Changes in Valued "Capacities" of Soils and Sediments as Indicators of Nonlinear and Time-Delayed Environmental Effects

This paper discusses the buffering, oxygen-donating, and sorption capacities of soils and sediments as an inter-connected system for regulating the retention and release of chemical pollutants. In this context, the author discusses the chemical conditions under which sediments may serve as a source or a sink for toxic materials, and conditions under which soils may retain or release them. It is demonstrated that nonlinear, time-delayed ecological transformations in soils and sediments often can be understood in terms of the interlinked system. The author discusses some possible future long-term environmental problems that might beset Europe, and some implications for a monitoring strategy for foreseeing such problems. Because the release of adsorbed toxic chemicals from heavily polluted sediments and soils can occur suddenly owing to changes in oxygen status (i.e., redox potential) or acidity, strategies for preventing the long-term release of such materials should not only consider current conditions of pH and redox potential, but also, how those conditions might change in the future

Trace metal chemical speciation and acute toxicity to Pacific oyster larvae

Access to the full-text thesis is no longer available at the author's request, due to 3rd party copyright restrictions. Access removed on 28.11.2016 by CS (TIS).Metadata merged with duplicate record (http://hdl.handle.net/10026.1/2252) on 20.12.2016 by CS (TIS).Controlled laboratory studies showed that the toxicity induced by biologically relevant trace metal species of Cu, Cd, Pb and Zn on embryo-larval development occurred at concentrations in excess of those found in the natural environinent, except for Cu in metal perturbed areas. Average free ion concentrations inducing 50% abnormal development( EC50feew) ere determineda s 0.23 nM CU2+8, 8.0 rim Cd2+,1 28 nM Zn2+a nd 3 62 nM Pb 2+ . However, the response to some binary metal combinations indicated enhanced (synergy) toxicity at concentrations relevant for estuarine waters (e. g. EC5of'. for Cu2+i n the presenceo f C(ý: +, Zn2+a nd Pb2 +w as 0.004,0.02 and 0.04 nM, respectively). A comparison of voltarnmetric instrumentation (voltammetric in situ profiling (VIP) system versus Hanging Mercury Drop Electrode with potentiostat) highlighted the advantage of high resolution measurements (ca. 20-60 min intervals) for environmental studies and the minimisation of artefacts associated with discrete sampling methodologies. Field-based studies were carried out in two contrasting estuaries in SW England, one heavily impacted with metal contaminants (Fal Estuary) and another subject to greater variety of anthropogenic influences (Tamar Estuary). High resolution in situ trace metal speciationm easurementsc, arried out over tidal cycles, identified important information on the temporal and spatial distributions of biologically relevant dynamic (<4 nm) metal species of Cd, Pb and Cu. Variation in embryo-larval responses to discrete samples from these estuaries, effectively paralleled the metal speciation measurements showing enhanced toxicity when the marine water influence was at its lowest. In both systems, the results indicated that the combined effect of the metals studied was likely to have provided a significant contribution to the bioassay response. However, the difficulty in de-coupling the speciation measurements with biological responses was evident and supports the need for more comprehensive campaigns to study the impact of contaminants on ecosystem functioning. Bioassay and metal speciation analysis techniques were complementary, exhibiting high sensitivity and rapid responses, and would be considered effective screening tools for waters subject to intermittent inputs of metal contaminants and areas with recognised pressures. The integrated approach has extended our knowledge of trace metal speciation in estuarine environments and their effects on the developing embryos of the Pacific oyster. This approach has the potential for wider application

Heavy Metal Contamination from Landfills in Coastal Marine Sediments: Kiribati and New Zealand.

