Effects of Lead (Pb) from Smelter Operations in an Urban Terrestrial Food Chain at a Colorado Superfund Site.

Lead (Pb) is ubiquitous in urban environments, and it is a risk factor for wildlife. But wildlife are particularly at risk for exposure near smelters in urban areas where higher than safe Pb levels in the soil have the potential to transfer to the food chain. Therefore, we investigated whether wildlife are at risk of Pb exposure and differences in Pb bioaccumulation in trophic levels at a Superfund site in an urban area of Colorado. We sampled soil, vegetation, arthropods, and birds at four sites: two contaminated sites (one at the Superfund site and one near the Superfund site) and two reference sites with low predicted Pb contamination. We found significantly higher Pb levels in the soil at the contaminated Slag pile at the Superfund site, compared to the other sites. At the Slag pile, Pb levels were the highest in vegetation and both arthropods and birds accumulated Pb. However, Pb did not increase between trophic levels in the terrestrial food web at the site. We concluded that smelter operations at the Superfund site resulted in significantly higher levels of Pb in the soil and sublethal accumulation in all taxa studied. This research can be used to mitigate the risks to vulnerable wildlife populations exposed to Pb at the Superfund site. Further examination of Pb toxicity in vulnerable taxa is critical to conserving wild populations and ecosystems near contamination zones.

Enhanced adsorptive removal of indigo carmine dye by bismuth oxide doped MgO based adsorbents from aqueous solution: equilibrium, kinetic and computational studies.

Novel doped MgO nanoadsorbents were effectively fabricated at various Bi2O3 doping concentrations (0, 2.5, 5 and 10%). DFT-D3 study showed that the doping is done by substitution of two magnesium atoms by two bismuth atoms with the creation of a vacancy of one Mg atom. TEM, SEM, EDX, BET, XRD, and FTIR were used to characterize the obtained nanostructures. The removal of indigo carmine (IC) dyes from wastewater by doped MgO nanoparticles is investigated. Experimental parameters such as the initial dye concentration, contact time, Bi2O3 doping concentration, and pH were optimized to enhance the adsorption capacity. Bi2O3 doped MgO prepared at 5% (MgOBi2) is the best adsorbent with a maximum IC adsorption capacity of 126 mg g-1 at a solution pH equal to 7.00 and contact time of 74 min. The results indicated that the adsorption process followed pseudo-second-order (PSO) reaction kinetics, and the Freundlich isotherm model gave a better goodness-of-fit than the linear Langmuir model. The FTIR study established that IC molecules are successfully adsorbed onto the surface of MgOBi2 via a chemisorption process.

Smelting Remains a Public Health Risk Nearly a Century Later: A Case Study in Pueblo, Colorado, USA.

Pueblo, Colorado has a long history of smelting activities, and recent studies raised concerns about lead exposure. This study tested 240 children in Pueblo for blood lead levels (BLLs) and found a significant association between distance from old smelters and children BLLs. Around 7.5% of Pueblo children had BLLs above the Centers for Disease Control and Prevention reference level of 5 µg/dL for elevated BLL, and 18.3% had BLLs between 3.3⁻4.9 µg/dL. Out of the 36 children who lived near former smelters, 13.9% had BLLs above 5 µg/dL vs. 6.37% for children living away from old smelters. The proportion of Pueblo children with elevated BLL was nearly three times the 2007⁻2010 United States national average (7.5% vs. 2.6%), and this was higher in the immediate vicinity of old smelters (13.9% vs. 2.6%). Genetic polymorphisms for ALAD-1 or ALAD-2 alleles, which play a role in susceptibility to lead toxicity, were not associated with children BBLs. Around 38.5% of houses sampled near the smelters had topsoil lead levels higher than the Environmental Protection Agency’s benchmark of 400 mg/kg. Our study resulted in the addition of areas of Pueblo to the EPA Superfund National Priorities List in December 2014, and cleanup is currently underway to minimize the public health risks.

Arsenite exposure compromises early embryonic development in the Golden hamster.

The toxicity of arsenite to 8-cell stage hamster embryos was evaluated. Females were superovulated and mated; embryos were collected and grown for 72 h in culture medium containing vehicle control, 25, 50, 250, 500, or 750 nM arsenite. Morphological observations were taken at 0 and 24h increments. A TUNEL assay was used for determining DNA damage. Survival was expressed by the ability to undergo zona escape. The control group had 78% survival and no evidence of deformities. Embryos in the 25, 50 and 250 nM groups had survival rates of 63%, 55% and 27%, respectively. Arsenite exposure caused total embryo lethality, major deformities, complete failure to undergo zona lysis, and significantly higher number of cells with fragmented DNA in embryos at the 500 and 750 nM concentrations. The study underscores the sensitivity of preimplantation stage embryos to the presence of even relatively small amounts of arsenic in luminal fluid.

Arsenic, cadmium, lead, and mercury in surface soils, Pueblo, Colorado: implications for population health risk.

Decades of intensive industrial and agricultural practices as well as rapid urbanization have left communities like Pueblo, Colorado facing potential health threats from pollution of its soils, air, water and food supply. To address such concerns about environmental contamination, we conducted an urban geochemical study of the city of Pueblo to offer insights into the potential chemical hazards in soil and inform priorities for future health studies and population interventions aimed at reducing exposures to inorganic substances. The current study characterizes the environmental landscape of Pueblo in terms of heavy metals, and relates this to population distributions. Soil was sampled within the city along transects and analyzed for arsenic (As), cadmium (Cd), mercury (Hg) and lead (Pb). We also profiled Pueblo's communities in terms of their socioeconomic status and demographics. ArcGIS 9.0 was used to perform exploratory spatial data analysis and generate community profiles and prediction maps. The topsoil in Pueblo contains more As, Cd, Hg and Pb than national soil averages, although average Hg content in Pueblo was within reported baseline ranges. The highest levels of As concentrations ranged between 56.6 and 66.5 ppm. Lead concentrations exceeded 300 ppm in several of Pueblo's residential communities. Elevated levels of lead are concentrated in low-income Hispanic and African-American communities. Areas of excessively high Cd concentration exist around Pueblo, including low income and minority communities, raising additional health and environmental justice concerns. Although the distribution patterns vary by element and may reflect both industrial and non-industrial sources, the study confirms that there is environmental contamination around Pueblo and underscores the need for a comprehensive public health approach to address environmental threats in urban communities.

Reproductive toxicity of the psoralens.

The psoralens are naturally occurring secondary metabolites in plants, including many fruits and vegetables. Health risks have been associated with handling or ingesting psoralen-containing plants, and with the use of synthetic psoralens in photochemotherapy of skin disorders. Our research has demonstrated that administration of the psoralens bergapten (5-methoxypsoralen) and xanthotoxin (8-methoxypsoralen) in the diet of female rats reduced birthrates, number of implantation sites, pups, corpora lutea, full and empty uterine weight, and circulating estrogen levels in a dose-dependent manner. Psoralens induced mRNAs of the liver enzymes CYP1A1 and UGT1A6, suggesting that enhanced metabolism of estrogens by psoralen treatment may explain the reproductive toxicity and the observed reduction of ovarian follicular function and ovulation. Rats also avoided repeated consumption of a flavored solution associated with psoralen administration. The findings indicate that the psoralens constitute a novel group of ovarian toxicants. Further examination of the safety of their use in photochemotherapy and diet is warranted.