方舟子用一升水,来举例,那么美国加州为什么把饮用水的标准设定的比环保署的标准还要高:为铬总含量为50ug/L,即0.05mg/L。 Chromium-6 is currently regulated under the 50-micrograms per liter (ug/L) MCL for total chromium. California's MCL for total chromium was established in 1977, when we adopted what was then a "National Interim Drinking Water Standard" for chromium. The total chromium MCL was established to address exposures to chromium-6, which is considered to be the more toxic form of chromium. The US EPA adopted the same standard, but in 1991 raised the federal MCL to 100 µg/L. California did not follow US EPA's lead and stayed with its 50-µg/L MCL for total chromium. http://www.cdph.ca.gov/certlic/drinkingwater/Pages/Chromium6.aspx
而且,加州饮用水对六价铬含量的最新目标是:0.02ug/L, 就是说0.00002mg/L。什么意思,这些加州人,疯了吗,怕这个6价铬怕的要死啊。 On July 27, 2011, the Office of Environmental Health Hazard Assessment (OEHHA) established a public health goal (PHG) for chromium-6 (hexavalent chromium) of 0.02 micrograms per liter (ug/L). The PHG will contribute to CDPH's development of a primary drinking water standard (maximum contaminant level, MCL) that is specific for chromium-6.