presence of run-off                                   knowledge of           strategy to deal
    run-off may be
                              sources is known, establish a                                  catchment/             with the effects
    influenced by land
                              strategy to:                                                   recharge               of contaminated
    use activities.
   Inadequate
                              – monitor water quality for                                    zone, and
                                                                                             sources of
                                                                                                                    run-off.

                                                                                             contamination 
                                 evidence of health-                                                                Consider
    collection, or               significant contaminants,1
                                                                                             in the area.           treatment
    treatment, of run-           and request the council                                                            options or
    off, and                     manages arrangements for                                                           development of
    inappropriate                reduced contaminant                                                                a new source.
    disposal.                    loading (if necessary)
   New activity in           – in association with councils,
    source protection            assess the risk
    zone.                        management of areas
                                 where hazardous
                                 substances are stored and
                                 used, or high contaminant
                                 loading is expected (eg,
                                 petrol stations). Work with
                                 owners and councils to
                                 address any inadequacies
                              – develop a plan with the
                                 council using monitoring
                                 and site inspection to
                                 provide „early-warning‟ of
                                 source contamination
                              – in collaboration with
                                 councils, provide public
                                 information on run-off from
                                 domestic activity and its
                                 impact on the water source
                              – identify and carry out
                                 measures that can be put
                                 in place to control
                                 contamination from run-off.
                             Ensure water supplier is
                              informed of new discharge
                              consent applications in the
                              source protection zone.

Event: SOURCE WATER RECEIVES MATERIAL FROM SURFACE IMPOUNDMENTS (WASTE PONDS OR LAGOONS)
EITHER TREATED DISCHARGE OR LEAKAGE
Possible hazards: Germs; chemical determinands. (depending on the nature of substances contained in the ponds).

S1.1.9                                                                  See S1.1.2.
Impoundments within
source protection zone
(See S1.1.2.)

1   The monitoring plan should take into account seasonal changes, as lower flows can lead to lead to higher contaminant
    concentrations. Situations in which contamination is most likely to occur should be identified so that monitoring can be suitably
    timed.




8            Public Health Risk Management Plan Guide:                                                           Ref S1.1
             Surface and Groundwater Sources                                                         Version 1, June 2001
       Causes                   Preventive measures                   Checking preventive measures                  Corrective action

                                                                     What to check       Signs that action
                                                                                            is needed

Event: SOURCE WATER RECEIVES TREATED EFFLUENT OR UNTREATED (LEAKAGE) FROM EFFLUENT PONDS
Possible hazards: Germs; chemical determinands. (depending on the nature of the waste).

S1.1.10                                                                   See S1.1.2.
Effluent ponds within
source protection zone.
(See S1.1.2.)

Event: SOURCE WATER QUALITY INFLUENCED BY WASTE DISPOSAL DOWN HOLE OR BORES
Possible hazards: Germs; chemical determinands. (depending on the nature of the waste).

S1.1.11                                                                   See S1.1.2.
Waste disposal down
holes or bores within
source protection zone.
(See S1.1.2.)

Event: SOURCE WATER RECEIVES LEAKAGE OF CONTAMINANTS DOWN ABANDONED OR DECOMMISSIONED
WELLS
Possible hazards: Germs; chemical determinands.

S1.1.12                                                                   See S1.1.2.
Abandoned or
improperly
decommissioned wells
within source
protection zone.
(See S1.1.2.)

Event: SOURCE WATER RECEIVES FAECAL MATTER FROM LIVESTOCK OR FERAL ANIMALS
Possible hazards: Germs; chemical determinands.

S1.1.13                      Develop an understanding of           Microbiological        Elevated                Improve
                              the extent of the source               quality of source       levels of                information
   Animals within
                              catchment or recharge zone.            water.                  nitrate, nitrite         available about
    source protection
                              Identify source protection                                     or E. coli in            catchment or
    zone.
                              Zones I, II and III.                  Nitrate.                source water.            recharge zone.
   Poor                                                         
                             Limit stock density and                Nitrite.               Reticulated             Erect stock
    understanding of
                              irrigation of pastures in source                               water not                fence an
    catchment or
                              protection Zone II so that                                     compliant with           appropriate
    recharge zone.
                              faecal material does not pass                                  DWSNZ:                   distance from
                              into the groundwater.                                          2000.                    the source, and
                              (Councils may be able to                                                                make sure stock
                              provide advice on the limits for                              Lack of                  are removed.
                              stock numbers that will protect                                knowledge of
                              the water resource.)                                           catchment/
                                                                                             recharge
                          (See P1 Guide series.)                                             zone.
                                                                                            Stock with
                                                                                             access to
                                                                                             source water.




