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Measures of pollutant concentration are used to determine risk assessment in public health. Industry is continually synthesizing new chemicals, the regulation of which requires evaluation of the potential danger for human health and the environment. Risk assessment is nowadays considered essential for making these decisions on a scientifically sound basis. Measures or defined limits include: *''No effect concentration'' (NEC), ''No Observed Effect Concentration'' (NOEC), ''No-observed-adverse-effect level'' (NOAEL) *''Lowest-observed-adverse-effect level'' (LOAEL) *''Acceptable Operator Exposure Level'' (AOEL)〔(thefreedictionary.com/AOEL ) Retrieved on June 19, 2009〕 *ECx (in percent) ==No effect concentration== ''No effect concentration'' (NEC) is a risk assessment parameter that represents the concentration of a pollutant that will not harm the species involved, with respect to the effect that is studied. It is often the starting point for environmental policy.〔Bruijn et al., 1997, Chen & Selleck 1969〕 There is not much debate on the existence of an NEC 〔Van Straalen 1997, Crane and Newman 2000〕 but the assignment of a value is another matter. Current practice consists of the use of standard tests. In the standard tests groups of animals are exposed to different concentrations of chemicals and different effects such as survival, growth or reproduction are monitored. These toxicity tests typically result in a ''No Observed Effect Concentration'' (NOEC, also called a No Observable Effect Level or NOEL). This NOEC has been severely criticized on statistical grounds by several authors 〔Suter 1996, Laskowski 1995, (Kooijman 1996 ), Van der Hoeven 1997〕 and it was concluded that the NOEC should be abandoned.〔(OECD Document No 54 of "Series on Testing Assessment", 2006 )〕 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「Measures of pollutant concentration」の詳細全文を読む スポンサード リンク
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