Association between Mediterranean diet and metal mixtures concentrations in pregnant people from the New Hampshire Birth Cohort Study

Diet is a primary source of nutrients but also toxic metal exposure. In pregnancy, balancing essential metal exposure while reducing non-essential ones is vital for fetal and maternal health. However, the effect of metal mixtures from diets like the Mediterranean, known for health benefits, remains unclear. This study aimed to explore the association between Mediterranean diet adherence and metals exposure, both individually and as mixtures. The study involved 907 pregnant participants from the New Hampshire Birth Cohort Study. We calculated the relative Mediterranean diet score (rMED) through a validated food frequency questionnaire, which includes 8 traditional Mediterranean dietary components. Also, at ~24-28 weeks of gestation, we used ICP-MS to measure speciation of Al, Cd, Co, Cu, Fe, Hg, Mo, Ni, Sb, Se, Sn, Zn, and As in urine, as well as Pb, Hg, As, Ni, and Se in toenails. We used multiple linear regression and Weighted Quantile Sum regression to analyze the association between rMED and metal mixtures. The models were adjusted for age, pre-pregnancy BMI, smoking during pregnancy, and educational level. High adherence to the Mediterranean diet was associated with increased urinary Al (® = 0.26 (95 % confidence interval (CI) = 0.05; 0.46)), Cd (β = 0.12 (95%CI = 0.00; 0.24)), Mo (β = 0.10 (95%CI = 0.00; 0.20)), and AsB (β = 0.88 (95%CI = 0.49; 1.27)) as well as toenail Hg (β = 0.44 (95%CI = 0.22; 0.65)), Ni (β = 0.37 (95%CI = 0.06; 0.67)), and Pb (β = 0.22 (95%CI = 0.03; 0.40)) compared to those with low adherence. The intake of fruits and nuts, fish and seafood, legumes, cereals, meat, and olive oil were found to be related to the metal biomarkers within the rMED. In conclusion, the Mediterranean diet enhances essential metal intake but may also increase exposure to harmful ones.

Supplementation of Ascophyllum nodosum meal and monensin: Effects on diversity and relative abundance of ruminal bacterial taxa and the metabolism of iodine and arsenic in lactating dairy cows

Previous research has shown that the brown seaweed Ascophyllum nodosum (ASCO) has antimicrobial and antioxidant properties and also increases milk I concentration. We aimed to investigate the effects of supplementing ASCO meal or monensin (MON) on ruminal fermentation, diversity and relative abundance of ruminal bacterial taxa, metabolism of I and As, and blood concentrations of thyroid hormones, antioxidant enzymes, and cortisol in lactating dairy cows. Five multiparous ruminally cannulated Jersey cows averaging (mean ± standard deviation) 102 ± 15 d in milk and 450 ± 33 kg of body weight at the beginning of the study were used in a Latin square design with 28-d periods (21 d for diet adaptation and 7 d for data and sample collection). Cows were fed ad libitum a basal diet containing (dry matter basis) 65% forage as haylage and corn silage and 35% concentrate and were randomly assigned to 1 of the following 5 dietary treatments: 0, 57, 113, or 170 g/d of ASCO meal, or 300 mg/d of MON. Supplements were placed directly into the rumen once daily after the morning feeding. Diets had no effect on ruminal pH and NH3-N concentration, which averaged 6.02 and 6.86 mg/dL, respectively. Total volatile fatty acid concentration decreased linearly in cows fed incremental amounts of ASCO meal. Supplementation with ASCO meal did not change the ruminal molar proportions of volatile fatty acids apart from butyrate, which responded quadratically with the lowest values observed at 56 and 113 g/d of ASCO supplementation. Compared with the control diet or diets containing ASCO meal, cows fed MON showed greater molar proportion of propionate. Diets did not affect the α diversity indices Shannon, Simpson, and Fisher for ruminal bacteria. However, feeding incremental levels of ASCO meal linearly decreased the relative abundance of Tenericutes in ruminal fluid. Monensin increased the relative abundance of the CAG:352 bacterial genus in ruminal fluid compared with the control diet. Linear increases in response to ASCO meal supplementation were observed for the concentrations and output of I in serum, milk, urine, and feces. Fecal excretion of As increased linearly in cows fed varying amounts of ASCO meal, but ASCO did not affect the concentration and secretion of As in milk. The plasma activities of the antioxidant enzymes and the serum concentrations of thyroid hormones did not change. In contrast, circulating cortisol decreased linearly in diets containing ASCO meal. The apparent total-tract digestibilities of dry matter, organic matter, and crude protein increased linearly with ASCO meal, but those of neutral and acid detergent fiber were not affected. In summary, feeding incremental amounts of ASCO meal decreased serum cortisol concentration, and increased I concentrations and output in serum, milk, feces, and urine.

