WASTE MANAGEMENT AND PUBLIC HEALTH HAZARDS

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WASTE MANAGEMENT AND PUBLIC HEALTH HAZARDS

• PROFESSOR JIM BRIDGES
• Emeritus Professor of Toxicology and
  Environmental Health
• Chair of the EU scientific committee SCENIHR

May 2006
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WASTE HEALTH CONSIDERATIONS

• 1.Waste contains many thousands of
  chemicals and many species of micro-organisms
• 2.All methods of waste treatment involve the
  destruction of some substances but the creation
  of others.
• .

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CONSIDERATIONS CONTINUED

• 3.The milder the treatment the less of the
  original chemicals are destroyed and the less new
  chemicals are created. None of these chemicals
  are unique to waste management
• 4.All chemicals are toxic if the exposure is
  high and long enough. However for the great
  majority of chemicals a threshold is found below
  which adverse effects are unlikely

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STAGES IN EVALUATION

• Hazard identification- a property of all natural
  and synthetic chemicals
• Assessing the risk- likelihood that adverse
  effects will occur at actual exposure levels
• Risk benefit analysis- Comparing risks and
  benefits

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METHODS OF WASTE TREATMENT- CONSIDERATION OF
EMISSIONS

• Microbiological/spontaneous
• Heat/combustion
• Chemical
• Physical separation
• the milder the treatment the more of the
  initial contaminants are left in the waste
  residue

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CHEMICALS THAT MAY BE EMITTED FROM LANDFILLS
(microbiological/ spontaneous)

• In landfill gas- benzene, styrene and many other
  volatile chemicals
• From Gas Burning- dioxins, PM10, metals, nitrogen
  dioxide
• In the leachate, metals, ammonia

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BIOPROSSING - SUBSTANCES EMITTED

• Volatile chemicals such as benzene, hydrogen
  suphide, toluene
• Microrganisms, including various pathogens

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MATERIALS EMITTED DURING COMPOSTING
(microbiological)

• Volatile chemicals such as benzene, styrene,
  methyl sulphide and toluene
• Micro-organisms. Various human, animal and plant
  pathogens and endotoxins
• Leachate containing ammonia, metals

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CHEMICALS EMITTED FROM AN INCINERATOR
(heat/combustion)

• Particulates eg PM10, mercury
• Less volatile organics, eg dioxins,
• chlorobenzenes
• Gases and volatile substances eg
• benzene, nitrogen dioxide

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SUMMARY OF SUBSTANCES THAT MAY BE EMITTED BY
WASTE FACILITIES INCLUDE

• Fine particles such as PM10
• Dioxins and polycyclic aromatic hydrocarbons
• Metals
• Acid gases
• Volatile organic compounds such as benzene
• Micro-organisms
• Allergenic proteins

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PUBLIC CONCERN (1)-DIOXINS

• Always present in MSW
• A family of chemicals created by any combustion
  process
• Many related compounds (eg PCBs), some very
  persistent
• Different dioxins have very different potencies.
  Some are carcinogenic, can also affect the
  nervous system, skin, reproduction outcome

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DIOXINS CONTINUED

• Total exposure over many months/years the key
  consideration
• Main source of human exposure is fatty foods
• Vulnerable groups children and foetuses

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PM1O FINE PARTICULATE MATTER

• - Range of sizes the smaller the particle the
  higher the potential risk
• - Many sources, eg cooking, diesel engines,
  nanotechnology products

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PM10 CONTINUED

• Acute health effects, such as respiratory and
  heart.
• Long term effects may include cancer
• - Vulnerable groups those with severe
  respiratory and coronary disease

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CHANGES IN INCINERATOR EMISSIONS

• Many incinerators in the 1950s-1960s caused
  local pollution
• Modern incinerators have 1/100th -1/1000th of
  the emission levels of dioxins, PM10 and metals
  compared to these old incinerators

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CONCLUSIONS

• Waste contains natural and synthetic
  chemicals. Treatment results in some chemicals
  being formed
• None of these chemicals is unique to waste
  treatment
• Key factors in determining possible health risks
  are - composition of the waste and form of
  treatment,
• - levels of exposure of the local
  residents
• - safe use/disposal of residual
  materials