Gillian Glegg

Multi-variate analysis of biomarker responses in Mytilus edulis and carcinus maenas from the Tees Estuary (UK)

Abstract A suite of six biomarkers was measured in shore crabs (Carcinus maenas) and mussels (Mytilus edulis) deployed at, or native to, the Tees Estuary in north-east England, as well as at several control sites. LC-50 tests on water samples from the field sites were carried out using the marine copepod Tisbe battagliai and Microtox™ assays. Biomarker responses varied among the sites. Results were analysed using novel multivariate statistical procedures. A clearer overall picture was obtained from multi-dimensional scaling plots than by examining the data for different biomarkers individually. It was possible to distinguish among contaminated and control sites, with the contaminated sites being further differentiated to reflect a pollution gradient. It was concluded that multi-dimensional scaling procedures are a valuable additional tool for improving the analysis and interpretation of complex suites of biomarker data.

Fluxes and retention of trace metals in the Humber Estuary

The Humber Estuary is a physically dynamic system into which industrial wastes contaminated with heavy metals have been discharged for many years. The total fluxes of Cd, Cu, Fe, Ni, Pb and Zn from the Humber Estuary to the North Sea have been estimated for December 1988, May 1990 and August 1990. These fluxes have been compared to inputs into the estuary from rivers, sewage and industry as reported by the Paris Commission. A discrepancy exists between the estuarine inputs and the fluxes to the North Sea, which suggests that the estuary is acting as a trap for fine, metal-contaminated sediments. An alternative approach to flux assessment also indicates that metal retention by sediments is a major feature of the Humber Estuary. The results are discussed in the context of the recovery of the estuary from metal contamination and the consequences for the coastal zone. This critical review allows assessment of effectiveness of current management strategies and new directions for the future to be proposed.

A Systems Approach Framework for the Transition to Sustainable Development: Potential Value Based on Coastal Experiments

This article explores the value of the Systems Approach Framework (SAF) as a tool for the transition to sustainable development in coastal zone systems, based on 18 study sites in Europe, where the SAF was developed and tested. The knowledge gained from these experiments concerns the practical aspects of (a) governance in terms of policy effectiveness, (b) sustainability science in terms of applying transdisciplinary science to social-ecological problems, and (c) simulation analysis in terms of quantifying dysfunctions in complex systems. This new knowledge can help broaden our perspectives on how research can be changed to better serve society. The infusion of systems thinking into research and policy making leads to a preference for multi- issue instead of single-issue studies, an expansion from static to dynamic indicators, an understanding of the boundaries between system-dependent and system-independent problems, and the inclusion of non-market evaluations. It also develops a real partnership among research, management, and stakeholders to establish a quantitative basis for collaborative decision making. Furthermore, the article argues that the transition to sustainable development for coastal systems requires consideration of the scale interdependency from individual to global and recognition of the probable global reorganizational emergence of scale- free networks that could cooperate to maximize the integrated sustainability among them.

The Braer oil spill—Hydrocarbon concentrations in intertidal organisms

The concentrations of non-specific narcotic toxins such as the aromatic hydrocarbons toluene, naphthalene and phenanthrene were determined in specimens of limpets (Patella vulgata) and razor shells (Ensis spp.) collected from Shetland at the time of the Braer oil spill (84 000 t of Gullfaks production crude) and 3, 6 and 15 months after the spill. The analytical methods involved the use of deuterated analogues of the toxins to account for losses of analytes during recovery by steam distillation and determination by cryogenic GC-MS selected ion monitoring of molecular ions. Although the organisms were impacted by oil, the concentrations of total determinants in dead razor shells collected just after the oil spill were below the tissue effective concentrations for 50% reduction in filtering activity (TEC50) for mussels (the most valid toxicological data available for comparative purposes). A portion of the unresolved monoaromatic hydrocarbons of Gullfaks crude would probably add to the burden of toxins, but this was not measured in this study. The distribution of aromatic hydrocarbons in the organisms (phenanthrenes > naphthalenes > toluene) was the reverse of that in the oil and correlates with the expected bioconcentration behaviour of hydrophobic organics whereby less water soluble compounds with higher octanol-water partition coefficients are concentrated. Concentrations of naphthalene to methylphenanthrenes in limpets collected in January at the time of the spill from sites close to the wreck were well below the TEC50 values for mussels but comparison with the lower concentrations in limpets from a more remote site in Shetland indicated that the oil had impacted organisms near to the spill, consistent with intertidal survey data. Comparison with limited literature data for limpets and more extensive data for mussels also supported this conclusion, as did the identification of the oil residues in the limpets by biomarker fingerprinting. As with the razor shells, bioconcentration of the more hydrophobic compounds was observed. Concentrations in Shetland limpets generally decreased with increasing distance from the spill site. Concentrations of aromatic hydrocarbons decreased with time after the spill, such that by July concentrations were at what can reasonably be assumed to be background levels, comparable to the concentrations found at all times in the more remote site. Concentrations in a limited number of samples collected 15 months after the spill, following a further winter of storms in which sediment-sorbed oil could have been reintroduced to the limpets, showed no increase.

