Mercury species in potable ground water in southern New Jersey

Water samples from 78 private potable wells in southern New Jersey were collected for mercury analysis in 1991–1992. Analyses were performed for the quantification of reactive, volatile and methyl mercury species. Relationships of mercury with other water quality parameters were evaluated also. Total mercury concentrations varied from <1 ng L^?1 to over 36 Μg L^?1. The dominant forms in which mercury occurred in the wells sampled were Hg? and HgCl₂?, although methyl mercury was present in some wells and comprised up to 8% of the total mercury in the ground water samples.     

Conservation of freshwater fishes of Sri Lanka

Sri Lanka supports a diverse fauna of freshwater fishes, 24% of which are endemic. A survey of the island's streams indicated that a number of the endemic fishes are threatened with extinction and others are depleted due to the interaction of deforestation, urbanization, gem mining, pesticides, exploitation, water diversions, and introductions of exotic species. It is clear that these declines should be halted for ethical, economic, and ecological reasons. Methods proposed to reverse the declines include captive breeding, better watershed management, translocation, and regulation of fisheries, especially that for aquarium fishes. The depauperate Second Peneplain is proposed as a site for translocation of endangered species.     

Ship noise and cortisol secretion in European freshwater fishes

Underwater noise pollution is a growing problem in aquatic environments and as such may be a major source of stress for fish. In the present study, we addressed the effects of ship noise and continuous Gaussian noise on adrenal activity in three European freshwater species. Underwater ship noise recorded in the Danube River and two Austrian lakes was played back to fish at levels encountered in the field (153 dB re 1 μPa, 30 min). Post exposure cortisol secretion was compared with control situations. Cortisol was measured with enzyme immunoassay techniques (EIA, ng cortisol/l water/g fish) in extracted aquarium water with corrections for fish mass. In the first series, two hearing specialists, the common carp (Cyprinus carpio) and the gudgeon (Gobio gobio) and one hearing generalist, the European perch (Perca fluviatilis) were exposed to ship noise. The noise level was well above hearing thresholds in these species. In a second series, fish were exposed to continuous Gaussian noise at a similar level (156 dB) which is known to induce temporary hearing loss in hearing specialists. All three species responded with increased cortisol secretion when exposed to ship noise. Interestingly, no elevation was observed when fish were exposed to continuous Gaussian noise. Our results indicate that ship noise characterized by amplitude and frequency fluctuations, constitutes a potential stressor in contrast to continuous noise. Surprisingly, the data also demonstrate no apparent differences between species possessing excellent hearing abilities (hearing specialists) and species with poor hearing abilities like perch.     

The conservation of freshwater fishes in the British isles

This paper briefly reviews the status and distribution of populations of freshwater fishes in the British Isles and their worth as a resource. The total value of freshwater fishes to the community is far greater than is normally appreciated and includes, in addition to the economic sport and commercial fisheries, amenity, recreational, educational, and scientific, aspects as well as a potentially useful store of genetic material for the future. The main human pressures on existing fish stocks are discussed under the headings of fisheries, pollution, and land-used. The principal trends in the British Isles are away from natural and stable mixed fish populations towards artificially maintained, unstable stocks of a few species of sporting or commercial value. In particular the rarer, more sensitive, fish stocks with poor powers of distribution are being eradicated and replaced by commoner, more robust forms with greater powers of distribution. The rarer species and genetic strains can only survive if constructive conservation projects are initiated expeditiously at a variety of levels.     

Mercury concentrations in forest trees from Slovakia

The concentration of mercury has been determined in assimilation organs of forest trees from 10 main industrial regions of Slovakia, four mountain forests and one military area and compared with concentration of mercury from 1356 permanent monitoring plots of Slovakia. The mercury concentration ranges for 2 yr old needles of Picea abies Karst. were (in mg kg^?1): 1.249–4.402 (Rudnany iron ore mines), 0.013–0.749 (nine other industrial regions), 0.021–0.737 (four mountain forests) and 0.053–0.538 (military area). The mercury content in the soil (0–5 cm) from a mercury smelting plant ranged from 9.9 to 130 mg kg^?1, and the moss Pleurozium schreberi contained 3.8–9.1 mg kg^?1. The values obtained were compared with the available literature data.     

