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B P Jackson

Publications and source records attributed to B P Jackson.

At least 19 recordsLinked to original sources
PubMed2006

Fate of arsenic compounds in poultry litter upon land application.

The use of the organic As compound, roxarsone, as an antibiotic additive to poultry feed continues to raise concern over potential negative environmental impacts. Total As concentration in poultry litter can reach >40 mg kg(-1) and both roxarsone and its mineralization product As(V) have been identified in poultry litters (PL). To investigate the fate of these As species upon land application of PL we conducted two studies. In the first, an Orangeburg soil (Ultisol from the Atlantic Coastal Plain) was spiked with either 20 mg kg(-1) As(V) or roxarsone and incubated at 10% moisture content for 4 months. Exchangeable As was determined periodically by extraction with 0.1M PO(4). Both As(V) and roxarsone displayed similar desorption; initially, approximately 70% of added As was ligand exchangeable and this decreased to 35% after 4 months incubation, presumably due to either slow sorption reactions or a change in solid phase speciation of As to less exchangeable forms. In the second study, various manipulations of two PL samples were applied to the Orangeburg soil at realistic field application rates. The treatments were wet to 10% moisture content and water soluble As, Cu and organic carbon (DOC) was measured over 30 days. Arsenic and Cu solubility were highest from the dried litter samples. Ashing of the PLs decreased soluble As and Cu, presumably because of the loss of organic matter from the ashed litter and subsequent decrease in DOC. Application of leachates from either PL resulted in higher concentrations of soluble As and Cu than when the soil was amended with equivalent concentrations of soluble As and Cu dissolved in DI H(2)O. We hypothesize that the increased levels of DOC from the PL treatments enhance As and Cu solubility through competitive sorption and complexation, respectively. In fact, As and Cu solubility was correlated to DOC levels in the amended soil extracts. Even though land application of PL introduced relatively low concentrations of As and Cu to soil it appeared that other soluble constituents of PL significantly enhanced As and Cu solubility.

Animals↗
PubMed2005

Evidence for biogenic pyromorphite formation by the nematode Caenorhabditis elegans.

The determination of chemical speciation and spatial distribution is a prerequisite for a mechanistic understanding of contaminant bioavailability and toxicity to an organism. We have employed synchrotron X-ray techniques to study Cu and Pb speciation and spatial distribution in the soil nematode Caenorhabditis elegans. Nematodes were exposed to each metal ion singly or simultaneously in solution for 24 h and were then rinsed thoroughly and preserved in formalin for transportation to the National Synchrotron Light Source. Experiments were conducted at the microprobe beamline X26A employing a focused beam of approximately 10 microm in diameter. Nematodes were mounted in agar gel on Kapton tape. Two-dimensional elemental maps for Cu- and Pb-exposed nematodes were collected in fluorescence mode. Copper was homogeneously distributed throughout the body of the nematode, but Pb exhibited a high degree of localization in the nematode, exclusively in the anterior pharynx region. Detectable localized concentrations of Pb in C. elegans occurred at aqueous exposure concentrations of 2.4 microM. Micro X-ray diffraction of these Pb hotspots gave a diffraction pattern indicating a crystalline Pb solid that was consistent with the Pb phosphate, pyromorphite. Biogenic inorganic phosphate granule formation is relatively common in soil invertebrates; however, these phosphates are typically amorphous, and we believe that this is the first report of crystalline pyromorphite formed internally in an organism.

Animals↗
PubMed2004

Responses of benthic fish exposed to contaminants in outdoor microcosms--examining the ecological relevance of previous laboratory toxicity tests.

Previous laboratory studies indicate that coal combustion wastes (a mixture composed of fly ash and other lower volume wastes such as bottom ash; hereafter collectively referred to as ash) adversely affect the health of benthic fish (Erimyzon sucetta; lake chubsucker), but fish in these studies were provided with ample uncontaminated food resources. Because aquatic disposal of ash can also adversely affect food resources for benthic fish, we hypothesized that changes in resources might exacerbate the effects of ash on fish observed in laboratory studies. We exposed juvenile E. sucetta in outdoor microcosms to water, sediment, and benthic resources from an ash-contaminated site or a reference site for 45 days and compared our findings to previous laboratory studies. Benthic invertebrate biomass was nearly three times greater in controls compared to ash microcosms. Total organic content of control sediment (41%) was also greater than in ash sediments (17%), suggesting that additional benthic resources may have also been limited in ash microcosms. Benthic invertebrates isolated from the ash microcosms had trace element concentrations (As, Cd, Co, Cr, Cs, Se, Sr, and V) up to 18 times higher than in weathered ash used in laboratory studies. The concentrations of trace elements accumulated by fish reflected the high dietary concentrations encountered in the ash microcosms and were associated with reduced growth (final mass = 0.07 g) and survival (25%) compared to controls (0.37 g and 67%, respectively). Accumulation of trace elements, as well as reductions in growth and survival, were more pronounced than in previous laboratory studies, suggesting that resource conditions may be important in mediating ash toxicity. Taken together, our studies suggest that ash discharge into aquatic systems is a more serious threat to the health of benthic fish than previously predicted based upon laboratory toxicity tests.

