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Ann Chalmers

Publications and source records attributed to Ann Chalmers.

4 recordsLinked to original sources
USGS2013

Characterization of mercury contamination in the Androscoggin River, Coos County, New Hampshire

The former chloralkali facility in Berlin, New Hampshire, was designated a Superfund site in 2005. Historic paper mill activities resulted in the contamination of groundwater, surface water, and sediments with many organic compounds and mercury (Hg). Hg continues to seep into the Androscoggin River in elemental form through bedrock fractures. The objective of this study was to spatially characterize (1) the extent of Hg contamination in water, sediment, and biota; (2) Hg speciation and methylmercury (MeHg) production potential rates in sediment; (3) the availability of inorganic divalent Hg (Hg(II)) for Hg(II)-methylation (MeHg production); and (4) ancillary sediment geochemistry necessary to better understand Hg speciation and MeHg production potential rates in this system. Concentrations of total mercury (THg) and MeHg in sediment, pore water, and biota in the Androscoggin River were elevated downstream from the former chloralkali facility compared with those upstream from reference sites. Sequential extraction of surface sediment showed a distinct difference in Hg speciation upstream compared with downstream from the contamination site. An upstream site was dominated by potassium hydroxide-extractable forms (for example, organic-Hg or particle-bound Hg(II)), whereas sites downstream from the point source were dominated by more chemically recalcitrant forms (largely concentrated nitric acid-extractable), indicative of elemental mercury or mercurous chloride. At all sites, only a minor fraction (less than 0.1 percent) of THg existed in chemically labile forms (for example, water extractable or weak acid extractable). All metrics indicated that a greater percentage of mercury at an upstream site was available for Hg(II)-methylation compared with sites downstream from the point source, but the absolute concentration of bioavailable Hg(II) was greater downstream from the point source. In addition, the concentration of tin-reducible inorganic reactive mercury, a surrogate measure of bioavailable Hg(II) generally increased with distance downstream from the point source. Whereas concentrations of mercury species on a sediment-dry-weight basis generally reflected the relative location of the sample to the point source, river-reach integrated mercury-species inventories and MeHg production potential (MPP) rates reflected the amount of fine-grained sediment in a given reach. THg concentrations in biota were significantly higher downstream from the point source compared with upstream reference sites for smallmouth bass, white sucker, crayfish, oligochaetes, bat fur, nestling tree swallow blood and feathers, adult tree swallow blood, and tree swallow eggs. As with tin-reducible inorganic reactive mercury, THg in smallmouth bass also increased with distance downstream from the point source. Toxicity tests and invertebrate community assessments suggested that invertebrates were not impaired at the current (2009 and 2010) levels of mercury contamination downstream from the point source. Concentrations of THg and MeHg in most water and sediment samples from the Androscoggin River were below U.S. Environmental Protection Agency (USEPA), the Canadian Council of Ministers of the Environment, and probable effects level guidelines. Surface-water and sediment samples from the Androscoggin River had similar THg concentrations but lower MeHg concentrations compared with other rivers in the region. Concentrations of THg in fish tissue were all above regional and U.S. Environmental Protection Agency guidelines. Moreover, median THg concentrations in smallmouth bass from the Androscoggin River were significantly higher than those reported in regional surveys of river and streams nationwide and in the Northeastern United States and Canada. The higher concentrations of mercury in smallmouth bass suggest conditions may be more favorable for Hg(II)-methylation and bioaccumulation in the Androscoggin River compared with many other rivers in the United States and Canada.

New Hampshire↗
USGS2005

Hydrogeologic framework and water quality of the Vermont Army National Guard Ethan Allen Firing Range, northern Vermont, October 2002 through December 2003

