In urban areas, a highly variable mixture of pollutants is deposited as particulate matter. The concentration and bioavailability of individual pollutants within particles need to be characterised to ascertain the risks to ecological receptors. This study, carried out at two urban parks, measured the deposition and water-solubility of metals to four species common to UK urban areas. Foliar Cd, Cr, Cu, Fe, Ni, Pb and Zn concentrations were elevated in at least one species compared with those from a rural control site. Concentrations were, however, only affected by distance to road in nettle and, to a lesser extent, birch leaves. Greater concentrations of metal were observed in these species compared to cypress and maple possibly due to differences in plant morphology and leaf surfaces. Solubility appeared to be linked to the size fraction and, therefore, origin of the metal with those present predominantly in the coarse fraction exhibiting low solubility. High density traffic resulted in elevated metal concentrations on vegetation, which were related to distance from road and plant species.

Particles of spent antifouling paint collected from a marine boatyard were ground and subsequently administered to the filter-feeding bivalve, Mytilus edulis, maintained in static aquaria. Concentrations of Cu and Zn were measured in seawater throughout a 16 h feeding phase and a 24 h depuration phase, in rejected and egested particles collected during the respective phases, and in the organisms themselves at the end of the experiments. Concentrations and distributions of Cu and Zn in processed particles indicated that M. edulis was able to ingest paint particles, regardless of whether nutritionally viable silt was present, and no mechanism of particle discrimination was evident. Enrichment of Cu and Zn in the visceral mass of individuals and in the aqueous phase during depuration supported these assertions, although elevated concentrations in other compartments of the organism (e.g. shell, gill) suggested that biotic and abiotic uptake of aqueous metal was also important. Particles of antifouling paint enriched in Cu and Zn are ingested and digested by the marine bivalve M. edulis.

Industrial activity such as burning of fossil fuels produces magnetically enhanced particulates. These particulates consist of coarse-grained multidomain and stable single domain magnetic minerals. Two threshold values of low field magnetic susceptibility (XLF) and frequency dependent susceptibility percentage (XFD%) discriminate ferrimagnetic minerals of these sizes and can act as a tracer of magnetic pollution. Application of the thresholds to a magnetic topsoil data set (n = 5656 across England and Wales) revealed 637 samples potentially dominated by pollution particulates. The magnetic parameters of these samples display a negative correlation with distance to urban areas and positive correlations with metals associated with anthropogenic activity (Cu, Pb, and Zn). Results of experimentation with threshold values and modelling of magnetic anomalies suggest that regional factors such as geology and potential for pedogenic secondary magnetic enhancement should be considered when setting threshold values.

Pteris vittata plants were grown on twenty-one UK soils contaminated with arsenic (As) from a wide range of natural and anthropogenic sources. Arsenic concentration was measured in fern fronds, soil and soil pore water collected with Rhizon samplers. Isotopically exchangeable soil arsenate was determined by equilibration with 73AsV. Removal of As from the 21 soils by three sequential crops of P. vittata ranged between 0.1 and 13% of total soil As. Ferns grown on a soil subjected to long-term sewage sludge application showed reduced uptake of As because of high available phosphate concentrations. A combined solubility-uptake model was parameterised to enable prediction of phytoremediation success from estimates of soil As, 'As-lability' and soil pH. The model was used to demonstrate the remediation potential of P. vittata under different soil conditions and with contrasting assumptions regarding re-supply of the labile As pool from unavailable forms. This paper presents a predictive model for phytoremediation of soils, historically contaminated with arsenic, by the hyperaccumulator P. vittata.

A series of European Marine Sites has been designated as Special Areas of Conservation (SAC) in England. The aim of this study was to develop a practical methodology to assess the condition of SACs by applying a suite of biomarkers. Biomarkers were applied to the blue mussel Mytilus edulis and the shore crab Carcinus maenas from the Fal and Helford SAC (Cornwall). Individual biomarkers provided useful diagnostic information on the activity of certain classes of contaminants and an integrated Biomarker Response Index (BRI) was used to achieve a more holistic understanding of the condition of the SAC. The BRI indicated that the general health of both organisms was impacted in the upper part of the SAC (Fal Estuary) which correlated well with known chemical hotspots and sources of contamination. The BRI allows a pragmatic way to prioritise SAC sites that may require further investigative studies. A suite of biomarkers was successfully used to create a Biomarker Response Index to assess the health of aquatic organisms from European Marine Sites.

Compost enriched with inorganic amendments has been evaluated in laboratory-based experiments for its effectiveness to immobilise heavy metals in contaminated soils. This paper reports the results pertaining to copper (Cu) and cadmium (Cd) only. The inorganic amendments used were naturally occurring zeolite-Clinoptilolite and synthetic iron oxide (Fe₂O₃). A series of experiments have been performed on the amended soils and the results demonstrated that a combination of compost/iron oxide was effective in reducing the uptake of Cu in rye grass (Lolium perenne L.) whereas compost/iron oxide as well as compost/zeolite mixture was effective for reducing Cd uptake. The amended compost performed better in re-vegetating contaminated soil compared to compost or amendments alone. The sequential extraction of the control sample showed that major fraction of both Cu and Cd were associated with organic fraction indicating that the metals might be available to plants under oxidising conditions of soil. The percentage of Cu in the control sample associated with different fractions was in the following order: Organic > Residual > Reducible > Exchangeable fraction whereas for Cd it was: Organic > Reducible > Residual > Exchangeable. The sequential extraction of amended soils showed that exchangeable Cu decreased by 50% to 92% compared to the control. An increase in residual fraction of Cd (up to 40%) was observed in the amended soils. It was concluded that zeolite and/or iron oxide enriched compost can be used effectively for immobilising Cu and Cd in contaminated soils. The effect of amended compost on other metals should be taken into consideration for real field applicaitons.