Bobby J. Presley
Texas A&M University
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Featured researches published by Bobby J. Presley.
Marine Environmental Research | 2001
Peter H. Santschi; Bobby J. Presley; Terry L. Wade; Bernardo Garcia-Romero; M. Baskaran
Profiles of trace contaminant concentrations in sediment columns can be a natural archive from which pollutant inputs into coastal areas can be reconstructed. Reconstruction of historical inputs of anthropogenic chemicals is important for improving management strategies and evaluating the success of recent pollution controls measures. Here we report a reconstruction of historical contamination into three coastal sites along the US Gulf Coast: Mississippi River Delta, Galveston Bay and Tampa Bay. Within the watersheds of these areas are extensive agricultural lands as well as more than 50% of the chemical and refinery capacity of the USA. Despite this pollution potential, relatively low concentrations of trace metals and trace organic contaminants were found in one core from each of the three sites. Concentrations and fluxes of most trace metals found in surface sediments at these three sites, when normalized to Al, are typical for uncontaminated Gulf Coast sediments. Hydrophobic trace organic contaminants that are anthropogenic (polycyclic aromatic hydrocarbons, DDTs, and polychlorinated biphenyls) are found in sediments from all locations. The presence in surface sediments from the Mississippi River Delta of low level trace contaminants such as DDTs, which were banned in the early 1970s, indicate that they are still washed out from cultivated soils. It appears that the DDTs profile in that sediment core was produced by a combination of erosion processes of riverine and other sedimentary deposits during floods. Most of the pollutant profiles indicate that present-day conditions have improved from the more contaminated conditions in the 1950-1970s, before the advent of the Clean Water Act.
Environmental Science & Technology | 1994
Mahlon C. Kennicutt; Terry L. Wade; Bobby J. Presley; A. G. Requejo; James M. Brooks; G.J. Denoux
An inventory-based approach to environmental assessment that determines concentrations of sedimentary contaminants, defines their origins, and assesses the potential for biological impact is illustrated in Casco Bay, ME. The most widespread contaminants in Casco Bay are petroleum and petroleum byproducts. The highest concentrations of contaminants are associated with population centers, effluent outfalls, and spills. The majority of PAH in sediments are the product of high-temperature combustion processes. PAH concentrations at sites in close proximity to Portland exceed values believed to produce toxic responses in marine benthic organisms. In contrast, PCB, DDTs, and chlordane concentrations in the sediments are below concentrations thought to produce toxic effects in marine organisms. Metal concentrations in sediments are also below those that elicit biological responses. The geographic distribution of contaminants is initially controlled by the proximity to sources, and the regional differences in concentrations are the result of sediment accumulation patterns. Detrital (terrestrial), autochthonous marine, pyrogenic, and petroleum sources for PAH, alkanes, and trace metals are defined. 21 refs., 10 figs., 6 tabs.
Environmental Science & Technology | 1995
Mahlon C. Kennicutt; Susanne J. McDonald; Jose L. Sericano; Paul. Boothe; John. Oliver; Stephen Safe; Bobby J. Presley; Hong Liu; Douglas A. Wolfe; Terry L. Wade; Alan. Crockett; Dan. Bockus
Polycyclic aromatic hydrocarbons (PAH), polychlorinated biphenyls (PCBs), pesticides, and trace metal concentrations in McMurdo Sound and Arthur Harbor, Antarctica, sediments and marine biota are reported. Biomarkers of contaminant exposure, biliary metabolites and EROD assays, were also measured. Hydrocarbon and trace metal contamination are generally limited to within hundreds of meters of human settlements. Local releases of fossil fuels, disposal of waste materials, and aging of ship and station structures contribute to contamination. High concentrations of PCBs were detected in sediments (250-4200 ng g{sup -1}) and organisms (up to 420 ng g{sup -1}) from Winter Quarters Bay (WQB). Trace metal and PAH sediment concentrations rarely exceed levels known to cause toxic effects in marine organisms, whereas PCBs in WQB often do. Biological responses to exposure include the formation of PAH metabolites and the inducement of the P4501A detoxification system in fish. Induction of EROD activity in in vitro rat hepatoma H4IIE cell bioassays by tissue extracts correlated with known levels of PCB contamination in invertebrate tissues. Local sources of contaminants greatly exceed those attributable to long-distance atmospheric transport. 31 refs., 4 figs.