The Ethan Allen Firing Range of the Vermont Army National Guard is a weapons-testing and training facility in a mountainous region of Vermont that has been in operation for about 80 years. The hydrologic framework and water quality of the facility were assessed between October 2002 and December 2003. As part of the study, streamflow was continuously measured in the Lee River and 24 observation wells were installed at 19 locations in the stratified drift and bedrock aquifers to examine the hydrogeology. Chemical analyses of surface water, ground water, streambed sediment, and fish tissue were collected to assess major ions, trace elements, nutrients, and volatile and semivolatile compounds. Sampling included 5 surface-water sites sampled during moderate and low-flow conditions; streambed-sediment samples collected at the 5 surface-water sites; fish-tissue samples collected at 3 of the 5 surface-water sites; macroinvertebrates collected at 4 of the 5 surface-water sites; and ground-water samples collected from 10 observation wells, and samples collected at all surface- and ground-water sites. The hydrogeologic framework at the Ethan Allen Firing Range is dominated by the upland mountain and valley setting of the site. Bedrock wells yield low to moderate amounts of water (0 to 23 liters per minute). In the narrow river valleys, layered stratified-drift deposits of sand and gravel of up to 18 meters thick fill the Lee River and Mill Brook Valleys. In these deposits, the water table is generally within 3 meters below the land surface and overall ground-water flow is from east to west. Streamflow in the Lee River averaged 0.72 cubic meters per second (25.4 cubic feet per second) between December 2002 and December 2003. Streams are highly responsive to precipitation events in this mountainous environment and a comparison with other nearby watersheds shows that Lee River maintains relatively high streamflow during dry periods. Concentrations of trace elements and nutrients in surface-water samples are well below freshwater-quality guidelines for the protection of aquatic life. Brook-trout samples collected in 1992 and 2003 show trace-metal concentrations have decreased over the past 11 years. concentrations in water samples are well below levels that restrict swimming at all five stream sites at moderate and low-flow conditions and in all observation wells. Comparisons among surface-water, streambed-sediment, and biological samples collected in 2003 to earlier studies at the Ethan Allen Firing Range indicate water-quality conditions are similar or have improved over the past 15 years. Ground water in the stratified-drift aquifers at the facility is well buffered with relatively high alkalinities and pH greater than 6. Concentrations of arsenic, cadmium, chromium, lead, nickel, uranium, and zinc were below detection levels in ground-water samples. Barium, cobalt, copper, iron, manganese, molybdenum, and strontium were the only trace elements detected in ground-water samples. Cobalt and iron were detected at low levels in two wells near Mill Brook, and copper was detected at the detection limit in one of these wells. These same two wells had concentrations of barium and manganese 2 to 10 times greater than other ground-water samples. Concentrations of nutrients are at or below detection levels in most ground-water samples. Volatile organic compounds and semivolatile organic compounds were not detected in any water samples from the Ethan Allen Firing Range.

Scientific Investigations Report↗
USGS2002

Trace elements and organic compounds in streambed sediment and fish tissue of coastal New England streams, 1998-99

Streambed sediment and fish tissue were collected at 14 river sites in eastern New England during low-flow conditions in 1998 and 1999 as part of the New England Coastal Basins (NECB) study of the U.S. Geological Survey National Water-Quality Assessment (NAWQA) Program. Sampling sites were selected over a range of urban settings. Population densities at selected sites ranged from 26 to 3,585 people per square mile, and urban land use ranged from 1 to 68 percent. The streambed sediment samples were analyzed for a total of 141 contaminants, including 45 trace elements, 32 organochlorine compounds, and 64 semi-volatile organic compounds. The fish tissue samples were analyzed for 22 trace elements and 28 organochlorine compounds. Concentrations of selected contaminants in both streambed sediment and fish tissue correlated more strongly with population density than with other watershed characteristics. Cadmium, copper, lead, mercury, zinc, total polycyclic aromatic hydrocarbons (PAHs), total polychlorinated biphenyls (PCBs), dichloro diphenyl trichloroethane and metabolites (DDTM), and total chlordane in streambed sediment all showed strong positive correlations with population density (rho = 0.71 to 0.85, p value = 0.005 to <0.001). Correlations between population density and selected contaminants in fish tissue were less significant than with streambed sediment (rho = 0.62 to 0.72, p value = 0.03 to 0.008). Organic carbon concentrations were correlated with concentrations of arsenic, selenium, total PAHs, total PCBs, and DDTM in streambed sediment. The relation between concentrations of contaminants in streambed sediment and fish tissue was stronger for organochlorine compounds (rho = 0.75 to 0.55, p = 0.005 to 0.065) than for trace elements (rho = 0.63 to 0.53, p = 0.029 to 0.069). The NECB study area had the highest median concentrations of lead, mercury, total PAHs, total PCBs, and DDTM in streambed sediment and the highest median concentration of PCBs in fish tissue compared to 45 other NAWQA study units across the Nation. Concentrations of many of these constituents in streambed sediment also were frequently above the consensus-based Sediment-Quality Guidelines for the protection of wildlife, suggesting they are a threat to the health of aquatic biota in New England.

Water-Resources Investigations Report↗