Chemical name: 1,1'-Biphenyl, chloro derivs. Final regulatory action has been taken for the category: Industrial Final regulatory action: The chemical is Severely Restricted Use or uses prohibited by the final regulatory action: The Regulations prohibit the manufacture, process, use, offer for sale or import of chlorobiphenyls for any of the following commercial, manufacturing or processing uses: a)in the operation of any product, machinery or equipment other that (i), (ii) or (iii) listed below; b)in the operation of electromagnets that are used to handle food, animal feed or any additive to food or animal feed. c)as a constituent of any product, machinery or equipment manufacture in or imported into Canada on or after September 1 1977, other than (i) listed below; d)as a constituent of electrical capacitors and electrical transformers and associated electrical equipment manufactured in or imported into Canada on or after July 1 1980; e)in the servicing or maintenance of any product, machinery, or equipment other than electromagnets and electrical transformers and associated electrical equipment from which the chlorobiphenyls are removed to allow servicing and maintenance; or f)as new filling or as make-up fluid in the servicing or maintenance of any electromagnet, electrical transformer or associated electrical equipment. Use or uses that remain allowed: The Regulations allow the manufacture, process, use, offer for sale or import of chlorobiphenyls for the following commercial, manufacturing or processing uses: (i) in electrical capacitors and electrical transformers and associated electrical equipment. (ii) in heat transfer equipment, hydraulic equipment, electromagnets, other than electromagnets referred to in b) above, and vapour diffusion pumps that were designed to use chlorobiphenyls and that were in use in Canada on or before September 1 1977; (iii) in machinery or equipment for the destruction of chlorobiphenyls. The prohibitions in the Regulations do not apply when chlorobiphenyls are adventitiously present in any product, machinery or equipment and the quantity or concentration of chlorobiphenyls in the product, machinery or equipment is not inconsistent with good manufacturing practice. The concentration of chlorobiphenyls that may be contained in any liquid in products, machinery or equipment referred to in (i) and (ii) that are manufactured, imported or offered for sale in Canada shall not exceed 50 parts per million by weight of the liquid. This does not apply in respect of concentrations of chlorobiphenyls in the liquid in any product, machinery or equipment where the product, machinery or equipment is: offered for sale as a necessary and integral part of a building, plant or structure; imported for the destruction of the chlorobiphenyls contained in that product, machinery or equipment; or offered for sale for destruction or storage while awaiting destruction of the chlorobiphenyls contained in that product. The final regulatory action was based on a risk or hazard evaluation: Yes Summary of the final regulatory action: The Chlorobiphenyl Regulations limit the concentration of chlorobiphenyls in products or the quantities that may be released. These Regulations address the manufacture, process, use, offer for sale or import of PCBs in Canada. The mono- and dichlorobiphenyls are considered less toxic than the more highly chlorinated biphenyls and are consequently not regulated. Other Regulations are also in place to address the storage, treatment and destruction of PCBs in Canada. The reasons for the final regulatory action were relevant to: Human health and environment Summary of known hazards and risks to human health: There are a number of reports that deal directly with the effects of PCBs on humans. The most famous occurrence was a contamination of cooking oil by kanechlor 500 (approximately 48% chlorine) in southern Japan in 1968 which cause what is known as "Yusho" or oil disease. A variety of symptoms were observed - chloracne, pigmentation changes and gastrointestinal upset were among the immediate effects: death was also reported. Some of these effects persisted for as long as six years after the ingestion of the contaminated cooking oil with the age group from 13 to 29 years being particularly affected. There were longer lasting effects as well. School children exposed were observed to have retarded growth and there were adverse effects on fat metabolism. Blood enzyme levels were changed, the immune system suffered dysfunction as did the lungs, liver and ovaries of affected persons. Most of these latter effects, however can not be statistically established due to the PCBs; chlorinated dibenzodioxins and furans were also present as impurities and are believed to be responsible for some of the observed effects. A similar incident occurred in Taiwan in 1979. Concentrations of impurities in the contaminated oil there were lower (at least an order of magnitude lower) and mean PCB levels of 49 ug/L were found nine months to one year after the original exposure. Similar acne and pigmentation symptoms were observed as were found in Japan; evidence of porphyria was also observed. One set of studies that requires comment because of its relevance to environmental exposure is the investigation of the effect of Lake Michigan fish in the diet of pregnant and nursing mothers. Various behavioural and developmental defects were noted in newborn children born to Michigan mothers who were consumers of fish contaminated with several substances, prominent among which were PCBs. Freshwater fish consumption by these mothers (at 6.7 kg/year) was considerably higher than the value computed for Canadian annual consumption (0.21 kg/year) and the degree of contamination is undoubtedly greater for the Michigan fish. The observation of these symptoms does not directly implicate these compounds but it does provide presumptive evidence. These PCB effects are being investigated further. A variety of symptoms associated with PCB exposure have been identified from a number of studies of occupational situations. Cancer, neurotoxicity and reproductive toxicity were listed in addition to those effects already mentioned. In a study of 2567 workers at a PCB transformation plant in the United States, only rectal and liver cancer appeared to be slightly increased, the significance of which has been questioned. A variety of neurological symptoms were reported in an examination of capacitor plant workers. human sperm density was adversely affected by PCB and other contaminants with the strongest correlations occurring with levels of higher chlorinated PCB congeners. These few reports do not exhaust the literature on effects and reference is made to the review papers already mentioned. Expected effect of the final regulatory action in relation to human health: The final regulatory action will reduce PCB inventories in Canada which will minimize their release into the environment. Summary of known hazards and risks to the