Analysis of Variance↗
PubMed2003

Maternal transfer of contaminants to eggs in common grackles (Quiscalus quiscala) nesting on coal fly ash basins.

Coal combustion is a major source of trace elements to the environment. Aquatic disposal of wastes from this process can result in reproductive failure in many wildlife species, but little is known regarding impacts on avian fauna. Individual eggs were collected from common grackles (Quiscalus quiscala) nesting in association with coal fly ash settling basins and a reference site to determine if females from the contaminated site transfered trace elements to their eggs. Whole clutches were also collected from both sites to examine inter- and intra-clutch variability of maternally transferred contaminants. Selenium was the only trace element found in significantly higher concentrations in ash basin eggs (x = 5.88 +/- 0.44 microg/g DW) than in reference eggs (x = 2.69 +/- 0.13 microg/g DW). Selenium concentrations in eggs from the ash basins were above background levels, but did not exceed higher proposed Se toxicity thresholds. Inter- and intra-clutch variation was higher for ash basin clutches than reference clutches. The relationship between selenium concentrations and laying order (estimated by egg mass) was not statistically significant, but increased Se concentration in the second egg of most ash basin clutches followed by declining concentrations in subsequent eggs suggested that further examination of this pattern might be warranted.

Animals↗
PubMed2003

Altered swimming performance of a benthic fish (Erimyzon sucetta) exposed to contaminated sediments.

Numerous field surveys suggest that coal combustion wastes (ash) adversely affect fish populations, but few controlled laboratory studies have evaluated the responses of individual fish to ash exposure. Available information suggests that sublethal effects of ash, including decreased growth rates and reduced fecundity, may be important manifestations of ash toxicity. Here, we hypothesized that ash may also alter swimming performance, which could ultimately have important implications for the autecology of affected species. To test this hypothesis, we measured sprint speed and critical swimming speed (U(crit)) of juvenile lake chubsuckers (Erimyzon sucetta) exposed to ash in the laboratory. Fish exposed to ash for 90-100 days accumulated significant concentrations of As, Se, Sr, and V; exhibited severe fin erosion; and had reduced sprint speed and U(crit). Compared to controls, sprint speed of ash-exposed fish was reduced by 30% at 5 cm and the percent reduction was further reduced to 104% at 20 cm. Critical swimming speed was approximately 50% lower in fish exposed to ash compared to controls. Additionally, the typical positive relationship between standard length and U(crit) was absent in fish exposed to ash. Because reductions in swimming performance could not be attributed to pollutant-induced differences in body condition or fin morphology, we hypothesize that physiological disruptions (e.g., increased energy demands, decreased oxygen uptake or transport) are responsible for the observed effects and warrant further attention.

Animals↗
PubMed2002

Trace element speciation in largemouth bass ( Micropterus salmoides) from a fly ash settling basin by liquid chromatography-ICP-MS.

Analytical techniques used to examine the chemical speciation of multiple trace elements are important for the investigation of biological systems. Size exclusion chromatography (SEC) coupled to ICP-MS was used to investigate the speciation of Se, As, Cu, Cd and Zn in tissue extracts from a largemouth bass (Micropterus salmoides) collected from a coal fly ash basin and results were compared to a largemouth bass collected at a reference site. Using a Biosil SEC column, with an effective separation range of 100-7 KDa, Cu, Zn and Cd were shown to be bound to metallothionein (MT) in the liver, gill and, to a lesser extent, gonad tissue extract. In liver, muscle and gill of the ash basin bass, Se was predominantly present as low molecular weight species. Only in the gonad extract was the major fraction of Se associated with high molecular weight species. For the liver and gill extracts, further SEC-ICP-MS on a column with an effective separation range of 7000-500 Da was performed, but Se species still eluted near the total volume of the column suggesting a low molecular weight organic or inorganic species. Ion chromatography (IC)-ICP-MS using an AS7 column and HNO(3) gradient elution indicated that the Se and As species in the liver and gill extracts had similar retention times but these retention times did not correspond to retention times for As(III), As(V), dimethylarsenate, arsenobetaine, Se(IV), Se(VI), seleno-methionine, or seleno-cystine.

