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Sydney estuary catchment supports the largest city in Australia and provides essential eco-social and environmental services; however, the region has been influenced by extensive anthropogenic modification. Soil metal concentrations in the catchment had been studied previously; however, the current investigation was designed to determine the risk posed by these contaminants to human health. Soil metal concentrations were higher than observed in most global capitals and increased substantially in the south and south-east of the catchment and close to the central business district. Road-side soils and road dust contained the highest concentration of metals in the catchment. Lead in catchment soils was closely related to traffic density and sourced from the historic use of Pb in petrol. A human health assessment indicated that soil Cd, Ni and Zn posed no non-carcinogenic risk (NCR), or carcinogenic risk (CR) for children, or adults in Sydney estuary catchment and that Cu and Cr may pose minor NCR for children. Vehicle-related Pb raised the greatest human health risk in catchment soils and may pose NCR at 32% and 4.3% of sites for children and adults, respectively. Inconsistent analytical techniques used in CR and NCR evaluations produce incomparable assessments and a consistent` methodology is suggested to improve interpretation. Human health risk may well be higher than commonly calculated due to pollutants present in urban soil not being included in assessments. [ABSTRACT FROM AUTHOR]

Narrabeen Lagoon is recognized as an Intermittently Closed and Open Lake or Lagoon (ICOLL) and is the largest coastal lagoon (2.2 km2) in the Sydney metropolitan region. The catchment (53 km2) supports five major river systems, and land use comprises of 56% residential, 42% parkland and 2% light industry, commercial, hospital and education. An initial screening environmental assessment was undertaken using sedimentary metals to determine the magnitude of anthropogenic change and level of ecological risk posed by these contaminants. Results illustrated an unusual example of an estuary significantly influenced by human-induced change, but exhibiting minimal ecological risk. This anomaly was due to high anthropogenic metal concentrations in the fine fraction of surficial sediment, which was considerably diluted by abundant metal-poor coarse material resulting in reduced adverse ecological impact for total sediment. Predictive modelling to 2020 suggested that Pb concentrations will decline and Cu and Zn levels will increase slightly. Modelling of river discharge and analyses of fluvial sedimentary metals suggested stormwater derived from the most urbanized catchments and a major roadway combined with poor flushing explained surficial sediment metal distributions in the lagoon. [ABSTRACT FROM AUTHOR]

A significant correlation between sedimentary metals, particularly the ‘bio-available’ fraction, and bioaccumulated metal concentrations in the native Sydney rock oyster (Saccostrea glomerata) tissues has been successfully demonstrated previously for Cu and Zn in a number of estuaries in New South Wales, Australia. However, this relationship has been difficult to establish in a highly modified estuary (Sydney estuary, Australia) where metal contamination is of greatest concern and where a significant relationship would be most useful for environmental monitoring. The use of the Sydney rock oyster as a biomonitoring tool for metal contamination was assessed in the present study by investigating relationships between metals attached to sediments and suspended particulate matter (SPM) to bioaccumulated concentrations in oyster tissues. Surficial sediments (both total and fine-fraction), SPM and wild oysters were collected over 3 years from three embayments (Chowder Bay, Mosman Bay and Iron Cove) with each embayment representing a different physiographic region of Sydney estuary. In addition, a transplant experiment of farmed oysters was conducted in the same embayments for 3 months. No relationship was observed between sediments or SPM metals (Cu, Pb and Zn) to tissue of wild oysters; however, significant relationship was observed against transplanted oysters. The mismatch between wild and farmed, transplanted oysters is perplexing and indicates that wild oysters are unsuitable to be used as a biomonitoring tool due to the involvement of unknown complex factors while transplanted oysters hold strong potential. [ABSTRACT FROM AUTHOR]

