E-learning module

1. E-learning module Introduction to POPs

2. E-learning module to POPs Module 1 – Overview of POPs • Overview of the course This module introduces POPs, with their properties and impacts upon health. • Contents What are POPs? List of POPs Groupings of POPs Group A Properties Sources POPs in the environment Exposure risks Health impacts Group B Properties Sources POPs in the environment Exposure risks Health impacts Group C Properties Sources POPs in the environment Exposure risks Health impacts

3. E-learning module to POPs • Learning outcomes Understand what POPs are. Gain an appreciation for properties of POPs and how this may reach a population. Appreciate the health impacts associated with various POPs. • Pre-requisites None • Follow-on Course Module 2 - Risk Assessment • Download the course as a pdf • Related information Chapter 1 of the Manual • Approximate time for this module 45 mins

4. E-learning module to POPs Introduction Persistent Organic Pollutants (POPs) are chemical substances that: • persist in the environment • biomagnify as they move up through the food chain • pose a risk causing adverse effects to human health and the environment • may travel long distances to regions where they have never been used or produced Consequently POPs pose threats to the global environment. Industrial wasteland potentially contaminated with POPs

5. E-learning module to POPs What are POPs? Persistent Organic Pollutants (POPs) are a range of chemical compounds that have been used or created from a range of activities associated with industrial processes and chemical manufacturing. The chemical composition of POPs are similar, they are hydrocarbons containing one or more chlorine atoms. Where are they from? Agricultural use – pesticides Electrical component production - oil additives Combustion products Pesticides spraying in 1945 containing POPs

6. E-learning module to POPs UNEP and UNIDO have identified 12 POPs that are of particular interest and concern: • Mirex has also been used as a fire retardant in plastics. • Fungicide HCB is also unintentionally produced in various combustion processes. • Some of the POPs i.e. PCBs, are family of 209 chlorinated compounds, called congeners. • Congeners are compounds which have same main structure, i.e. PCBs main structure is biphenyl, and different number of substituents, i.e. chlorine

7. E-learning module to POPs Groupings of POPs For the purpose of this e-learning course, POPs are considered in 3 groups based on their application. Note: these groups do not correlate exactly with Annexes A, B and C of the Stockholm Convention.

8. E-learning module to POPs Group A Properties Sources POPs in the environment Exposure risks Health impacts Aerial pesticide application (containing POPs) Group A Properties Sources POPs in the environment Exposure Risks Health Impacts Group B Group C

9. E-learning module to POPs Group A: Properties Some of the chemical characteristics include: • very low water solubility • high lipid solubility (high solubility in oils) • semi-volatility • high molecular masses • resistance to chemical, biological and photolytic degradation In pure form they mainly occur in powder or crystalline form with mild or no odour. Group A POPs were mainly used as: • organic solvent formulations • wettable powders • granules • aerosols Commercial product containing 5% DDT Group A Properties Sources POPs in the environment Exposure Risks Health Impacts Group B Group C

10. E-learning module to POPs Group A: Sources All chemicals in Group A were produced for the control of insects or as a fungicide. DDT and Heptachlor are still produced in very limited quantities. Some countries use DDT for the control of malaria carrying mosquitoes. Heptachlor is currently used to control fire ants in power transformers. DDT spraying for insect vector control Group A Properties Sources POPs in the environment Exposure Risks Health Impacts Group B Group C

11. E-learning module to POPs Group A: POPs in the environment • Group A POPs were applied mainly on ground and are expected to be immobile in soil. • Volatilization from ground occurs within first few weeks after application. • May exist as vapour or particulate phases in the ambient atmosphere. • May be removed from air by wet and dry deposition. • Do not dissolve in water and in aquatic environment therefore Group A POPs will be present in sediments. Remediation of POPs contaminated site Group A Properties Sources POPs in the environment Exposure Risks Health Impacts Group B Group C

12. E-learning module to POPs Group A: Exposure risks • Eating foods contaminated with this chemicals. • Drinking contaminated water. • Breathing air and dust with POPs particles. • Skin contact with contaminated soil at hazardous waste site. • Living at homes which has been treated for insect or pest vector control (termites, mosquitoes). • Children may be exposed by drinking breast milk. Obsolete pesticide packagings Group A Properties Sources POPs in the environment Exposure Risks Health Impacts Group B Group C

