Efficient Mammal Biodiversity Surveys for Ecological Restoration Monitoring.

Efficient biodiversity surveys are critical for successful restoration monitoring and management. We studied the effect of varying sampling effort on the observed species richness of surveys of small mammals (trapping transects), bats (passive acoustic detection), and medium to large mammals (trail cameras). Field studies provided mammalian biodiversity data for 4 bottomland hardwood restoration sites in northeastern Indiana. Subsampled data were used to simulate monitoring surveys with a range of levels of effort. We then used hierarchical Bayesian nonlinear mixed models to analyze how different components of sampling effort affected observed species richness, a key monitoring outcome. We found that observed small mammal richness increased with the increased number of transects in a survey, while observed bat and medium to large mammal richness increased with the increased duration of sampling. Variation between sites was important for the observed richness of small mammals and bats but not for medium to large mammals. The key driver of richness observed in simulated surveys was related to the spatial scale at which target fauna interact with the habitat, with decreasing richness accompanied by a greater spatial scale of animal-habitat interactions. Our findings suggest taxon-specific recommendations for efficiently quantifying the mammalian diversity of managed sites. Integr Environ Assess Manag 2020;00:1-13. © 2020 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

Reprint of: CYP1A protein expression and catalytic activity in double-crested cormorants experimentally exposed to Deepwater Horizon Mississippi Canyon 252 oil.

Double-crested cormorants (Phalacrocorax auritus, DCCO) were orally exposed to Deepwater Horizon Mississippi Canyon 252 (DWH) oil to investigate oil-induced toxicological impacts. Livers were collected for multiple analyses including cytochrome P4501A (CYP1A) enzymatic activity and protein expression. CYP1A enzymatic activity was measured by alkoxyresorufin O-dealkylase (AROD) assays. Activities specific to the O-dealkylation of four resorufin ethers are reported: benzyloxyresorufin O-debenzylase (BROD), ethoxyresorufin O-deethylase (EROD), methoxyresorufin O-demethylase (MROD), and pentoxyresorufin O-depentylase (PROD). CYP1A protein expression was measured by western blot analysis with a CYP1A1 mouse monoclonal antibody. In study 1, hepatic BROD, EROD, and PROD activities were significantly induced in DCCO orally exposed to 20ml/kg body weight (bw) oil as a single dose or daily for 5 days. Western blot analysis revealed hepatic CYP1A protein induction in both treatment groups. In study 2 (5ml/kg bw oil or 10ml/kg bw oil, 21day exposure), all four hepatic ARODs were significantly induced. Western blots showed an increase in hepatic CYP1A expression in both treatment groups with a significant induction in birds exposed to 10ml/kg oil. Significant correlations were detected among all 4 AROD activities in both studies and between CYP1A protein expression and both MROD and PROD activities in study 2. EROD activity was highest for both treatment groups in both studies while BROD activity had the greatest fold-induction. While PROD activity values were consistently low, the fold-induction was high, usually 2nd highest to BROD activity. The observed induced AROD profiles detected in the present studies suggest both CYP1A4/1A5 DCCO isoforms are being induced after MC252 oil ingestion. A review of the literature on avian CYP1A AROD activity levels and protein expression after exposure to CYP1A inducers highlights the need for species-specific studies to accurately evaluate avian exposure to oil.

CYP1A protein expression and catalytic activity in double-crested cormorants experimentally exposed to deepwater Horizon Mississippi Canyon 252 oil.

