Annex 1 to the Interim Report
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- Bioaccumulation
- Toxicity
PersistenceThe results from screening tests on biodegradability of lindane are highly variable, but it is notable that lack of transformation was demonstrated in a few tests even after adaptation of the microorganisms (3). Reported half-lives for lindane in aquatic systems also vary considerably, from a few days to >700 days (3). From laboratory studies in soil, half-lives of 260-708 days (3) and 133-980 days (4) have been reported. From field studies maximum half-lives of >300 days have been reported (3). In the report produced under EU's Plant Protection Directive (91/414/EEC), it is concluded that DT90 after incorporation into soil (commonly used within the EU) in most cases is <1 year, but that the persistency can be significantly prolonged under certain conditions (4). The first dehydrochlorination step to pentachlorocyclohexene is considered as a rate limiting step for degradation. Metabolites has been found in very low amounts in laboratory studies (4). Data suggests that degradation of lindane is accelerated under anaerobic conditions (4). Since substantial volatilization of lindane is expected, many of the reported half-lives are considered to be very uncertain estimates. By use of a level III multimedia model, the overall persistence of lindane in source areas or in remote areas (e.g. assuming 100% emission to air, or 20% emission to air, 80% to soil etc.) was calculated to 613- 873 days (3). For -HCH data are conflicting: this isomer is reported to be less persistent than lindane (3), or it is reported to more slowly biodegraded than lindane (2). -HCH seems to be the most persistent isomer (2). The expected persistence is confirmed by identification of HCH (-, - and -) in air, rain water, plants, and in aquatic and terrestrial animals, including man. Therefore, the criterion for persistency is considered to be met for HCH, despite the considerable variation in reported half-lives. BioaccumulationReported values for log Kow for lindane varies between 3.2 and 3.7. Bioconcentration factors (BCF) for lindane in a study on four different fish species were 12 800-15 400, however, usually the reported BCFs are a factor of 10 lower than these values (3). In the EU report on lindane (4), a BCF of 1 300 was reported, with 15% of the radioactivity remaining in the fish after 14 days in clean water. The report concludes that the detection of residues in wild birds and mammals indicates that organisms consuming fish are at risk.- as well as -HCH have log Kow values of 3.8 (2). BCF for -HCH in fish varies from 313 to 1 216 (2), however, based on measured amounts in muscle and fat in bream collected in the River Elbe, BCF has been calculated to 10 000-50 000 (2). For -HCH, BCF in fish of 250-1 500 was reported however it has also been concluded that the bioconcentration is higher and the elimination is slower for -HCH than for the other isomers (2). Recent data from the Swedish Museum of Natural History indicates that the concentrations of HCHs in biota from the Baltic Sea as well as from the Swedish west coast are decreasing by a rate of 10% or more per year since the end of the 1980's (6). -HCH is in general decreasing faster than lindane. The ratio lindane/-HCH was found to be higher in fish from the Kattegatt compared to the Baltic. This could reflect that in the former east-bloc countries technical HCH has been used whereas the use of lindane has been more common in western countries. The concentrations of lindane (-HCH) varies from 5 to 30 µg/kg lipid in fish and mussel and the - and -isomers are detected at similar concentrations. Also within the OSPAR Convention area concentrations of lindane in fish and mussel tissues has generally been decreasing during the period 1990 to 1995, especially in relatively polluted regions (3). In contrast, a significant upward trend was observed in dab muscle from southern Norway (3). In biota in the Arctic Ocean the following concentrations of HCH were reported for the first half of the 1990's: mussels <0.5-0.82 µg/kg ww; fish liver <0.6-153 µg/kg ww; seabird liver 0.2-25 µg/kg ww; marine mammals blubber 17-473 µg/kg ww; marine mammals fat n.d.