Zn and Cu removal kinetics in Estuarine waters

The time-dependent removal of dissolved Zn and Cu in the presence of suspended particles has been studied in the laboratory using conditions closely resembling the aquatic environment encountered in the Tamar Estuary. The metals were removed from both river water and low salinity waters and the uptake profiles were of an exponential form. The removal profiles were interpreted in terms of a reversible, heterogeneous, pseudo-first order reaction, for which the forward and reverse rate constants were evaluated. The forward rate constants for Zn were salinity dependent and varied between 0.08 h −1 and 0.61 h −1 . In contrast, the rate constants for Cu ranged from 0.10 h −1 to 0.75 h −1 and in freshwater they were dependent on the suspended particle concentration. The reaction response times, τ resp (defined as the time for the attainment of 63% of a new equilibrium), were 1 to 10 h for Zn and 1 to 8 h for Cu. These values were compared with calculated flushing times of the Tamar Estuary and a new interpretation of field observations of the non-conservative behaviour of dissolved Zn and Cu in the Tamar Estuary was evolved.

Persistence and metallic composition of paint particles in sediments from a tidal inlet.

Concentrations of Cu, Pb, Sn and Zn have been determined in sediment (<500 μm) and macroscopic paint particles (>500 μm) retrieved from sections of two cores collected from a tidal inlet of the Plym estuary, southwest England. Paint particles contributed up to about 0.2% of the total mass retrieved from each section and were most abundant towards the base of the cores where, according to (210)Pb dating, deposition took place about a decade prior to sampling. Metal concentrations in the paint particles pooled from the sections were highly variable, typically spanning two orders of magnitude in each core, and were greatest for Cu and Zn (up to 460,000 and 170,000 μg g(-1), respectively) due to their use in contemporary antifouling formulations applied to boat hulls. Concentrations of metals in the sediment were, however, relatively invariant, an effect attributed to the abundance and dispersion of microscopic paint particles throughout the cores.

Surface areas and porosities of particulate matter in turbid estuaries

A vacuum microbalance technique has been used to determine the specific surface areas and porosities of suspended solids and sediments from two turbid estuaries. In the Tamar Estuary, the suspended solids had specific surface areas in the range 8–20 m2 g−1 whereas the sediments were in the range 5–15 m2 g−1. Sediments from the iron-rich system of Restronguet Creek were in the range 5–26 m2 g−1. The specific surface areas and porosities of the particles were influenced by the carbon and non-detrital iron contents. The results are relevant to sorption behaviour of dissolved trace constituents in the presence of natural particles.

Contamination of limpets (Patella vulgata) following the Sea Empress oil spill

Abstract Following the grounding of the Sea Empress oil tanker at the entrance to Milford Haven, UK, in February 1997, samples of limpets ( Patella vulgata ) were collected from local coastal sites (after 2 weeks and 4 and 7 months) and analysed for oil contamination. Initially, relatively high concentrations of volatile two and three ring aromatic hydrocarbons (up to 86 μg g −1 dry weight) were found which decreased by orders of magnitude between surveys. These results are compared with a similar study of the Braer oil spill which show a similar rapid decrease in concentrations of volatile hydrocarbons while loss of heavier components is slower. An assessment of the non-volatile fingerprint sterane hydrocarbons showed limpet samples to be contaminated with hydrocarbons but was inconclusive about the source of those hydrocarbons. Another common fingerprint, the pristane: phytane ratio was investigated but this was found to be masked by the presence of natural biogenic compounds.

Intra- and inter-estuarine variability of particle microstructure

Abstract A systematic study has been made of the particle microstructure and chemical composition of suspended solids from large U.K. estuaries (Humber, Mersey, Tamar) and a German estuary (Elbe). The mean specific surface areas of the suspended solids were in the sequence Elbe (25.6 m2 g−1) = Humber (24.0 m2 g−1) > Tamar (14.9 m2 g−1) > Mersey (9.6 m2 g−1). In addition, the Elbe, Humber and Tamar estuaries had higher specific surface areas in the very low salinity, turbidity maximum zone. There was no evidence of similar effects in the Mersey Estuary. These differences in specific surface areas (and hence the heterogeneous chemical reactivity of the particles) are interpreted in terms of the relative proportions of carbon to iron and manganese in the samples. Thus, the high specific surface area in the Humber is associated with a C/Fe + Mn ratio of 4, whereas that for the Mersey is about 11. The implication of these results is that the surface chemical composition determines the particle reactivity and where adsorbed ions are ultimately located on the particle (i.e. either on the surface or in the internal pore structure). This finding is discussed in the context of the uptake of dissolved constituents and the potential for irreversible adsorption.

The use of monitoring data for identifying factors influencing phytoplankton bloom dynamics in the eutrophic Taw Estuary, SW England

Using the Taw Estuary as an example, data routinely collected by the Environment Agency for England and Wales over the period 1990-2004 were interrogated to identify the drivers of excessive algal growth. The estuary was highly productive with chlorophyll concentrations regularly exceeding 100 microg L(-1), mostly during periods of low freshwater input from the River Taw when estuarine water residence times were longest. However, algal growth in mid estuary was often inhibited by ammonia inputs from the adjacent sewage treatment works. The reported approach demonstrates the value of applying conventional statistical analyses in a structured way to existing monitoring data and is recommended as a useful tool for the rapid assessment of eutrophication. However, future estuarine monitoring should include the collection of dissolved organic nutrient data and targeted high temporal resolution data because the drivers of eutrophication are complex and often very specific to a particular estuary.