Mercury concentrations in two “great waters”

Although many sources of Hg to surface waters have been identified including atmospheric deposition, resuspension of contaminated sediments, and direct discharges, there are very few recent data on ambient concentrations in the large lakes. Thus, an investigation of Hg concentrations in Lake Champlain and Lake Michigan was completed in the summer of 1993. Three depths of water including the microlayer, 30 cm below the surface, and 1 m below the thermocline were collected for each sampling event using ultra-clean techniques. All samples were processed in the field for dissolved and particulate fractions in a portable plastic enclosure equipped with a HEPA filter, and then analyzed by dual amalgamation and cold vapor atomic fluorescence spectroscopy in a Class 100 clean room at the University of Michigan. In addition, samples were analyzed for other trace metals by ICP-MS. Results from the two field investigations include the following: (1) On average, Lake Michigan water samples had higher concentrations of Hg than Lake Champlain; (2) There was no consistent pattern of Hg concentrations in the water column; (3) There was variability in the concentrations of Hg from the same depths over consecutive sampling periods. This paper discusses these results, and examines the relationship between the patterns in mercury concentrations and other physical and chemical data collected during the investigation.     

Mercury concentrations in fish in a remote Canadian Arctic lake

Lac Ste. Thérèse, a remote Canadian Arctic lake in the Northwest Territories, Canada, has high natural (non-point source) mercury concentrations in fish. The high mercury levels have persisted for over 18 years. Lac Ste. Thérèse has had consistently higher mercury concentration in fish than the other three lakes sampled within the basin, regardless of species tested.     

Environmental change and its impact on the freshwater fishes of Iran

Factors affecting the distribution and abundance of freshwater fishes in Iran are described. These include climate, devegetation, irrigation, and natural water level fluctuations (termed pre-industrial) and such factors related to industrialisation and population increase as devegetation, water abstraction, fishing, pollution, and faunal introductions. Conservation schemes are outlined and commented on and a list of threatemed fishes is given.     

Elemental concentrations in fishes from the Salton Sea,Southeastern California

The Salton Sea is a 93 000 ha saline lake fed by drainage water from more than 283 000 ha of irrigated lands in the Imperial and Coachella valleys of California. A total of 21 composite samples of four recreationally important fish species — bairdiella (Bairdiella icistia), orangemouth corvina (Cynoscion xanthulus), sargo (Anisotremus davidsoni), and Mozambique tilapia (Tilapia mossambica) —collected there were analyzed for 14 elements. Twelve of these elements were detected in one or more of the samples: As, B, Co, Cu, Fe, Hg, Mo, Ni, Pb, Se, V, and Zn. Cadmium and Tl were not detected. The ranges in concentrations of elements in the skinless fillets of bairdiella, corvina, and sargo, and in whole bodies of all four fishes were comparable to levels that are typically measured in saltwater fishes. Only Se concentrations were elevated (as much as 14 µg g^?1 dry weight in both fillets and whole bodies) in this series of samples. Elevated concentrations of Se have already led to public health advisories concerning the consumption of fish and might eventually cause the demise of fish populations from toxic effects.     

Avian utilisation on six salt marshes in New Jersey

Bird use was measured on six salt marshes in New Jersey from 18 April to 18 July 1977 (2 impoundments, 2 ditched marshes and 2 natural salt marshes) in terms of species diversity, numbers of individuals and biomass. Seventy-eight species of birds were recorded in all six marshes although not all species occurred on each marsh. Species diversity was highest on the impoundments, intermediate on the ditched marshes, and lowest in the natural marshes. Species diversity and the number of individuals directly related to the amount of open surface area. The traditional species typical of salt marshes on the East Coast of North America (clapper rails Rallus longirostris, seaside and sharp-tailed sparrows Ammospiza spp.) occurred primarily in the natural salt marshes and were absent from the impoundments. Considerations of species diversity suggest that diversity in salt marsh types is essential to maintaining high species diversity in salt marsh ecosystems. Red-winged blackbirds Agelaius phoeniceus and swallows were the most numerous species, followed by gulls and terns. The impoundments had over five times as many individuals as the natural marshes. Waterfowl, gulls, terns and waders accounted for over 90% of the cumulative biomass in the six marshes, with waterfowl contributing over 50%. This study suggests that conservationists should encourage the maintenance of natural salt marshes because they are necessary habitats for some species even though the diversity and avian biomass is less on natural salt marsh areas than it is on managed areas.     

