ENVIRONMENTAL FATE OF POLYCHLORINATED BIPHENYL (PCB).pptx

Polychlorinated biphenyls (PCBs) are a class of artificial organic compound that are produced by the direct chlorination of the biphenyl ring.
This seminar presentation looks into key headings such as:
i. uses of PCBs
ii. routes of entry into the environment
iii. Current sources of PCBs
iv. Toxicity
v. Management and Control of PCBs

1. BY ADEGBUYI, IYANUOLUWA EMMANUEL MATRICULATION NUMBER: 209077015 DATE: 02/11/2022 UNIVERSITY OF LAGOS DEPARTMENT OF ZOOLOGY ZLY 890: POSTGRADUATE ORAL SEMINAR 1 SEMINAR TITLE: ENVIRONMENTAL FATE OF POLYCHLORINATED BIPHENYL (PCB): EFFECTS AND MITIGATION IN THE AQUATIC ECOSYSTEM 1 UNIVERSITY OF FIRST CHOICE AND THE NATION’S PRIDE

2. INTRODUCTION USES OF PCBs ROUTE OF ENTRY OF PCBs CURRENT SOURCES OF PCBs TOXICITY OF PCB MANAGEMENT AND CONTROL OF PCBs CASE STUDY CONCLUSION AND RECOMMENDATIONS OUTLINE 2 2

3. Polychlorinated biphenyls (PCBs) are a class of artificial organic compound that are produced by the direct chlorination of the biphenyl ring ( Ahmed et al ., 2016). They consist of carbon, Hydrogen and Chlorine atoms. PCBs comprises of 209 possible chemical formulas (also called as congeners). PCBs are toxic persistent organic pollutants (POPs) ( Daniel I.E, 2015 ) INTRODUCTION 3 3

4. PCBs were produced commercially in the period between 1930s and 1970s United States, Germany, Russia, France, the United Kingdom, Japan, Italy, Spain,Czech Republic, China, and Poland. They were commonly known as Aroclor (USA), Clophen (Germany), Kanechlor (Japan), Phenoclor and Pyralene (France) and Santotherm (Mitsubishi, Japan) ( Zhifu . et.al ., 2013) PCBs production was banned by Environmental Protection Agencies (EPA) in US in 1977, in Japan in 1972, other countries by 1993 ( Breivik et al ., 2007 ). HISTORY OF PCB 4 4

5. 5 STRUCTURE AND CONGENERS OF PCB There are 209 possible congeners which are formed depending on the position and number of chlorine atoms attached to the biphenyl ring structure(Mills et al ., 2007). 5 Fig 2: Congeners of PCB ( Zhifu . et.al ., 2013 ) Fig 1. Molecular structure of PCBs ( Breivik et.al., 2007 )

6. 6 PCBs are light yellow or colorless, viscous liquids PCBS are C hemically stable, have a high boiling point PCBs have no known smell or taste PCBs posses electrical insulating properties PCBs have l ow vapor pressures at room temperature PCBs are flame retardant PHYSICO-CHEMICAL PROPERTIES OF PCBS 6 (C. Zhang, et.al., 2013) Fig 3: Applicationsof PCBs ( Zhifu . et.al ., 2013)

7. 7 ROUTE OF ENTRY OF PCBs 7 Fig 4 : Occurrence of PCBs in the Environment (Hoang et.al ., 2021)

8. 8 BIOACCUMULATION AND BIOMAGNIFICATION OF PCBS IN AQUATIC ECOSYSTEM 8 Fig 5: Trophic pathways of PCB biomagnification in saltmarsh food webs ( Kimber et.al ., 2021)

9. 9 Toxicity to Aquatic Life 9 Toxicity Equivalent Factors: TEQ = ∑(C i × TEF i ) n i =1 Studies have shown that PCBs shows different toxicity depending on the structure, placement of chlorines, and number of chlorines i.e : Planar/nonplanar. Dioxin like PCBs such as: 77*, 81*, 105, 114, 118, 123, 126*, 156, 157, 167, 169*, 189 *= most potent in activating AhR and Cyp1A Fig 6 : Toxic equivalency factor of dioxin-like PCBs ( Zhifu . e t.al ., 2013)

10. 10 The adverse effects of PCBs on animals also includes: GENOTOXIC EFFECTS ENDOCRINE DISTRUPTION CARCINOGENIC EFFECTS REPRODUCTIVE EFFECTS NEUROLOGICAL EFFECTS (USEPA 2012b) Toxicity to Aquatic Life- Cont’d