Journal of Toxicology and Environmental Health | 2000
Tamara D Zadorozhnaja; Ruth E. Little; Richard K. Miller; Nikola A Mendel; Robert J. Taylor; Bobby J. Presley; Beth C. Gladen
Ukraine is a highly industrialized country with major environmental problems and deteriorating reproductive health. Heavy metals are known reproductive toxins; a study was undertaken to determine whether they were present at sufficient concentrations to be playing a major role in these health problems. Placental concentrations of arsenic, cadmium, copper, lead, mercury, and zinc were determined in 200 women from the general population of two urban areas of Ukraine, Kyiv and Dniprodzerzhinsk. Arsenic was detected in only 5% of the samples, lead in 22%, and mercury in 28%. Cadmium was detected in almost all samples, with a median of 5.2 ng/g. Concentrations of lead, mercury, and cadmium were low compared to those reported elsewhere, while zinc and copper concentrations were comparable.Ukraine is a highly industrialized country with major environmental problems and deteriorating reproductive health. Heavy metals are known reproductive toxins; a study was undertaken to determine whether they were present at sufficient concentrations to be playing a major role in these health problems. Placental concentrations of arsenic, cadmium, copper, lead, mercury, and zinc were determined in 200 women from the general population of two urban areas of Ukraine, Kyiv and Dniprodzerzhinsk. Arsenic was detected in only 5% of the samples, lead in 22%, and mercury in 28%. Cadmium was detected in almost all samples, with a median of 5.2 ng/g. Concentrations of lead, mercury, and cadmium were low compared to those reported elsewhere, while zinc and copper concentrations were comparable.
Marine Environmental Research | 1996
Sally Jo Palmer Locarnini; Bobby J. Presley
Parts of Lavaca Bay on the central Texas coastline are closed to fishing by the Texas Department of Health due to Hg contamination. This is the first report on Hg concentrations in potential prey organisms for the contaminated fish, oysters and crabs of the area. Organisms were taken from parts of Lavaca Bay known to be contaminated with Hg and from a less contaminated area in nearby Keller Bay. All samples from Lavaca Bay analysed (algae, polychaetes, bivalves, Crustacea, detritus and wood) were higher in mercury concentration than were similar samples from Keller Bay (typically 1–10 μg/g vs < 0.5 μg/g). The mechanism for mercury uptake could not be determined in this study but for organisms confined to the contaminated areas seemed to be largely independent of species, feeding strategy or life stage.
Estuaries | 1994
David J. Velinsky; Terry L. Wade; Christian E. Schlekat; Beth L. McGee; Bobby J. Presley
Thirty-three bottom sediments were collected from the Potomac and Anacostia rivers, Tidal Basin, and Washington Ship Channel in June 1991 to define the extent of trace metal contamination and to elucidate source areas of sediment contaminants. In addition, twenty-three sediment samples were collected directly in front of and within major storm and combined sewers that discharge directly to these areas. Trace metals (e.g., Cu, Cr, Cd, Hg, Pb, and Zn) exhibited a wide range in values throughout the study area. Sediment concentrations of Pb ranged from 32.0 μg Pb g−1 to 3,630 μg Pb g−1, Cd from 0.24 μg Cd g−1 to 4.1 μg Cd g−1, and Hg from 0.13 μg Hg g−1 to 9.2 μg Hg g−1, with generally higher concentrations in either outfall or sewer sediments compared to river bottom-sediments. In the Anacostia River, concentration differences among sewer, outfall, and river sediments, along with downriver spatial trends in trace metals suggest that numerous storm and combined swers are major sources of trace metals. Similar results were observed in both the Tidal Basin and Washington Ship Channel. Cadminum and Pb concentrations are higher in specific sewers and outfalls, whereas the distribution of other metals suggests a more diffuse source to the rivers and basins of the area. Cadmium and Pb also exhibited the greatest enrichment throughout the study area, with peak values located in the Anacostia River, near the Washington Navy Yard. Enrichment factors decrease in the order: Cd>Pb>Zn>Hg>Cu>Cr. Between 70% and 96% of sediment-bound Pb and Cd was released from a N2-purged IN HCl leach. On average, ≤40% of total sedimentary Cu was liberated, possibly due to the partial attack of organic components of the sediment. Sediments of the tidal freshwater portion of the Potomac estuary reflect a moderate to highly components area with substantial enrichments of sedimentary Pb, Cd, and Zn. The sediment phase that contains these metals indicates the potential mobility of the sediment-bound metals if they are reworked during either storm events or dredging.
Environmental Pollution | 1996
A.V. Tkalin; Bobby J. Presley; P.N. Boothe
New data on trace metal distribution in bottom sediments of Peter the Great Bay (the Sea of Japan) are presented. Much higher concentrations were detected near the most likely anthropogenic sources of trace metal inputs (waste water discharges from Vladivostok and Nakhodka, and the Vladivostok coastal landfill). Sediments in these contaminated areas were up to 700 ppm in Zn, 530 ppm in Pb, 7 ppm in Cd and 3 ppm in Hg. River runoff is of minor importance as a metal source in the investigated areas. The spatial distribution of trace metals outside the areas directly influenced by sewage discharges is regulated by natural processes such as sediment sorting by grain size. Based on radiometric dating of sediment cores, increases in the trace metal content of bottom sediments near Vladivostok begun in approximately 1945.
