Heavy Metals Speciation and Human Health Risk Assessment at an Illegal Gold Mining Site in Igun, Osun State, Nigeria

Background. There is increasing global concern over the health effects of heavy metals arising from various anthropogenic activities, especially mining. Mining activities in developing countries are often carried out at an artisanal level using a variety of extraction methods with human health and environmental consequences. Objectives. The broad objective of this study is to assess the chemical forms, distribution pattern, and health risks due to mining and processing techniques at a gold mining site in Igun, Osun State, Nigeria. Methods. Samples were collected from 28 active mine pits and sequentially extracted using standard methods. Extracts were analyzed for metals using inductively coupled plasma optical emission spectrometer (ICP/OES), while health risk was assessed using United States Environmental Protection Agency (USEPA) and Dutch methods. Chemical speciation of heavy metals and health risk assessment was calculated using mobile phase fraction summation. Results. Metals were exclusively present in the residual fractions, indicating that these metals are strongly bound to the resistant components of the soil matrix. The percentage in the residual fraction ranged from 9.41% (tin) to 99.42% (aluminium). The heavy metals geoaccumulation index for the site ranged from 0 (no contamination) to 6 (extremely contaminated). The cancer risk ranged from 6.17E-13 to 7.77E-05 and 2.73E-12 to 4.64E-04 for adults and children, respectively. Discussion. Cancer risk and non-cancer risk (hazard index) assessment showed that arsenic poses a higher risk in adults and children compared to other metals through the dermal exposure route.

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An Integrated Approach for Source Apportionment and Health Risk Assessment of Heavy Metals in Subtropical Agricultural Soils, Eastern China

Land ◽

10.3390/land10101016 ◽

2021 ◽

Vol 10 (10) ◽

pp. 1016

Author(s):

Ping Li ◽

Tao Wu ◽

Guojun Jiang ◽

Lijie Pu ◽

Yan Li ◽

...

Keyword(s):

Heavy Metals ◽

Risk Assessment ◽

Health Risk ◽

Human Health ◽

Health Risk Assessment ◽

Agricultural Soil ◽

Agricultural Soils ◽

Adults And Children ◽

The Mean ◽

Industrial Sources

Unreasonable human activities may cause the accumulation of heavy metals (HMs) in the agricultural soil, which will ultimately threaten the quality of soil environment, the safety of agricultural products, and human health. Therefore, the accumulation characteristics, potential sources, and health risks of HMs in agricultural soils in China’s subtropical regions were investigated. The mean Hg, Cu, Zn, Pb, and Cd concentrations of agricultural soil in Jinhua City have exceeded the corresponding background values of Zhejiang Province, while the mean concentrations of determined 8 HMs were less than their corresponding risk-screening values for soil contamination of agricultural land in China. The spatial distribution of As, Cr, Ni, Cu, and Pb were generally distributed in large patches, and Hg, Zn, and Cd were generally sporadically distributed. A positive definite matrix factor analysis (PMF) model had better performance than an absolute principal component–multiple linear regression (APCS-MLR) model in the identification of major sources of soil HMs, as it revealed higher R2 value (0.81–0.99) and lower prediction error (−0.93–0.25%). The noncarcinogenic risks (HI) of the 8 HMs to adults and children were within the acceptable range, while the carcinogenic risk (RI) of children has exceeded the safety threshold, which needs to be addressed by relevant departments. The PMF based human health risk assessment model indicated that industrial sources contributed the highest risk to HI (32.92% and 30.47%) and RI (60.74% and 61.5%) for adults and children, followed by agricultural sources (21.34%, 29.31% and 32.94% 33.19%). Therefore, integrated environmental management should be implemented to control and reduce the accumulation of soil HMs from agricultural and industrial sources.

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Human Health Risk Assessment for Exposure to Potentially Toxic Elements in Polluted Rivers in the Ecuadorian Amazon

Water ◽

10.3390/w13050613 ◽

2021 ◽

Vol 13 (5) ◽

pp. 613

Author(s):

Samantha Jiménez-Oyola ◽

Kenny Escobar Segovia ◽

María-Jesús García-Martínez ◽

Marcelo Ortega ◽

David Bolonio ◽

...

Keyword(s):

Risk Assessment ◽

Cancer Risk ◽

Health Risk ◽

Human Health ◽

Health Risk Assessment ◽

Toxic Elements ◽

Human Health Risk ◽

Potentially Toxic Elements ◽

Ecuadorian Amazon ◽

Polluted Rivers

Anthropogenic activities performed in the Ecuadorian Amazon have released potentially toxic elements (PTEs) into the rivers, causing severe environmental pollution and increasing the risk of exposure to the residents of the surrounding areas. This study aims to carry out a human health risk assessment using deterministic and probabilistic methods to estimate the hazard index (HI) and total cancer risk (TCR) related to multi-pathway human exposure to PTEs in polluted rivers. Concentrations of Al, Cd, Cr, Cu, Hg, Ni, Pb, and Zn in surface water and sediment samples from rivers on the Ecuadorian Amazon were considered to assess the potential adverse human health effects. As a result, deterministic and probabilistic estimations of cancer and non-cancer risk through exposure to surface waters and sediments were above the safety limit. A sensitivity analysis identified the concentration of PTEs and the exposure duration (ED) as the two most important variables for probabilistic health risk assessment. The highest risk for receptors was related to exposure to polluted sediments through incidental ingestion and dermal contact routes. According to the deterministic estimation, the human health risk through ingestion of water was above the threshold in specific locations. This study reveals the potential health risk to which the population is exposed. This information can be used as a baseline to develop public strategies to reduce anthropogenic pollution and exposure to PTEs in Ecuadorian Amazon rivers.

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