Ref S1.1                                            Public Health Risk Management Plan Guide:                                       9
Version 1, June 2001                                        Surface and groundwater sources
        Causes                  Preventive measures                  Checking preventive measures                   Corrective action

                                                                   What to check           Signs that action
                                                                                              is needed

Event: AGRICHEMICALS (INCLUDING STOCK DIP) OR POISONS ENTER SOURCE WATER
Possible hazards: Chemical determinands. (depending on the nature of the agrichemicals).

S1.1.14                      Develop an understanding of         Chemical                 Concentrations          Get more
                              the extent of the source             determinands                of                     information
    Agrichemical
                              catchment or recharge zone.          (depending on the           agrichemicals          about
     and/or poison use
                              Identify source protection           agrichemicals in            more than              catchment or
     within source
                              Zones I, II and III.                 use).                       50% of their           recharge zone.
     protection zone.
                                                                                               MAV in the
                             Identify farming activities in                                                         Approach the
    Poor                                                                                      source water.
                              the area. Prepare a list of                                                             council and
     understanding of
                              agrichemicals used for these                                  Reticulated              MAF to arrange
     catchment or
                              farming activities.                                              water not              a seminar for
     recharge zone.
                                                                                               compliant with         farmers on good
                             Monitor water quality for
    Inappropriate                                                                             DWSNZ: 2000.           practices with
                              evidence of health-significant                                                          respect to use of
     location of stock                      1
                              contaminants, and request                                     Lack of                  agrichemicals
     dips.
                              that the council manage                                          knowledge of           and poisons.
    Inappropriate            arrangements that will help to                                   catchment/
     construction of          reduce the contaminant                                           recharge zone.
     stock dips and           loading.
                                                                                            Agrichemicals
     post dip drainage
                             Ensure farmers are aware of                                      still being
     area.
                              codes of practice (if                                            applied in a
    Inappropriate            applicable) for agricultural                                     way that is
     disposal of used         chemical use, and the need                                       likely to
     dip.                     for backflow prevention for                                      contaminate
                              their source water.                                              the source.
    Poor
     understanding by
     the farmer of the
     potential
     consequences of
     their farming
     practices.
    Lack of backflow
     prevention
     measures in
     chemical
     preparation
     facilities.

Event: CONTAMINANTS WASHED INTO SOURCE WATER DURING IRRIGATION
Possible hazards: Germs; chemical determinands.

S1.1.15                      Develop an understanding of         Microbiological            Elevated              Approach the
Irrigation being              the extent of the source             quality of the              levels of              council and
undertaken within             catchment or recharge zone.          source water.               contaminants           MAF to arrange
                              Identify source protection                                       in source              a seminar for
source protection zone.
                              Zones I, II and III.                Chemical                    water.                 farmers on good
                                                                   determinands                                       irrigation
                             Ensure that farmers use              (particularly nitrate      Reticulated            practices.
                              appropriate irrigation systems       and nitrite).               water not
                              for effective coverage without                                   compliant with        Start periodic
                              causing flooding.                                                DWSNZ:                 inspections of
                                                                                               2000.                  the catchment.
                                                                                              Farmers
                                                                                               unaware of
                                                                                               possible
                                                                                               effects of
                                                                                               irrigation.

1   The monitoring plan should take into account seasonal changes, as lower flows can lead to lead to higher contaminant
    concentrations. Situations in which contamination is most likely to occur should be identified so that monitoring can be suitably
    timed.




10           Public Health Risk Management Plan Guide:                                                             Ref S1.1
             Surface and Groundwater Sources                                                           Version 1, June 2001
        Causes                  Preventive measures                     Checking preventive measures                  Corrective action

                                                                       What to check        Signs that action
                                                                                               is needed

Event: SOURCE WATER RECEIVES SEDIMENT AND AGRICHEMICALS FROM FORESTRY ACTIVITIES
Possible hazards: Germs; chemical determinands.