Double-crested cormorants (Phalacrocorax auritus, DCCO) were orally exposed to Deepwater Horizon Mississippi Canyon 252 (DWH) oil to investigate oil-induced toxicological impacts. Livers were collected for multiple analyses including cytochrome P4501A (CYP1A) enzymatic activity and protein expression. CYP1A enzymatic activity was measured by alkoxyresorufin O-dealkylase (AROD) assays. Activities specific to the O-dealkylation of four resorufin ethers are reported: benzyloxyresorufin O-debenzylase (BROD), ethoxyresorufin O-deethylase (EROD), methoxyresorufin O-demethylase (MROD), and pentoxyresorufin O-depentylase (PROD). CYP1A protein expression was measured by western blot analysis with a CYP1A1 mouse monoclonal antibody. In study 1, hepatic BROD, EROD, and PROD activities were significantly induced in DCCO orally exposed to 20ml/kg body weight (bw) oil as a single dose or daily for 5 days. Western blot analysis revealed hepatic CYP1A protein induction in both treatment groups. In study 2 (5ml/kg bw oil or 10ml/kg bw oil, 21day exposure), all four hepatic ARODs were significantly induced. Western blots showed an increase in hepatic CYP1A expression in both treatment groups with a significant induction in birds exposed to 10ml/kg oil. Significant correlations were detected among all 4 AROD activities in both studies and between CYP1A protein expression and both MROD and PROD activities in study 2. EROD activity was highest for both treatment groups in both studies while BROD activity had the greatest fold-induction. While PROD activity values were consistently low, the fold-induction was high, usually 2nd highest to BROD activity. The observed induced AROD profiles detected in the present studies suggest both CYP1A4/1A5 DCCO isoforms are being induced after MC252 oil ingestion. A review of the literature on avian CYP1A AROD activity levels and protein expression after exposure to CYP1A inducers highlights the need for species-specific studies to accurately evaluate avian exposure to oil.

Integrated risk and recovery monitoring of ecosystem restorations on contaminated sites.

Ecological restorations of contaminated sites balance the human and ecological risks of residual contamination with the benefits of ecological recovery and the return of lost ecological function and ecosystem services. Risk and recovery are interrelated dynamic conditions, changing as remediation and restoration activities progress through implementation into long-term management and ecosystem maturation. Monitoring restoration progress provides data critical to minimizing residual contaminant risk and uncertainty, while measuring ecological advancement toward recovery goals. Effective monitoring plans are designed concurrently with restoration plan development and implementation and are focused on assessing the effectiveness of activities performed in support of restoration goals for the site. Physical, chemical, and biotic measures characterize progress toward desired structural and functional ecosystem components of the goals. Structural metrics, linked to ecosystem functions and services, inform restoration practitioners of work plan modifications or more substantial adaptive management actions necessary to maintain desired recovery. Monitoring frequency, duration, and scale depend on specific attributes and goals of the restoration project. Often tied to restoration milestones, critical assessment of monitoring metrics ensures attainment of risk minimization and ecosystem recovery. Finally, interpretation and communication of monitoring findings inform and engage regulators, other stakeholders, the scientific community, and the public. Because restoration activities will likely cease before full ecosystem recovery, monitoring endpoints should demonstrate risk reduction and a successional trajectory toward the condition established in the restoration goals. A detailed assessment of the completed project's achievements, as well as unrealized objectives, attained through project monitoring, will determine if contaminant risk has been minimized, if injured resources have recovered, and if ecosystem services have been returned. Such retrospective analysis will allow better planning for future restoration goals and strengthen the evidence base for quantifying injuries and damages at other sites in the future.

Interactive effects of climate change with nutrients, mercury, and freshwater acidification on key taxa in the North Atlantic Landscape Conservation Cooperative region.

