Bioavailability, accumulation and effects of heavy metals in sediments with special reference to United Kingdom estuaries: a review

Trace metal behaviour in estuarine and riverine floodplain soils and sediments: A review

Aquatic surface chemistry: Edited by Werner Stumm. Wiley, New York. 1987. $69.95 (ISBN 0471822951)

Historic and ongoing sediment contamination adversely affects estuaries, among the most productive marine ecosystems in the world. However, all estuaries are not the same, and estuarine sediments cannot be treated as either fresh or marine sediments or properly assessed without understanding both seasonal and spatial estuarine variability and processes, which are reviewed. Estuaries are physicochemically unique, primarily because of their variable salinity but also because of their strong gradients in other parameters, such as temperature, pH, dissolved oxygen, redox potential, and amount and composition of particles. Salinity (overlying and interstitial) varies spatially (laterally, vertically) and temporally and is the controlling factor for partitioning of contaminants between sediments and overlying or interstitial water. Salinity also controls the distribution and types of estuarine biota. Benthic infauna are affected by interstitial salinities that can be very different than overlying salinities, resulting in large-scale seasonal species shifts in salt wedge estuaries. There are fewer estuarine species than fresh or marine species (the paradox of brackish water). Chemical, toxicological, and community-level assessment techniques for estuarine sediment are reviewed and assessed, including chemistry (grain size effects, background enrichment, bioavailability, sediment quality values, interstitial water chemistry), biological surveys, and whole sediment toxicity testing (single-species tests, potential confounding factors, community level tests, laboratory-to-field comparisons). Based on this review, there is a clear need to tailor such assessment techniques specifically for estuarine environments. For instance, bioavailability models including equilibrium partitioning may have little applicability to estuarine sediments, appropriate reference comparisons are difficult in biological surveys, and there are too few full-gradient estuarine sediment toxicity tests available. Specific recommendations are made to address these and other issues.

https://setac.onlinelibrary.wiley.com/doi/pdf/10.1002/etc.5620200102

Assessing sediment contamination in estuaries.

Polychaetes are usually the most abundant taxon in benthic communities and have been most often utilized as indicator species of environmental conditions. This review finds that, while the use of indicator species for a particular pollutant is not simple, polychaetes can provide a useful means of assessing the effects of poor environmental conditions. Polychaetes may be used as sensitive monitors of water quality especially in terms of the effects of pollutants on life history characteristics. They may also be utilized as general indicators of community diversity but those species indicative of lower diversity may differ geographically and temporally. While sewage is often a mixture of high organic material and other pollutants such as heavy metals and pesticides, high organic situations associated with aquaculture facilities indicates that members of the Capitella capitata species complex and the dorvilleid genus Ophryotrocha are often dominant. Some species of polychaetes are able to live in sediments very high in trace metal content and body burden of these metals often does not reflect sediment concentrations due to regulation by these species. Many species seem relatively resistant to organic contaminants and pesticides and the effects of these pollutants on life history characteristics of these species may provide a more sensitive assay method. Recent studies using biomarkers in polychaetes to indicate general heavy metal or pesticide contamination has shown some success. Polychaete species known to occur in appreciable densities in the Gulf of Nicoya, Costa Rica, and which have been most often used as indicator species of pollution, are listed as potential taxa for environmental monitoring in this tropical estuary. Rev. Biol. Trop. 56 (Suppl. 4): 11-38. Epub 2009 June 30.

https://revista-ciencia-tecnologia.ucr.ac.cr/index.php/rbt/article/download/27162/27262

The use of polychaetes (Annelida) as indicator species of marine pollution: a review

Complexation reactions with ligands in solutions1 and on solid surfaces2–4 are essential features of the biogeochemical cycling of trace metals such as cadmium5 Field studies6–8 and laboratory experiments8–11 show that cadmium can be mobilized from riverine participate matter when river water mixes with sea water Although this mobilization is often attributed to the formation of cadmium chloro complexes in solution6,9,11, the role of these competitive complexation processes has not been quantified Moreover, there is controversy concerning the reversibility of the interaction of cadmium with particulates11–13, which is an essential factor controlling the amount of cadmium that can be mobilized Here we report the results of laboratory experiments and equilibrium calculations which demonstrate that cadmium partition between suspended particles and solution is completely reversible, and that complexation reactions in solution can completely account for the amount of cadmium released from suspended particles Apparently, this toxic metal is not irreversibly fixed on particles, but can be released in response to changes in the aquatic environment This may have important implications for the bioavailability of particle-bound cadmium

Clemens Van Dijk

Papers

Role of complexation processes in cadmium mobilization during estuarine mixing

Controls On Illite Cementation In Unayzah Sandstones, Saudi Arabia: Mineralogy, K-Ar Dating, Numerical Modeling, and Hydrothermal Experiments

Adsorption/desorption behaviour of cadmium on natural suspended particles under fresh water conditions and at increased salinity

Mapping solid reservoir bitumen by deconvoluting formation mechanism