13. E-learning module to POPs Group A: Health impacts • All Group A POPs have health risks from acute and chronic exposure. • Health risks can be assessed only in conjunction with toxicological data. • Toxicity of substance is represented by dose (in mg of substance per kg of body weight) at which adverse health effects occur. • The US EPA and WHO categorized Group A POPs as moderately or highly toxic substances. • IRAC and US EPA classified Group A substances as possible or probable carcinogens. • The carcinogenic classification reflects weight of available evidence. DDT was used in many countries for insect vector control Group A Properties Sources POPs in the environment Exposure Risks Health Impacts Group B Group C

14. E-learning module to POPs Group B Properties Sources POPs in the environment Exposure risks Health impacts Collection and labelling of PCBs containing equipment Group A Properties Sources POPs in the environment Exposure Risks Health Impacts Group B Group C

15. E-learning module to POPs Group B: Properties Polychlorinated biphenyls (PCBs): • are a class of 209 individual chlorinated compounds known as congeners • do not occur in nature • are highly stable and heat resistant properties to breakdown • are either oily liquids or solids • either colourless or light yellow • have no smell or taste • were used in a variety of primarily coolant, lubricant and hydraulic applications PCB chemical formula Group A Group B Properties Sources POPs in the environment Exposure Risks Health Impacts Group C

16. E-learning module to POPs Group B: Sources PCBs have been released to the environment solely by human activity. PCBs can enter the soil, water and air environments: • by accidental leaks and spills from older electrical equipment • deposition of vehicular emissions • incineration of PCB-containing wastes Old PCBs containing transformer Group A Group B Properties Sources POPs in the environment Exposure Risks Health Impacts Group C

17. E-learning module to POPs Group B: POPs in the environment • PCBs are highly persistent in the environment and, as other POPs, can bio-accumulate. • In water, PCB congeners with less chlorine atoms dissolve, but mostly PCBs bind to soils within the upper layers of the sediment load. • In the atmosphere, PCBs are present both in the vapour phase and sorbed to particles. • PCBs are removed from the atmosphere by wet and dry deposition. PCB-contaminated creek Group A Group B Properties Sources POPs in the environment Exposure Risks Health Impacts Group C

18. E-learning module to POPs Group B: Exposure risks The main exposure to humans is from: • eating fish, meat or dairy products contaminated with PCBs • drinking water from a contaminated source • inhalation of dust or dermal contact from sites near waste sites • from exposure to vapours in the use and repair of old electrical equipment or florescent light • in the disposal of PCB contaminated materials and oils PCB warning sign near the Housatonic River, USA Group A Group B Properties Sources POPs in the environment Exposure Risks Health Impacts Group C

19. E-learning module to POPs Group B: Health impacts • Different PCB congeners have varying harmful effects. • People exposed to high levels are likely to have suffered liver disease, changes to the blood and skin complaints, in particular Chloracne. • The DHHS, US EPA and IARC have determined that PCBs are a probable carcinogen to humans. • Studies of pregnant women and nursing mothers exposed to high levels of PCBs in foods, revealed children born with: • decreased average birth weights • decreased motor skills • decreased short-term memory • a reduced immune system Labelling of electrical goods containing PCB oils Group A Group B Properties Sources POPs in the environment Exposure Risks Health Impacts Group C

20. E-learning module to POPs Group C Properties Sources POPs in the environment Exposure risks Health impacts Possible unintentional emission of POPs Group A Group B Group C

21. E-learning module to POPs Group C: Properties Dioxins formally known as polychlorinated dibenzo-p-dioxins (PCDDs) • are a class of 75 individual chlorinated compounds known as congeners • in pure form they are a colourless crystal or solid • 2,3,7,8-tetrachloro dibenzo-p-dioxin (2,3,7,8-TCDD), one of the most toxic dioxins, is odourless • the odour of other dioxins is not known • in the environment dioxins occur as a mixture of different congeners together with furans 2,3,7,8-TCDD chemical formula Group A Group B Group C Properties Sources POPs in the environment Exposure Risks Health Impacts

