Mercury In Sediments Research Articles

Transport of mercury on the finest particles results in high sediment concentrations in the absence of significant ongoing sources

The mercury contaminated upper Penobscot Estuary in Maine provided a unique opportunity to rigorously examine the effect of sediment type and particle size on mercury concentrations in sediments, and to explain why sediments at different locations in the estuary had different mercury concentrations. This is because the Penobscot Estuary contains a large, well-mixed pool of mobile sediments of many different types (muds, sand, gravel, wood chips), which are the source of material for the permanently deposited surface sediments. Despite this mixing, average surface sediment mercury concentrations were very different in different locations, ranging from 238 ng/gdw to 1032 ng/gdw in the 11 subareas studied. Average total mercury concentrations were highly related to the type of sediment (wood chips > muds > sands) regardless of location in the estuary. The characteristics in both mobile and surface sediments that were positively related to total mercury concentrations were % organic matter (measured as loss on ignition) and %fines (measured usually as <62.5 μ). Also, in a subset of samples it was shown that mercury was positively associated only with the very finest (<44 μ) particles. Thus, side embayments of the estuary such as the Orland River and Mendall Marsh, which experience lower velocity currents and so accumulate more fine particles, tended to be much higher in mercury concentrations. This knowledge will be important in managing remediation of this system, as fine particles can be the most difficult to trap or to retain if dredging is employed. Methyl mercury was well correlated with total mercury and so its distribution would also be affected by transport characteristics. This was the case even in the mobile sediments, which were more oxic and not expected to provide a good habitat for methylation.

Distribution and speciation of mercury affected by humic acid in mariculture sites at the Pearl River estuary

At the Pearl River Estuary of southern China, mercury and its environmental problems have long been a great concern. This study investigated the distribution and speciation of mercury compounds that are significantly influenced by the increasing content of humic acid (HA, a model natural organic matter) in this region. The inorganic mercury and methyl mercury, being adsorbed and converted at different HA levels, were studied in sediments and surface water at both mariculture and their reference sites. In mariculture sediments with higher HA content (up to 4.5%), more mercury were adsorbed at different compound levels, promoting the methylation and accumulation of mercury (P < 0.05) at the sediment-water interface. Seasonal shift in environmental temperature might control the HA content, subsequently favouring mercury methylation (maximum 1.75 ± 0.08 mg L−1 d−1) under warm weather conditions. In reference sites received less HA wastes, lower adsorption capacity and methylation rate were observed for mercury in sediments and surface water. Our work points to the significant roles of HA on mercury distribution and speciation both spatially and seasonally, thus addressing the impacts of mariculture activities on estuary eco-system.

Historical records, distributions and sources of mercury and zinc in sediments of East China sea: Implication from stable isotopic compositions

The distribution and source of mercury (Hg) and zinc (Zn) in surface sediments from East China Sea (ECS) were studied using stable isotopes. Hg concentrations in surface sediments varied from 12.6 to 133.2 ng g−1. Zn concentrations ranged between 45.9 and 133.6 ng g−1. Hydrodynamic circulation and sedimentary process within the ECS were the dominant factors controlling the distribution and fate of heavy metals, referring from relationships of Hg and Zn concentrations and total organic carbon (TOC) and clay contents. Spatial variations in Hg isotopic compositions (δ202Hg) were observed in the ECS, with δ202Hg ranging from −1.86 to −0.83‰ and Δ199Hg ranging from −0.07 to +0.26‰. The high δ202Hg values and relatively negative Δ199Hg values in estuarine and inner shelf sites indicated that the riverine inputs from Yangtze River played an important role in delivering Hg to ECS. In contrast, Hg isotopic signatures in outer shelf sediments had relatively low δ202Hg and positive Δ199Hg, implying that atmospheric Hg deposition could be relatively dominant source for Hg. Moreover, application of zinc isotopes to trace anthropogenic sources has been tested, with δ66Zn ranging from 0.20 to 0.67‰. The results showed significant variations of δ66Zn in the ECS, implying that Zn isotope compositions can be tracers of anthropogenic sources. Using these Hg isotope compositions, the source attributions of sediments in ECS were estimated based on a mixing model, suggesting that river-dominated inputs, discharging pollutants from industrial sources, and atmospheric deposition could dominate in the occurrence and fate of Hg in sediments of ECS.

