Heavy metal contamination and health risk assessment associated with abandoned barite mines in Cross River State, southeastern Nigeria

The Qinghai-Tibet Plateau is the highest geographical unit in the world. Thus, it serves an important role in evaluating long-term ecologic conditions and environmental status and changes over time. This study summarizes major and trace element concentrations in biota and in water and soil. It also pays attention to gaseous pollutant and particle concentrations in air around the Qinghai-Tibet Plateau. The degree of soil heavy metal contamination and the water heavy metal hazard index were respectively evaluated. The contamination degrees of two sampling areas around the Qinghai-Tibet Plateau reached extremely high levels with soil mC d (modified degree of contamination) values exceeding 20. Surprisingly, over 54% of sampling areas showed moderate or more serious soil contamination degree (mC d N 1.5). Moreover, the hazard indexes of two important rivers were 1.56 and 7.59, reaching unacceptable level. The potential risk might be beyond our expectation. Therefore, it should be an urgent and top priority to identify and confirm possible pollution sources around the Qinghai-Tibet Plateau. Then, it is imperative to implement feasible and effective environmental quality control strategies.

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“…More detailed information refers to research articles written by Park and Choi (2013) and Adamu et al (2015).…”

Section: Methodsmentioning

confidence: 99%

“…This studied used maximal concentrations as C x i to obtain the possibly maximal contamination degree. Water hazard index (HI) caused by heavy metals was calculated using the following equation (Park and Choi, 2013;Adamu et al, 2015):…”

Section: Methodsmentioning

confidence: 99%

Inorganic pollution around the Qinghai-Tibet Plateau: An overview of the current observations

Duan

Lü

et al. 2016

Science of The Total Environment

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“…Risk assessment consisted of hazard identification, exposure assessment, dose-response (toxicity) and risk characterization (Adamu, Nganje, & Edet, 2015). The health risk assessment of each potentially toxic HM was done based on the quantification of the risk level and expressed in terms of cancer and non-cancer health risks (Sun, Zhang, Ma, & Chen, 2015).…”

Section: Human Health Risk Assessmentmentioning

confidence: 99%

“…Cancer risks were expressed in terms of incremental lifetime cancer risk (ILCR), which is the probability that one may develop cancer over a 70-year lifetime due to a 24 hour exposure to a potential carcinogen (Adamu, Nganje, & Edet, 2015). Cancer risk was calculated as the product of CDI (mg/kg-day) and cancer slope factor (CSF) measured in (mg/kg/day) -1…”

Section: Cancer Risksmentioning

confidence: 99%

“…The health risk assessment of each potentially toxic HM was done based on the quantification of the risk level and expressed in terms of cancer and non-cancer health risks (Sun, Zhang, Ma, & Chen, 2015). Two toxicity risk indices reported were the cancer slope factor (CSF) for cancer risk characterization and the oral reference dose (RfD) for non-cancer risk characterization (Adamu, Nganje, & Edet, 2015).…”

Section: Human Health Risk Assessmentmentioning

confidence: 99%

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Human Health Risk Assessment of Heavy Metals in Kampala (Uganda) Drinking Water

Bamuwamye¹,

Ogwok²,

Tumuhairwe³

et al. 2017

JFR

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Levels of aluminium, arsenic, cadmium, chromium, copper, iron, mercury, manganese, nickel, lead and zinc in tap water, groundwater-fed protected spring and bottled water were determined. The cancer and non-cancer risks associated with ingestion of heavy metals (HM) were also assessed for both children and adults. Forty seven water samples obtained from five divisions of Kampala city were analyzed using atomic absorption spectrophotometry. Cancer and non-cancer risks were determined using incremental lifetime cancer risk (ILCR) and non-carcinogenic hazard quotient (HQ), respectively. Lead content was higher than permissible limits (PL) according to East African Standard, World Health Organization, European Union and United States Environmental Protection Agency (USEPA). Arsenic showed minor exceedances above guideline values in tap water and groundwater-fed protected spring, whereas mercury, manganese and nickel were higher than PL. Levels of aluminium, cadmium, chromium, copper, iron, and zinc were below the PL. The lifetime risk of developing cancer through the oral route was greater than the USEPA acceptable level for both children and adults, revealing that exposure to HM in drinking water posed an unacceptable potential cancer risk. Arsenic contributed ca. 90% of the ILCR in tap water and groundwater-fed protected spring. The combined non-cancer risk of the HM expressed as hazard index (HI) was greater than one, with values for children being higher than those for adults. Lead contribution towards HI was in all cases above 90%. These results demonstrate the presence of alarming non-cancer risks for children.

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