22. E-learning module to POPs Group C: Properties Furans formally known as polychlorinated dibenzofurans (PCDFs) • are a class of 135 individual chlorinated compounds known as congeners • in pure form they are a colourless solid • do not readily dissolve in water • in the environment furans occur as a mixture of different congeners together with dioxins Note: Not all Furans have been studied PCDFs chemical formula Group A Group B Group C Properties Sources POPs in the environment Exposure Risks Health Impacts

23. E-learning module to POPs Group C: Sources Dioxins and Furans are substances produced un-intentionally from the combustion of organic compounds and materials containing chlorine. Some examples: • combustion of fossil fuels • waste incinerators • bleaching in paper mills • volcanic activities and forest fires • home heating • even home frying and barbeque (salt contains chlorine) A fossil fuel power station Group A Group B Group C Properties Sources POPs in the environment Exposure Risks Health Impacts

24. E-learning module to POPs Group C: POPs in the environment • Dioxins and furans enter the environment as mixtures containing a variety of individual components and impurities. • PCDDs along with PCDFs are known to occur naturally. • These substances are removed from the atmosphere to earth as fine particles in rain and/or snow. • In waste water they mainly attach to sediments in the water environment and settle out, or are either broken down by sunlight or evaporated to air. Indonesia volcano emitting hot ashes and gases containing dioxins and furans into the atmosphere Group A Group B Group C Properties Sources POPs in the environment Exposure Risks Health Impacts

25. E-learning module to POPs Group C: Exposure risks Dioxins and furans: • Bio-accumulate in the food chain (meat, dairy products and fish). • Inhalation of dust. • Drinking low levels in water. • Skin contact with certain herbicides and pesticides contaminated by PCDDs. • Living near/ working at a incinerator or Hazardous waste site • Working at a paper mill or water treatment plant. Eating contaminated foods is most important pathway of POPs exposure Group A Group B Group C Properties Sources POPs in the environment Exposure Risks Health Impacts

26. E-learning module to POPs Group C: Health impacts • Acute and chronic toxicity varies for diferent dioxin and furan congeners. • The most toxic dioxin is 2,3,7,8-TCDD (2,3,7,8-tetrachlorodibenzo-p-dioxin). • The most toxic furan is 2,3,7,8-TCDF (2,3,7,8-tetrachlorodibenzofuran). Group A Group B Group C Properties Sources POPs in the environment Exposure Risks Health Impacts Dioxins

27. E-learning module to POPs Severe chloracne Group C: Health Impacts Health effects of exposure to dioxins include: • severe Chloracne, particularly the upper body and face • skin rashes • excessive and discoloured body hair • possible liver damage • changes in glucose metabolism and hormone levels Long term exposure to dioxins may cause birth defects. Animal studies on the exposure to 2,3,7,8-TCDD revealed that acute exposure can cause death. The WHO and DHHS have concluded that 2,3,7,8-TCDD is a probable carcinogen. Group A Group B Group C Properties Sources POPs in the environment Exposure Risks Health Impacts Dioxins Furans

28. E-learning module to POPs Group C: Health Impacts Human acute exposure to furans showed: • skin and eye irritation • severe acne • darkening skin colour • swelling eyelids and eye discharges Children exposed in the womb have had skin irritation and increased learning difficulties. Animal studies showed much the same effects as those in humans only often more severe. The DHHS, IARC and US EPA do not classify furans as a carcinogen. Group A Group B Group C Properties Sources POPs in the environment Exposure Risks Health Impacts Dioxins Furans

29. E-learning module to POPs Conclusions • POPs are very stable, and exhibit only very slow decay in the environment. • The main mechanisms of exposure are bio-accumulation, inhalation and dermal contact. • POPs are considered to be of low solubility in water. • All POPs are probable or possible carcinogens. • Their mobility and bioaccumulation properties have the most influence upon the choice of mitigation and remedial measures, rather than their toxicity.