11. The Activation of the AhR Pathway MODE OF ACTION OF PCBS 11 11 Fig 7: A ctivation of the AhR Pathway (Monika et.al ., 2019)

12. REMEDIATION OF PCBS- THERMAL TREATMENT 12 Incineration treats organic contaminants in solids and liquids by subjecting them to temperatures typically greater than 760°C in the presence of oxygen, which causes volatilization, combustion, and destruction of these compounds (EPA. 2007) . INCINERATION 12 Fig 8 : Typical Mobile/Transportable Incineration Process (Ralph et.al ., 2011 )

13. It involves physical separation of volatile and semi-volatile contaminants from soil, sediment by heating the matrices at temperatures high enough to volatilize the organic contaminants ranging from 90 to 560°C. It reduces PCBs concentration in soil from 2200pm to less than 2ppm 13 MITIGATION OF PCBS- THERMAL TREATMENT THERMAL DESORPTION 13 Fig 9 : Typical Thermal Desorption Process with an Afterburner (Ralph et.al ., 2011 )

14. 14 Microorganisms may break down most organic Contaminants to metabolites and ultimately to harmless end products, mainly carbon dioxide and water. PCBs, however, are very difficult to degrade by biological processes (Pieper and Seeger 2008 ). Examples include: Achromobacter sp. NP03 Ochrobactrum sp. NP04 Lysinibacillus sp. NP05 Pseudomonas sp. NP06 Acinetobacter Comamonas testosterone Rhodococcus opacus NON-THERMAL TREATMENT BIOREMEDIATION 14 Fig 10 : Degradation of PCBs by naturally occurring facultative anaerobic bacteria ( Ohtsubo et.al ., 2004)

15. 15 PHYTOREMEDIATION 15 Fig 11: Phytoremediation of PCB Contaminated Soil (Van Aken et al . , 2010).

16. The PCB studies undertaken in 2008 and 2009 threw up challenges for the environmentally sound management of PCBs in Nigeria, and issues to bring the country into full compliance with its obligations to the Stockholm Convention. Some of the key issues opened by the studies were: The need for a comprehensive and detailed PCBs Inventory covering all PCBs users in all the states and the FCT. The confirmation of all chlorination positive fields screening test results with laboratory analysis in an environmental laboratory experienced and equipped for organo-chlorines analysis. Development of mechanisms for the final elimination of PCBs in the country by 2025. Development of Environmental, health and safety practices for on-line and off-line equipment, wastes and oil in PHCN facilities. PCBs IN NIGERIA : Management and Control 16

17. The four main organizations identified as major players in the management of chemicals in the country a re: The Federal Ministry of Environment ; Federal Ministry of Health; National Agency for Food and Drug Administration and Control (NAFDAC) – an agency under the Federal Ministry of Health; T he Factory Inspectorate Division of the Federal Ministry of Labor and Productivity Policy, Legislation and Guidelines 17

18. Legal Instrument (type, reference year) Responsible Ministries or bodies Chemicals Use Category Covered Objectives of Legislature Relevant Articles, Provisions Resources Allocated Enforcement Ranking S.1.8 National Environnent Protection (Effluent Limitation) Regs.1991 FEPA Chemicals and Chemical Waste Environmental protection; effluent and wastewater pollution control Section 1-6 N/A 2   S.1.9 National Environment protection (pollution Abatement in ind. ssand facilities Generation wastes). Rags 1991 FEPA chemicals and chemical waste Environnemental protection, pollution Abattement; safety Section 1-23 N/A 2 S.1.5 National Environment protection (management of solid and Hazardous Wastes).Regs.1991 FEPA Industrial and Consumer Chemicals radioactive substances agrochemical Environmental protection, sound environmental management of solid and hazardous waste including storage trasnboundary movement, treatment and disposal Part 1-12 N/A 2 Pesticides Registration Regulation 1996 NAFDAC Pesticides Registration of Pesticides safety of pesticides Section 1-9 N/A 1   Harmful Waste ( special Criminal Provision etc.)Decree 1988   FEPA   Agrochemical; industrial and consumer chemicals toxic hazardous waste   Environmental protection; human health;   N/A   2 18 Existing Legal Instruments which Address the Management of Chemicals in Nigeria

19. 19 CASE STUDY TITLE : ASSESSMENT AND RISK OF POLYCHLORINATED BIPHENYLS IN Chrysichthys nigrodigitatus , Cynoglossus senegaliensis AND Pseudolithus elongatus TO CONSUMERS: A STUDY OF LAGOS LAGOON. BY (OSUALA et.al., 2019) AIM : To investigate the levels of polychlorinated biphenyls (PCBs) in three marine fish species from the Lagos Lagoon and to calculate the associated health risks to humans due to the consumption of these species. 19

