Particle and heavy metal accumulation by two plant species in a coal mining area of Odisha, India

Mining activities lead to severe particulate matter (PM) pollution that consequently has a detrimental effect on ecosystem. A study was therefore conducted in a coal mining area of Odisha, India with an objective to assess the particulate matter pollution on the basis of differential aerodynamic size (PM10 and PM2.5) of the particles, the metallic (Zn and Fe) composition, and also to evaluate their nature of deposition on two identified plant species. The results suggest a significant variation in particle and heavy metal fractions in the ambient air of different sites (p < 0.05). Fe dominated the finer particle (PM2.5) fraction while Zn dominated the coarser counterpart (PM10) in the ambient air. When evaluated for the particle and heavy metal deposition on leaf surface, Shorea robusta performed better in trapping the coarser particles (PM10) while Holarrhena floribunda was found to be an efficient scrubber of the finer particles (PM2.5). Fe deposition on surface of leaves was comparatively higher than Zn irrespective of plant species or size fractions. Therefore, it is concluded that both S. robusta and H. floribunda should be planted in a schematic manner to tackle the particulate pollution in coal mining areas.

Bioavailability and uptake of smelter emissions in freshwater zooplankton in northeastern Washington, USA lakes using Pb isotope analysis and trace metal concentrations

The upper Columbia River and associated valley systems are highly contaminated with metal wastes from nearby smelting operations in Trail, British Columbia, Canada (Teck smelter), and to a lesser extent, Northport, Washington, USA (Le Roi smelter). Previous studies have investigated depositional patterns of airborne emissions from these smelters, and documented the Teck smelter as the primary metal contamination source. However, there is limited research directed at whether these contaminants are bioavailable to aquatic organisms. This study investigates whether smelter derived contaminants are bioavailable to freshwater zooplankton. Trace metal (Zn, Cd, As, Sb, Pb and Hg) concentrations and Pb isotope compositions of zooplankton and sediment were measured in lakes ranging from 17 to 144 km downwind of the Teck smelter. Pb isotopic compositions of historic ores used by both smelters are uniquely less radiogenic than local geologic formations, so when zooplankton assimilate substantial amounts of smelter derived metals their compositions deviate from local baseline compositions toward ore compositions. Sediment metal concentrations and Pb isotope compositions in sediment follow significant (p < 0.001) negative exponential and sigmoidal patterns, respectively, as distance from the Teck smelting operation increases. Zooplankton As, Cd, and Sb contents were related to distance from the Teck smelter (p < 0.05), and zooplankton Pb isotope compositions suggest As, Cd, Sb and Pb from historic and current smelter emissions are biologically available to zooplankton. Zooplankton from lakes within 86 km of the Teck facility display isotopic evidence that legacy ore pollution is biologically available for assimilation. However, without water column data our study is unable to determine if legacy contaminants are remobilized from lake sediments, or erosional pathways from the watershed.

Tracking long-distance atmospheric deposition of trace metal emissions from smelters in the upper Columbia River valley using Pb isotope analysis of lake sediments

Heavy metal discharge from mining and smelting operations into aquatic ecosystems can cause long-term biological and ecological impacts. The upper Columbia River is highly contaminated with heavy metal wastes from nearby smelting operations in Trail, British Columbia, Canada, and to a lesser extent, Northport (Le Roi smelter), Washington, USA. Airborne emissions from the Trail operations were historically and are currently transported by prevailing winds down the Columbia River canyon, where particulate metals can be deposited into lakes and watersheds. In lakes, sediment cores contain records of past environmental conditions, providing a timeline of fundamental chemical and biological relationships within aquatic ecosystems, including records of airborne metal depositions. We analyzed trace metal concentrations (Ni, Cd, Zn, As, Cu, Sb, Pb, Hg) and Pb isotope compositions of sediment cores from six remote eastern Washington lakes to assess potential sources of atmospheric heavy metal deposition. Sediment cores displayed evidence to support trace metal loading as a direct consequence of smelting operations in Trail. Smelter contamination was detected 144 km downwind of the Trail Smelter. Cd, Sb, Pb (p < 0.001), and to a lesser extent As and Hg (p < 0.05) concentrations were correlated with Pb isotope compositions, suggesting that the Trail operations were likely the main source for these trace metals.