S1.1.16                       Develop an understanding of            Microbiological         Elevated               Visit forest
Poor forestry                  the extent of the source                quality of the           levels of               owners to
management practices.          catchment or recharge zone.             source water.            contaminants            discuss how
                               Identify source protection                                       (including              forestry
                               Zones I, II and III.                   Chemical                 turbidity) in           management
                                                                       determinands             source water.           can affect
                              Identify forestry in the source         (particularly                                    source water
                               protection zone, and monitor            agrichemicals           Treated water           quality.
                               water quality for evidence of           used in forestry).       not compliant
                               health-significant                                               with DWSNZ:            Start periodic
                                               1
                               contaminants. Where there              Turbidity.               2000.                   inspections of
                               is high contaminant loading                                                              the catchment.
                               seek assistance from the                                        Unsatisfactory
                               forestry company and council                                     practices still
                               in reducing it.                                                  being used in
                                                                                                the
                              Seek assistance from the                                         management
                               forestry company in making its                                   of the forest.
                               workers aware of how their
                               activities can affect source
                               water quality. Correct
                               practices should be compiled
                               in a code of practice.
                              Request erosion management
                               plans from the forestry
                               company when logging
                               activities are planned, or new
                               ground is prepared for
                               planting.

Event: FERTILISER ENTERS SOURCE WATER DURING APPLICATION
Possible hazards: Nitrate/nitrite; algal toxins from blooms caused by the nutrients.

S1.1.17                       Develop an understanding of            Nitrate.                Elevated               Approach the
                               the extent of the source                                         levels of               council and
   Application of                                                    Nitrite.
                               catchment or recharge zone.                                      contaminants            MAF to arrange
    fertiliser in the
    catchment or
                               Identify source protection             Other nutrients          in source               a seminar for
                               Zones I, II and III.                    that may                 water.                  farmers on good
    recharge zone.
                                                                                                                        practices
                              Gather information on the use           contribute to           Treated water
   Farmer unaware                                                     eutrophication of                                relating to
                               of fertiliser in the source                                      not compliant           fertiliser
    of the extent of the                                               source waters.
                               protection zone, and monitor                                     with DWSNZ:             application.
    catchment or
                               water quality for evidence of                                    2000.
    recharge zone.
                               health-significant                                                                      Lobby the
                                                                                               Poor fertiliser
   Poor fertiliser            contaminants.1 Where there                                                               council
                               is a high contaminant loading                                    application             introduction of
    application
                               seek assistance from the                                         practices in            bylaw to limit
    practices.
                               council in reducing it.                                          use.                    fertiliser
                                                                                                                        application (eg,
                              Inform farmers with property in                                                          through
                               the catchment or recharge                                                                introduction of
                               zone of this, and the effects                                                            designated
                               their activities can have on                                                             Nitrate Sensitive
                               source water quality.                                                                    Areas).
                              Inform farmers of correct
                               fertiliser application practices.

1   The monitoring plan should take into account seasonal changes, as lower flows can lead to lead to higher contaminant
    concentrations. Situations in which contamination is most likely to occur should be identified so that monitoring can be suitably
    timed.




Ref S1.1                                              Public Health Risk Management Plan Guide:                                     11
Version 1, June 2001                                          Surface and groundwater sources
        Causes                 Preventive measures                  Checking preventive measures           Corrective action

                                                                   What to check     Signs that action
                                                                                        is needed

Event: GEOTHERMAL CONTAMINANTS ENTER SOURCE WATER
Possible hazards: Arsenic, boron, lithium and fluoride.

S1.1.18                      Before selecting a source in        Arsenic.          Concentrations        Where an
                              an area that may be subject to                            of geothermal        existing source
    Geothermal                                                   Boron.
                              geothermal activity, undertake                            contaminants         is found to be
     activity in the
     source water
                              a monitoring programme for          Fluoride.            are more than        contaminated,
                              possible geothermal                                       50% of their         seek a second
     catchment or
                              contaminants. From this             Lithium.             MAV3 in the          source of better
     recharge zone.
                              determine whether they                                    source water.        quality. This
    Poor                     constitute a risk to public                                                    should used
                              health, and if so, select                              Reticulated            instead of the
     understanding of
                              another source. Extended                                  water not            existing source,
     the catchment or
                              monitoring may be required to                             compliant with       or to dilute it, if
     recharge zone
                              determine whether their                                   DWSNZ:2000.          its production is
     when the source
     was selected.            concentrations are changing                            New source             low.
                              with time. (See Guide S2.)                                developed with 
    No, or limited,                                                                                         Obtain advice
                                                                                        geothermal           on appropriate
     water quality
                                                                                        contaminant          treatment
     monitoring
                                                                                        problems.            options.
     undertaken when
     selecting the
     source.
    Lack of
     information
     regarding the
     geology, and
     geothermal nature
     of the area.