Seasonal changes of mercury speciation in the coastal sediments

PurposeMercury speciation in sediments is linked to environmental conditions and processes. Domination of particular mercury species depends on its source, displays considerable seasonal behavior, and may be further modified due to oxygen levels, icing conditions, or the input of fresh organic matter. The purpose of this study was to examine the coastal area of the Gulf of Gdańsk in terms of mercury contamination and the influence of seasonal environmental changes on its speciation.Materials and methodsIn three highly dynamic coastal sites, mercury speciation in sediments was studied in relation to other environmental parameters (redox conditions, organic matter concentration, bacteria abundance, etc.). Sediment and water samples were collected monthly during a 3-year study. Sequential extraction of sediments was used for identification of four inorganic mercury species: dissolved, bound with fulvic and humic acids, mercury sulfide, and residual fraction. Cold vapor atomic fluorescence spectrometry (CV-AFS) was used for extracts and liquid sample analysis. Total mercury in sediments was measured with atomic absorption spectrometry (AAS). Changes in salinity were analyzed by measurements of chloride and sulfate ion concentrations using ion chromatography. Bacteria number and biomass were measured by direct counting using epifluorescence microscopy.Results and discussionSeasonal changes in mercury speciation were observed at all sites and attributed to different processes. Labile mercury fraction contribution varied from 0 to 80%. The speciation patterns varied locally as the stations selected for the study are diversified in terms of anthropogenic impact, water dynamics, and output from land. Mercury concentrations at all stations fluctuated during phytoplankton blooms, icing of marine waters, precipitation, or increased surface runoff from the land. In this local scale, the global climate changes are visible already as environmental conditions in studied area changed in comparison to elder research.ConclusionsObtained results suggest that although mercury emissions to the environment have decreased in recent years, local weather conditions, which may be intensified by climate change, seriously affect the bioavailability of past mercury deposits in coastal sediments.

Migration and Transformation of Mercury in Unsubmerged Soil and Sediment at One Typical Forest Reservoir in Southwest China

Mercury (Hg) has been regarded as a global pollutant due to its volatility and toxicity. The sediment in the reservoirs or lakes is an important compartment for Hg methylation and it has also been considered as a sensitive area of Hg. In this study, a typical forest reservoir surrounding by evergreen broad-leaved forest in Chongqing of southwest China was selected to investigate the migration and transformation of Hg in unsubmerged soil and sediment. The unsubmerged soil and sediment were also replaced to each other to observe the dynamics of THg and TMeHg concentrations in equilibrium processes. The results were as follows:① The THg and TMeHg mean concentrations in Dahonghai reservoir water were (1.89±0.72) ng·L-1 and (0.13±0.04) ng·L-1, respectively, which were lower than the first class water quality standards in environmental quality standard of China and other reservoirs or lakes, implying that this study area did not affect by Hg pollution. Meanwhile, the THg and TMeHg mean concentrations in unsubmerged soil and sediment were also lower than those in other reservoirs or lakes. ② Seasonal variations of THg and TMeHg concentrations in reservoir water and soil were both observed higher in warm seasons, and more obvious variations occurred for TMeHg which probably influenced by meteorological parameters, such as, temperature and rainfall. ③Compared with unsubmerged soil, the THg and TMeHg mean concentrations in sediment were both elevated, suggesting the sediment was an important sink of Hg. While, the sediment would be a source of Hg (especially TMeHg) with a high THg and TMeHg level. ④ The THg and TMeHg mean concentrations in unsubmerged soil and sediment after situ replacement were equilibrated with ambient soil in a short time (one or two months), implying the hydro-fluctuation belt of reservoir promoting the geochemical cycle of Hg.

Optimization and application of a low cost, colorimetric screening method for mercury in marine sediment.

A rapid, inexpensive, colorimetric screening method for mercury (Hg) has been optimized to provide a semi-quantitative measurement of Hg concentration in marine sediment within the range 0.038 to 1.5mgkg-1 encompassing the interim sediment quality guideline (ISQG) value of 0.13mgkg-1 (CCME 1999) and the probable effects level (PEL) of 0.7mgkg-1 for Hg in marine sediment (CCME 1999). Neither salinity (up to 41 practical salinity units (psu)) nor sediment organic matter (ΟΜ) content (up to 10%) affected the performance of the method. Accurate results were obtained for spike recovery experiments and analysis of certified reference material (CRM) BCR 580 Estuarine Sediment. The method was applied to sediment samples from Elefsina Bay, Greece. Screening results indicated Hg contamination in the bay, with concentrations exceeding the PEL value. Findings were confirmed by quantitative analysis of the samples by cold vapor atomic absorption spectrometry (CV-AAS), where results in the range 1.4-2.96mgkg-1 were determined.

