1. 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

2. 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..

3. 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

4. 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

5. 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

6. 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

7. BIOPROSSING - SUBSTANCES EMITTED  Volatile chemicals such as benzene, hydrogen suphide, toluene  Microrganisms, including various pathogens

8. 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

9. 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

10. 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

11. PUBLIC CONCERN (1)- DIOXINS I Always present in MSW I A family of chemicals created by any combustion process I Many related compounds (eg: PCBs), some very persistent I Different dioxins have very different potencies. Some are carcinogenic, can also affect the nervous system, skin, reproduction outcome

12. DIOXINS CONTINUED Total exposure over many months/years the key consideration Main source of human exposure is fatty foods Vulnerable groups: children and foetuses

13. PM1O FINE PARTICULATE MATTER - Range of sizes; the smaller the particle the higher the potential risk - Many sources, eg cooking, diesel engines, nanotechnology products

14. PM 10 CONTINUED -Acute health effects, such as respiratory and heart. -Long term effects may include cancer - Vulnerable groups: those with severe respiratory and coronary disease

15. CHANGES IN INCINERATOR EMISSIONS Many incinerators in the 1950’s- 1960’s caused local pollution Modern incinerators have 1/100 th - 1/1000 th of the emission levels of dioxins, PM10 and metals compared to these old incinerators

16. 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