20. 20 CASE STUDY CONT’D- METHODOLOGY: One hundred and twelve (112) locally consumed fishes such as Silver-catfish, Sole-fish and Croaker were collected from the Lagos Lagoon by using set nets over a three (3) month period (August to October in 2016) The fishes’ muscle tissues were harvested for analysis of PCBs. PCB congeners were identified and quantified using the gas chromatograph (GC) conditions as outlined by USEPA (1996). Human health risk were calculated using the guidelines of USEPA (2000). 20

21. 21 CASE STUDY- RESULT The Mean concentrations of PCBs in the tissues of Silver Catfish ( C. nigrodigitatus ), ( P. elongatus ) is shown in Figure 1 below: The concentration trends of Σ PCBs in the fishes were: Silver Catfish ( 16.28 ± 5.05 mg/kg wet weight) > Sole-fish ( 12.50 ± 3.48 mg/kg wet weight) > Croaker (8.97 ± 5.62 mg/kg wet weight) The mean concentrations of ΣPCBs in the fish species exc exceeded the WHO maximum limit (0.2 mg/kg) (WHO and FAO, 2011). Fig . 12: Mean concentrations of ΣPCBs in fish 21

22. Fig 13: Distribution of PCB congeners in fish. The predominant congeners in Silver Catfish, Sole-Fish , and Croaker were 18, 52, and 170 , respectively. RESULTS CONT’D 22 22

23. 23 RESULT CONT’D Fig 14: Comparison of congeners among species Croaker had the highest mean concentrations of PCB congeners 138, 170 and 180 (1.48 ± 1.12, 1.66 ± 1.66 and 0.74 ± 0.67 mg/kg wet weight, respectively. . Stole-Fish had the highest mean concentrations of PCB congeners 8, 101, 126 and 128 (1.17 ± 1.17, 1.20 ± 0.33, 1.22 ± 0.13 and 1.48 ± 0.59 mg/kg wet weight, respectively. Silver Catfish presented the highest mean concentrations of PCB congeners 18, 28, 52, 77, 105 and 153 (4.09 ± 2.90, 0.99 ± 0.99, 3.44 ± 3.13, 1.67 ± 0.95, 2.20 ± 1.24 and 1.12 ± 1.12 mg/kg wet weight, respectively. 23

24. TABLE 1: Estimated daily intake of PCBs and lifetime daily dose through consumption of fish The EDI values of DL-PCB in all the fish species were generally higher in children than in adults. The values were above USEPA reference dose (2 × 10-5 mg/kg/d) for children and adults RESULT CONT’D 24 Fish species EDI ( mg/kg/d ), children 1–11 years EDI ( mg/kg/d ), Adults Silver Fish (C. nigrodigitatus ) 1.37 × 10-3 5.88 × 10-4 Sole- Fish (C. senegaliensis ) 9.62 × 10-4 4.12 × 10-4 Croaker (P. Elongatus) 6.16 × 10-4 2.64 × 10-4 24

25. It was e stablished that the selected fish species collected from the Lagos Lagoon are contaminated with PCBs which bioaccumulated and biomagnified. T he concentrations of PCBs in the fish species do not pose significant cancer risks to humans because the values were below USEPA acceptable risk level (10-4). However, the exposed population is at risk of non-cancer adverse health effects and lifetime cancer. CONCLUSION 25

26. 26 RECOMMENDATIONS U rgent action should be taken by relevant environmental and public health agencies to implement strategies to prevent subsequent exposure of humans to PCBs through consumption of fish species exposed to PCBs. E limination of sources of PCBs pollution in the water body such as the Lagos lagoon which in turn leads to the sustainable management of the pollution. Ensure that wild caught fish and game, or animals raised for personal consumption have not been contaminated with PCBs. Use appropriate respiratory protection around PCB waste sites and do not drink contaminated well water. 26

27. 27 RECOMMENDATIONS- CONT’D Avoid the use of old fluorescent lighting fixtures and old appliances such as televisions and refrigerators that were made more than 30 years ago. These may leak small amounts of PCBs during operation. Take precautions when replacing, repairing or maintaining materials containing PCBs, and equipment such as old capacitors, fluorescent lighting ballasts, and transformers. F urther studies that will incorporate organisms lower in the food chain to determine the possible biomagnification of PCBs along the food chain in Lagos Lagoon. 27

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