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					 6th ALPS-ADRIA SCIENTIFIC WORKSHOP
 30 April - 5 May, 2007 Obervellach, Austria




INAPPROPRIATELY STORAGED DDT AS
   A POTENTIAL RISK FOR HUMAN
    HEALTH AND ENVIRONMENT



                                       by Sanja Miloš
                                    Croatian Food Agency
  DDT (dichlorodiphenyltrichloroethane)
  and its metabolites:


• very significant for environment and public
  health worldwide
• normally regulated trough maximum residue
  levels (MRLs) - permitted in food on sale
• MRLs are not strictly “safety limits”
       DDT now banned in most countries:

• was used mainly to control mosquito-borne malaria
• civilian populations to control typhus and malaria vectors
• extensively used as an
  agricultural insecticide after 1945

During seventieths of the last century DDT was proscribed mainly because
 of the environmental effects (persistency, bioaccumulation, negative
  impact wildlife), but not because of eventually toxics effect on humans.
      Prohibited use of DDT in Croatia:

• during seventieths of the last century by taking the
  model from other countries
• Stocholm Convention about Persistent Organic
  Pollutants (held in 2001, with appliance from 2004)
• National Plan for Implementation of Stockholm
  Convention Principals in December, 2004.
  . . . after the ban implementation:
remaining quantities of DDT



• entombed all around the
agricultural properties and
forestry sectors

                              • several decades later,
                              during old storehouse
                              disintegration, the
                              unknown quantities of DDT
                              were split around
     ... possibility of well water pollution
     becomes quite realistic in these
     situations
• consumption of water at the area of
  Osijek-Baranya County is mostly provided by
  exploitation of ground waters
• 20 % of populations drink water from shallow wells
  independently of public water supply availability
    In this very case the story started…

                       ALARM


suspicious pesticide intoxication of a woman hospitalized
 in Osijek clinical hospital
epidemiological investigation

identified origin of exposure


 uncontrolled effusion of buried DDT stocks during old
 storehouse disintegration
      Sampling in a disputable area

Soil sample was sampled   Water well was sampled in
from 30 and 60 cm depth    concentric distance of 200 m




    • concentration
    of DDT was 2                        • 30 (60) m
    g/kg dry matter                  distance had 3.85
    (MRL is 0,5                          (2.31) µg/l
    mg/kg)                         • 100 m
                                   distancehad (n=3)
                                   0.012 – 0.057 µg/l
The results of measuring concentration
of DDT (µg/l) in water from wells


                  Distance from             Elapsed Time from pollution (weeks)
     Location   source of pollution
                       (m)              0             2            4              10

       1.              30             3.85*        1.093*       0.12*       0.0152
       2.              60             2.31*        0.025        0.010        0.049
       3.              100             0.08        0.057         0.01             -
       4.              150            0.026        0.012        0.008             -
       5.              200            0.0022       0.038        0.003             -
• in the well water samples,    • sampling two and four
sampled several days after      weeks after the incident
the incident and heavy rain,    was performed in the
the measurements have           period without rainfalls and
shown higher                    high temperatures,
concentrations on two           concentration of DDT has
locations 30-60 m apart         been reduced upon the
from the origin of pollution    standard referred in the
                                literature

    DDT was detected by gas chromatography (Aglient 6890 ECD)
    and confirmed by GC MS (Thermo – Finnigen)
Dynamics of DDT remission in one of the tested wells


                          6

                          5
      conc DDT/microg/l




                          4       3,85
                          3

                          2

                          1                  1,039

                          0                              0,12        0,015
                              0          2           4          10
                                             weeks
               Exposure assessment
as part of Chemical Risk Assessment performed:

  Considering known values it was estimated that the EDI*
    (estimated daily intake) was 0,005775 mg/l
       EDI=average daily consumption of water
                          ×
                maximal measured
            concentration of DDT in water

       It is expected that water for human consumption
       should be out for use throw several weeks.
             Whats that mean ?


For a grown - up man of 70 kg body weight it was less than
  ADI* and RfD**, but in the percentage zone of ADI
  (30%). But under various scenarios such elevated
  concentration and water consumption (increased
  consumption lead to breakthrough of ADI)


  The consequence may be far reaching

  *ADI – acceptable daily intake, 0.02 mg/kg/day for DDT
 **RfD – reference dose, 0.0005 mg/kg/day
         Contexts of food safety
 Stocks of expired and banned pesticides are still
“hot” issues in high number, especially developing countries
 Risk assessments may play a significant role in the
 evaluation of risks posed by pesticides


        if concentration exceedes above MRL
        estimation of (EDI) indicates that there is
              possible acute health risk


 These findings indicate the necessity of environmental
 monitoring on the sites of known or suspected chemical
 storage, whether obsolete or currently in usage
Thank You for attention !

				
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