Integrated hazard, risk and impact assessment of tropical marine sediments from Tema Harbour (Ghana).

The potential ecological hazard, risk and impact of tropical marine sediments from the Tema Harbour (Greater Accra, Ghana) was investigated by integrating Corophium volutator and Hediste diversicolor whole-sediment toxicity bioassays with data on the metals (Cd, Pb, Cr, Ni, Cu, Zn and As) concentrations of the sediments. The whole-sediment toxicity bioassay results showed that sediments of the Tema Harbour are potentially hazardous to marine benthic invertebrates. C. volutator exhibited a higher vulnerability to the sediment toxicity than H. diversicolor, although the latter showed higher biota-sediment accumulation factors for the investigated metals. Statistically significant correlations were observed between C. volutator mortality and sediment Cd concentration (r = 0.84, p < 0.05; n = 6) and between H. diversicolor mortality and sediment Cu concentration (r = 0.94, p < 0.05; n = 5). Comparison of metal concentrations with international action levels for contaminated sediment disposal indicates that the Tema Harbour sediments contain potentially hazardous concentrations of Cu and Zn. This study shows that sediments from the Tema Harbour are not suitable for disposal at sea without remediation. There is, therefore, a need to improve environmental management and regulate the disposal of dredged material originating from the Tema Harbour.

Expert opinion on toxicity profiling--report from a NORMAN expert group meeting.

This article describes the outcome and follow-up discussions of an expert group meeting (Amsterdam, October 9, 2009) on the applicability of toxicity profiling for diagnostic environmental risk assessment. A toxicity profile was defined as a toxicological "fingerprint" of a sample, ranging from a pure compound to a complex mixture, obtained by testing the sample or its extract for its activity toward a battery of biological endpoints. The expert group concluded that toxicity profiling is an effective first tier tool for screening the integrated hazard of complex environmental mixtures with known and unknown toxicologically active constituents. In addition, toxicity profiles can be used for prioritization of sampling locations, for identification of hot spots, and--in combination with effect-directed analysis (EDA) or toxicity identification and evaluation (TIE) approaches--for establishing cause-effect relationships by identifying emerging pollutants responsible for the observed toxic potency. Small volume in vitro bioassays are especially applicable for these purposes, as they are relatively cheap and fast with costs comparable to chemical analyses, and the results are toxicologically more relevant and more suitable for realistic risk assessment. For regulatory acceptance in the European Union, toxicity profiling terminology should keep as close as possible to the European Water Framework Directive (WFD) terminology, and validation, standardization, statistical analyses, and other quality aspects of toxicity profiling should be further elaborated.

Toxicity profiling: An integrated effect-based tool for site-specific sediment quality assessment.

A toxicity profile is a toxicological "fingerprint" of an environmental sample, obtained by testing its extract in a battery of bioassays. Each represents a different mode of action. The present work explores the applicability of in vitro toxicity profiles as an effect-based tool for sediment quality assessment. For this purpose, a previously published dataset was used, in which sediment extracts from 15 different locations in the Rhine-Meuse estuary were tested in 5 different bioassays. Three useful approaches could be distinguished for applying toxicity profiles in sediment quality assessment. In the first approach, toxicity profiles are translated into hazard profiles, indicating the relative distance to the desired or acceptable sediment quality status for each toxic mode of action. Hazard profiles can be considered as location-specific characteristics; sampling locations with similar hazard profiles can be classified into clusters. This approach seems directly applicable but requires a very careful selection of a reference toxicity profile that is either measured at a reference location or is designated as a desirable or acceptable toxicity profile for that particular location. In the second approach, toxicity profiles are translated into ecological risk profiles indicating for each toxic mode of action the ratio between the actual measured bioassay response and the bioassay response level that is considered safe for environmental health. This approach has a high ecological relevance but is only feasible for a few modes of action for which toxicity data are available at the ecological level of population or higher that allow derivation of ecologically safe bioassay responses for sediment extracts. In the third approach, toxicity profiles and their derived hazard profiles are used to select samples with unusually or unexpectedly high bioassay responses for further in-depth effect-directed analysis (EDA). EDA is a powerful strategy to identify emerging compounds that contribute significantly to the toxic load on the environment. EDA is an expensive and laborious strategy, however, making it currently suitable only for investigative monitoring on a limited scale and not for routine monitoring. Future perspectives in toxicity profiling include expansion of the battery of bioassays with test methods that cover other toxic endpoints or multiple endpoints, are high throughput, and improve the ecological relevance.

A weight-of-evidence approach to assessing the ecological impact of organotin pollution in Dutch marine and brackish waters; combining risk prognosis and field monitoring using common periwinkles (Littorina littorea).

In the present study an integrated ecological risk assessment based on multiple lines of evidence (LOEs) was evaluated in order to better assess the risk from TBT in Dutch harbours and open coastal waters. On the basis of spatial distributions of measured tributyltin (TBT) concentrations in sediments and suspended matter, predictions of the intersex index (ISI) in Littorina littorea and the ecological risk expressed as the Potentially Affected Fraction (PAF) of species were made. The results were compared to actual ISI measurements and presence of L. littorea in the field. The PAF calculated on the basis of TBT levels for open coastal waters ranged from 4.2% to 15.3%; for harbours it ranged from 3.5% to 26.9%. Significant intersex levels were observed only in waters where the risk was calculated above 10% PAF. This study suggests that the absence of L. littorea from some harbours with high ecological risk values can be explained by high TBT concentrations. A call is made for the use of integrated approaches like weight-of-evidence (WOE) to help practitioners improve ecological risk assessment.