Long-term dynamics of total mercury in surficial bottom sediments of the Volga River's reservoir in central Russia.

The long-term dynamics of mercury in bottom sediments of Uglich Reservoir were examined. Samples of the 0-5-cm surface layer of bottom sediment collected during research expeditions in 1958, 1977, 1991, and 2012 were analyzed. An increase in the average mercury concentration from 1958 to 1977 (0.440 ± 0.039 and 0.668 ± 0.065mg/kg d.w., respectively) was followed by a decrease in 2012 (0.260 ± 0.021mg/kg d.w.). During all years except 1991, a significant correlation was found between mercury content and the amount of organic matter in the sediments (r = 0.54-0.87, p < 0.01), flow velocity (r = 0.38-0.53, p < 0.01), and the rate of sedimentation in the reservoir (r = - 0.51 to - 0.69, p < 0.01). Calculations based on these results and previously published data from the study region on the density of atmospheric mercury precipitation showed that the watershed as a whole received 2.4-3.0t on an annual basis, and in the same period, the water surface received 9.7-12.8kg of mercury. The bottom sediment contained 4.31 (2012)-7.40 (1977) tons of mercury. Thus, most of the mercury in the Uglich Reservoir is assumed to originate from runoff and terrigenous sources within the watershed.

Distribution and contamination assessment of arsenic and mercury in surface sediments from the intertidal zone of Yantai Sishili Bay, China

ABSTRACTSixty surface sediment samples from the intertidal zone of Yantai Sishili Bay (YSB) have been analyzed for arsenic (As) and mercury (Hg) to evaluate their contamination levels and potential ecological risks. Concentrations of As and Hg ranged from 7.01–23.56 and 0.00–0.01 μg g−1 in the dry season; during the wet season, the corresponding data were 1.44–6.17 and 0.00–0.02 μg g−1. The geoaccumulation index (Igeo) and potential ecological risk index (Eri) were used to conduct a pollution assessment. The results demonstrated that the intertidal zone of YSB has good sediment quality and that As and Hg are not likely to cause negative environmental impacts in the region.

Occurrence and speciation of arsenic and mercury in estuarine sediments affected by mining activities (Asturias, northern Spain)

Sediments contaminated by Hg and As from two historical mining areas have been deposited in the Nalón estuary (Asturias, northern Spain) since 1850. Total mercury (Hgtotal) concentrations in the sediments range from 0.20 μg g−1 to 1.33 μg g−1, most of it in the form of sulphides. Concentrations of methylmercury (303.20–865.40 pg g−1) are up to two orders of magnitude lower than the concentration of Hgtotal. Total As concentration (Astotal) is enriched compared to the background level for the area. The relative abundance of As(V) on As(III) in the sediments ranges from 97.6% to 100%, whereas inorganic Hg accounts for more than 99% of the total Hg. The occurrence of the most toxic species, inorganic As(III) and organic methylmercury, seem to be related to redox conditions together with the amounts of sulphur which act as natural barriers which inhibit the biological and chemical speciation processes. Despite the high amounts of Hg and As present in the sediments, their transference to the water column appear to be limited thus converting sediments in an effective sink of both elements. Special attention should be paid to potential variations of the environmental conditions which might increase the element mobility and exchange between sediments and the water column.

Distribution of total mercury in surface sediments and African catfish (Clarias gariepinus) from Akaki River catchment and Aba Samuel Reservoir, downstream to the mega-city Addis Ababa, Ethiopia

Abstract Total mercury (THg) levels were determined in sediment (n = 22) and muscle of Clarias gariepinus (n = 36) in dry and rainy seasons from Akaki River catchment and Aba Samuel Reservoir, Ethiopia in 2016-2017. The analyses of THg were performed using cold vapor-atomic absorption spectrometer (CV-AAS) after acid digestion technique. The relationship of THg levels to size of the fish has also been investigated. The THg levels in sediments range from 9.5–43.8 mg/kg dry wt in the dry and 20.6–175.4 mg/kg dry wt in the rainy seasons. This study indicated that the levels of THg in sediments varies spatially and seasonally. In both seasons, THg levels increased from upstream to downstream areas, revealing increased anthropogenic inputs of mercury pollution. It was also found that the THg concentrations in all the sediment samples were below the US EPA guideline value of 200 mg/kg dry wt. The THg levels in Clarias gariepinus were in the range from 360–924 mg/kg dry wt in the dry and 325–1233 mg/kg dry wt in the rainy seasons, and had positive relationship to the total length and body weight. The THg concentrations found in Clarias gariepinus were within the acceptable guidelines of the FAO/WHO. Therefore, the muscle of Clarias gariepinus from the study area is not hazardous to human health with respect to mercury. However, the average value of THg seems to be slightly higher than results reported from other Ethiopian freshwater bodies. Thus, monitoring of mercury species in sediment and different organs of fish are strongly recommended.