Industrial activities and urbanization have had a major consequence for estuarine ecosystem health and water quality globally. Likewise, Sydney estuary has been significantly impacted by widespread, poor industrial practices in the past, and remediation of legacy contaminants have been undertaken in limited parts of this waterway. The objective of the present investigation was to determine the effectiveness of remediation of a former Pb-contaminated industrial site in Homebush Bay on Sydney estuary (Australia) through sampling of inter-tidal sediments and mangrove ( Avicennia marina) tissue (fine nutritive roots, pneumatophores, and leaves). Results indicate that since remediation 6 years previously, Pb and other metals (Cu, Ni and Zn) in surficial sediment have increased to concentrations that approach pre-remediation levels and that they were considerably higher than pre-settlement levels (3-30 times), as well as at the reference site. Most metals were compartmentalized in fine nutritive roots with bio-concentration factors greater than unity, while tissues of pneumatophores and leaves contained low metal concentrations. Lead concentrations in fine nutritive root, pneumatophore, and leaf tissue of mangroves from the remediated site were similar to trees in un-remediated sites of the estuary and were substantially higher than plants at the reference site. The situation for Zn in fine nutritive root tissue was similar. The source of the metals was either surface/subsurface water from the catchment or more likely remobilized contaminated sediment from un-remediated parts of Homebush Bay. Results of this study demonstrate the problems facing management in attempting to reduce contamination in small parts of a large impacted area to concentrations below local base level. [ABSTRACT FROM AUTHOR]

The spatial and temporal variations of Fe, K, Co, V, Cr, Cu, Ni, Zn, and Pb were determined in the sediments of Taihu Lake, the third largest freshwater lake in China and categorized into natural origin (Fe, K, Co, and V) and human contamination (Cr, Cu, Ni, Zn, and Pb) groups by principal component analysis. Most of the metals were positively correlated with the clay content (<4 μm) and negatively correlated with the >16 μm fraction, indicating the dominant role of grain size in regulating metals concentrations. Geochemical normalization and enrichment factors (EFs) were introduced to reduce the confounding of variable grain size and to quantify anthropogenic contributions. Higher EF values for Cr, Cu, Ni, and Zn occurred in the north Zhushan, Meiliang, and Gonghu Bays, indicating a high level of human contamination from the northern cities, such as Wuxi and Changzhou. Higher EF values of Pb were also present in the southwest and east lake areas, denoting the existence of additional anthropogenic sources. Chrome, Cu, Ni, Zn, and Pb showed increasing EF values in the top layers of sediment cores, indicating enhancing contamination since 1970s with rapid economy development in the catchment. These results indicate that geochemical normalization is a necessary and effective method in quantifying heavy metals contamination, and that historic sediment should be used as background values in calculating EFs. Potential risks of the heavy metals were assessed linking the consensus-based sediment quality guidelines and human contamination. Concentrations of Ni and Cr are greater than the threshold effect concentration (TEC) values, even in the sediments before 1970s, due to higher background concentrations in terrestrial parent materials. Concentrations of Ni and Cr are generally lower than the probable effect concentration (PEC) values, and concentrations of Cu and Zn are below the TEC values in the open lake areas. Whereas, concentrations of Ni and Cr are surpassing the PEC values and Cu and Zn are surpassing the TEC values in the north bays due to the high level of human contamination, where they were with EFs over 1.2, denoting higher potential eco-risks. [ABSTRACT FROM AUTHOR]

We present a sedimentary geochemical record of human perturbation in the watershed and related changes in trace metals (Cr, Ni, Zn and Pb), phosphorus and abundant rock-forming elements (Al, Fe, K, Mg, etc.) in Chaohu Lake over the past 500 years, a period spanning historical agricultural expansion and modern economic development. The record exhibited a stable terrestrial detrital input to Chaohu Lake before ca. 1540 AD, a period with less human perturbation of the watershed, which resulted in low and constant values of trace metals and phosphorus (TP) concentrations as well as Al, Fe, K, Mg, fine silt (<16 μm), the chemical index of alteration (CIA) and K/Na ratio. Two periods of successive marked increases in Al, Fe, K, Mg, fine silt, chemical index of alteration (CIA) and K/Na ratio occurred after ca. 1540 AD and 1950 AD. The former period apparently resulted from enhanced well-weathered topsoil erosion in the watershed related to the expansion of arable land, and the latter resulted from further enhancement of human perturbation in the watershed during the modern period. Concentrations of trace metals and TP were positively correlated with that of the rock-forming elements and fine silt. Trace metal pollution was limited during 1540-1950 AD, according to the low enrichment factors (EFs = 0.8-1.1), when an increase in trace metal concentrations was also linked to changes in detrital input. In addition to detrital regulation, pollution also contributed to an increase in TP concentrations (average EF 1.4) during 1540-1950 AD and the average accumulation rate of anthropogenic phosphorus was 87.3 mg ma. Anthropogenic phosphorus increased further and Pb and Zn pollution also occurred after 1950 AD, reaching maximum values after 1980 AD, when the average accumulation rates of anthropogenic Zn, Pb and phosphorus (mainly in the form of NaOH-P) were 242.2, 43.3 and 811.8 mg ma, respectively. The increase in phosphorus pollution in recent decades is probably from the domestic sewage sources of Hefei City and non-point sources related to agricultural utilization of commercial fertilizer, whereas Zn and Pb pollution is probably derived mainly from industrial sources of Hefei City, as deduced from their spatial variations in the sediments of the river mouths. [ABSTRACT FROM AUTHOR]

