Chapter 2.3
Environmental impacts and health
risks
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Hazard and exposure
• Many activities have the potential to result in harm to
health or the environment
• Hazardous wastes have properties (eg toxicity,
persistence, flammability) which increase that
potential
Risks :
– to human health
– to wider environment
– at the point of generation
– along the chain
Those exposed to the risks include:
– manufacturing workers
– waste handlers
– general public
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Hazardous properties
Chemical wastes may exhibit … and may pose
•Toxicity
Health hazard
•Corrosivity
•Ignitability
•Reactivity
Physical hazard
•Eco-toxicity
Environmental harm
Ubiquitous wastes - small quantities, widespread may pose greatest risks in developing economies
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Exposure routes 1
Source: Jolley et al Effective and safe waste management, Interfacing Sciences and
Engineering with Monitoring and Risk Analysis, 1992
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Exposure routes 2
• Direct physical harm
• Biological infection
• Chemical contamination
• Chemical alteration
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Minimising risks by good
management
• Little evidence of harm to general public health
from well managed wastes
• Risks for industrial and waste workers reduced by
proper management procedures and correct use
of protective clothing and equipment
Health risks may be higher :
• In countries or regions without modern hazardous waste
management systems
• Around old sites with residual contamination of land or
water
• For some groups eg children
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Evidence of harm
• Epidemiological evidence of health effects
is variable
• Most ‘evidence’ is based on toxic effects
from pure chemicals, not waste
• Often tests are based on animals, not
humans
• Epidemiological evidence of causal links
often weakened by confounding information
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Public concerns about hazardous
waste
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Fear of damage to health
Actual (chronic or acute) health effects
Nuisance from noise, dust, traffic etc
Effects on quality of life
Damage to natural environment
Reduction in property values
Lack of trust in responsible authorities
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Public perception of risk
• Public concerns are increased by high profile
accidents and rare catastrophes
• Most concern is about ‘involuntary’ risks
• Most people over-estimate risks
• There is most anxiety about long term exposure
to low concentrations of compounds
• ‘Actual’ risks can be as imprecise as ‘perceived’
risks
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Occupational exposure
In the absence of proper
management systems and
without the correct protection,
waste workers have been shown
to suffer from elevated levels of:
•Respiratory illnesses
•Skin infections
•Eye infections
•Gastric problems
Moving from uncontrolled waste management to a
properly controlled system will greatly reduce
occupational risks
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Scavenging
Scavengers:
• are widespread in developing economies
• may rely on on open dumps for their living
• have raised incidence of respiratory illnesses and
skin and eye infections
• need an education programme
• need good personal hygiene
Scavenging:
• should be phased out in the long term
• in the short term can pose lower risks by keeping
high-risk wastes out of open dumps
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Risk assessment 1
Risk assessment procedures include making
estimates of:
• The type of harm associated with a chemical or waste
substance
• The degree of certainty of the potential harm
• The causal connection between the exposure and the
potential harm
• The probability of the exposure and its duration
• The combined probabilities of harm and exposure that
determine the magnitude of the risk
The severity of any health or environmental
impact depends on the length of exposure and
the ‘dose’ or amount of the harmful compound
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Risk assessment 2
Conducting risk assessments:
•requires specialist skills
•is time consuming
Enables comparison of relative risks from:
•wastes from different industries
•waste treatment and disposal methods
•locations and sites
Helps set priorities for:
•control measures
•expenditure
•appropriate technologies
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Chapter 2.3 Summary
This chapter covers:
•Need to identify hazard and exposure routes
•Reducing risks by good management
•Little evidence of harm
•Public concerns eg health, impacts, and public
perception of risk
•Occupational exposure
•Scavenging
•Risk assessment
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