Arsenic exposure in relation to apple consumption among infants in the New Hampshire Birth Cohort Study

Infants and young children commonly consume apple-based products, which may contain high concentrations of inorganic arsenic (iAs). As yet, iAs exposure from ingesting apple products has not been well-characterized in early childhood. Therefore, we investigated the association between urinary arsenic concentrations and intake of apple products in one-year-old infants participating in the New Hampshire Birth Cohort Study. A three-day food diary prior to collection of a spot urine sample was used to determine infant's consumption of apple products. The sum of urinary iAs, monomethylarsonic acid, and dimethylarsinic acid, referred to as ΣAs, was used to estimate iAs exposure. A total of 242 infants had urinary arsenic speciation analyzed without indication of fish/seafood consumption (urinary arsenobetaine < 1 μg/L) and with a completed three-day food diary. Of these, 183 (76%) infants ate apples or products containing apple. The geometric mean urinary ΣAs among the 59 infants who did not consume any type of apple product was 2.78 μg/L as compared to 2.38, 2.46, 2.28, and 2.73 μg/L among infants who exclusively consumed apple juice (n = 30), apple puree (n = 67), apples as whole fruit (n = 20) or products mixed with apples (n = 21), respectively. Differences in urinary ΣAs associated with apple consumption were not statistically significant in generalized linear models adjusted for urine dilution, rice consumption, and household water arsenic. Thus, while infants in our study frequently consumed apples and apple products, we did not find evidence that it increased iAs exposure.

Nutrient and pollutant metals within earthworm residues are immobilized in soil during decomposition

Earthworms are known to bioaccumulate metals, making them a potential vector for metal transport in soils. However, the fate of metals within soil upon death of earthworms has not been characterized. We compared the fate of nutrient (Ca, Mg, Mn) and potentially toxic (Cu, Zn, Pb) metals during decomposition of Amynthas agrestis and Lumbricus rubellus in soil columns. Cumulative leachate pools, exchangeable pools (0.1 M KCl + 0.01 M acetic acid extracted), and stable pools (16 M HNO₃ + 12 M HCl extracted) were quantified in the soil columns after 7, 21, and 60 days of decomposition. Soil columns containing A. agrestis and L. rubellus had significantly higher cumulative leachate pools of Ca, Mn, Cu, and Pb than Control soil columns. Exchangeable and stable pools of Cu, Pb, and Zn were greater for A. agrestis and L. rubellus soil columns than Control soil columns. However, we estimated that > 98 % of metals from earthworm residues were immobilized in the soil in an exchangeable or stable form over the 60 days using a mass balance approach. Micro-XRF images of longitudinal thin sections of soil columns after 60 days containing A. agrestis confirm metals immobilization in earthworm residues. Our research demonstrates that nutrient and toxic metals are stabilized in soil within earthworm residues.

Trace Metals and Metalloids in Forest Soils and Exotic Earthworms in Northern New England, USA

Trace metals and metalloids (TMM) in forest soils and invasive earthworms were studied at 9 uncontaminated sites in northern New England, USA. Essential (Cu, Mo, Ni, Zn, Se) and toxic (As, Cd, Pb, Hg and U) TMM concentrations (mg kg^-1) and pools (mg m^-2) were quantified for organic horizons (forest floor), mineral soils and earthworm tissues. Essential TMM tissue concentrations were greatest for mineral soil-feeding earthworm Octolasion cyaneum. Toxic TMM tissue concentrations were highest for organic horizon-feeding earthworms Dendobaena octaedra, Aporrectodea rosea and Amynthas agrestis. Most earthworm species had attained tissue concentrations of Pb, Hg and Se potentially hazardous to predators. Bioaccumulation factors were Cd > Se > Hg > Zn > Pb > U > 1.0 > Cu > As > Mo > Ni. Only Cd, Se Hg and Zn were considered strongly bioaccumulated by earthworms because their average bioaccumulation factors were significantly greater than 1.0. Differences in bioaccumulation did not appear to be caused by soil concentrations as earthworm TMM tissue concentrations were poorly correlated with TMM soil concentrations. Instead, TMM bioaccumulation appears to be species and site dependent. The invasive Amynthas agrestis had the greatest tissue TMM pools, due to its large body mass and high abundance at our stands. We observed that TMM tissue pools in earthworms were comparable or exceeded organic horizon TMM pools; earthworm tissue pools of Cd were up 12 times greater than in the organic horizon. Thus, exotic earthworms may represent an unaccounted portion and flux of TMM in forests of the northeastern US. Our results highlight the importance of earthworms in TMM cycling in northern forests and warrant more research into their impact across the region.