Relationships between total suspended solids (TSS) and metals (Cu, Pb and Zn) were tested and compared amongst base and high flows of three urbanised catchments in Sydney Estuary, Australia. Significant relationships between TSS and Cu, Pb and Zn were detected for high flows within each catchment; however, no significant relationship was detected for TSS/Zn and TSS/Cu in one of the creeks (Whites Creek) and for TSS/Zn in another (Hawthorne Canal) in 2010 during base flow. Relationships between metals and TSS also varied significantly in locations of intercept and slope between high and base flow and amongst catchments. Spatial variance in TSS/metal relationships were likely caused by specific anthropogenic activities because land uses, meteorology and geology within the study catchments were similar. Results suggest TSS may be used as a surrogate for estimating metal loading in real time for urban catchments, once relationships between metals and TSS were established for individual catchments and for base and high flow conditions. Moreover, no differences in TSS/metal relationships were detected between 2009 and 2010 in Hawthorne Canal during high flow conditions, suggesting that this method of real-time monitoring may be reliable for assessing Cu, Pb and Zn loads during high flows over inter-annual periods. However, long-term consistency of TSS/metal relationships for base flow may need testing since changes in TSS/Zn and TSS/Cu relationships were detected between 2009 and 2010 in Hawthorne Canal. Although irregular discharges to stormwater did not conform to TSS/metal relationships, irregular discharges may be detected in real time by increased flow during dry weather conditions, which may facilitate regulation of these conditions that currently result in potential environmental harm to aquatic biota in Sydney Estuary. [ABSTRACT FROM AUTHOR]

Stormwater discharged from highly urbanised catchments on the southern shore of Sydney estuary, Australia, has been identified as the primary source of contaminants responsible for ecological degradation and reduction in recreational value of the waterway. Effective management of this pollution requires knowledge of contaminant loads associated with various stormwater flow conditions in three highly urbanised catchments in Sydney estuary catchment. The majority (>90%) of metal (Cu, Pb and Zn) and total suspended solid annual loads were contributed during high-flow conditions (>50 mm rainfall day), whereas ≤55% of TN and ≤21% of total phosphorus were contributed to annual loading by dry weather base-flow conditions. All flow conditions posed an in-stream ecological threat because contaminant concentrations exceeded water quality guidelines for all analytes measured, except Pb. Irregular, temporal variability in contaminant concentrations associated with base-flow (within day and amongst days), high-flow (amongst events) and irregular discharges indicated that contaminant contributions in stormwater were strongly controlled by human activity in the three catchments. Significant variation in contaminant concentrations under all flow conditions revealed unique chemical signatures for each catchment despite similarities in land uses, location and geology amongst catchments. These characteristics indicate that assessment and management of stormwater pollution needs to be conducted on an individual-catchment basis for highly urbanised regions of Sydney estuary catchment. [ABSTRACT FROM AUTHOR]

