Annex 1 to the Interim Report
Potential for long-range transport
Download 172.3 Kb.
|
Potential for long-range transportThe vapour pressure of lindane is 1.2-7.4 x 10-3 Pa (20-25C) (3). Henry's Law Constant has been calculated to the order of 1 x 10-1 Pa x m3 x mol-1. Estimated half-life in air is 4.6 days (4) or 43 days (3), however, there is also other data available which indicates that the substance is persistent in air with estimated half-lives of >11 000 days (4). Monitoring data seem to support that the substance is relatively persistent in air. Laboratory as well as field studies indicate a substantial distribution to air; 90% loss from soil surfaces was observed within 24 hours, while loss from plant surfaces was even faster, 86% within 6 hours (4). Soil incorporation reduces the distribution to air; 13% loss was observed within 24 hours at the laboratory, while field studies have indicated presence of lindane above background levels still 6 months after soil incorporation (4). Vapour pressure of -HCH is 2.7 Pa (20) (2) and the calculated Henry's Law Constant is 390 Pa x m3 x mol-1. This isomer is therefore considerably more volatile than lindane. Monitoring data supports the high potential for volatilization. -HCH has a slightly lower potential for volatility, 0.67 Pa at 20 (2). The estimated Characteristic Travel Distance (CTD) describes the long-range transport potential as the distance at which the initial concentration drops to 37% (1/e). For the standard scenario (100% emission to air), the CTD for lindane is 7 400 km (3). The atmospheric background concentration of lindane has been reported to be in the range of 0.015-0.3 ng/m3 (3). A relationship has been found between global use of technical HCH and air concentrations of -HCH in the Arctic air between 1979 and 1994 (3). Elevated levels of persistent organic pollutants (including HCH) are positively correlated with long-range transport episodes from use areas in the mid-latitudes of North America, Europe and Asia (3). Such correlation between levels of PCBs and HCHs and episodes with air masses originating mainly in Europe has been reported from Svalbard (3). Measurements in Sweden (Rörvik station) show 0.010-0.050 ng/m3 of each one of the - and -isomers, and a deposition of 0.2-0.7 ng -HCH/m2 per day, 0.2-0.9 ng lindan/m2 per day (10). In Swedish measurements in rain water (three stations in Skåne, Uppland and Lappland) during 1990-92, - and -HCH were detected in nearly 100% of the samples (5). Highest concentrations of lindane were detected in the south of Sweden (median concentration 13 ng/l). In contrast, the levels of -HCH showed little variation between stations and season. The ratio /-HCH therefore increases from the south to the north (5). The results indicate that atmospheric transport of lindane occurs despite the fact that European usage mainly has been limited to treatment of seeds which are incorporated in soil. For -HCH a long time trend in muscle of pike from lake Storvindeln, near the Arctic circle in Sweden, has been presented. As there is little agricultural activity in this remote area, atmospheric transport and deposition is expected to be the only significant source of -HCH (3). The emission of lindane to the atmosphere from Europe (38 countries) was estimated to 1 310 tonnes per year in 1990, to 765 tonnes/year in 1997 (3). From the 15 Contracting Parties of the OSPAR Convention, the emission was estimated to 417 tonnes/year in 1990, and to 733 tonnes/year in 1997 (3). Lindane is also being transported from the application areas via water. A total of 800-940 kg was estimated to reach the North Sea in 1998, mainly by riverine input but also from direct discharges (3). HCH is included in The list of priority substances in the field of water policy, established under Directive 2000/60/EC of the European Parliament and of the Council, establishing a framework for Community action in the field of water policy (7). In the context of the Water Framework Directive, the following mean concentrations have been reported for European surface waters (8):
For the sediment phase, the following mean concentrations were reported (8):
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:
|