Environmental quality standards bioassays

Methods. As discussed in the previous chapter, a number of approaches have been used to assess the presence of potentially toxic trace elements in water. The approaches used in this assessment include comparative media evaluation, a human health and aquatic life guidelines assessment, a mass balance evaluation, probability plots, and toxicity bioassays. Concentrations of trace elements were determined by atomic absorption spectrometry according to standard methods (21,22) by the Oregon State Department of Environmental Quality and the U.S. Geological Survey. 

Pica-Granados, Y., Trujillo, G.D. and Hernandez, H.S. (2000) Bioassay standardization for water quality monitoring in Mexico, Environmental Toxicology 15 (4), 322-330. 

Chemical analyses are an indispensable complement to ecotoxicological investigations, but they are not directly integrated in the application of the pT-scale for industrial effluent assessment. Performed in parallel, assessment of chemical substances is governed by a set of criteria, which are derived from ecotoxicological threshold (NOEC) values, in order to derive quality objectives or standards. When bioassay and chemistry results are both available for effluent assessment, they should be ranked equally. For determining the overall hazard of wastewaters, the most conservative information with respect to aquatic health will serve as the yardstick to ensure environmental protection. 

Efforts have been undertaken mainly be the United States Environmental Protection Agency to develop standard procedures and criteria for the assessment of environmental impact of sediment-associated pollutants. Initial discussions (Anon., 1984, 1985) suggested five methodological approaches which merit closer consideration (i) "background approach", (ii) "water quality/pore water approach", (iii) sediment/water equilibrium partitioning approach , (iv) sediment/organism equilibrium" approach, and (v) "bioassay" approach. Of these possibilities, applications of "bioassays" and "background approach" have been outlined in sections 6.1 and 6.2, respectively. 

The routine chemical analysis for the quality control of compost and soil will not be suitable to detect (unknown) metabolites which are harmful to the environment. Bioassays will be necessary to supplement other analyses and to complete the information about the environmental behaviour of biodegradable polymers. This requirement is already expressed in the inclusion of mandatory bioassays in the relevant standards for compostable products. 

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