Total topsoil 50th percentile Cu, Pb and Zn concentrations ( n = 491) in the Sydney estuary catchment were 23 μg g, 60 μg g and 108 μg g, respectively. Nine percent, 6% and 25% of samples were above soil quality guidelines, respectively and mean enrichment was 14, 35 and 29 times above background, respectively. Soils in the south-eastern region of the catchment exhibited highest metal concentrations. The close relationship between soil metal and road network distributions and outcomes of vehicular emissions modelling, strongly suggested vehicular traffic was the primary source of metals to catchment soils. Catchment soil and road dust probably make an important contribution to contamination of the adjacent estuary. The concentration of soil metals followed the land use trend: industrial > urban > undeveloped areas. A high proportion (mean 45%, 62% and 42%, for Cu, Pb and Zn, respectively) of metals in the soils may be bioavailable. [ABSTRACT FROM AUTHOR]

The detailed spatial distribution of atmospheric deposition flux of pollutants in metropolitan Sydney, Australia (ca. 480 km) is investigated through the direct simultaneous sampling of bulk deposition adjacent to roads with various traffic volumes and at background sites over a period of 1 year. Based on the field results and detailed land-use analyses, atmospheric deposition rates of copper, lead and zinc are calculated for the metropolitan region, and the contributions to stormwater pollutant loads are evaluated. Total particulates and heavy metals in bulk atmospheric deposition are found to be temporally consistent, and to exhibit strong correlations with road proximity and traffic volume. The material captured adjacent to major roads has a distinct average composition of 862 mg/kg copper, 364 mg/kg lead and 4,617 mg/kg zinc. Modelling accounting for road proximity, traffic volume and land-use affords annualised stormwater-entrainable depositional fluxes of 6.5, 4.1, 47.2 and 10,800 kg/km/year for copper, lead and zinc. [ABSTRACT FROM AUTHOR]

Purpose: The objective of the current research was to provide a strategy to remediate stormwater from an old, high-developed catchment dominated (94%) by diffuse sources. Contaminated catchment soils, a dense road network and extensive residential development have resulted in degraded sediments in the receiving basin. Retrofitting stormwater remedial devices in such catchment-estuarine systems is difficult, costly and long term. Materials and methods: The metal content of soils, road dust and gully pot deposits was investigated to assess catchment sources. Fluvial input was assessed using loading models and analyses of water and bedload sediments in two canals draining the catchment, whereas 45 surficial samples were collected from the adjacent estuary to determine impact. All materials were digested using aqua regia and analysis was by inductively coupled plasma (ICP) mass spectrometer and ICP plasma atomic emission spectrometer. Sediment quality guidelines were used to make an initial assessment of degradation by single chemicals and the mean ERM quotient approach was used to determined probable toxicity for mixtures of contaminants. An additional 13 samples were subjected to four laboratory ecotoxicological tests. Results and discussion: Soil (mean 62, 410 and 340 μg g for Cu, Pb and Zn, respectively) and sediments (mean 180, 320 and 640 μg g, respectively) in the catchment-estuary system (Iron Cove, Sydney Harbour, Australia) contain greatly elevated metal concentrations. Contaminants associated with baseflow (none, or <5 mm day rainfall) are deposited close to the mouths of two canals discharging to the estuary and this sediment is toxic to benthic animals, whereas chemicals carried by high flow (>50 mm day rainfall) bypass the cove in a buoyant, freshwater plume. Remediation of baseflow and some first-flush stormwater will remove approximately 10% metals and 30-50% TN trapped in the embayment and harvest 2 to 4 ML day of urban water runoff. Conclusions: The current approach provides an opportunity to remove a large proportion of total stormwater-derived metals and TN trapped in the adjacent embayment, inexpensively and rapidly. The scheme will prevent stormwater-related chemicals from being deposited in the waterway where adverse biological risk is highest. The potential for recycling and harvesting enormous volumes of treated stormwater in highly desirable parts of intensely urbanised environments is in keeping with the concept of 'cities as water supply catchments'. [ABSTRACT FROM AUTHOR]