The North Atlantic Landscape Conservation Cooperative LCC (NA LCC) is a public-private partnership that provides information to support conservation decisions that may be affected by global climate change (GCC) and other threats. The NA LCC region extends from southeast Virginia to the Canadian Maritime Provinces. Within this region, the US National Climate Assessment documented increases in air temperature, total precipitation, frequency of heavy precipitation events, and rising sea level, and predicted more drastic changes. Here, we synthesize literature on the effects of GCC interacting with selected contaminant, nutrient, and environmental processes to adversely affect natural resources within this region. Using a case study approach, we focused on 3 stressors with sufficient NA LCC region-specific information for an informed discussion. We describe GCC interactions with a contaminant (Hg) and 2 complex environmental phenomena-freshwater acidification and eutrophication. We also prepared taxa case studies on GCC- and GCC-contaminant/nutrient/process effects on amphibians and freshwater mussels. Several avian species of high conservation concern have blood Hg concentrations that have been associated with reduced nesting success. Freshwater acidification has adversely affected terrestrial and aquatic ecosystems in the Adirondacks and other areas of the region that are slowly recovering due to decreased emissions of N and sulfur oxides. Eutrophication in many estuaries within the region is projected to increase from greater storm runoff and less denitrification in riparian wetlands. Estuarine hypoxia may be exacerbated by increased stratification. Elevated water temperature favors algal species that produce harmful algal blooms (HABs). In several of the region's estuaries, HABs have been associated with bird die-offs. In the NA LCC region, amphibian populations appear to be declining. Some species may be adversely affected by GCC through higher temperatures and more frequent droughts. GCC may affect freshwater mussel populations via altered stream temperatures and increased sediment loading during heavy storms. Freshwater mussels are sensitive to un-ionized ammonia that more toxic at higher temperatures. We recommend studying the interactive effects of GCC on generation and bioavailability of methylmercury and how GCC-driven shifts in bird species distributions will affect avian exposure to methylmercury. Research is needed on how decreases in acid deposition concurrent with GCC will alter the structure and function of sensitive watersheds and surface waters. Studies are needed to determine how GCC will affect HABs and avian disease, and how more severe and extensive hypoxia will affect fish and shellfish populations. Regarding amphibians, we suggest research on 1) thermal tolerance and moisture requirements of species of concern, 2) effects of multiple stressors (temperature, desiccation, contaminants, nutrients), and 3) approaches to mitigate impacts of increased temperature and seasonal drought. We recommend studies to assess which mussel species and populations are vulnerable and which are resilient to rising stream temperatures, hydrological shifts, and ionic pollutants, all of which are influenced by GCC.

Inorganic elements in green sea turtles (Chelonia mydas): relationships among external and internal tissues.

Inorganic elements from anthropogenic sources have entered marine environments worldwide and are detectable in marine organisms, including sea turtles. Threatened and endangered classifications of sea turtles have heretofore made assessments of contaminant concentrations difficult because of regulatory restrictions on obtaining samples using nonlethal techniques. In the present study, claw and skin biopsy samples were examined as potential indicators of internal tissue burdens in green sea turtles (Chelonia mydas). Significant relationships were observed between claw and liver, and claw and muscle concentrations of mercury, nickel, arsenic, and selenium (p < 0.05). Similarly, significant relationships were observed between skin biopsy concentrations and those in liver, kidney, and muscle tissues for mercury, arsenic, selenium, and vanadium (p < 0.05). Concentrations of arsenic, barium, chromium, nickel, strontium, vanadium, and zinc in claws and skin biopsies were substantially elevated when compared with all other tissues, indicating that these highly keratinized tissues may represent sequestration or excretion pathways. Correlations between standard carapace length and cobalt, lead, and manganese concentrations were observed (p < 0.05), indicating that tissue concentrations of these elements may be related to age and size. Results suggest that claws may indeed be useful indicators of mercury and nickel concentrations in liver and muscle tissues, whereas skin biopsy inorganic element concentrations may be better suited as indicators of mercury, selenium, and vanadium concentrations in liver, kidney, and muscle tissues of green sea turtles.

The influence of global climate change on the scientific foundations and applications of Environmental Toxicology and Chemistry: introduction to a SETAC international workshop.

This is the first of seven papers resulting from a Society of Environmental Toxicology and Chemistry (SETAC) international workshop titled "The Influence of Global Climate Change on the Scientific Foundations and Applications of Environmental Toxicology and Chemistry." The workshop involved 36 scientists from 11 countries and was designed to answer the following question: How will global climate change influence the environmental impacts of chemicals and other stressors and the way we assess and manage them in the environment? While more detail is found in the complete series of articles, some key consensus points are as follows: (1) human actions (including mitigation of and adaptation to impacts of global climate change [GCC]) may have as much influence on the fate and distribution of chemical contaminants as does GCC, and modeled predictions should be interpreted cautiously; (2) climate change can affect the toxicity of chemicals, but chemicals can also affect how organisms acclimate to climate change; (3) effects of GCC may be slow, variable, and difficult to detect, though some populations and communities of high vulnerability may exhibit responses sooner and more dramatically than others; (4) future approaches to human and ecological risk assessments will need to incorporate multiple stressors and cumulative risks considering the wide spectrum of potential impacts stemming from GCC; and (5) baseline/reference conditions for estimating resource injury and restoration/rehabilitation will continually shift due to GCC and represent significant challenges to practitioners.