environment: Aquatic organisms It is the contention of the authors of the relevant documentation that PCBs are transported extensively via the atmosphere and that the load there is probably a dynamic one turning over frequently. This being the case, it is possible that most of the country received comparable surface loadings of these compounds, altered by local inputs but at comparable magnitudes. In the Great Lakes, with their large volumes, areas and retention times, the material is retained in the system while still remaining available for accumulation by resident biota - either directly from the water or indirectly via the food web. It is this accumulation in particular which has given rise to the environmental concern there. Levels of PCBs in fish of the Great Lakes ecosystem have fallen somewhat from those reported in the Task Force Report. Dissolved water values of less than 0.001 ug/L for Lake Ontario (considered to be the most polluted in the system) may be an artifact of new procedures employed in analysing large samples and any presumption of a decreasing trend in water should therefore be investigated. The upper limit for levels of dissolved PCBs in the lower Great Lakes is estimated to be approximately 0.001 ug/L and concentrations in the St Lawrence should be about the same. Limits in other parts of Canada could be one or more orders of magnitude lower based on levels in biota other than humans. However, because there has been little direct determination of water levels in other locations and because human adipose tissue concentrations do not differ as extensively as do residues in other organisms, it is recommended that the 0.001 ug/L level be considered as a "worst-case scenario" for water in Canada. No toxic effects to aquatic organisms are indicated that come closer than a factor of fifty times this level, although the effect observed at this level was death. More information on sublethal effects are required for sensitive species (such as lake trout). the information on human exposure indicates that there is little concern for humans from such levels. There are, however, concerns about the indirect accumulation of PCBs. In the Great Lakes, as elsewhere, there are residues in the tissues of aquatic organisms which serve as food for other organisms. The levels of PCBs in the recipient organisms accumulate, possibly to toxic levels but concentrations vary greatly. A minimum estimate of whole body residues for fish and fish-eating birds would be at least 0.1 ug/g. This is coincidentally close to that which would be estimated using the above water level and a bioaccumulation factor of 100 000. The ratio of the lowest dietary effect level for aquatic organisms (rainbow trout) to this tissue level is only four times and the effects observed include mortality. This "safety margin" is small and should be cause for considerable concern. Many fish species in this system have whole body concentrations well above this level. Since many of the effects are subtle and difficult to distinguish from those caused by other stresses, it can only be assumed that effects are being felt by predator species at almost every trophic level. In their 1974 report, the Water Quality Objectives Subcommittee opted to provide a second line of defence against PCBs by defining a maximum fish tissue level intended to protect consumers of Great lakes fish. While it has not reduced the exposures to anywhere near the level, it has at least served to identify the problem. Terrestrial Organisms Unlike the aquatic environment, there are three major routes that terrestrial organisms can come in contact with PCBs - in the air they breathe, the food they eat and the water they drink. This, at least, is the case for the mammalian and avian species. For humans, dermal contact may be an occupational concern, but htis is not considered here. Effects on soil insects are not well known. An evaluation of the loadings of PCBs that are likely to be deposited from rain (assuming a Canadian-wide mean of 0.004 ug/L) in the rain and an annual precipitation of 75cm) and allowing a factor of three times for vapour phase transfer, leads to the conclusion that some 10 ug/m2yr-1 could be deposited. This amount would only increment the concentration of the top 1 cm by 0.0002 ug/g annually and deeper layers correspondingly less. Direct exposure of most terrestrial organisms to such levels is probably not a concern although it may be in areas utilizing sewage sludge. Although worms live in and eat a medium which receives atmospheric depositions, there is inadequate information on the effects of PCBs in these organisms. The vital volumes of air for terestrial organisms other than humans are not well documented. On the assumption this is dependent on body weight (perhaps more true for mammals than for birds), it is unlikely that breathing is a major exposure route for terrestrial organisms. As estimated for man, this mechanism appears to represent only about 2% of the total exposure estimated from fish and other food. It appears that food is the major cause for the various tissue residues that have been found in the Canadian environment. For both the avian and non-human mammalian species, there are virtually no data on PCB levels in their food sources. An exception to this would be commercial mink and the herring gull both of which subsist substantially, at least in the Great Lakes area, on fish. Data indicate that the lowest effect level, albeit probably reversible enzymatic ones, occurs in the range of 0.1 to 0.5 ug PCB/G (diet) for birds and 0.2 to 0.3 ug/g for mammals. Such effects may influence the ability of the organism to cope with its environment and should therefore be considered detrimental. Fish in the Great Lakes area and other areas such as the coastal region of British Colombia, the St Lawrence River region of Quebec, and possibe marine mammals in parts of the Arctic region contain PCBs at levels above these effect levels and regular consumers of them must be considered to be at some risk from PCBs. Plant grazing animals may also be at risk. While the amount of PCBs deposited by precipitation is small on an areal basis, it may well form high concentration on the surface of leaves and grasses. It undoubtedly volatizes from such surfaces but is also re-deposited. The steady-state levels on such material are unknown but it is suspected to be significant since grazing animals do accumulate PCBs in their tissues and milk at levels which are probably responsible for the human adipose tissue levels of the Canadian population. The shortage of data on residues in wildlife and birds is a major difficulty in making conclusions concerning the hazard of PCBs to terrestrial organisms. Expected effect of the final regulatory action in relation to the environment: The final regulatory action will reduce PCB inventories in Canada, which will minimize their release into the environment. Date of entry into force of the final regulatory action: 31/03/2000 |