Stormwater modelling indicated an average annual discharge from Sydney estuary catchment of 215,300 mL and loadings of 0.8, 0.5, 1.7, 3.2, 1.1, 3.6 and 17.7 tonnes for As, Cd, Cr, Cu, Ni, Pb and Zn, respectively. Priority for remediation should be given to creeks with high-metal loads in the upper and central estuary, as well as discharging to the western shores of Middle Harbour. Managerial strategies need to target dissolved and particulate metal phases to ensure effective remediation. The proportion of metals discharged under low- (<5 mm rainfall/day), medium- (>5 to <50 mm/day) and high-flow conditions (>50 mm/day) was approximately 10%, 60% and 30% of total loading, respectively. Under high-flow conditions the estuary becomes stratified and most metals are exported to the sea, whereas metals discharged during low-flow may be remediated by infiltration. Effective remediation will depend on the extent to which ‘first-flush’ metals associated with medium-flow conditions can be remediated. [ABSTRACT FROM AUTHOR]

Sydney estuary (Australia) catchment is substantially urbanised (80%) and small (480 km2) with a large population (2.5 million) and is therefore highly sensitive to anthropogenic influence. The Model for Urban Stormwater Improvement Conceptualisation used to model nutrient export to the estuary determined an average annual load of 475 t total nitrogen, 63.5 t total phosphorus and 343,000 t total suspended solids. Model verification included intense, short-term water sampling and analysis undertaken in the current project and use of published data spanning 10 years. Under high-rainfall conditions (>50 mm day − 1), the estuary becomes stratified and nutrients are either removed from the estuary directly in a plume or indirectly by advective/dispersive remobilisation. The majority of the nutrient load is delivered during moderate rainfall (5–50 mm day − 1) conditions and accumulates close to discharge points and remains in the estuary. To significantly reduce nutrient load, management strategies should aim to minimise low and moderate rainfall pollutant loads. [ABSTRACT FROM AUTHOR]

The article explores the application of surficial sediment metal and geographic information system (GIS) to identify anthropogenic change in Lake Macquarie, New South Wales. It forecasts the increase concentration of copper (Cu) in the lake in 2020. Moreover, it cites that the new method provides data on past, present and future conditions which are essential on estuarine system improvement.

This study evaluated the suitability of sealed containers for toxicity testing to prevent loss of volatile chlorinated hydrocarbons (VCHs) with a range of Australian marine organisms including: micro-algae; sea urchin and oyster larvae in 44 mL sealed vials and fish larvae; amphipods; and juvenile polychaetes in 1 L sealed jars. Vials prevented volatilisation of VCHs during testing. Jars were less effective, with average losses of 46%. Growth and development of algae, sea urchins and oysters in vials was acceptable, indicating suitability of the methodology. Jars were suitable for amphipods and polychaetes; however, further evaluation of the fish test is required. [ABSTRACT FROM AUTHOR]

This study investigated physico-chemical characteristics of the water column and chemistry of suspended particulate material (SPM) under quiescent, high-wind and high-wind/heavy-rainfall conditions in Homebush Bay, a highly contaminated embayment of Port Jackson (Australia) to distinguish source and possible adverse effects to benthic and pelagic animals. Mean concentrations in surficial sediment were <1, 14, 181, 141, 37, 290 and 685 μg g−1 for Cd, Co, Cr, Cu, Ni, Pb and Zn, respectively. Sediment chemistry indicated these metals had multiple sources, i.e. the estuary, stormwater and industry. Mean total suspended solids (TSS) were 7, 17 and 20 mg L−1 during quiescent, high-rainfall and heavy rainfall/high wind conditions, respectively, whereas SPM Cd, Co, Cr, Cu, Ni, Pb and Zn concentrations varied between 13–25, 166–259, 127–198, 38–82, 236–305 and 605–865 μg g−1, respectively under these conditions. TSS and total water metal concentrations were lowest during quiescent conditions. High TSS and metal loads in surface water characterised high-rainfall events. Wind-induced resuspension contributed the greatest mass of SPM and metals to the water column. Benthic animals may be adversely affected by Pb and Zn in sediment. Total water Cu and Zn concentrations may pose a risk to filter-feeding animals in the water column due to resuspension of contaminated sediment. [ABSTRACT FROM AUTHOR]

