Nutrient leaching, soil pH and changes in microbial community increase with time in lead-contaminated boreal forest soil at a shooting range area

Copper Bioremediation Ability of Ciliate Paramecium multimicronucleatum Isolated from Industrial Wastewater

The growing problems of environmental damage have been caused by the continuous outrush of heavy metals from industrial wastewater. To resolve this issue, bioremediation is playing a safe and eco-friendly role in the removal of these heavy metals from environmental wastewater bodies. It has provoked demand with regard to understanding the mechanisms of bioaccumulation and detoxification developed by the organisms living in the heavy metal-exposed industrial wastewater. The present investigation focuses on Paramecium multimicronucleatum, a ciliated protozoan isolated from industrial wastewater, with the objective of assessing its capabilities as an environmental bioremediator. Purified cell culture was maintained in bold basal salt medium and optimum growth conditions were determined. A maximum growth rate of 6.0–9.0 × 103 cells/mL at 25–30 °C and pH 7.0 was observed, and therefore revealed to be the optimal growth conditions for this species. It can tolerate 40–50 µg/mL of copper ion stress with little effect on growth rate as compared to control. It is able to uptake more than 80% of copper ions from the medium in 96 h. A significant twofold rise in glutathione content and non-protein thiols was recorded as an indication of a defensive mechanism in place to fight against the oxidative stress caused by the copper treatment. A notable increase of 50–70 µg/mL in total protein content of stressed cells in comparison to non-stressed was also observed as potential induction of some particular proteins for the purpose of resistance against copper stress.

Lead contamination of soils, sediments, and vegetation in a shooting range and adjacent terrestrial and aquatic ecosystems: A holistic approach for evaluating potential risks

It is well accepted that shooting ranges constitute hotspots of Pb contamination. This study evaluated the degree of Pb contamination of soils, sediments and vegetation within the boundaries of a highly visited shooting range, as well as the fluvial transport and dispersal of Pb, and therefore the contamination of adjacent river and water reservoir. Soils in the shooting range were severely contaminated with Pb, as indicated by the values of enrichment and contamination factor. The concentration of Pb in these soils ranged from 791 mg kg^-1 to 7265 mg kg^-1, being several dozens or even hundreds of times higher compared with control background samples. A temporary stream being in close proximity was also polluted, though to a much lesser extent. The degree of Pb contamination was negatively correlated with the distance from the shooting range. To this effect, the degree of contamination of the river and the water reservoir being in the vicinity of the shooting range was negligible, as sediments and water samples preserved similar Pb concentrations with control samples. However, cultivated (olives) and wild native plant species grown in the area of the shooting range were found to uptake and accumulate high concentrations of Pb in their tissues (even 50 times higher compared with control samples). The severe contamination of soils, sediments and vegetation in the studied shooting range can provoke very high ecological risks. Overall, results suggest that management measures should be undertaken within the boundaries of the studied shooting range.

Metal accumulation capacity in indigenous Alaska vegetation growing on military training lands

Permafrost thawing could increase soil contaminant mobilization in the environment. Our objective was to quantify metal accumulation capacities for plant species and functional groups common to Alaskan military training ranges where elevated soil metal concentrations were likely to occur. Plant species across multiple military training range sites were collected. Metal content in shoots and roots was compared to soil metal concentrations to calculate bioconcentration and translocation factors. On average, grasses accumulated greater concentrations of Cr, Cu, Ni, Pb, Sb, and Zn relative to forbs or shrubs, and bioconcentrated greater concentrations of Ni and Pb. Shrubs bioconcentrated greater concentrations of Sb. Translocation to shoots was greatest among the forbs. Three native plants were identified as candidate species for use in metal phytostabilization applications. Elymus macrourus, a grass, bioconcentrated substantial concentrations of Cu, Pb, and Zn in roots with low translocation to shoots. Elaeagnus commutata, a shrub, bioconcentrated the greatest amounts of Sb, Ni, and Cr, with a low translocation factor. Solidago decumbens bioconcentrated the greatest amount of Sb among the forbs and translocated the least amount of metals. A combination of forb, shrub, and grass will likely enhance phytostabilization of heavy metals in interior Alaska soils through increased functional group diversity.