Event: SOURCE WATER IN CONTACT WITH MINERAL DEPOSITS
Possible hazards: Metals, fluoride (depending on the nature of the deposit).

S1.1.19                      Before selecting a source in        Heavy metals.       Health-             Where an
                              an area that may be subject to                            significant          existing source

                              geothermal activity, undertake 
     Mineral deposit(s)                                            Fluoride.            determinands         is found to be
     in the catchment
                              a monitoring programme for                                are more than        contaminated,
     or recharge zone.
                              possible health-significant                               50% of their         seek a second
    Poor                     determinands. From this                                   MAV in the           source of better
     understanding of         assess whether they                                       source water.        quality. This
     the catchment or         constitute a risk to public                                                    should used
                              health, and if so, select                                Reticulated          instead of the
     recharge zone
                              another source. Extended                                  water not            existing source,
     when the source
                              monitoring may be required to                             compliant with       or to dilute it, if
     was selected.
                              determine whether their                                   (note heavy          its production is
    No, or limited,          concentrations are changing                               metals due to        low.
     water quality            with time. (See Guide S2.)                                corrosion are
     monitoring                                                                         excluded)           Obtain advice
     undertaken when                                                                    DWSNZ:               on appropriate
     selecting the                                                                      2000.                treatment
     source.                                                                                                 options.
                                                                                       New source
    Lack of                                                                            developed
     information                                                                        with
     regarding the                                                                      contaminant
     geology of the                                                                     problems
     area.                                                                              associated
                                                                                        with minerals.




12           Public Health Risk Management Plan Guide:                                                      Ref S1.1
             Surface and Groundwater Sources                                                    Version 1, June 2001
       Causes                   Preventive measures                     Checking preventive measures               Corrective action

                                                                       What to check      Signs that action
                                                                                             is needed
                                                               4
Event: SOURCE WATER INTRUDED BY SALINE WATER
Possible hazards: Bromine-containing disinfection by-products brominated trihalomethanes (chlorination, chlorine dioxide,
ozonisation) or bromate (ozonisation).

S1.1.20                       Use a test bore to obtain              Chloride.             Chloride              Where an
                               water quality information when                                 concentration          existing source
   Bore too deep for                                                 Conductivity.
                               planning a source near the                                     more than its          is found to be
    its proximity to the
                               coast. Monitoring samples                                      guideline              contaminated,
    sea.
                               should be taken over a full                                    value (See             seek a second
   Abstraction of             tidal cycle, and data obtained                                 DWSNZ:                 source of better
    water too great            during the lowest and highest                                  2000.)                 quality. This
    leading to                 tides.                                                                                should used
                                                                                             Reticulated            instead of the
    increased
                              Ensure that the aquifer is                                     water not              existing source,
    drawdown and
                               properly developed and that                                    compliant with         or to dilute it, if
    ingress of
                               its capacity to provide good                                   DWSNZ:                 its production is
    seawater into the
                               quality water, at the maximum                                  2000.                  low.
    aquifer.
                               abstraction rate, is tested.
                                                                                             Complaints of    
   Abstraction from
                                                                                              salty taste.
                                                                                                                     Obtain advice
    other bores                                                                                                      on appropriate
    depresses water                                                                          New source             treatment
    table.                                                                                    developed              options.
                                                                                              with sea-
   Changes in aquifer
                                                                                              water
    characteristics due
                                                                                              intrusion.
    to changes in
    meteorological
    conditions.

Event: SOURCE WATER EXPERIENCES ALGAL BLOOM
Possible hazards: Algal toxins.