Forest Floor Lead Changes from 1980 to 2011 and Subsequent Accumulation in the Mineral Soil across the Northeastern United States

Quantifying the transport rate of anthropogenic lead (Pb) in forest soils is essential for predicting air pollution impacts on northeastern United States soil quality. In 2011, we resampled the forest floor at 16 sites across the northeastern United States previously sampled in 1980, 1990, and 2002 and also sampled the upper two mineral soil horizons. The mean forest floor Pb concentration decreased from 151 ± 29 mg kg in 1980 to 68 ± 13 mg kg in 2011. However, the mean forest floor Pb amount per unit area remained similar (10 ± 2 kg ha in 1980 and 11 ± 4 kg ha in 2011). Study sites were divided into three geographic regions: western, central, and northern. The modeled forest floor Pb response time (1/) was longer at frigid soil temperature regime sites (61 ± 15 yr) compared with mesic sites (29 ± 4 yr). Mineral soil Pb concentration and amount were approximately four times greater at western and central sites compared with northern sites for both mineral horizons. Furthermore, mean isotope ratios of Pb/Pb (1.201 ± 0.006) and Pb/Pb (2.060 ± 0.021) indicated that Pb in the western and central forest floor and mineral soil was primarily gasoline derived. Our combined analytical approach using long-term forest floor monitoring and stable Pb isotopes suggest that the majority of anthropogenic Pb deposited on soils in the western and central sites has been transported to the mineral soil, whereas it continues to reside in the forest floor at northern sites.

Coal fly ash basins as an attractive nuisance to birds: parental provisioning exposes nestlings to harmful trace elements

Birds attracted to nest around coal ash settling basins may expose their young to contaminants by provisioning them with contaminated food. Diet and tissues of Common Grackle (Quiscalus quiscala) nestlings were analyzed for trace elements to determine if nestlings were accumulating elements via dietary exposure and if feather growth limits elemental accumulation in other tissues. Arsenic, cadmium, and selenium concentrations in ash basin diets were 5× higher than reference diets. Arsenic, cadmium, and selenium concentrations were elevated in feather, liver, and carcass, but only liver Se concentrations approached levels of concern. Approximately 15% of the total body burden of Se, As, and Cd was sequestered in feathers of older (>5 days) nestlings, whereas only 1% of the total body burden of Sr was sequestered in feathers. Feather concentrations of only three elements (As, Se, and Sr) were correlated with liver concentrations, indicating their value as non-lethal indicators of exposure.

Iron and CF-related anemia: expanding clinical and biochemical relationships

INTRODUCTION

This cross-sectional study was conducted to assess the relationship between iron levels in the plasma and sputum of cystic fibrosis (CF) patients.

METHODS

Demographic, clinical, and iron-related laboratory data were prospectively obtained from 25 patients with stable clinical features and 14 patients with worsened clinical features since their most recent evaluations.

RESULTS

Compared to patients with stable clinical features, those who experienced clinical deterioration demonstrated significantly worse lung function and were more frequently malnourished and diabetic. Members of the latter group were also significantly more hypoferremic and had higher sputum iron content than patients with stable clinical features. No significant correlation was found between plasma and sputum iron levels when the groups were analyzed together and separately.

CONCLUSIONS

Sputum iron content does not correlate with iron-related hematologic tests. Hypoferremia is common in CF and correlates with poor lung function and overall health.

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.

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.

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.

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.

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.