Senegalese artisanal gold mining leads to elevated total mercury and methylmercury concentrations in soils, sediments, and rivers

The largest source of global mercury (Hg) anthropogenic inputs to the environment is derived from artisanal and small-scale gold mining (ASGM) activities in developing countries. While our understanding of global Hg emissions from ASGM is growing, there is limited empirical documentation about the levels of total mercury (THg) and methylmercury (MeHg) contamination near ASGM sites. We measured THg and MeHg concentrations in soil (n = 119), sediment (n = 22), and water (n = 25) from four active ASGM villages and one non-ASGM reference village in Senegal, West Africa. Nearly all samples had THg and MeHg concentrations that exceeded the reference village concentrations and USEPA regulatory standards. The highest median THg concentrations were found in huts where mercury-gold amalgams were burned (7.5 μg/g), while the highest median MeHg concentrations and percent Hg as MeHg were found in river sediments (4.2 ng/g, 0.41%). Median river water concentrations of THg and MeHg were also elevated compared to values at the reference site (22 ng THg/L, 0.037 ng MeHg/L in ASGM sites). This study provides direct evidence that Hg from ASGM is entering both the terrestrial and aquatic ecosystems where it is converted in soils, sediment, and water to the neurotoxic and bioavailable form of MeHg.

Mercury toxicity potential from artisanal and small scale gold mines in Lebong Regency, Bengkulu Province

Artisanal and small scale gold mining (ASGM) is considered as the largest source of mercury pollution worldwide. The ASGM has been practiced for years in the area of Lebong Regency of Bengkulu Province. To extract gold from the ores, miners use a simple technique called Gelondong. This practice involves amalgamation process which forms amalgam, a mixure composed of mercury and gold. These amalgamation generates liquid and solid wastes (tailings) which still contain significant amount of mercury. Consequently, ASGM activities can potentially create mercury contamination of the environment, especially aquatic ecosystems. This study was aimed to investigate the concentration and distribution of total mercury in rivers to which wastes from ASGM communities in three villages of North Lebong District were dumped. Water and streambed sediments along the rivers were collected and brought to the laboratory for total mercury analysis. Data showed that total mercury was not detected in the river water but high in the river sediments with high variations among lactions from 0.11 to 110.37 mg kg-1. Apparently, total mercury tended to decrease with the distance from it source. High amounts of mercury in the river sediments could potentially spread to wider area and cause bioaccumulation in aquatic organisms, especially fish which can be dangerous to consume.

Mercury in sediments of harbor areas of the Baltic Sea: compilation of data and comparison of legislation in the individual countries

Mercury is a very toxic chemical element and presents a very high level of chemical and biological activity. Long-term emissions of this element into the environment created a global pool of mercury, as a result of mercury forms has been constantly mobilised, deposited and re-mobilised up till now. The continued releases increase the overall values of the global mercury cycle in the air, water, sediments/soil as well as flora and fauna. Port sediments, which containing large deposits of mercury compounds may constitute a potential threat to the marine environment. Moreover harbour basins, which are mainly located in the estuary areas, can be exposed on the pollutants collected by the river flowing through the whole basin area. Furthermore, some contamination can be also supplied to the harbour areas as a result of cargo handling, ship traffic, the discharge of industrial and municipal wastewater etc. These contamination are largely deposited in the benthic sediments. This study summarizes results of mercury concentration in the sediments collected from the marine ports of the Baltic Sea (31 ports). Additionally, it references them to the existing legislation of the individual countries. These data came from the various sources: scientific articles, data submitted by different ports, port-related organisations within the framework of the project SMOCS [35], as well as own research..It has been found differences between each country's legal system. These are related to the different limit values used for the contamination assessment of mercury in port sediments. Another issue is an application of different analytical methodologies in environmental survey. The common analytical methodolody for the determination of mercury compounds together with defined similar limit values for the polluted sediments seems to be extremly important issue in terms of planning as well as managing Baltic Sea port’s sediments