Interactions between chemical and climate stressors: a role for mechanistic toxicology in assessing climate change risks.

Incorporation of global climate change (GCC) effects into assessments of chemical risk and injury requires integrated examinations of chemical and nonchemical stressors. Environmental variables altered by GCC (temperature, precipitation, salinity, pH) can influence the toxicokinetics of chemical absorption, distribution, metabolism, and excretion as well as toxicodynamic interactions between chemicals and target molecules. In addition, GCC challenges processes critical for coping with the external environment (water balance, thermoregulation, nutrition, and the immune, endocrine, and neurological systems), leaving organisms sensitive to even slight perturbations by chemicals when pushed to the limits of their physiological tolerance range. In simplest terms, GCC can make organisms more sensitive to chemical stressors, while alternatively, exposure to chemicals can make organisms more sensitive to GCC stressors. One challenge is to identify potential interactions between nonchemical and chemical stressors affecting key physiological processes in an organism. We employed adverse outcome pathways, constructs depicting linkages between mechanism-based molecular initiating events and impacts on individuals or populations, to assess how chemical- and climate-specific variables interact to lead to adverse outcomes. Case examples are presented for prospective scenarios, hypothesizing potential chemical-GCC interactions, and retrospective scenarios, proposing mechanisms for demonstrated chemical-climate interactions in natural populations. Understanding GCC interactions along adverse outcome pathways facilitates extrapolation between species or other levels of organization, development of hypotheses and focal areas for further research, and improved inputs for risk and resource injury assessments.

Genome-wide association identifies three new susceptibility loci for Paget's disease of bone.

Paget's disease of bone (PDB) is a common disorder characterized by focal abnormalities of bone remodeling. We previously identified variants at the CSF1, OPTN and TNFRSF11A loci as risk factors for PDB by genome-wide association study. Here we extended this study, identified three new loci and confirmed their association with PDB in 2,215 affected individuals (cases) and 4,370 controls from seven independent populations. The new associations were with rs5742915 within PML on 15q24 (odds ratio (OR) = 1.34, P = 1.6 × 10(-14)), rs10498635 within RIN3 on 14q32 (OR = 1.44, P = 2.55 × 10(-11)) and rs4294134 within NUP205 on 7q33 (OR = 1.45, P = 8.45 × 10(-10)). Our data also confirmed the association of TM7SF4 (rs2458413, OR = 1.40, P = 7.38 × 10(-17)) with PDB. These seven loci explained ∼13% of the familial risk of PDB. These studies provide new insights into the genetic architecture and pathophysiology of PDB.

Behavioral, clinical, and pathological characterization of acid metalliferous water toxicity in mallards.