Marine Pollution Bulletin | 1998
Yungkul Kim; Eric N. Powell; Terry L. Wade; Bobby J. Presley; Jose L. Sericano
The National Status and Trends Mussel Watch data for 1997 were used to compare the distribution of parasites between sentinel bivalves of the East, West, Gulf and Great Lakes coasts of the USA and to assess the relationship of parasitism to contaminant body burden. Overall, five patterns dominated the geographic distribution of the parasite fauna. (1) Certain parasites, such as Nematopsis, were principally associated with oysters from the southeast and Gulf coasts. (2) Discounting Nematopsis, oysters and mussels did not differ significantly in total parasite infection intensity. (3) West coast mussel populations were always lower in infection intensity than East coast mussels and rarely showed anything but a sporadic pattern of infection. (4) East coast mussels typically had a focus of infection in the Boston Harbor region. (5) With the exception of Nematopsis, mussels on the West coast, Mytilus edulis and Mytilus californianus, did not differ significantly in their parasite fauna. The geographic distributions of most parasites and disease-causing organisms varied independently. Any two parasites rarely co-occurred predictably over wide areas and never on more than one coast. Certain contaminants were correlated with certain parasites on one coast but not the other or in one bivalve type but not another. Statistics that emphasized infection intensity found significant relationships between parasitism and contaminant body burden most often in East and Gulf coast oysters and West coast mussels and, in most cases, higher body burdens were associated with lower infection intensities. Statistics that emphasized prevalence also identified significant relationships most often in East and Gulf coast oysters and West coast mussels. In contrast to infection intensity, most significant results occurred because parasites were observed more often in locales characterized by higher contaminant body burdens. In no case was a parasite/ contaminant pair significant for both infection intensity and prevalence.
Helgoland Marine Research | 1992
Elizabeth A. Wilson; Eric N. Powell; Terry L. Wade; R. J. Taylor; Bobby J. Presley; James M. Brooks
As part of NOAAs Status and Trends Program, oysters were sampled from 43 sites throughout the Gulf of Mexico from Brownsville, Texas, to the Florida Everglades from 1986 to 1989. Oysters were analysed for body burden of a suite of metals and petroleum aromatic hydrocarbons (PAHs), the prevalence and intensity of the oyster pathogen,Perkinsus marinus, and condition index. The contaminants fell into two groups based on the spatial distribution of body burden throughout the Gulf. Arsenic, selenium, mercury and cadmium were characterized by clinal reduction in similarity with distance reminiscent of that followed by mean monthly temperature and precipitation. Zinc, copper, PAHs and silver showed no consistent geographic trend. Within local regions, industrial and agricultural and use andP. marinus prevalence and infection intensity frequently correlated with body burden. Contaminants and biological attributes followed one of three temporal trends. Zinc, copper and PAHs showed concordant shifts over 4 years throughout the eastern and southern Gulf. Mercury and cadmium showed concordant shifts in the northwestern Gulf. Selenium, arsenic, length, condition index andP. marinus prevalence and infection intensity showed concordant shifts throughout most of the entire Gulf. Concordant shifts suggest that climatic factors, the El Niño/Southern Oscillation being one example, exert a strong influence on biological attributes and contaminant body burdens in the Gulf. Correlative factors are those that probably affect or indicate the rate of tissue turnover and the frequency of reproduction; namely, temperature, disease intensity, condition index and length.
Ecotoxicology | 2003
Carol D. Swartz; Kirby C. Donnelly; Arif Islamzadeh; Gilbert T. Rowe; William J. Rogers; A. A. Mekhtiev; Rafik Kasimov; Thomas J. McDonald; Jeffery K. Wickliffe; Bobby J. Presley; John W. Bickham
Sediment from a wetland adjacent to an industrial wastewater treatment plant in Sumgayit contained concentrations of total PAHs, total PCBs, aldrin, biphenyl, chlordane, DDT, mercury, β-endosulfan, heptachlor, α-hexacyclohexane (α-HCH), γ-HCH, and several individual PAH congeners that were elevated relative to published sediment quality guidelines. Chemical analyses of tissues from European pond turtles (Emys orbicularis) had increased levels of many of the same chemicals including aldrin, chlordane, heptachlor, α-HCH, total PCBs, total PAHs, and mercury, compared to reference turtles. In addition, turtle tissues contained elevated levels of DDD, hexachlorobenzene (HCB), and pentachlorobenzene that were not elevated in the sediment sample. Some differences were observed in contaminant levels between European pond turtles and Caspian turtles (Mauremys caspica) taken from the ponds in Sumgayit. Salmonella/microsome mutagenicity assays on pond sediments were negative or weakly positive. Micronuclei in European pond turtles were statistically correlated with tissue levels of mercury, heptachlor, DDD, HCB, and trans-nonachlor. Microcosm experiments using Russian sturgeon (Acipenser gueldenstaedtii) showed a positive dose–response relationship between exposure to suspended contaminated pond sediment and acute toxicity. Chemical and biological assays used in this study show the industrial area of Sumgayit is heavily contaminated with a complex mixture of toxic pollutants. Exposure to contaminated sediments produced acute effects in Russian sturgeon, but genotoxic effects appear to be slight.