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A screening-level assessment of dissolved zinc from inactive and abandoned metal mines in the Cement Creek Basin was performed. The basin is part of the Upper Animas River Basin in the San Juan Mountains of southwestern Colorado. Stream discharge and dissolved zinc concentrations were measured at 49 stations below nonpoint sources including tailings and waste rock, point sources such as adits, and background areas. One measurement was made at a station during three flow events: storm runoff, peak snowmelt runoff, and baseflow. The highest concentrations occurred in the upper part of the basin immediately downstream from nonpoint and point source discharges, especially in the North Fork of Cement Creek. The mean...
This release is for data on Zinc concentrations and isotopic signatures of an aquatic insect (mayfly, Baetis tricaudatus). Mayflies were exposed to an aqueous zinc concentration gradient in a laboratory experiment. Zinc concentrations were measured in water, algae (mayfly food), and different mayfly lifestages. Natural abundances of carbon and nitrogen isotopes were also measured in different life stages. This data set includes on Zinc data. Isotope data are provided in a separate file. The abstract for a journal article explaining the results of the experiment follows below: Insect metamorphosis often results in substantial chemical changes that can fractionate isotopes and alter contaminant concentrations. We...
This release is for data on Zinc concentrations and isotopic signatures of an aquatic insect (mayfly, Baetis tricaudatus). Mayflies were exposed to an aqueous zinc concentration gradient in a laboratory experiment. Zinc concentrations were measured in water, algae (mayfly food), and different mayfly lifestages. Natural abundances of carbon and nitrogen isotopes were also measured in different life stages. This data set includes on Zinc data. Isotope data are provided in a separate file. The abstract for a journal article explaining the results of the experiment follows below: Insect metamorphosis often results in substantial chemical changes that can fractionate isotopes and alter contaminant concentrations. We...
The influences of spiked Zn concentrations (1-40 micromol/g) and equilibration time (approximately 95 d) on the partitioning of Zn between pore water (PW) and sediment were evaluated with estuarine sediments containing two levels (5 and 15 micromol/g) of acid volatile sulfides (AVS). Their influence on Zn bioavailability was also evaluated by a parallel, 10-d amphipod (Leptocheirus plumulosus) mortality test at 5, 20, and 85 d of equilibration. During the equilibration, AVS increased (up to twofold) with spiked Zn concentration ([Zn]), whereas Zn-simultaneously extracted metals ([SEM]; Zn with AVS) remained relatively constant. Concentrations of Zn in PW decreased most rapidly during the initial 30 d and by 11-...
Ingestion of enhanced zinc can cause memory impairments and copper deficiencies. This study examined the effect of zinc supplementation, with and without copper, on two types of memory. Rats raised pre- and post-natally on 10 mg/kg ZnCO3 or ZnSO4 in the drinking water were tested in a fear-conditioning experiment at 11 months of age. Both zinc groups showed a maladaptive retention of fearful memories compared to controls raised on tap water. Rats raised on 10 mg/kg ZnCO3, 10 mg/kg ZnCO3 + 0.25 mg/kg CuCl2, or tap water, were tested for spatial memory ability at 3 months of age. Significant improvements in performance were found in the ZnCO3 + CuCl2 group compared to the ZnCO3 group, suggesting that some of the cognitive...
The impact of human activities on biogeochemical cycles in terrestrial environments is nowhere more apparent than in urban landscapes. Trace metals, collected on roadways and transported by storm water, may contaminate soils and sediments associated with storm water management systems. These systems will accumulate metals and associated sediments may reach toxic levels for terrestrial and aquatic organisms using the retention basins as habitat. The fate and bioavailability of these metals once deposited is poorly understood. Here we present results from a dose-response experiment that examines the application of synchrotron X-ray fluorescence methods (μ-SXRF) to test the hypothesis that earthworms will bio-accumulate...
Categories: Publication; Types: Citation; Tags: Earthworms, Soils, Synchrotron, Urban, Zinc
Brown trout, Salmo trutta, exposed to heavy metals (mainly Cd and Zn) for at least 2 years in the Eagle River, Colorado, were examined for liver size and activity of the growth-promoting enzyme, ornithine decarboxylase (ODC) and compared to trout living in an uncontaminated site. Liver-somatic index (LSI) was greater for trout living in the uncontaminated site with the LSI of females being significantly greater than that of males. The LSI for females at the uncontaminated site was greater than that of females at the contaminated site, but males were not different statistically. ODC activity in the livers of both males and females was lower at the contaminated site. However, males and females did not differ with...
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Desertification is a global problem, costly to national economies and human societies. Restoration of biological soil crusts (BSCs) may have an important role to play in the reversal of desertification due to their ability to decrease erosion and enhance soil fertility. To determine if there is evidence that lower fertility may hinder BSC recolonization, we investigated the hypothesis that BSC abundance is driven by soil nutrient concentrations. At a regional scale (north and central Colorado Plateau, USA), moss and lichen cover and richness are correlated with a complex water?nutrient availability gradient and have approximately six-fold higher cover and approximately two-fold higher species richness on sandy soils...
Phosphorus (P) efficiency (shoot dry weight at low P/shoot dry weight at high P) of a cultivar is the ability to produce a high yield in a soil that is limited in that element for a standard genotype. The large variation in P efficiency of different crops provides opportunities for screening crop species that perform well on low phosphorus soil. To explain the differences in P efficiency of sunflower (Helianthus annuus L.) cultivars a glasshouse pot experiment was conducted by using P-deficient soil [0.5 M sodium bicarbonate (NaHCO3)-extractable P 8.54 mg kg-1] treated with 0 (low P) and 100 mg P kg-1 soil (high P). The relationship between P efficiency and P, calcium (Ca), iron (Fe), zinc (Zn), and manganese (Mn)...
The influences of spiked Zn concentrations (1-40 micromol/g) and equilibration time (approximately 95 d) on the partitioning of Zn between pore water (PW) and sediment were evaluated with estuarine sediments containing two levels (5 and 15 micromol/g) of acid volatile sulfides (AVS). Their influence on Zn bioavailability was also evaluated by a parallel, 10-d amphipod (Leptocheirus plumulosus) mortality test at 5, 20, and 85 d of equilibration. During the equilibration, AVS increased (up to twofold) with spiked Zn concentration ([Zn]), whereas Zn-simultaneously extracted metals ([SEM]; Zn with AVS) remained relatively constant. Concentrations of Zn in PW decreased most rapidly during the initial 30 d and by 11-...
Insect metamorphosis often results in substantial chemical changes that can fractionate isotopes and alter contaminant concentrations. We exposed larval mayflies (Baetis tricaudatus) to an aqueous zinc gradient (3-340 µg Zn/l) and measured the change in zinc tissue concentrations at different stages of metamorphosis. We also measured changes in stable isotopes (δ15N and δ13C) in unexposed B. tricaudatus. Zinc concentrations in larvae were positively related to aqueous zinc, increasing 9-fold across the exposure gradient. Zinc concentrations in adults were also positively related to aqueous concentrations, but were 7-fold lower than larvae. However, this relationship varied according to adult substage (subimago vs...
    map background search result map search result map Evidence for micronutrient limitation of biological soil crusts- Importance to arid-lands restoration Evidence for micronutrient limitation of biological soil crusts- Importance to arid-lands restoration