Mercury in litterfall and sediment using elemental and isotopic composition of carbon and nitrogen in the mangrove of Southeastern Brazil

Mercury and elemental and isotopic compositions of carbon and nitrogen were determined in litterfall and sediments from the mangrove of the Paraíba do Sul River, Rio de Janeiro, Brazil. Total mercury (THg) and monomethylmercury (MMHg) concentrations in sediment ranged from 33 to 123 ng g−1 and 0.20–1.38 ng g−1, respectively. The δ13C in sediment varied from −29.4 to −26.5‰ and from 2.4 to 5.8‰ in δ15N. The THg concentration in litterfall and its annual input to the mangrove was 21 ± 2 ng g−1 and 16 ± 4 μg m−2 for the species Laguncularia racemosa, 18 ± 1 ng g−1 and 17 ± 3 μg m−2 for Rhizophora mangle, and 53 ± 4 ng g−1 and 33 ± 4 μg m−2 for Avicennia germinans, respectively. The isotopic composition of leaf litter ranged from −28.6 to −26.9‰ for δ13C and 4.5–7.2‰ for δ15N. Both the highest annual Hg input via litterfall and highest sediment Hg concentration were observed in areas dominated by A. germinans. These results suggest that the rate of litterfall of plant species and the atmospheric deposition have played an important role in the Hg biogeochemical cycle in the mangrove ecosystem.

RISK ANALYSIS OF HEAVY METAL WEIGHT MERCURY IN SEA SEDIMENT IN THE COASTAL AREAS OF MAKASSAR CITY

Monitoring of marine sediments as an indicator of heavy metal mercury pollution in waters has been conducted. This study used an observational design with an Environmental Risk Analysis approach with the objective of knowing the concentration of mercury (Hg) heavy metals and the risk of metal contamination in marine sediments. Sediment sampling was conducted at 10 points in 5 (five) urban villages of Makassar City. The results showed that the highest mercury concentration was in Cambayya Village at 1.871 mg / kg and the lowest mercury concentration was in Lae-Lae Island Kelurahan at 1,550 mg / kg. In general, the content of heavy metals mercury in marine sediments in coastal areas of Makassar City has exceeded the threshold of 0.13 mg / kg with the enormous environmental risk occurring in coastal areas of Makassar City due to exposure to mercury metals, ranging from 11-22 under the risk category high HQ&gt; 10.Keywords : Risk Analysis, Sea Sediments, Mercury

Patterns and controls of mercury accumulation in sediments from three thermokarst lakes on the Arctic Coastal Plain of Alaska

The biogeochemical cycle of mercury will be influenced by climate change, particularly at higher latitudes. Investigations of historical mercury accumulation in lake sediments inform future predictions as to how climate change might affect mercury biogeochemistry; however, in regions with a paucity of data, such as the thermokarst-rich Arctic Coastal Plain of Alaska (ACP), the trajectory of mercury accumulation in lake sediments is particularly uncertain. Sediment cores from three thermokarst lakes on the ACP were analyzed to understand changes in, and drivers of, Hg accumulation over the past ~ 100 years. Mercury accumulation in two of the three lakes was variable and high over the past century (91.96 and 78.6 µg/m2/year), and largely controlled by sedimentation rate. Mercury accumulation in the third lake was lower (14.2 µg/m2/year), more temporally uniform, and was more strongly related to sediment Hg concentration than sedimentation rate. Sediment mercury concentrations were quantitatively related to measures of sediment composition and VRS-inferred chlorophyll a, and sedimentation rates were related to various catchment characteristics. These results were compared to data from 37 previously studied Arctic and Alaskan lakes. Results from the meta-analysis indicate that thermokarst lakes have significantly higher and more variable Hg accumulation rates than non-thermokarst lakes, suggesting that certain properties (e.g., thermal erosion, thaw slumping, low hydraulic conductivity) likely make lakes prone to high and variable Hg accumulation rates. Differences and high variability in Hg accumulation among high latitude lakes highlight the complexity of predicting future climate-related change impacts on mercury cycling in these environments.