From September to November 2000, United States Fish and Wildlife Service biologists investigated incidents involving 221 bird deaths at 3 mine sites located in New Mexico and Arizona. These bird deaths primarily involved passerine and waterfowl species and were assumed to be linked to consumption of acid metalliferous water (AMW). Because all of the carcasses were found in or near pregnant leach solution ponds, tailings ponds, and associated lakes or storm water retention basins, an acute-toxicity study was undertaken using a synthetic AMW (SAMW) formulation based on the contaminant profile of a representative pond believed to be responsible for avian mortalities. An acute oral-toxicity trial was performed with a mixed-sex group of mallards (Anas platyrhynchos). After a 24-h pretreatment food and water fast, gorge drinking was evident in both SAMW treatment and control groups, with water consumption rates greatest during the initial drinking periods. Seven of nine treated mallards were killed in extremis within 12 h after the initiation of dose. Total lethal doses of SAMW ranged from 69.8 to 270.1 mL/kg (mean ± SE 127.9 ± 27.1). Lethal doses of SAMW were consumed in as few as 20 to 40 min after first exposure. Clinical signs of SAMW toxicity included increased serum uric acid, aspartate aminotransferase, creatine kinase, potassium, and P levels. PCV values of SAMW-treated birds were also increased compared with control mallards. Histopathological lesions were observed in the esophagus, proventriculus, ventriculus, and duodenum of SAMW-treated mallards, with the most distinctive being erosion and ulceration of the kaolin of the ventriculus, ventricular hemorrhage and/or congestion, and duodenal hemorrhage. Clinical, pathological, and tissue-residue results from this study are consistent with literature documenting acute metal toxicosis, especially copper (Cu), in avian species and provide useful diagnostic profiles for AMW toxicity or mortality events. Blood and kidney Cu concentrations were 23- and 6-fold greater, respectively, in SAMW mortalities compared with controls, whereas Cu concentrations in liver were not nearly as increased, suggesting that blood and kidney concentrations may be more useful than liver concentrations for diagnosing Cu toxicosis in wild birds. Based on these findings and other reports of AMW toxicity events in wild birds, we conclude that AMW bodies pose a significant hazard to wildlife that come in contact with them.

Acute oral toxicity of the organophosphorus pesticide fenitrothion to fat-tailed and stripe-faced dunnarts and its relevance for pesticide risk assessments in Australia.

The scarcity of information on the effects of pesticides on native Australian vertebrates constrains the development of biologically relevant risk assessments in Australia for the registration of pesticides. The concern that endemically old and unique Australian vertebrate fauna might display high sensitivity to pesticides used for locust control provoked examination of the acute oral toxicity of the organophosphorus pesticide fenitrothion for the fat-tailed dunnart, Sminthopsis crassicaudata (Gould 1844), and the stripe-faced dunnart, S. macroura (Gould 1845). By using the up-and-down method for determining acute oral toxicity, S. crassicaudata and S. macroura were found to have estimated median lethal doses (LD50s) of 129 mg/kg (95% confidence interval [CI] = 74.2-159.0) and 97 mg/kg (95% CI = 88.3-120.0), respectively. These values are 10 to 14 times lower than the reported LD50 values for a similar-sized eutherian mammal, Mus musculus (L. 1758; LD50 = 1,100-1,400 mg/kg) and lower than all other reported mammalian LD50 values. Such wide interspecific variation in sensitivity to fenitrothion may be a consequence of underlying differences in the metabolic pathway for fenitrothion detoxification in mammals and a possible explanation for the increased toxicity of fenitrothion to dunnarts, compared with other mammals, is proposed. The unexpectedly high sensitivity of these Australian marsupials to fenitrothion emphasises the importance of adequately evaluating the risks of pesticides to endemic Australian fauna.

Fipronil toxicity in northern bobwhite quail Colinus virginianus: reduced feeding behaviour and sulfone metabolite formation.

Fipronil is a phenyl pyrazole insecticide registered for agricultural use in many countries. Avian exposure to fipronil occurs mainly by ingesting contaminated insects or seeds. There is little information regarding the toxicological effects of fipronil in avian species and even less research documenting avian behavioural responses to fipronil ingestion. We examined the effects of a single oral dose of fipronil in northern bobwhite quail, the most fipronil-sensitive species tested to date, in respect to signs of intoxication and the metabolic fate of fipronil. Fipronil-treated birds did not eat or drink following pesticide administration, and as a result lost a significant amount of body mass. Treated birds also appeared withdrawn and did not respond to disturbance within the first hour after treatment. Identifiable signs of fipronil toxicity were not observed until at least 2d after treatment. Chemical analyses indicated a difference between fipronil and fipronil-sulfone residue distribution and bioaccumulation, with significantly higher (30- to 1000-fold) tissue concentrations of the sulfone detected at all time points from 8 to 96 h post-dose in brain, liver and adipose tissues. Tissue sulfone concentrations increased significantly in fipronil-treated birds, peaking at 72 h post-dose. Body mass decreased at all time points in dosed birds. The coincidence of the particular intoxication symptoms with the time course of rise in brain sulfone levels after fipronil dosing gives insight into possible mechanisms of toxicity in this highly sensitive species.

