Geology topics

Mary G. Henry

Publications and source records attributed to Mary G. Henry.

5 recordsLinked to original sources

USGS1999

Assessing environmental contaminant threats to lands and biota managed by the U.S. Fish and Wildlife Service

The Contaminant Assessment Process (CAP) is a standardized approach for documenting and assessing threats posed by environmental contaminants to lands and biota managed by the Department of the Interior (DOI). The Biomonitoring of Environmental Status and Trends (BEST) Program of the U.S. Geological Survey Biological Resources Division (USGS/BRD) developed the CAP cooperatively with the U.S. Fish and Wildlife Service's (FWS) Division of Environmental Contaminants (DEC). The CAP involves two parts, a retrospective analysis, and if needed, field-sampling. The retrospective analysis documents the ecological characteristics, management goals, areas potentially vulnerable to hazardous substance spills, and habitats of importance for the DOI land unit of interest. In addition, contaminant transport pathways and sources (point and nonpoint) are identified and potentially contaminated areas delineated. The second part of the CAP involves developing field-sampling plans to confirm the presence or effects of contaminants identified in the retrospective analysis. Field-sampling deemed necessary to confirm contaminant issues on national wildlife refuges identified through the retrospective analyses of CAP is handled as part of DECs on- and off-refuge investigation programs. By gathering and interpreting information, the CAP generates valuable insight regarding contaminant issues that may be affecting refuges. Findings from the CAP can help FWS stewards select options that reduce contaminant impacts on the habitats and species that they manage. Information synthesized through the CAP also contributes to the development of Comprehensive Conservation Plans mandated through the National Wildlife Refuge System Improvement Act of 1997. To insure that this information has the maximum benefit to the agency, DEC and the BEST Program jointly developed a data management system to support the CAP. This system facilitates information acquisition from remote sources and serves as a permanent data repository. Thus, the system documents CAP findings, enhances FWS's institutional memory, and supports informed management decisions. This document is a user's guide, intended for use by FWS field biologists responsible for applying the retrospective analysis portion of the CAP to FWS national wildlife refuge lands and provides instructions for entering information into the data management system. This is the third revision of the original document written in 1993 by scientists of the Idaho National Engineering and Environmental Laboratory.

Open-File Report↗

USGS1993

Factors affecting feeding behavior and survival of juvenile lake trout in the Great Lakes

We explored the importance of experience with feeding on live prey, of cataracts, of strain, and of maternally transferred contaminants for the feeding rate and predator avoidance behavior of young lake trout Salvelinus namaycush . Hatchery-reared and feral juvenile lake trout were tested separately as predators on lake trout fry in tanks with artificial cobble reefs. Feral fish captured more prey per day and more prey per strike than did hatchery lake trout. The predatory performance of hatchery and feral fish did not improve significantly with experience. Feeding rates did not differ between lake trout with unilateral cataracts and normal-eyed fish, but significantly diminished for lake trout with bilateral cataracts. Neither strain nor contaminant background affected the ability of fry to feed or to avoid predators. Of the factors studied, previous experience with live food under natural conditions (i.e., the experience of feral fish) was the most important factor affecting feeding behavior of young lake trout.

Transactions of the American Fisheries Society↗

USGS1991

Feeding rate of slimy sculpin and burbot on young lake charr in laboratory reefs

Predation and contaminants are two possible factors in the poor recruitment of young lake charr Salvelinus namaycush in the Great Lakes. We measured the feeding rate of slimy sculpins Cottus cognatus and burbot Lota lota on young lake charr (uncontaminated young from eggs of a hatchery brood stock and contaminated young from eggs of Lake Michigan lake charr) in laboratory test chambers with a cobble substrate. The median daily consumption rate of sculpins for all tests was 2 lake charr eggs (N = 22 tests; 95% confidence interval, O-13) and 2 lake charr free embryos (N = 31 tests; 95% confidence interval, O-10). Feeding rate did not differ between hatchery and contaminated prey. Slimy sculpins continued to feed on lake charr when another prey organism, the deepwater amphipod Pontoporeia hoyi , was present. Feeding by burbot on free embryos (4-36 d -l ) increased as the mobility of young increased, but burbot consumed about 10% of their body weight weekly in free-swimming young (140-380 d -l ). Predation on lake charr eggs by sculpins could beconsiderable over the 100 to 140 d incubation period, and burbot could eat large numbers of free-swimming lake charr as the young fish left the reef. Predation pressure on young lake charr may inhibit rehabilitation ofself-sustaining populations of lake charr on some reefs unless a critical egg density has been reached.

Environmental Biology of Fishes↗

USGS1990

Toxicokinetics of PAHs in Hexagenia

The accumulation kinetics of two waterborne polycyclic aromatic hydrocarbons (PAHs), benzo[a]pyrene (BAP) and phenanthrene (PHE), were studied in the mayfly nymph ( Hexagenia limbata ). The uptake clearance decreased while the bioconcentration of BAP increased with an increase in weight of the H. limbata nymph. The relationship between uptake clearance and bioconcentration for PHE was variable, and bioconcentration was greater for the heavier animals. Two kinetic models were used to evaluate the effect of nymph weight on disposition of PAHs: (a) the amount-uptake clearance model, similar to models most frequently used in environmental toxicology; and (b) a clearance-volume model, similar to models used in clinical pharmacology. The two models gave similar predictive results but were different in a few cases. These differences in common parameter estimation probably resulted from methodologies used and high data variability rather than the models themselves, since they are mathematically equal. Some of the parameters are unique to each of the models and are defined and described. The clearance of oxygen from water is inversely and linearly related to the weight of the mayfly nymphs, but oxygen clearances were always much less than the uptake clearances of the PAHs. The high PAH uptake clearance compared to oxygen clearance implies a greater surface area or efficiency for PAH accumulation from water.

Environmental Toxicology and Chemistry↗

USGS1990

Benthic invertebrate bioassays with toxic sediment and pore water

The relative sensitivities of bioassays to determine the toxicity of sediments were investigated and three methods of making the sample dilutions required to generate dose-response relationships were compared. The assays studied were: (a) Microtox®, a 15-min assay of Photobacterium phosphoreum bioluminescence inhibition by pore water; (b) 48-h Daphnia magna lethality test in pore water; (c) 10-d subchronic assay of lethality to and reduction of weight gain by Chironomus tentans performed in either whole sediment or pore water; (d) 168-h acute lethality assay of Hexagenia limbata in either whole sediment or pore water. The three methods of diluting sediments were: (a) extracting pore water from the toxic location and dilution with pore water from the control station; (b) diluting whole sediment from the toxic location with control whole sediment from a reference location, then extracting pore water; and (c) diluting toxic, whole sediment with whole sediment from a reference location, then using the whole sediment in bioassays. Based on lethality, H. limbata was the most sensitive organism to the toxicity of Detroit River sediment. Lethality of D. magna in pore water was similar to that of H. limbata in whole sediment and can be used to predict effects of whole sediment toxicity to H. limbata. The concentration required to cause a 50% reduction in C. tentans growth (10-d EC50) was approximately that which caused 50% lethality of D. magna (48-h LC50) and was similar to the toxicity that restricts benthic invertebrate colonization of contaminated sediments. While the three dilution techniques gave similar results with some assays, they gave very different results in other assays. The dose-response relationships determined by the three dilution techniques would be expected to vary with sediment, toxicant and bioassay type, and the dose-response relationship derived from each technique needs to be interpreted accordingly.

Environmental Toxicology and Chemistry↗