Landfill leachates are a concern in the Pacific Region where they may contribute contaminants to the coastal marine environment. Poor waste management and pollution of coastal waters are amongst the major environmental problems in Kiribati, particularly in South Tarawa. An investigation of areas adjacent to coastal landfill sites; Betio, Kiribati and Auckland, New Zealand was undertaken. The Kiribati case study investigated metal contamination in marine sediments at an operational landfill while the New Zealand study was adjacent to a coastal landfill decommissioned in the 1970s. Surficial sediments (top 15 cm) were collected along transects. At both the New Zealand and Kiribati sites, 3 transects adjacent to the landfill and 1 control transect were sampled. The sediments were analyzed for particle size distribution, organic matter content, and Cd, As, Cr, Cu, Pb, Hg, Ni and Zn concentrations. The pH was also measured. The Kiribati study site had a groundwater pH of 7.14 - 8.85, and sediment materials were dominated by sand with a low organic matter content (1.60 - 2.21 %). At the Kiribati sites Cd, As, and Ni were below the detection limits. The Cr, Cu, Pb and Zn concentrations were lower at the Kiribati control transect than the landfill transects. Cr level decreased away from the landfill indicating the landfill as a possible source. However, Cu and Zn did not show any distribution pattern suggesting other potential sources (port and shipwrecks) may have contributed to the elevated levels. At the Kiribati landfill and control transects the Cr, As, Cd, Cu, Pb, Ni, and Zn concentration were below the Effects Range-Low (ERL) and the threshold Effects levels (TEL) of the Sediment Quality Guidelines (SQCs) of the National Oceanographic and Atmospheric Administration (NOAA) and the Florida Department of Environmental Protection, indicating no potential adverse ecological effects on the biota. At the Kiribati control site the Cr, As, Cd, Cu, Pb, Ni and Zn concentrations were within the background ranges published for clean reef sediment but the concentration at the landfill transects exceeded the background ranges. The concentration of mercury at both the control and landfill transects in Kiribati exceeded the Effects Range-Median (ERM) and the Probable Effects Level (PEL) of the SQGs indicating potential adverse ecological effects on the local benthic communities. The New Zealand study site sediments had a pH of 6.22 - 7.24, and comprised up to 90 % clay/silt, with an organic matter content of 5 - 22 %. At the New Zealand landfill transects Arsenic concentrations decreased away from the landfill indicating the landfill as a possible source. Other metals such as Cr did not show a pattern of distribution along the transects, or with depth, suggesting that the landfill was not the only source of these metals. There was a weak correlation between organic matter content, particle size distribution, and metal enrichment. At the New Zealand site, there were no marked differences in metal concentrations between the landfill and control transects suggesting the landfill was not the only source of metals and that the wider urban or industrial run-off may have contributed. All the metal concentrations, except Hg and Zn, exceeded the ERL and the TEL values indicating the potential for adverse ecological effects of metals on the benthic communities. At the New Zealand site the Hg and Zn concentrations exceeded both the ERM and PEL of the SQGs and are considered highly contaminated

Toxic Pollution in Casco Bay: Sources and Impacts

This report complements and expands upon the information in the 2005 Casco Bay Estuary Partnership report State of the Bay. This current report, Toxic Pollution in Casco Bay, details studies undertaken by Casco Bay Estuary Partnership (CBEP) and others on some of the sources of toxic chemicals entering the Bay and its watershed, on the impacts of toxic chemicals on Casco Bay wildlife, and on potential risks to human consumers of fish and shellfish. The report does not, however, address groundwater pollution and drinking water issues. The report conludes with ways that CBEP and partner organizations are working to reduce the loading of toxic chemicals to the Bay and its watershed

Volunteer Estuary Monitoring

This online method manual from EPA describes how to conduct estuary monitoring programs, with step-by-step guides for chemical, physical and biological sampling and data interpretation. Also describes how to plan and maintain a volunteer force, with tips on liability and financial issues, volunteer recruiting training and retention. Addresses quality assurance so that results have weight. Provides an overview of estuarine science, threats to estuaries and some solutions. Educational levels: General public, High school

Spatial and temporal variability of trace metal concentrations and speciation in Connecticut surface waters

