Health problems
Public Health
Protecting the health of the general
population is a fundamental goal of
environmental technology
Main problems
- polluted air
- polluted water
- polluted soil
- radiation
- noise
• We can be hurted:
– digestion (drink, food, washing tooth)
– contact (skin)
– respiration
– hematogenious – via blood
Air
Pollution sources:
- point
- line
- area
Traffic
- it’s near to the ground→we breath it
- its volume is growing
- emission: NOx, CO, CxHz
- the faster a car goes:
the lower CO and CxHz
and the more NOx emissions are made
Traffic
- 50-70 km/h would be optimal
- can’t be used because of the safety:
traffic lights
pedestrians, bikers
Pollutants
- anthropogenic:
materials from burning (CO, CO2, NOx
dust
smog
aerosol
fibre (asbestos)
Pollutants
- natural (biological):
pollens
CH4
dust
Rn gas
Water
- Water treatment : main aim is to avoid
infections = eliminate pathogens
(decrease their concentrations)
- Pathogens = microorganisms causing
health problems
(Viruses, bacteria, protozoa)
Transmission of diseases:
– Direct: contact or droplet spray
– Indirect:
• Airborne: aerosol, dust
• Vehicle-borne: water, food, milk
• Vector-borne: insects, animals
Infectious diseases
• Water-borne: • Rodent-borne:
– Typhoid fever – Typhus
– Cholera – Bubonic
– Infectious plague
hepatitis
– Dysentery • Airborne:
– Legionella
• Insect-borne:
– Malaria
– Yellow fewer
Increased importance of infections
• Change in ecosystem – new habitats
– Air conditioning
– Waste disposal sites
– Rodents – rats is sewage collection systems
• Change in human habits
– Urbanisation – high population density
– Public transport
• Global movement of people and goods
– Migration
– Export, import
Important factors
• Infectious dose:
– Amount of microorganisms causing
health problem to one certain person
– Depends on:
• Type of microorganism (viruses: 1-2, bacteria:
thousands)
• General health of person
• Physical condition
• Age
• Immune system
Important factors
• Virulancy:
– Ability to change according to the change
in the environment
– Antibiotics – resistency, new variants
• Persistency in water treatment
• Resistancy against chlorine and other
disinfecting agents – e.g. Clostridium
Soil
- the groundwater will be polluted also
- plants growing on the polluted area
accumulate some pollutants
Radiation
- Ionizing (radioactive)
-a
-b
-g
- neutron
- not ionizing (electromagnetic)
Noise
- Physical pricess
- sense
- Psychological process
- periodic change of pressure in a point
(oscillation)
- individual
Noise
- serious health problems, even if we cannot
hear it
- 30-40 dB – sleeping problems
- 40-60 dB – feeling tired
- 80 dB – demage of hearing
Reduction of noise
- distance
- plant-zone
- other objects
Micropollutants
• Causing health problems in very small
concentrations (g/l)
- organic
- inorganic
Inorganic micropollutants
• Heavy metals: Pb, Hg, Cd, Cr, etc.
• Long lasting health problems in small
concentrations
• Problem: protein denaturation
– Aminoacids contain S – heavy metals bind to S
– Enzime (protein) can not work
– Biodegradation is blocked
– Different matters accumulate
• Limiting values for drinking water, treated
sewage, sewage sludge, etc.
Heavy metals
Cd
– Itai-itai illness
– From metal mine (heavy rains) – solid form
– River sediment – floods
– Rise production – anaerob environment
– Became soluble
– Deformation of bones (Ca-Cd)
Heavy metals
Hg
– Minamata Bay – Japan 1950
– Mercury compound (in solid form) – discharged to the
sea (HgSO4 – catalizator)
– Reductive (anaerob) environment, bacteria, B12
vitamine
– Transformation to HgS, then methylmercury [CH3-
Hg]+
– Accumulation in fish – and in people
– Death, blindness, paralysis, irritation, depression
Organic micropollutants
- rock oil and its spin-offs
- detergents
- pesticides: DDT, herbicides, fungicides
- PCBs, PAHs
Lots of them has been banned from use
(DDT, PCB)
PCB
– Polychlorinated biphenyls (organic, aromatic,
containing chlorine)
– 200 compounds: C12H10-nCln
– Oily substance - synthetic
– Used in paints, electrical transformer fluids,
rubber, cooling fluid
– Non biodegradable (because of Cl)
– Accumulate in river sediments
– Toxic to Daphnia (0.2 mg/l), to fish (2 mg/l)
– Causing death, cancer
DDT
– Chlorinated hydrocarbons
– Toxic to animals (contact, oral, inhalation)
– More chlorine, more effective the chemical –
less biogedradable
– Accumulation (soluble in fat, non-soluble in
water)
– Concentration can increase to 10000*
– Nerve toxin, cause death, paralysis
- Still found in the body tissues of animals
(Antarktis)
Toxicology
Studies the effect of chemicals that are
harmful or fatal when consumed by
organisms in relatively small amounts
- Toxic
- Carcinogenic
- Mutagenic
- Teratogenic
Toxicology
– Acute (immediate)
– Chronic (long-lasting)
LD50, LC50
– Lethal dose/concentration 50%
– The dose when 50% of the test animals dies
Toxicology
- Correlation between environmental
factors and the health of humans/other
organisms
- One parameter sholuld be changed while
others are the same – experiments
needed
Toxicology
- Humans can not be tested directly
- Toxicology tests: bacteria, algae,
Daphnia, fish, rats, etc.
- acute (48-72-96 h)
- semi-chronic (2-3 weeks – Model
Eco-System)
- chronic (2-6 month - life-cycle)
Toxicology
Toxic risk assessment:
– Toxic identification
• Determines if a chemical is toxic
– Dose-response assessment
• Strength of toxicity
– Exposure assessment
• How often humans are exposed to the chemical
– Risk characterisation
Toxicology
• NOAEL = non observable adverse effect
level
• LOAEL = lowest observable adverse effect
level
• Maximum daily uptake