Animals↗
PubMed2002

Effects of food ration on survival and sublethal responses of lake chubsuckers (Erimyzon sucetta) exposed to coal combustion wastes.

Study organisms in chronic toxicological bioassays are often provided with excessive resources to remove food limitations as a confounding experimental variable. Under more ecologically realistic situations, resources are often less abundant and such restrictions may alter the responses of organisms to environmental contaminants. Here, we investigated the interaction between resource level and sediment toxicity in the lake chubsucker, Erimyzon sucetta. For 78 days we fed fish one of three ration levels (1X, 2X, 4X; uncontaminated food) that was grazed directly from either clean sand or coal ash-contaminated sediments. Despite provision of uncontaminated food, fish exposed to the contaminated sediments accumulated significant whole body concentrations of As, Se, Sr, and V. Food ration affected the pattern of Se accumulation, with lowest concentrations accumulated by fish supplied with the lowest rations (1X). Paradoxically, fish in the 1X-ash treatment were most adversely effected by ash-exposure, despite having Se burdens much lower than fish in the 2X- and 4X-ash treatments. Fish in the 1X-ash treatment exhibited higher mortality, lower proportional growth, and increased incidence of fin erosion compared to fish provided with higher rations. Such results may, in part, be explained by the apparent inability of fish with reduced rations to maintain positive energy balance, as evidenced by their higher standard metabolic rates compared to control fish fed similar rations. Our results underscore the importance of considering resource quantity and nutritional factors in chronic bioassays in order to draw more ecologically realistic conclusions about contaminant effects.

Animal Feed↗
PubMed2001

Determination of arsenic speciation in poultry wastes by IC-ICP-MS.

The aromatic organoarsenic compounds 4-hydroxy 3-nitrobenzenearsenic acid (Roxarsone, ROX) or 4-aminoben-zenearsenic acid (p-arsanilic acid, p-ASA) are used as feed additives in the poultry industry for disease control and enhanced feed efficiency. While federal regulations govern acceptable As concentrations in edible tissue, elevated As concentrations occur in poultry litter, which raises concerns over repeated land application of poultry litter in agriculture. As a precursor to studying the fate of these organoarsenic compounds in soils, three speciation methodologies were developed to separate ROX and p-ASA from the more common and more toxic As species arsenate, arsenite, dimethyl arsenic acid (DMA), and monomethyl arsenic acid (MMA). The six arsenic species were separated on a Dionex AS14 column using a PO4 eluant, an AS16 column using a OH- eluant, and an AS7 column using a HNO3 eluant. While all three methods provided detection limits below 0.5 microg L(-1) for all species, detection limits were lowest for the AS16 and AS7 columns, where all detection limits were generally < 0.05 microg L(-1). The major arsenic species in a water extract of a poultry litter sample was identified as ROX by all three methods with trace concentrations of DMA and As(V) also detected. The AS14 and AS16 separations also revealed a number of unidentified As species present at low concentrations, presumably metabolites of ROX. This methodology should prove useful in identifying organoarsenic compounds and the more toxic inorganic species in soils subject to poultry litter application.

Animals↗
PubMed2001

Nondestructive indices of trace element exposure in squamate reptiles.

Compared with birds, mammals, fish, and even amphibians, very little is known about the effects of contaminants on reptiles. Recent evidence that many reptile populations may be declining has stimulated demand for toxicological studies of reptiles as well as development of nondestructive sampling techniques useful for assessing and monitoring contaminant exposure. The current study experimentally evaluated the utility of shed skins, tail clips, and blood samples as nondestructive indices of trace element exposure in banded water snakes, Nerodia fasciata. For 13.5 months, snakes were either fed fish from a coal ash-contaminated site or uncontaminated food from a reference site. Snakes fed contaminated prey accumulated As, Cd, Se, Sr, and V in various organs (i.e. liver, kidney, and/or gonads). Moreover, non-parametric discriminant function analysis revealed that snakes could be placed in two groups that reliably reflected their experimental diet based upon Se, Sr, and As concentrations in tail clips, blood, and/or shed skins. We suggest that nondestructive sampling techniques, particularly analyses of blood and tail clips, may be easily applied in evaluations of contaminant exposure in the field and laboratory and may prevent excessive destructive sampling of potentially threatened reptile species.

Animals↗
PubMed2000

Detrimental effects associated with trace element uptake in lake chubsuckers (Erimyzon sucetta) exposed to polluted sediments.

