|
The town of Hinkley, California, located in the Mojave Desert, (about 121 miles driving distance north-northeast of Los Angeles) had its groundwater contaminated with hexavalent chromium starting in 1952, resulting in a legal case against Pacific Gas & Electric (PG&E) and a multimillion-dollar settlement in 1996. The legal case was dramatized in the film ''Erin Brockovich'', released in 2000. ==Pollution of groundwater== PG&E operates a compressor station in Hinkley for natural gas transmission pipelines. The natural gas has to be re-compressed approximately every , and the station uses large cooling towers to cool the gas after it has been compressed. (Between 1952 and 1966 ), the water used in these cooling towers contained hexavalent chromium – now recognized as a carcinogen – to prevent rust in the machinery. The water was stored between uses in unlined ponds, which allowed it to percolate into the groundwater. This led to groundwater pollution, affecting soil and contaminating water wells near the compressor station, with a plume approximately long and nearly wide.〔(PG&E Hinkley Chromium Cleanup ) California Environmental Protection Agency, 9/10/08〕 Average hexavalent chromium levels in Hinkley were recorded as 1.19 parts-per-billion (ppb) with an estimated peak of 20 ppb. The PG&E Topock Compressor Station averaged 7.8 ppb and peaks at 31.8 ppb based on the PG&E Background Study.〔(PG&E Background Study )〕 The proposed California health goal for hexavalent chromium is 0.02 ppb. The US EPA sets the regulatory limit of total chromium at 100ppb. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Hinkley groundwater contamination」の詳細全文を読む スポンサード リンク
|