-1 150 µg/kg ww (3). From end of 1980's to mid-1990's, mean concentrations of approximately 160-600 µg HCH/kg lipid in Arctic polar bears were reported (9). Lindane is also found in animal food items; the substance was found in 10-50% of meat samples and in more than 50% of fish, crab and mollusc samples in Germany in the period 1995 to 1998 (3). Other HCH isomers were found less often. HCHs are also found in human breast milk. As an example, the mean concentration of lindane in more than 7 000 samples of breast milk samples collected in Germany between 1969-1984 was 0.01-0.11 mg/kg on a fat basis (1). A slow decrease was observed during the last years. From Swedish measurements (10) of -HCH, concentrations of 5.2-127 µg/kg fat have been reported (mean concentration 14.8 µg/kg fat, n=31). Lindane has been found in serum samples from Swedish women at <2-13.4 µg/kg serum fat; -HCH at <2-7.4 µg/kg (10). In the OSPAR report (3) it is suggested that also a not so lipophilic substance like lindane may be a candidate for biomagnification. It has been suggested that not only the degree of lipophilicity but also the degree and position of chlorination and particularly the elimination pathways determine the potential for biomagnification (3). Some data (such as measured levels in fisheating tuna fish and dolphins in relation to concentrations in fish, and measured levels in eggs of pelicans in relation to concentration in pelican's food items) suggests a potential for biomagnification (3). In contrast, others have shown that even though HCH occurs in Arctic air, snow and sea water and is efficiently accumulated by species at low trophic levels, the biomagnification potential is low at the upper end of the food web, with HCHs only in 10% or less of the samples (3).As an overall conclusion, the frequency at which the HCH isomers are being detected in biota indicates that the criterion for bioaccumulation is met, despite the fact that some of the reported BCF values are relatively low. It is worth noting that the measured concentrations in various environmental compartments show a decreasing trend.ToxicityLC/EC50 values in short-term studies on toxicity studies of lindane to fish and daphnia are 0.022-0.063 mg/l and 1.6-2.6 mg/l, respectively (4). Reported NOECs following long-term exposure are 0.0029-0.054 mg/l (4). The lowest NOAEL determined in standard toxicity tests on mammals for lindane is 0.47 mg/kg bw/d based on effects on the liver (4). A range of different effects caused by endocrine disruption, have been indicated in studies on different mammalian species. One example is reduced ovulation rate seen in rabbits at a dose of 0.8 mg/kg bw/d (4). In the rat, effects related to hormonal disruption as well as increased foetal mortality occurred at 0.5 mg/kg bw/d (3). The International Agency for Research on Cancer (IARC) has concluded that lindane is a "possible human carcinogen" (Class 2B), however the substance is not considered to pose a mutagenic risk (3). Within the EU, lindane has not been classified in relation to criteria for carcinogenicity, reproductive toxicity or mutagenicity. Based on presence in mother's milk the substance is classified with R 64 ("May cause harm to breastfed babies"). The criterion for adverse effects is considered to be met for lindane. The other isomers are less toxic than lindane; LC/EC50 for - and -HCH in fish and aquatic invertebrates are of the order of 1 mg/l (2). In long-term study on daphnids however NOEL was as low as 0.05 mg/l for -HCH; from a long-term study on -HCH in fish, NOEL was 0.03 mg/l (2). -HCH has been shown to cause a clear increase in the activity of liver enzymes at 5 mg/kg diet, equivalent to 0.25 mg/kg bw. A weak estrogenic effect of -HCH has been described (2). The criterion for adverse effects is considered to be met also for these isomers. Directory: fileadmin -> DAM -> env DAM -> United Nations st/SG/AC. 10/C. 3/2016/42 DAM -> United nations e DAM -> United Nations ece/trans/2016/33 DAM -> United Nations ece/trans/WP. 15/AC. 1/2014/13 DAM -> Technical Report on the development of a World-wide Worldwide harmonised Light duty driving Test Procedure (wltp) DAM -> WP. 29-153-32 (153rd wp. 29, 8-11 March 2011, agenda item 8) Korea Motor Vehicle Safety Standards Enactment/Revision Procedure for Automobile Management Act and Self Certification System DAM -> United nations e Download 172.3 Kb. Share with your friends:
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