In this research, two studies were conducted to investigate the spatial distribution and seasonal variation of trace metal concentrations and speciation in Connecticut surface waters. In the first part, along with the monthly vertical profile of background biogeochemistry parameters (pH, Temperature, Dissolved oxygen, Major ions, Total dissolved solids, Nutrients, Acid neutralizing capacity, dissolved organic carbon), competitive ligand exchange – adsorptive cathodic stripping voltammetry was used to determine cobalt speciation in Linsley Pond, North Branford. Vitamin B12 (VB12) via enzyme-linked immunosorbent assay (ELISA) was measured in an American stratified lake for the very first time. During summer stratification, the patterns of Co and Mn are similar, very low in surface water, and reach the highest concentration across the redoxcline caused by the bacterial activity of PSB. The different patterns of Co in the hypolimnion between 2017 and 2018 are caused by the formation of CoS. Higher epilimnetic particulate Co is observed in July and August, corresponding to the highest DO and DOC, respectively, indicating that cobalt is closely related to the photosynthesis of phytoplankton, the metabolism of organisms. Total dissolved Co was dominated by its natural organic ligand complex. The measured VB12 ranged from 0.033 – 0.048 nM, comparable to [Co2+] detected in freshwater systems. In the second part, an estuary with self-regulating tide gates (SRTGs) installed was studied about the combination of watershed flood flow and tidal flushing impact at both short and long time scales. The cycling of particle-reactive contaminants represented by the metals was studied over the course of several tidal cycles during both baseflow and storm event conditions. TSS and turbidity were highly correlated at the inlet but not consistently at the tide gates. In contrast, at the tide gates, TSS was dominantly affected by tides unless extreme storms. Cobalt and 7Be budgets over one tidal cycle were determined. Cobalt was mostly in the dissolved form at the tide gates and the inlet, under baseflow conditions. However, particulate Co became the dominant component of total Co at the inlet during storm events, contributed by sediments delivered from the watershed. According to the 7Be mass balance over a tidal cycle, perhaps owing to the large ratio of its watershed to estuary, most of the 7Be (86%) enters the West River estuary from its watershed. Direct atmospheric deposition is a significant but lesser source. In addition to 3% decay in the water column, only 1.5% of 7Be is gained from Long Island Sound via tidal flushing. More than 40% of added 7Be is deposited in sediments within the estuary during a single tidal cycle, meanwhile, Co received from the watershed (ca. 60 g) is approximately equal to the net loss of Co by the tidal exchange. The West River estuary is a tight trap for contaminants that behave like Be, but not for Co or probably other substances that are not strongly particle reactive as well

In Situ Contaminated Sediments Project – Work Package 1A Report

Project aims Defra is seeking to understand the magnitude of risks (e.g. to aquatic ecology and human health) or impacts (e.g. on the way that water bodies are managed) posed by contaminated sediment in England, as part of its work towards meeting its environmental objectives. In the context of this project, in-situ contaminated sediment is defined as: Chemically contaminated sediment within the water column, bed, banks and floodplain of a surface water body that has been transported alongside the normal sediment load and deposited by fluvial or coastal processes. This project considers the risk posed by non-agricultural diffuse pollution sources in England that result in the contamination of in-situ sediments (for example, contamination from toxic metals, hydrocarbons and surfactants). The scope encompasses both freshwater and marine sediments in England and extends to one nautical mile off-shore (the seaward limit of coastal waters under the Water Framework Directive (WFD) in England). Previous national strategies, including the 2007 Defra UK Strategy for Managing Contaminated Marine Sediments (CDMS), focussed on characterising the risks associated with contaminated sediments in the marine environment. However, while extensive research has been carried out in many locations (including as part of WFD implementation studies) and for particular sources of contamination (e.g. historical metal mining; Environment Agency, 2008) there has not been a comprehensive overview of sediment contamination on a national scale. This project seeks to build on the existing evidence base, drawing together information on the freshwater environment to complement that already gathered for marine waters. This project’s overall aim is to provide a sound evidence base on the contamination of in-situ sediments, which can underpin the development of tools and methods that will help Defra, the Environment Agency and other bodies engaged in regulation and protection of water quality