Lake chubsuckers (Erimyzon sucetta) were exposed to coal ash-polluted sediments under conservative experimental conditions (filtered artificial soft water and abundant uncontaminated food). After 4 months of exposure, fish grazing the polluted sediments had significantly elevated body burdens of Se, Sr, and V. Selenium levels were particularly elevated, reaching mean whole body concentrations of 5.6 microg/g dry mass by the end of experimental manipulations. Twenty-five percent of fish exposed to pollutants died during the study. All surviving fish exposed to ash exhibited substantial decreases in growth and severe fin erosion. Total nonpolar lipids were two times higher in fish from the control treatment, but percent lipid did not differ between treatments. Because fish were presented with the same amount of food during the study, it appears fish exposed to ash utilized more energy for daily activities and/or were less efficient at converting available energy to tissues for growth and storage. The results were particularly interesting because we were unable to detect differences in standard metabolic rate (SMR) of fish between treatments. Increased energy expenditures not detectable in estimates of maintenance based on SMR, such as costs of digestion or activity, may have contributed to decreased energetic efficiency. Our findings corroborate previous studies which have documented the toxicity of ash-derived pollutants in fish.

Animals↗
PubMed1997

DAD1- and DAD2-like agonist effects on motor activity of C57 mice: differences compared to rats.

Studies on rats indicate that DAD1- and DAD2-like agonists produce a biphasic action on motor activity, with low doses reducing activity below control levels, and higher doses initially reducing, then elevating, activity for a prolonged period. Although some of the reported effects of DAD1- and DAD2-like receptor agonists on motor activity of mice are consistent with their effects on rats, the possibility of species differences is also apparent. In the current study the effects of DAD1- and DAD2-like agonists on motor activity of C57BL/6 (C57) mice were determined to establish species consistencies and differences with respect to their effects on rats. The partial DAD1-like agonist SKF 38393 reduced the activity of C57 mice at low doses and elevated activity above control levels at higher doses, if the mice were thoroughly habituated to the test chamber. The full DAD1 agonist SKF 82958 also increased the activity of C57 mice, and along with the SKF 38393 results indicates a response to DAD1 receptor stimulation similar to that reported for rats. In contrast to the species similarity in response to DAD1 stimulation, the DAD2-like agonist quinpirole produced only a dose-responsive monotonic reduction in the activity of C57 mice, whether the animals were nonhabituated or well-habituated to the testing environment, male or female, young or mid-aged, injected intraperitoneally (i.p.) or subcutaneously (s.c.), and with either low or high doses. This apparent species difference in response to quinpirole might reflect distinguishable functional properties of the DA subreceptor systems.

2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-ben↗
PubMed1995

Fast-scan cyclic voltammetry of 5-hydroxytryptamine.

Fast-scan cyclic voltammetry, a demonstrated analytical method for the in vivo detection of dopamine, is extended to the detection of in vitro and in vivo 5-hydroxytryptamine (5-HT) with the use of a specific potential wave form applied at 1000 V/s. The wave form, 0.2 to 1.0 to -0.1 to 0.2 V, is employed to accelerate electrode response times which are significantly slower with other wave forms due to the adsorption of 5-HT. The scan rate of 1000 V/s enables follow-up reactions which lead to the formation of strongly adsorptive products to be outrun. The peak current at a carbon fiber disk microelectrode exposed to 1 microM 5-HT in flow injection experiments is 1 nA, with a half-rise time of less than 200 ms. The peak current of Nafion-coated electrodes exposed to the same concentration of 5-HT is 5 nA, with a half-rise time on the order of 400 ms. The rate of adsorption of 5-HT was determined to be 4.22 +/- 0.33 s-1. Several compounds present in brain tissue as well as the pharmacological agents used to elicit 5-HT release in the caudate of the rat were evaluated. Those which gave a response could be differentiated from 5-HT on the basis of respective oxidative and reductive peak potentials. Nafion-coated electrodes were used to monitor transient increases in both dopamine and exogenous 5-HT in the caudate of the anesthetized rat in response to electrical stimulation. The rate of cellular uptake of 5-HT was shown to be 3-fold slower than dopamine uptake. NS-15841

Animals↗
PubMed1995

Dynamics of 5-hydroxytryptamine released from dopamine neurons in the caudate putamen of the rat.

Fast-scan cyclic voltammetry has been used for the detection of 5-hydroxytryptamine (5-HT) in vivo. The applied potential waveform was previously optimized to maximize response times to concentration changes. This technique has been used to reinvestigate 5-HT release from striatal dopaminergic terminals after pharmacological pretreatment as reported by Stamford et al. [13]. Our results concur with those set forth by Stamford and further show that the dopamine transporter is responsible for 5-HT uptake in this experiment.

Animals↗