Bird's feather as an effective bioindicator for detection of trace elements in polymetallic contaminated areas in Anhui Province, China

Formation processes of groundwater in a non-ferrous metal mining city of China: Insights from hydrochemical and strontium isotope analyses

Tongling is a significant non-ferrous metal mining city in China, which produces waste that negatively impacts the area's water environment. It is essential to comprehend the hydrochemical properties and formation processes of groundwater to safeguard and utilize it efficiently. We explored major ions, strontium, and its isotopes in water and river-bottom samples from the northern (i.e., A-A' section) and southern (i.e., B-B' section) areas. The hydrochemical facies show the mining activities have a greater impact on surface water than on groundwater. Groundwater hydrochemical formation results from several factors, with water-rock interaction and ion exchange being primary. Additionally, the dissolution of calcite, dolomite, and feldspar, oxidation of pyrite, and hydrolysis of carbonate minerals also impact the formation of groundwater chemistry. Our analysis of strontium and its isotopes indicates that carbonate dissolution primarily occurred in the recharge area; the runoff from the recharge to the discharge area results in the dissolution of certain silicate rocks; calcite dissolution sources account for > 70% contribution in both surface water and groundwater water-rock interactions, whereas silicate rock dissolution sources and dolomite dissolution sources account for < 30%. Due to changed order of dissolved carbonate and silicate minerals during groundwater flow, the distribution of strontium and its isotopes in the A-A' section is opposite to that in the B-B' section. The findings provide a basis for developing, utilizing, managing, and protecting groundwater resources, especially in similar mining areas.

Birds of different feeding habits as biomonitors for trace elements in a wetland of the Central Asian Flyway, Sri Lanka

Monitoring the environmental exposure of wildlife to toxic trace elements is important for conservation. Sri Lanka does not have a biomonitoring programme for exposure of wildlife to pollutants. We measured levels of Hg, Pb, Cd, As, and Se in feathers of resident and migratory birds with different food habits in a wetland ecosystem of Sri Lanka, which is located at the southern-most point of the Central Asian Flyway. Diet and migratory status significantly affected concentrations of Hg, Pb, and As. Migrant invertivores showed the highest concentration of Hg and As. The highest concentration of Pb was in resident frugivores. Diet was the only significant explanatory variable for Cd, with frugivores recording the highest concentrations. Migratory status was the only factor significantly affecting feather Se, with migrant birds recording higher levels of Se; however, migratory status did not affect the Se: Hg ratio. The mean Se: Hg ratio was significantly affected by diet, but was >1 in birds of all food habits. Some birds in our study had concentrations of Hg, Pb, and Cd at higher levels than thresholds for adverse effects. High levels of these elements were recorded in both resident and migratory birds of differing food habits. Our study highlights the necessity of including biomonitors from diverse habitats and foraging guilds. This study establishes the baseline information for exposure of wildlife to several toxic trace elements necessary to establish a long-term biomonitoring programme important for the conservation of birds both in a national and global context.