As in most large capital cities, urban stormwater discharging into Port Jackson (Sydney) is highly enriched in a wide range of contaminants, which has resulted in degradation of the receiving basin waters and bottom sediments. The objective of the current investigation was to determine the removal efficiency of contaminants in urban stormwater by a wetland constructed in the Sydney catchment. The wetland (700 m²) drains a residential urban catchment of about 480,000 m² comprising predominantly houses, streets, gardens, and street parking areas. Samples of stormwater influent and effluent were obtained during rainfall events between April and June 2000. Eight samples were collected at the inlet and outlet to the wetland during each event and analyzed for nutrients, trace metals, total suspended solids (TSS), and organochlorine pesticides and polycyclic aromatic hydrocarbons (PAHs). Water quality parameters (temperature, dissolved oxygen, pH, turbidity, conductivity) were measured concurrently. The average removal efficiency of trace metals Cr, Cu, Pb, Ni, and Zn was 64%, 65%, 65%, 22%, and 52%, respectively for the six events measured, whereas for Fe and Mn, removal efficiencies were negative for most events (mean-84% and-294%, respectively). The average removal efficiency of NOx and TN was 22% and 16%, respectively. The average removal efficiencies of total Kjeldahl nitrogen (TKN) and total phosphorus (TP) were 9% and 12%, respectively. During four high-flow events, the removal efficiency of TSS in stormwater effluent from the wetland was between 9% and 46%; however, substantially higher TSS concentrations were observed in effluent than influent waters during two very high-flow events (removal efficiency-98% and-67%). Fecal coliform counts in the stormwater in this catchment are high (maximum: 620,000 cfu/100 ml), but mean removal efficiency was 76% (range 26% to 98%) during the four high-flow events monitored. Nevertheless, ... [ABSTRACT FROM AUTHOR]

Chemical analyses of sediment are used for assessing the ability of sediment to support a healthy benthos (sediment quality) and for determining contaminant source and dispersion in aquatic systems. Total sediment analysis is used for sediment quality assessment, whereas source identification and dispersion requires normalised contaminant data. Normalized contaminant data are obtained by physical fractionation (size-normalization) of the sediment and analyses of a constant size fraction (usually the 62.5 μm fraction), whereas elemental normalization uses the total sediment analysis normalized to a conservative element. Elemental normalization is preferable, as it is cheaper and less time consuming than size-normalization techniques. In addition, some contaminants associated with oxides and oxyhydroxides in the coarse fraction are excluded in fine fraction analyses. Five techniques used to normalize sedimentary contaminant data were tested in the current study, including a new post-extraction normalization method where total sediment data are normalized to the residue after digestion, on the assumption that this fraction acts as a diluent only. Results of the tests indicated that simple normalization to the mud fraction provides useful dispersion information, but that the post-extraction normalization method produced a superior indication of source. Limited source and dispersion information was gleamed from the elemental-normalization (Al, Fe) approach, whereas the size-normalization technique provided the clearest indication of source and dispersion. Simple mud normalization and post-extraction normaliaation methods should be considered because only one analysis provides sediment quality, as well as source and dispersion information. However, for detailed information on source and dispersion, size normalization is recommended. [ABSTRACT FROM AUTHOR]

Comprehensive investigations of estuaries in central New South Wales has identified Port Jackson as the most contaminated waterway on the eastern seaboard of Australia. Extensive areas of the estuary are mantled in sediment containing high concentrations of a large range of metallic and organic contaminants. Although extensive, this database does not provide an effective basis for determining the potential adverse effects of chemicals on living resources. In the absence of any ecotoxicological information, the recently published (1999) draft Australian and New Zealand Environmental and Conservation Council (ANZECC) sediment quality guidelines have been used to assess possible adverse biological effects of these toxicants. The ANZECC guidelines use the lower effects range of the widely used U. S. National Oceanic and Atmospheric Administration (NOAA) scheme to identify potentially contaminated sediment and as a threshold to trigger for additional investigative work. This guideline level has been used in the current study to assess possible toxicity of contaminated sediments in Port Jackson. It is estimated that sediments in approximately 26% of the estuary, mainly the upper parts of the harbour and much of the central harbour, have a 67% probability of being toxic. Sediments in the central harbour and a major tributary, the Middle Harbour, comprising about 40% of the estuary, have a 13 to 25% probability of toxicity. All sediments in the harbour, except at the mouth of the estuary, would require additional environmental assessment based on the proposed draft ANZECC sediment quality guidelines. [ABSTRACT FROM AUTHOR]