Trace element speciation in poultry litter

Trace elements are added to poultry feed for disease prevention and enhanced feed efficiency. High concentrations are found in poultry litter (PL), which raises concerns regarding trace element loading of soils. Trace metal cation solubility from PL may be enhanced by complexation with dissolved organic carbon (DOC). Mineralization of organo-As compounds may result in more toxic species such as As(III) and As(V). Speciation of these elements in PL leachates should assist in predicting their fate in soil. Elemental concentrations of 40 PL samples from the southeastern USA were determined. Water-soluble extractions (WSE) were fractionated into hydrophobic, anionic, and cationic species with solid-phase extraction columns. Arsenic speciation of seven As species, including the main As poultry feed additives, roxarsone (ROX; 3-nitro-4-hydroxyphenylarsonic acid) and p-arsanilic acid (p-ASA; 4-aminophenylarsonic acid), was performed by ion chromatography-inductively coupled plasma-mass spectrometry (IC-ICP-MS). Total As concentrations in the litter varied from 1 to 39 mg kg(-1), averaging 16 mg kg(-1). Mean total Cu, Ni, and Zn concentrations were 479, 11, and 373 mg kg(-1), respectively. Copper and Ni were relatively soluble (49 and 41% respectively) while only 6% of Zn was soluble. Arsenic was highly soluble with an average of 71% WSE. Roxarsone was the major As species in 50% of PL samples. However, the presence of As(V) as the major species in 50% of the PL samples indicates that mineralization of ROX had occurred. The high solubility of As from litter and its apparent ready mineralization to inorganic forms coupled with the large quantity of litter that is annually land-applied in the USA suggests a potential detrimental effect on soil and water quality in the long term.

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.

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.

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.

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.

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.

The influence of extraction procedure on ion concentrations in sediment pore water

Sediment pore water has the potential to yield important information on sediment quality, but the influence of isolation procedures on the chemistry and toxicity are not completely known and consensus on methods used for the isolation from sediment has not been reached. To provide additional insight into the influence of collection procedures on pore water chemistry, anion (filtered only) and cation concentrations were measured in filtered and unfiltered pore water isolated from four sediments using three different procedures: dialysis, centrifugation, and vacuum. Peepers were constructed using 24-cell culture plates and cellulose membranes and vacuum extractors consisted of fused-glass air stones attached with airline tubing to 60-cc syringes. Centrifugation was accomplished at two speeds (2,500 and 10,000 g) for 30 min in a refrigerated centrifuge maintained at 4 degreesC. Only minor differences in chemical characteristics and cation and anion concentrations were found among the different collecting methods with differences being sediment-specific. Filtering of the pore water did not appreciably reduce major cation concentrations, but trace metals (Cu and Pb) were markedly reduced. Although the extraction methods evaluated produced pore waters of similar chemistries, the vacuum extractor provided the following advantages over the other methods: ease of extraction, volumes of pore water isolated, minimal preparation time, and least time required for extraction of pore water from multiple samples at one time.

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.

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

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.

An Investigation of the Stem Bark of Bersama abyssinica

The barks of two subspecies of BERSAMA ABYSSINICA, subspecies ABYSSINICA and subspecies PAULLINIOIDES have been shown to contain two bufadienolides: 5beta, 14beta-dihydroxy-3,6-diacetoxy-Delta (6)-bufa-20,22-trienolide ( 1) and 3-acetoxy-14beta-hydroxy-bufa-20,22-dienolide ( 2). Three sterols : beta-sitosterol, Delta (4)-stigmasten-3alpha-ol ( 3) and 4-methyl-Delta (5,23)-stigmast-dien-3beta-ol ( 4) have also been isolated. 3 is a new compound and 3 and 4 are reported for the first time from the Melianthaceae. The presence of the xanthone mangiferin is a possible taxonomic marker for the genus within this family. Differences between the two subspecies were seen on examining the glycoside fractions. The alcoholic extracts did not exhibit any anti-tumour activity in the standard test.

Scopolia lurida, Dunal; the structure of the leaves and stem

The aerial parts of Scopolia lurida contain large quantities of tropane alkaloids and are a possible source of hyoscyamine and hyoscine. The leaves and stems are very similar to those of Atropa belladonna but they can be distinguished by certain microscopical characters; these include the presence of branched covering trichomes on the leaves and stems of Scopolia lurida and the absence of idioblasts containing microsphenoidal crystals of calcium oxalate from the leaf lamina.

The structure of buckwheat, Fagopyrum esculentum Moench

The morphology and anatomy of the aerial parts of Fagopyrum esculentum have been described and the most important microscopical characters of value in the identification of commercial Buckwheat have been indicated.