S1.1.21                       Take steps to limit nutrient           Temperature.          Elevated              Undertake
                               concentrations in the source                                   levels of              catchment
Conditions are suitable
                               water (see S1.1.5, S1.1.7,             Nutrient               contaminants           survey to
for algal growth:                                                      concentrations.
                               S1.1.10, S1.1.13, S1.1.15,                                     (nutrients and         determine
   elevated nutrient          S1.1.17), starting with a              Copper (from           toxins) in             nutrient sources.
    levels                     survey of the catchment to                                     source water.
                               identify any sources of
                                                                       copper sulphate                              Start application
   sunshine                   nutrients.
                                                                       algicide).            Reticulated            of algicide
   warmth                                                            Algal toxins (as       water not              earlier in future
                                                                       these analyses are     compliant with         years (see
   relatively still                                                   expensive,             DWSNZ:                 Guide P4.1), or
    water.                                                             sampling for these     2000.                  undertake
                                                                                                                     destratification
                                                                       determinands          Complaints of          of the source
                                                                       should be targeted     symptoms
                                                                       and used                                      water (see
                                                                                              consistent             Guide P4.2).
                                                                       sparingly).            with toxin
                                                                                              poisoning.       (See also Figure and
                                                                                                               Table below.)

Event: NOT ENOUGH WATER AVAILABLE
Possible hazards: Germs and chemicals that get into the water because of low system pressure; hazards associated with poor
hygiene.

S1.1.22
The causes, preventive measures, checks and corrective actions associated with this event are covered in each of the Guides
dealing with abstraction from the source. (See P1 Guide series.)

4   Bromide in the water (from seawater) can lead to brominated disinfection by-products, and bromide is not removed by
    conventional treatment processes.




Ref S1.1                                           Public Health Risk Management Plan Guide:                                       13
Version 1, June 2001                                       Surface and groundwater sources
Table (S1.1):            Ability of oxidants to destroy algal toxins

 Oxidants                         PSP*               Microcystin               Nodularin           Cylindro-spermopsin

 Ozone                            Yes#                     Yes                   Yes                          Yes

 Chlorine                          No                      Yes                   Yes                          Yes

 KMnO4                              ?                      Yes                       ?                         ?

* Paralytic shellfish poisoning.
#
  When PSP concentrations are low or moderate.
Ref: Steffensen D, Burch M, Nicholson B, Drikas, M and Baker, P (1999) “Management of toxic blue-green algae
(cyanobacteria) in Australia”, Environ. Toxicol., 14: 183–95.



Figure (S1.1): Rapid assessment of health hazard of a drinking-water supply system with
               possible toxic cyanobacteria at source

                                                                                           Relative risk of
 Do you have advanced water               Do you have regular monitoring
                                   No                                                      health effects
   treatment facilities with              information to indicate potential
                                                                                No
  ozonation and/or granular               for cyanobacteria in your water
  activated carbon filtration?                    supply source?


                                                              Yes                          Very High
      Conditions which can
      lead to cell lysis:
      •   Use of algicides
                                           If cyanobacteria present, could     Yes
      •   Pre-chlorination
                                            conditions lead to cell lysis or
      •   Senescent (eg, late
                                                      rupture?
          summer) bloom
      •   Pumping regimes
                                                              No


                                             Is there likely to be effective    No
      Effective methods:                                                                       High
                                            removal of cells by the water
      •   Underground
                                              treatment system in place?
          filtration
      •   Coagulation/
          flocculation and                                    Yes
          filtration
      •   Slow sand filtration
                                          Are the species present likely to    Yes
                                               produce saxitoxins or
                                                    anatoxins?
      Taxa that can produce
      saxitoxins or anatoxins
      •   Aphanizomenon                                       No
      •   Anabaena
                                                                                No
      •   Oscillatoria                                                                      Moderate
                                              Is chlorination practised?
      •   Lyngbya
      •   Cylindrosperum
      •   Cylindrospermopsis                                  Yes
                                                                                No

      Chlorination conditions              Is chlorination being operated
      adequate to destroy                      adequately to destroy
      microcystins requires                         microcystins?
      0.5 mg/L free chlorine
                                                                               Yes              Low
      residual after a full 30
      minutes contact time
      Other cyanotoxins may
      not be inactivated
      under normal
      chlorination conditions.                                                 Yes
                                                                                            Very Low


Figure based on data provided by A Kouzminov, Ministry of Health, 2000.




