Effects of Toxic Metal Contamination in the Tri-State Mining District on the Ecological Community and Human Health: A Systematic Review

Cleansing our waters: how riffle fish communities in the Spring River of Kansas responded to pollution legislation, mining remediation, and improved water quality

Metal pollution from mining is a threat to lotic fishes, although legislation that requires improved water quality and provides funding for remediation has been enacted to combat this stressor. The Spring River in southeastern Kansas historically received inputs of cadmium, copper, lead, and zinc that reduced the prevalence of several sensitive and imperiled fishes. Long-term reductions in these toxic metals have occurred since the 1990's because of management activities, but presently it is unknown how riffle fish communities responded to improved water quality. As such, the objective of our research was to quantify changes in riffle fish community structure between 1993-1995 and 2019-2021 using a before-after-control-impact (BACI) study design. Responses were quantified with univariate analyses to examine the interactive effects of time period (i.e., historical versus contemporary), pollution tolerance classification (i.e., intolerant, moderately-intolerant, moderately-tolerant, and tolerant), and site position (i.e., above versus below the most severe historical metal pollution inputs) on relative abundance, occupancy, and species richness of riffle fishes. We used multivariate analyses to examine temporal changes in community structure above and below pollution inputs. Our findings indicated that intolerant fish species relative abundance increased between the historical and contemporary time periods throughout the Spring River. Occupancy of all fishes increased over time in the formerly metal contaminated portion of the Spring River, becoming similar to values in the reference reach. Changes in species richness depended on site position and pollution tolerance, as temporal increases of intolerant and moderately intolerant species richness were most pronounced in the lower Spring River below historical metal pollution inputs. Multivariate analyses revealed a significant interaction between time period and site position, as there was a shift in community structure over time in the lower reach that was less pronounced in the upper reach. Most of the intolerant species that increased in prevalence are of high conservation priority, thus our research suggested that legislation enacted to improve water quality produced a ripple effect that stimulated the recovery of imperiled fish species.

The impact of heavy metal concentrations on aquatic insect populations in the Asan Wetland of Dehradun, Uttarakhand

This study, centered on the Asan Wetland in Uttarakhand, examines the ecological impact of heavy metals on aquatic insects biodiversity. It highlights the detrimental effects of metals like chromium, mercury, and lead, stemming from natural and anthropogenic sources, on aquatic insects diversity. Aquatic insects, particularly sensitive to water quality, are emphasized as key indicators of environmental health, illustrating the importance of understanding and managing the influences on wetland ecosystems. Wetland ecosystems are vulnerable to various environmental stressors, including pollution from heavy metals. These toxic substances can alter water quality parameters, disrupt nutrient cycling, and negatively impact the biodiversity and ecological balance of the system. This study aimed to evaluate the impact of several heavy metals (namely Cd, As, Cu, Fe, Pb, Ni, Zn, Al, Cr) on the distribution and biodiversity of various aquatic insect species, including Coeleoptera, Diptera, Ephemeroptera, Odonata, Plecoptera, and Trichoptera. The research utilized data collected between November 2021 and October 2022 from specifically chosen sites (S1, S2, S3) within the Asan Wetland in Dehradun, Uttarakhand. After collecting and identifying samples, various statistical (Sorenson, Shannon-Weiner diversity index, Margelef index) and multivariate tests (CCA, PCA, One-way Anova), have been applied to show the effects of these parameters. This study offers significant findings regarding the distribution patterns of heavy metals, the abundance of aquatic insects, and their interconnectedness within the ecosystem of the Asan Wetland. The abundance of aquatic insects, represented by 13 genera belonging to 6 orders, was assessed at three different sites (S1, S2, and S3) within the wetland. It was concluded that the heavy metals concentration and aquatic insects' density increases and decreases vice-versa in monsoon and winter seasons might be due to unfavourable factors. These findings contribute to the understanding of ecological dynamics and potential impacts of heavy metals on aquatic biota in wetland environments.

Using Peromyscus leucopus as a biomonitor to determine the impact of heavy metal exposure on the kidney and bone mineral density: results from the Tar Creek Superfund Site

Background

Human population growth and industrialization contribute to increased pollution of wildlife habitats. Heavy metal exposure from industrial and environmental sources is still a threat to public health, increasing disease susceptibility. In this study, I investigated the effects of heavy metals (cadmium (Cd), lead (Pb), and zinc (Zn)) on kidney and bone density.

Objective

This study aims to determine the concentrations of Cd, Pb, and Zn in soil and compare them to the levels of the same metals in Peromyscus leucopus kidney tissue. Furthermore, the study seeks to investigate the impact of heavy metals on bone density and fragility using the fourth lumbar vertebra (L4) of P. leucopus.

Methods

Cd, Pb, and Zn concentrations in soil specimens collected from Tar Creek Superfund Site (TCSFS), Beaver Creek (BC), and two reference sites (Oologah Wildlife Management Area (OWMA) and Sequoyah National Wildlife Refuge (SNWR)). Heavy metal concentrations were analyzed using inductively coupled plasma-mass spectroscopy (ICP-MS). Micro-computed tomography (µCT) was used to assess the influence of heavy metals on bone fragility and density.

Results

On the one hand, soil samples revealed that Pb is the most common pollutant in the sediment at all of the investigated sites (the highest contaminated site with Pb was TCSFS). Pb levels in the soil of TCSFS, BC, OWMA, and SNWR were found to be 1,132 ± 278, 6.4 ± 1.1, and 2.3 ± 0.3 mg/kg in the soil of TCSFS, BC and OWMA and SNWR, respectively. This is consistent with the fact that Pb is one of the less mobile heavy metals, causing its compounds to persist in soils and sediments and being barely influenced by microbial decomposition. On the other hand, the kidney samples revealed greater Cd levels, even higher than those found in the soil samples from the OWMA and SNWR sites. Cd concentrations in the kidney specimens were found to be 4.62 ± 0.71, 0.53 ± 0.08, and 0.53 ± 0.06 µg/kg, respectively. In addition, micro-CT analysis of L4 from TCSFS showed significant Pearson's correlation coefficients between Cd concentrations and trabecular bone number (-0.67, P ≤ 0.05) and trabecular separation (0.72, P ≤ 0.05). The results showed no correlation between bone parameters and metal concentrations at reference sites. This study is one of the few that aims to employ bone architecture as an endpoint in the field of biomonitoring. Furthermore, this study confirmed some earlier research by demonstrating substantial levels of heavy metal contamination in soil samples, kidney samples, and P. leucopus L4 trabecular bone separations from TCSFS. Moreover, this is the first study to record information regarding bone microarchitecture parameters in P. leucopus in North America.