Genome-wide association study identifies variants at CSF1, OPTN and TNFRSF11A as genetic risk factors for Paget's disease of bone.

Paget's disease of bone (PDB) is a common disorder with a strong genetic component characterized by focal increases in bone turnover, which in some cases is caused by mutations in SQSTM1. To identify additional susceptibility genes, we performed a genome-wide association study in 750 individuals with PDB (cases) without SQSTM1 mutations and 1,002 controls and identified three candidate disease loci, which were then replicated in an independent set of 500 cases and 535 controls. The strongest signal was with rs484959 on 1p13 near the CSF1 gene (P = 5.38 x 10(-24)). Significant associations were also observed with rs1561570 on 10p13 within the OPTN gene (P = 6.09 x 10(-13)) and with rs3018362 on 18q21 near the TNFRSF11A gene (P = 5.27 x 10(-13)). These studies provide new insights into the pathogenesis of PDB and identify OPTN, CSF1 and TNFRSF11A as candidate genes for disease susceptibility.

Predicting avian distributions to evaluate spatiotemporal overlap with locust control operations in eastern Australia.

Locusts and grasshoppers cause considerable economic damage to agriculture worldwide. The Australian Plague Locust Commission uses multiple pesticides to control locusts in eastern Australia. Avian exposure to agricultural pesticides is of conservation concern, especially in the case of rare and threatened species. The aim of this study was to evaluate the probability of pesticide exposure of native avian species during operational locust control based on knowledge of species occurrence in areas and times of application. Using presence-absence data provided by the Birds Australia Atlas for 1998 to 2002, we developed a series of generalized linear models to predict avian occurrences on a monthly basis in 0.5 degrees grid cells for 280 species over 2 million km2 in eastern Australia. We constructed species-specific models relating occupancy patterns to survey date and location, rainfall, and derived habitat preference. Model complexity depended on the number of observations available. Model output was the probability of occurrence for each species at times and locations of past locust control operations within the 5-year study period. Given the high spatiotemporal variability of locust control events, the variability in predicted bird species presence was high, with 108 of the total 280 species being included at least once in the top 20 predicted species for individual space-time events. The models were evaluated using field surveys collected between 2000 and 2005, at sites with and without locust outbreaks. Model strength varied among species. Some species were under- or over-predicted as times and locations of interest typically did not correspond to those in the prediction data set and certain species were likely attracted to locusts as a food source. Field surveys demonstrated the utility of the spatially explicit species lists derived from the models but also identified the presence of a number of previously unanticipated species. These results also emphasize the need for special consideration of rare and threatened species that are poorly predicted by presence-absence models. This modeling exercise was a useful a priori approach in species risk assessments to identify species present at times and locations of locust control applications, and to discover gaps in our knowledge and need for further focused data collection.

Responses of glutamate cysteine ligase and glutathione to oxidants in deer mice (Peromyscus maniculatus).

Sensitivities of a wildlife species, deer mice, to oxidants were evaluated. A single dose (1589 mg/kg body weight by intraperitoneal injection) of carbon tetrachloride, a typical hepatotoxicant, caused changes in GCL activity and GSH content in multiple organs of deer mice. Hepatic GCL activity and GSH content were depleted substantially (P<0.01), renal GCL activity increased (P<0.05). Blood, brain and heart GCL activities increased (P<0.05), whereas GSH contents decreased significantly. Deer mice were exposed to Pb, or Pb together with Cu and Zn via drinking water for 4 weeks. GCL activities were not significantly affected by treatments. GSH contents were increased significantly by Pb alone, Pb with medium and high concentrations of Cu and Zn. Effects of multi-metal-contaminated soil were investigated via lactational, juvenile and lifelong exposure to feed supplemented with soils. Metal-contaminated soils did not lead to significant effects in pups via lactation, 50-day exposure altered GSH content marginally, while 100-day exposure resulted in marked GCL activity depletion. After 100-day exposure, GCL activities of the medium soil-, high soil- and Pb-treated deer mice were only 53%, 40% and 46% of the control, respectively (P<0.0001).