Certification for trace elements and methyl mercury mass fractions in IAEA-456 marine sediment sample

Marine sediment certified reference material (CRM), IAEA-456 was recently produced by the Environment Laboratories of the International Atomic Energy Agency (IAEA) and certified for trace elements and methyl mercury (CH3Hg). This paper presents the sample preparation methodology, material homogeneity and stability studies, evaluation of results from the characterisation campaign, the assignment of property values and their associated uncertainty. The reference values and associated expanded uncertainty for nine trace elements (Al, As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, V and Zn) and CH3Hg in marine sediment sample are established. The new CRM can be used for the development and validation of analytical methods, for the determination of trace elements and methyl mercury in sediments and also for quality assurance/quality control purposes.

ASSESSMENT OF TOXICITY AND POLLUTION OF BOTTOM SEDIMENTS IN THE NORTHWESTERN PART OF THE BLACK SEA WITH HEAVY METALS

The northwestern shelf is the most polluted regions of Black sea. The aim of the work was to compare the levels of bottom sediment’s toxicity and pollution with heavy metals (As, Cd, Hg, Pb, Zn, Cu, Ni, Co, Cr) in the Odesa Region and seaside of Kylyia branch of the Danube (further: Seaside of the Danube). In this article we used the methodology of EU Frame Work Directive. The criterion for the quality of bottom sediments was the Target value (TV) indicator, developed in the Netherlands. Acute toxicity of bottom sediments extract on distilled water was determined using laboratory cultures of Hyalea azteca (Saussure, 1858). According of the result of biotesting, in the Odesa Region the bottom sediments of quality class 3 (moderate) were formed under the inflence of bilge waters from the roadstead of ships, trans fer of polluted water from Odesa Sea Commercial Port area and Treatment plant “Northern”. The rest of the bottom sediments of the polygon were assigned to a quality class 2 (good) and a quality class 1 (excellent). At the Seaside of the Danube the bottom sediments of quality class 3 (moderate) were formed by carrying the polluted river waters out of Bystroie (Novostambulskoie) and Starostambulskoie branches. The bottom sediments of the rest of the polygon were assigned to quality class 2 (good) and quality class 1 (excellent). The average content of mercury in the bottom sediments was 0.21∙g–1on dry mass (0.7 TV) in the Odesa Region, and 2.26 g–1 on dry mass (7.53 TV) at the Seaside of the Danube. The greatest impact to pollution of bottom sediments was made by mercury – 11.77 TV, copper 2.09 TV and cobalt – 1.50 TV in the Odesa Region, and mercury – 118.23 TV, nickel – 7.15 TV and cobalt – 4.33 TV at the Seaside of the Danube.

Chemical characteristics of dissolved mercury in the pore water of Minamata Bay sediments

Methylmercury concentrations in fish from the historically polluted Minamata Bay remain higher than in fish from other coastal seas around Japan. To obtain a better understanding of this phenomenon, the chemical characteristics of pore water from Minamata Bay sediments were investigated. Samples were taken from two stations over a 1-year period. Total average values in the pore water at the two stations for dissolved total mercury and methylmercury concentrations were 6.64±4.93 and 2.69±2.07ng/l, respectively. The pore water was centrifuged at 1000rpm to 3000rpm. The highest ratio of dissolved methylmercury to dissolved total mercury exceeded 60% for pore water centrifuged at 3000rpm. Furthermore, because total average values of Log Kd of total mercury and methylmercury in sediment (St1 and St2) were 5.42 and 2.32 (Lkg−1), methylmercury in Minamata Bay sediment is more eluted than other mercury species.

PAH, PCB, TPH and mercury in surface sediments of the Delaware River Estuary and Delmarva Peninsula, USA

Surface sediment concentrations of polycyclic aromatic hydrocarbons (PAH) and polychlorinated biphenyls (PCB), total petroleum hydrocarbons (TPH) and mercury, were compared from two areas with contrasting land use history, the industrial Delaware Estuary and the rural Delmarva Peninsula (USA). TPH in the Delaware (38–616mg/kg) and saturate/aromatic fractions suggested petroleum/industrial sources compared to biogenic sources in the Delmarva coastal control (<34–159mg/kg). Within the Delaware the ∑PAH18 ranged from 3749 to 22,324μg/kg with isomeric ratios indicative of petroleum combustion source/s, conversely, those in the Delmarva (5–2139μg/kg) also yielded relatively higher perylene that were consistent with natural background levels derived from vegetation/coal combustion source/s. ∑PCB(tri-hepta) concentrations in the Delmarva (0.6–6.5μg/kg) were less than the threshold effect concentration (TEC), whereas the Delaware had received much higher PCB loading (18.1–136.8μg/kg) as evidenced by a significantly higher amounts in some samples (>TEC).