Sediments in the Port Jackson estuary are polluted by a wide range of toxicants and concentrations are among the highest reported for any major harbor in the world. Sediment quality guidelines (SQGs), developed by the National Oceanographic and Atmospheric Administration (NOAA) in the United States are used to estimate possible adverse biological effects of sedimentary contaminants in Port Jackson to benthic animals. The NOAA guidelines indicate that Pb, Zn, DDD, and DDE are the most likely contaminants to cause adverse biological effects in Port Jackson. On an individual chemical basis, the detrimental effects due to these toxicants may occur over extensive areas of the harbor, i.e., about 40%, 30%, 15% and 50%, respectively. The NOAA SQGs can also be used to estimate the probability of sediment toxicity for contaminant mixtures by determining the number of contaminants exceeding an upper guideline value (effects range medium, or ERM), which predicts probable adverse biological effects. The exceedence approach is used in the current study to estimate the probability of sediment toxicity and to prioritize the harbour in terms of possible adverse effects on sediment-dwelling animals. Approximately 1% of the harbor is mantled with sediment containing more than ten contaminants exceeding their respective ERM concentrations and, based on NOAA data, these sediments have an 80% probability of being toxic. Sediment with six to ten contaminants exceeding their respective ERM guidelines extend over approximately 4% of the harbor and have a 57% probability of toxicity. These areas are located in the landward reaches of embayments in the upper and central harbor in proximity to the most industrialised and urbanized part of the catchment. Sediment in a further 17% of the harbor has between one and five exceedences and has a 32% probability of being toxic. The application of SQGs developed by NOAA has not been tested outside North America, and the validity of using them in Port Jackson has yet to be demonstrated. The screening approach adopted here is to use SQGs to identify contaminants of concern and to determine areas of environmental risk. The practical application and management implications of the results of this investigation are discussed. [ABSTRACT FROM AUTHOR]

Assesses the possible adverse biological effects of sedimentary contaminants in the estuary of Port Jackson in Sydney, Australia. Availability of sediment quality guidelines (SQG) for fresh and marine environments; Empirical analysis of matching chemical and biological data; Estimation of the probability of acute sediment toxicity by calculating mean quotients for a large range of contaminants.

A serious health scare involving the supply of drinking water to Sydney, Australia has recently focussed attention on the environmental status of river catchments of the main reservoir, Lake Burragorang. Although the Coxs River – a major catchment of Lake Burragorang – comprises mainly forests and grazing land, it supports a moderate sized town, power stations and coal mines. The heavy metal content of stream-bed sediments characterises environmental impact in this rural catchment and sources of contamination. Sediment in a creek flowing through a country town (population 12 000) is markedly enriched in Cr, Pb and Zn (3×, 18× and 52×, respectively) over background, probably due to a long history of metal-based industry. The highest Cu, Pb and Zn concentrations (204, 332 and 2460 μg g-1, respectively) in fluvial sediment in the town are, however associated with discharges from a sewage treatment plant. Two coal-based power stations in the catchment contribute considerable Cu and Ni (maximum concentrations 562 and 157 μg g-1, respectively) to ambient fluvial sediments, possibly from cooling towers and coal storage areas. The highest Co and Cr concentrations (113 and 490 μg g-1) in fluvial sediments of this catchment are associated with coal-mining activities. Selective extraction indicates that about 50% of the anthropogenic fraction may be bioavailable, whereas sequential extraction procedures suggest that <25% is associated with the easily exchangeable/adsorbed phase. Two dams restrict the migration of heavy metals down the Coxs River and sediment discharging into Lake Burragorang is low in metals. [ABSTRACT FROM AUTHOR]

Examines the use of size-normalized procedures in the analysis of organic contaminants in estuarine sediments. Reasons for use of sediments for monitoring the aquatic environment; Ways in which the confounding effects of variable grain size of sediments can be reduced; Association of a majority of contaminants with the fine fraction of sediments.