Characterization of the structural and functional diversity of indigenous soil microbial communities in smelter-impacted and nonimpacted soils.

A century of mining and smelting activity at the Anaconda Smelter site in Anaconda, Montana, USA, has contaminated the surrounding soils and groundwater with metals. Soil microbial communities from six smelter-impacted sites and a nonimpacted site were compared to determine the long-term effects of a gradient of metal concentrations on microbial activity, biomass, functional diversity (Biolog microtiter plates), and structural diversity (denaturant gradient gel electrophoresis of 16S ribosomal DNA). Microbial activity and biomass were decreased in the smelter-impacted soils. Likewise, the functional and structural diversity of the microbial communities native to the smelter-impacted soils were shifted, relative to the microbial community, from the nonimpacted site. These shifts were significantly correlated with soil metal concentration and several soil physicochemical properties (pH, organic matter, NO(3), NH(4), etc.), which provides evidence of the importance of many environmental variables on microbial community dynamics in soils. Preliminary evidence of functional redundancy was observed within microbial communities native to the smelter-impacted sites, based on overlapping carbon substrate utilization patterns. However, due to culture-based selection bias, redundancy pertains only to a subset of the community and may not be ecologically relevant. Nevertheless, the effects of metal contamination on microbial communities in the present study are pronounced and results provide preliminary insight into the complex relationship between soil microbial community structure and function in anthropogenically disturbed soils.

Optimization and application of glutamate cysteine ligase measurement in wildlife species.

Glutamate cysteine ligase (GCL), synthesizing gamma-glutamylcysteine from glutamate and cysteine, is the rate-limiting enzyme in glutathione (GSH) biosynthesis. GCL activity measurement was optimized in tissues from deer mice, Sprague Dawley rats, and mallard ducks. Varying glutamic acid concentrations from 5 to 80 mM did not affect GCL activities markedly, whereas cysteine concentrations from 2.5 to 40 mM influenced GCL activities substantially. Optimal cysteine concentrations for deer mouse, Sprague Dawley rat, and mallard duck (respectively) were 30, 30, and 20 mM in liver, 10, 10, and 20 mM in kidney, 20, 20, and 30 mM in brain, and 30 mM in heart for all three species. Responses of mallard duck GCL activity to acid metalliferous water were evaluated. After subacute exposure, low doses increased GCL activity and GSH content in liver by 48.3% and 54.4%, respectively. High doses reduced GCL activities significantly in liver and kidney to 31.2% and 43.0% of the control, respectively.

Soil lead (Pb) in residential transects through Lubbock, Texas: a preliminary assessment.

Residential lead (Pb) contamination, resulting from decades-long use of leaded gasoline and lead-based paint, is likely to be present in soils in most urban areas. A screening level sampling effort demonstrated that Lubbock, Texas, USA, like other cities of its age and size, has areas of elevated soil Pb. This effort was based on soil sampling performed on residential, commercial and thoroughfare properties. The focus of this study was to investigate that component of soil contamination due to combustion of leaded gasoline. Soils were collected from the 1-2 cm surface layer from street-side property borders, well away from buildings that might lead to soil contamination from leaded paint chips. All samples were analyzed for Pb after a 1 M HNO(3) mild extraction to determine the amount of bioavailable Pb. Two of three transects through the city demonstrated significant trends of decreasing Pb concentrations with distance from the city center, paralleling a decrease in developed property age. Peak soil Pb concentrations outside city development was 4.9 +/- 0.6 mg/kg while the median concentration for the city was 35.4 mg/kg. Peak soil Pb concentrations in the city center ranged from 90.0 to 174.0 mg/kg and decreased exponentially to 6.0-9.0 mg/kg at the furthest terminus of the residential transects.