14           Public Health Risk Management Plan Guide:                                                      Ref S1.1
             Surface and Groundwater Sources                                                    Version 1, June 2001
Contingency Plans
If an event happens despite preventive and corrective actions you have taken, you may
need to consult with the Medical Officer of Health to assess how serious a problem is.

Event – Hazardous substances used or spilled from storage

Indicators:                 Spill has been reported in the source protection zone.
                            Elevated concentrations of hazardous substances, or their
                             breakdown products, detected in the source water.

Required actions:           Identify responsible body and inform relevant authorities
                             including civil defence, if necessary.
                            Ensure that spill is contained.
                            Check quality of source water, use alternative drinking-water
                             supply, if necessary and inform the public.
                            Responsible body remediates area affected by spill.
                            Monitor water quality to see whether corrective action has
                             worked.
                            Record incident and action taken.
                            Request that responsible body document the incident and
                             determine management procedures to prevent future spills
                            Check quality of drinking-water throughout and at end of
                             remedial work to determine whether alternative supply is
                             needed.
                            Determine whether there are any ways in which the source
                             water can be protected from spills.
                            Modify PHRMP if necessary.

Responsibility:        Manager designated responsible for the water supply must ensure
                       that the source is protected, body responsible for the spill must be
                       responsible for all action to address the impact of the spill.




Ref S1.1                              Public Health Risk Management Plan Guide:               15
Version 1, June 2001                          Surface and groundwater sources
Event – Volcanic activity – leading to ash fall, pyroclastic flows and surges, lava flows,
lahars, volcanic gases, landslides, tsunami, seiches and hydrothermal eruptions
Indicators:                Media coverage of activity.
                           Notification from Institute of Geological and Nuclear
                            Sciences.

Required actions:          Normal range of conductivity and pH values need to be known
                            (to provide baseline data, some monitoring needs to have been
                            undertaken before the event).
                           If conductivity values are not elevated and the pH is above 5,
                            continue to use the source water. If conductivity is elevated
                            (estimated increase of 5–10 mS/m), and pH is depressed below
                            5, inform MOH, use alternative source water or close the
                            supply and obtain water from elsewhere until chemical
                            analysis of the water shows it is acceptable, and inform the
                            public.
                           If turbidity is increased, take steps to make sure disinfection of
                            the water is still effective.
                           When the volcanic activity has ceased, measure conductivity,
                            pH and other chemical determinands associated with the event
                            until they return to normal range. Resume use of the source
                            water.
                           Record incident and action taken.
                           Modify PHRMP if necessary.

Responsibility:      Manager designated responsible for the water supply.




16       Public Health Risk Management Plan Guide:                                  Ref S1.1
         Surface and Groundwater Sources                                Version 1, June 2001
Event – Extreme rain events

Indicators:                 Quality of surface water visibly deteriorates.

Required actions:           Increase frequency of measurements of turbidity, plus all other
                             parameters that are critical to the satisfactory functioning of
                             treatment processes.
                            Increase disinfectant dose, if necessary, to make sure
                             disinfection is still effective.
                            If water quality is too poor to treat, use alternative source, or
                             close the supply and obtain water from elsewhere until there is
                             a return to acceptable levels, or issue ‘boil water’ notice.
                             Inform MOH.
                            See D2 Guide series for a contingency plan for the reticulation
                             network.
                            After extreme rain event, check all water supply infrastructure
                             for maintenance requirements. Clean UV lamp if this form of
                             disinfection is used.
                            If source water is affected by rain events frequently, consider
                             alternative source, or upgrade treatment to cope with the
                             variability of source water quality (eg, pre-treatment storage).
                            Record incident and action taken.
                            Modify PHRMP if necessary.

Responsibility:        Manager designated responsible for the water supply.




Ref S1.1                             Public Health Risk Management Plan Guide:            17
Version 1, June 2001                         Surface and groundwater sources
Event – Earthquake

Indicators:               An earthquake may cause damage to the source, treatment
                           plant or distribution system. The water supply may be shut
                           down as a result.