Atmospheric Wet Deposition of Total Phosphorus in New Jersey

Wet deposition of total phosphorus has been measured as part of the New Jersey Atmospheric Deposition Network (NJADN). Precipitation samples were collected in 1999—2001, using automated wet-only precipitation collectors at four sites in New Jersey, representing different land-use regimes. Total phosphorus volume-weighted mean concentrations (VWM) and the wet depositional fluxes were estimated on seasonal and annual timescales. VWM concentrations (± standard error) of total phosphorus ranged from 4.1 ± 0.80 to 15 ± 8.8 μg L^-1 at all sites and were of similar magnitude across the region. The wet deposition flux estimates ranged from 3.9 to 14 mg m^-2 y^-1. VWM concentrations and fluxes were similar to those measured at other locations in the eastern United States.     

Mercury pollution of fishes in Minamata Bay and surrounding water: Analysis of pathway of mercury

Water, Air, & Soil Pollution - In 1973, the Environment Agency of Japan made an intensive survey of Hg pollution in Minamata Bay and its surrounding water. About 200 sediment samples and 1600...     

Gaseous Elemental Mercury Fluxes in New York City

As with many urban environments, a number of sources of airborne elemental mercury (Hg°) exist in New York City, yet little research has been conducted to examine the flux and sources of mercury in New York. In this study, we conducted ambient monitoring of Hg° at six locations in New York City. Airborne Hg° averaged 3.84±0.10 ng m^-3 and 3.70±0.08 ng m^-3 in the boroughs of Manhattan and Brooklyn respectively, yet only 2.69±0.03 ng m^-3 in a more residential neighborhood in Queens. Both precipitation and ambient temperature were significantly correlated with ambient Hg° levels in New York City, suggesting that the surface emission of mercury from urban surfaces plays a role in urban Hg° concentrations. Local sources were also seen to contribute to urban Hg° levels by leading to `spikes' of Hg° in which elevated concentrations were recorded for short periods of time.     

Mercury concentrations in an aquatic ecosystem during twenty years following abatement the pollution source

Phenyl Hg was widely used as a slimicide in Finnish pulp industry until the end of 1967. The use of Hg caused a significant increase of Hg levels in fish in several areas. High concentrations were measured in Lake Kirkkojärvi in Hämeenkyrö, SW Finland. Vast amounts of Hg are still present in the lake sediments. Since 1968 uncontaminated fibres have partly covered the contaminated layers. Since 1971 Hg has been monitored in fish, sediments and aquatic plants in the water course downstream from the pulp and paper factory. The Hg concentration of a 1-kg pike (Esox lucius) has decreased from 1.5 µg g^?1 in the years 1971–74 to 0.8 µg g^?1 in 1990.     

Soil microbial communities and extracellular enzyme activity in the New Jersey Pinelands

We have much to learn about the roles of various groups of soil microorganisms in the decomposition of soil organic matter. Any changes in the type or amount of organic matter entering the soil, due to increasing atmospheric nitrogen (N) deposition and elevated carbon dioxide, could directly affect soil microbial community structure or the decompositional functions performed by the various microbial groups. We experimentally altered soil microbial communities using a factorial combination of trenching and in-growth bags crossed with fertilization treatments consisting of two forms of inorganic N and three N-containing organic molecules of increasing molecular weight and complexity. We tested three hypotheses: (1) Different components of soil microbial communities change in different ways following the application of fertilization treatments; (2) soil fungi decrease with increased inorganic N but increase following the application of organic molecules; and (3) activity of the extracellular enzymes peroxidase and phenol oxidase, which are important in lignin degradation, decrease following the addition of inorganic N. We found that the abundance of soil microbes and their composition (measured by lipid analysis) was significantly altered following the addition of glutamic acid, but not with inorganic N or more complex N-containing organic molecules. Lipids indicative of ectomycorrhizal fungi experienced the greatest increase in abundance. Extracellular enzyme activity, in contrast, changed very little and did not parallel changes in the structure of the soil microbial community that resulted from the isolation treatments. We conclude that small additions of N-containing organic compounds can cause changes in the structure of the soil microbial community but that community changes do not necessarily have an impact on extracellular enzyme activity.     

