Ecotoxicologically relevant concentration

Nanoparticles have found their way for many human use products over the years. They are in the colloidal or subcolloidal size range. Nowack and Bucheli (2007) present a review of classes of nanoparticles relevant to the environment and summarize their formation, emission, and occurrence in the environment. At elevated concentrations, they reported the toxic ecotoxicological effects of certain nanoparticles. 

An ecotoxicological profile analysis is a procednre developed to evalnate the environmental relevance of chemicals (commonly used for pesticides). The base for a risk assessment is a list of properties of the investigated chemical. That list includes concentration used, pattern of application, biodegradability, type and properties of metabolites, environmental dispersion and accumulation. Related results from laboratory tests are weighted and classified following very specific rules. Finally one relative index number is obtained which allows a simple comparison between ecological impacts of different chemicals (for details see Freitag and co-workers [30]). 

The ecotoxicological effects which, given rapid biodegradabiUty of the substances, continue to lose relevance in an overall ecological risk assessment, show favorable findings in aU test systems. The no-observed-effect concentrations (NOEC) for acute or chronic toxicity, as determined on single-species or bio-... 

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