Required actions:         Contact the Ministry of Civil Defence in the event of an
                           earthquake emergency. (Keep a list of the contact details for
                           the nearest Ministry office and of the Earthquake
                           Commission.)
                          Check all structures associated with water storage, abstraction,
                           treatment and distribution.
                          If water supply structure is damaged so that water cannot be
                           distributed, or cannot be distributed with a satisfactory quality,
                           use alternative supply. Provide another source of potable
                           water until water of acceptable quality can again be supplied.
                           Contact the MOH.
                          Record incident and action taken.
                          Modify PHRMP if necessary.

Responsibility:      Manager designated responsible for the water supply.

Event – Water shortage

Indicators:               Low flow of rivers and springs, low level of lakes or dams,
                           low water table of groundwaters.
                          Unexpectedly high usage, or gradually increasing usage, due to
                           increasing population.

Required actions:         If low flow of river is the issue, determine whether water
                           quality presents problems for adequate disinfection. Contact
                           the MOH and issue ‘boil water’ notice if needed.
                          Consider restricting water use.
                          If water table has dropped to an extent where water can no
                           longer be abstracted, use alternative source until water level
                           has risen.
                          If water shortages occur frequently, consider additional, or
                           alternative source.
                          Record incident and action taken.
                          Modify PHRMP if necessary.

Responsibility:      Manager designated responsible for the water supply.




18       Public Health Risk Management Plan Guide:                                 Ref S1.1
         Surface and Groundwater Sources                               Version 1, June 2001
PHRMP Performance Assessment
To make sure that your supply’s Public Health Risk Management Plan is working properly,
periodic checks are needed. The Overview document outlines what needs to be done. The
following table provides the detailed information for checking this particular supply
element.

What to measure or           E. coli.
observe:
                             Chemical determinands expected from the source of
                              contamination.
                        Follow the protocols set out in DWSNZ:2000.

How often:                   See DWSNZ:2000 for E. coli and P2 determinands;
                              minimum of twice per year (winter and summer) for all
                              contaminants that are not P2 determinands, but that may
                              arise from contaminant sources.

What to do with the          Results need to be recorded to meet legislative
results:                      requirements or to allow PHRMP performance
                              assessment. The WINZ database is good for this.
                             The collected data need to be periodically reviewed to see
                              whether problems with this supply element are
                              developing. This should be done as frequently as the
                              manager responsible considers necessary to minimise risk
                              to public health arising from this supply element.
                             Should this review show any unusual incidents, indicate
                              that proper procedures are not being carried out, highlight
                              poor laboratory results or indicate that poor water quality
                              is reaching customers, then review the procedures for
                              managing raw water sources.
                             Evaluate the monitoring results, and any actions taken as
                              the result of having to implement a contingency plan, to
                              see if the PHRMP needs modification – eg, preventive
                              measures are up to date; the contingency plan steps are
                              still adequate; any change to the source water used is
                              recognised in the plan.

Responsibility:         Manager designated responsible for the water supply.




Ref S1.1                          Public Health Risk Management Plan Guide:          19
Version 1, June 2001                      Surface and groundwater sources
Appendix (S1.1): Source Protection
Zones (SPZ)
The actions needed to manage an activity that may contaminate your raw water will depend
on the level of risk created by the activity. The level of risk is affected, amongst other
things, by the closeness of the activity to the point where you draw water from the source
(so long as the separation is not too great).

SPZs are used in some countries to help assess the level of risk. This is done by
identifying three areas, or zones, around the abstraction point. SPZ I is closest to the
abstraction point, and activities within it present a high risk; those farthest away, in SPZ
III, present a low risk. The methods for determining where these zones lie can be generally
applicable, but the zones themselves will be specific to each source.

New Zealand does not have a standard national method for defining SPZs, although some
councils may have developed methods for deciding where SPZs lie. Seek advice from your
regional council, district council or unitary authority as a first step in identifying SPZs for
your source.

Documents such as Guidelines for Delineation of Wellhead Protection Areas USEPA
(1987) and Guide to Groundwater Protection Zones in England and Wales National Rivers
Authority (HMSO) (1995) provide some indication of the methods used for identification
of SPZs in the USA and UK. In the UK, the boundary for SPZ I is defined by a 50-day
travel time of the water from that point to the source, and SPZ II by a 400-day travel time.




20       Public Health Risk Management Plan Guide:                                  Ref S1.1
         Surface and Groundwater Sources                                Version 1, June 2001

								
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