Biomarkers and Integrated Environmental Risk Assessment: Are There More Questions Than Answers?

Abstract

The introduction of the European Commission's Water Framework Directive (WFD; 2000/60/EC) established a new era in environmental risk assessment. In addition to incorporating the compliance of chemical quality standards, the key objective of the WFD is the general protection of the aquatic environment in its entirety. This new approach emphasizes the need for an integrated environmental risk assessment and offers the potential for the incorporation of biological effects measures, including the use of biomarkers in this process. Biomarkers have been suggested as practical tools for environmental management for a number of decades, but their inclusion has not been universally accepted because of a number of unanswered questions regarding sensitivity, practicality, and reproducibility. With this in mind, this paper addresses these potential questions and shows how, by taking a weight-of-evidence approach, biomarkers may be successfully incorporated within environmental risk assessment frameworks such as the WFD.

Potential influence of confounding factors (size, salinity) on biomarkers in the sentinel species Scrobicularia plana used in programmes monitoring estuarine quality

“…Several reasons can explain this, among which is the existence of natural fluctuations of biomarker measures that may concealed those changes attributable to differences in chemical stress. This spatial and temporal variability may be attributed to biotic and abiotic factors, called confounding factors, which include for example size of organisms, season, temperature, salinity (Handy et al 2003;Hagger et al 2006).…”

Plasma esterases in the tegu lizard Tupinambis merianae (Reptilia, Teiidae): impact of developmental stage, sex, and organophosphorus in vitro exposure

“…However, when biomarkers are included within the set of biological variables to be integrated in a weight-of-evidence framework for the environmental assessment of pesticide exposure, it is necessary to know the impact of biological (i.e., life stage or sexual development) and environmental factors (i.e., temperature or light/dark cycles) on biomarker responses (Peakall 1992;Sanchez-Hernandez 2001) (Forbes et al 2006;Hagger et al 2006). In the case of blood esterases, the understanding of normal fluctuation of their activities would enable to know the moment of critical vulnerability of the organism to pesticide intoxication as well as to identify the stressors responsible for esterase responses.…”

“…Measurement of multiple biomarkers rationally involved in the toxic mechanism and detoxification pathways of a pesticide in particular would be a recommended approach to assess the observed detrimental effects from the pesticide at whole individual level (Beliaeff and Burgeot 2002;Hagger et al 2006); however, it is necessary to establish the naturally occurring variation of esterase responses and the environmental and biological factors contributing to their normal fluctuation to avoid misinterpretations (Forbes et al 2006;Hagger et al 2006). In the case of BChE and CbE activities, because of their direct implication in the modulation of OP and CM toxicity, a marked variation of their natural activity levels by factors such as light/dark cycles, sex, and age could be useful to identify the moment of a higher risk of pesticide toxicity or a group of individuals more sensitive to pesticide exposure (Thompson 1993;Maul and Farris 2004).…”

Biomarker responses in the crab Carcinus aestuarii to assess environmental pollution in the Lagoon of Venice (Italy)

“…Biomarkers, defined as quantitative measures of changes at various biological levels indicative of exposure to pollutants, have been proposed as sensitive tools for measuring biological effects in environmental quality assessment (McCarthy and Shugart 1990). In addition, since organisms are exposed to a multiplicity of chemical and physical stresses in field conditions, a multibiomarker approach is now deemed the most suitable strategy for more exhaustive evaluations in biomonitoring studies (Hagger et al 2006). The use of a suite of biomarkers is an appropriate procedure for studying a complex environment such as the Lagoon of Venice (Italy).…”

“…A moderately mobile sentinel species, the crab Carcinus aestuarii, was also considered with the purpose of comparing both single sites and the larger northern and southern areas. Among aquatic organisms, although fish and molluscs have been widely used in biomonitoring programmes (see Hagger et al 2006 for a review), there is a general lack of studies on crustaceans, particularly crabs (Elumalai et al 2007;Martin-Diaz et al 2005). However, crabs are valuable sentinel organisms, since they are ubiquitous in the Lagoon, able to accumulate contaminants both from water and different kind of food and often reach contamination levels higher than those of other organisms, such as mussels (Micheletti et al 2007).…”