Low sulfide concentrations affect nitrate transformations in freshwater and saline coastal retention pond sediments

Coastal areas in the southeastern USA are prone to hurricanes and strong storms that may cause salt-water influx to freshwater aquatic sediments. These changes in environmental conditions may impact sediment processes including nitrogen (N) cycling. The relative abilities of sediment microbial communities from two freshwater golf course retention ponds that drain into the adjacent wetlands, and two proximal saline wetland ponds, to remove nitrate (NO₃⁻) were compared to assess whether low concentrations of sulfide changed N-transformation processes. Microcosms were incubated with NO₃-N (300 μg g dw⁻¹) alone, and with NO₃-N and sulfide (H₂S) (100 and 200 μg g dw⁻¹). Nitrous oxide (N₂O), nitrite (NO₂⁻), NO₃⁻, ammonium (NH₄⁺), SO₄²⁻ and acid volatile sulfides were analyzed over time. The acetylene block technique was used to measure denitrification in sediment microcosms with no added H₂S. Denitrification was measured without acetylene (C₂H₂) addition in microcosms with added H₂S. With no added H₂S, denitrification was greater in the freshwater retention ponds than in the wetland ponds. Although low H₂S concentrations generally increased NO₃-N removal rates at all sites, lag periods were increased and denitrification was inhibited by low sulfide in the freshwater sediments, as evidenced by the greater concentrations of N₂O that accumulated compared to those in the wetland sediments. In addition to the inability of the freshwater sediments to convert N₂O to N₂ in the absence of C₂H₂, anomalously high transient NO₂-N concentrations accumulated in the retention pond samples. NH₄-N formation generally decreased due to H₂S addition at the freshwater sites; NH₄-N formation increased initially at the wetland sites, but was greater when no H₂S was added. Storm events that allow influx of SO₄²⁻-containing seawater into freshwater systems may change the dominant N species produced from nitrate reduction. Even low concentrations of sulfide produced incomplete denitrification and decreased formation of NH₄⁺ in these coastal freshwater sediments.     

Mercury evolution (1978–1988) in fishes of the La Grande hydroelectric complex,Quebec, Canada

From 1978 to 1988, the evolution of the Hg content of fish has been monitored in the areas affected by the La Grande hydroelectric complex. Four fish species were considered: two non piscivorous, lake whitefish (Coregonus clupeaformis) and longnose sucker (Catostomus catostomus), and two piscivorous, northern pike (Esox lucius) and walleye (Stizostedion vitreum). The evolution of Hg concentrations in time depends upon fish species and type of reservoirs. Non piscivorous fish react more rapidly than piscivorous. Five years after filling, their Hg level had increased by a factor of four in reservoirs with rapid filling and short renewal rate; levels decreased thereafter. In the La Grande 2 reservoir, the Hg concentration of 400 mm lake whitefish went from 0.16 mg kg⁻¹ before impoundment to 0.57 mg kg⁻¹ 5 yr after filling, and then started to decrease. For 700 mm northern pike, the Hg level went from 0.61 mg kg⁻¹ to 2.99 mg kg⁻¹ and was still increasing 9 yr after initial filling. In reservoirs where filling spans over a few years or with long renewal rate, their Hg content evolves more slowly. In river sections located downstream from reservoirs, the Hg content of non piscivorous species was significantly higher than in reservoirs. In 1988, whitefish exhibited values of 1.22 mg kg⁻¹ in the tailwater of the La Grande 2 power station, compared to 0.48 mg kg⁻¹ in the forebay. This phenomenon could be related to the drift of food organisms from the upstream reservoir. A study of several reservoirs of the Canadian Shield, which were created between 6 and 67 yr ago suggests that it could take between 20 and 30 yr before Hg concentration in fish return to preimpoundment levels.     

Mercury in the surface water of Swedish forest lakes —concentrations,speciation and controlling factors

Concentrations of total Hg and five operationally defined Hg species were determined in the surface water of 25 Swedish forest lakes of different type. Regional and seasonal variations were studied during the ice-free season of 1986. The concentration of total Hg was usually in the range of 2 to 10 μg m-3. Hg concentrations were highly correlated to the concentration of humic matter measured as water color. Hg concentrations were about twice as high in acidic lakes (pH 5) than in circumneutral lakes, which is attributed basically to the acidity of humic compounds acting as Hg carriers in boreal waters. Significant seasonal variations were caused by hydrological processes. During periods of high water flow, Hg concentrations increased dramatically, especially in humic lakes. Between spring and autumn, chemically reactive Hg compounds were gradually replaced by more inert species. Hg/C ratios were higher than in surface runoff from forest watersheds, indicating a significant impact of direct deposition of Hg on lake surfaces during summer. Regional differences were small despite differences in Hg contamination.