Ecotoxicological risk

Encouraged by recent legislations all over the world aimed to protect human health and environment, alternative methods have proved their abilities to assess the toxicity of chemicals. Hence, a possible solution to the characterization of the toxicological and ecotoxicological risk of the chemicals could be represented by the application of in silico and in vitro techniques. 

The link between the ecological/ecotoxicological risk assessment and the risk management frameworks is demonstrated. The ecological risk assessment consists of seven interactive elements (Fig. 17). The quantitative and descriptive science used to conduct ERA (Table 5) does not answer, in a direct way, the question of what should be done to manage the risk. Science determines adversity, but the public determines acceptability (Fig. 18). But acceptable risk is a highly subjective and relative term. It is time and space-specific and depends upon definitions of quality of life and robustness of the environment. 

In broad terms risk assessments are carried out to examine the effects of an agent on humans (Health Risk Assessment) and ecosystems (Ecological Risk Assessment). Environmental Risk Assessment (ERA) is the examination of risks resulting from technology that threaten ecosystems, animals and people. It includes human health risk assessments, ecological or ecotoxicological risk assessments, and specific industrial applications of risk assessment that examine end-points in people, biota or ecosystems. 

Emmanuel E, Perrodin Y, Keck G, Blanchard JM, Vermande P (2005) Ecotoxicological risk assessment of hospital wastewater a proposed framework for raw effluents discharging into urban sewer network. J Hazard Mater Al 17 1-11... 

Van Beelen, P. Doehnann, P. Significance and apphcation of microbial toxicity tests in assessing ecotoxicological risks of contaminants in soil and sediment. Chemosphere 1997, 34, 455-499. 

Ecotoxicological Risk Assessment for Chlorinated Organic Chemicals. Alliston, Ontario, Canada, 25 to 29 Jul 1994. Published by SETAC, 1998. Application of Life-Cycle Assessment to Public Policy. Wintergreen, Virginia, 14 to 19 Aug 1994. Published by SETAC, 1997. 

Box B) Ecotoxicological risk assessment, using additional bioassays... 

For specific situations, a full ecotoxicological risk assessment could be performed for disposal of dredged harbour sediments. For example, when there are indications for the need for additional toxicity testing or when the outcome of the basic testing (Box A) is not sufficiently... 

Table 8 Calculated annual input of TEQ in the Dutch coastal zone from the rivers, atmospheric emission and disposal of dredged material (period 1999-2005). For the TEQ-lev-els in sediment, the ecotoxicological risk is estimated as % Potentially Affected Fraction of species (PAF) and calculated based on the SSD for chronic dioxin-toxicity (Figure 6). 

In vitro and in vivo bioassays have been shown to be useful tools in the process of hazard, ecotoxicological risk and impact assessment of dredged harbour sediments, provided they are consciously chosen. Three different purposes for application were distinguished (Fig. 1) for which the considerations differ. 

Solomon, K.R. (1996). Overview of recent developments in ecotoxicological risk assessment. Risk Anal., 16 627-633. 

Solomon, K.R. (1999). Integrating environmental fate and effects information The keys to ecotoxicological risk assessment for pesticides. In G.T. Brooks and T.R. Roberts, eds., Pesticide Chemistry and Bioscience The Food-Environment Challenge, London, UK Royal Society of Chemistry, pp. 313-326. 

Brunstrom, B., Halldin, K., 2000. Ecotoxicological risk assessment of environmental pollutants in the Arctic. Toxicol. Lett. 112-113, 111-118. 

Roghair, C.J., Buijze, A. and Schoon, H.N.P. (1992) Ecotoxicological risk evaluation of the cationic fabric softener DTDMAC. I. Ecotoxicological effects, Chemosphere 24 (5), 599-609. 

BA Batteiy Approach study ERA Ecotoxicological Risk Assessment study. 

The following steps (proposed by the Committee) show how the information for assessment of ecotoxicological risks is developed once a system is in place ... 

It may appear to be a nearly overwhelming task to conduct ecotoxicological risk assessments for herbicides in forestry. 

Giesy J. P., S. Dobson, and K. R. Solomon. 2000. Ecotoxicological risk assessment for Roundup herbicide. Reviews of Environmental Contamination and Toxicology 167 35-120. 

Recently, some models have been derived to analyze the occurrence of interactive joint action in binary single-species toxicity experiments (Jonker 2003). Such detailed analysis models are well equipped to serve as null models for a precision analysis of experimental data, next to the generalized use of concentration addition and response addition as alternative null models. However, in our opinion these models are not applicable to quantitatively predict the combined toxicity of mixtures with a complexity that is prevalent in a contaminated environment, because the parameters of such models are typically not known. Recently a hazard index (Hertzberg and Teus-chler 2002) was developed for human risk assessment for exposure to multiple chemicals. Based on a weight-of-evidence approach, this index can be equipped with an option to adjust the index value for possible interactions between toxicants. It seems plausible that a comparable kind of technique could be applied in ecotoxicological risk assessments of mixtures for single species. However, at present, the widespread application of this approach is prevented by lack of available information. 

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