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Kapwata T, Wright CY, Reddy T, Street R, Kunene Z, Mathee A. Relations between personal exposure to elevated concentrations of arsenic in water and soil and blood arsenic levels amongst people living in rural areas in Limpopo, South Africa. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:65204-65216. [PMID: 37079235 PMCID: PMC10116462 DOI: 10.1007/s11356-023-26813-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Accepted: 03/31/2023] [Indexed: 05/03/2023]
Abstract
Exposure to arsenic even at low levels can lead to adverse health outcomes, however, there is a paucity of research from South Africa in relation to human exposure to arsenic. We investigated long-term exposure of residents in Limpopo province, South Africa, in a cross-sectional study by analysing water, soil and blood arsenic concentrations from two arsenic-exposed (high and medium-low exposure) villages and one non-exposed (control) village. There were statistically significant differences in the distribution of arsenic in water, soil and blood amongst the three sites. The median drinking water arsenic concentration in the high-exposure village was 1.75 µg/L (range = 0.02 to 81.30 µg/L), 0.45 µg/L (range = 0.100 to 6.00 µg/L) in the medium- / low-exposure village and 0.15 µg/L (range = < limit of detection (LOD) to 29.30 µg/L) in the control site. The median soil arsenic concentration in the high-exposure village was 23.91 mg/kg (range = < LOD to 92.10 mg/kg) whilst arsenic concentrations were below the limit of detection in all soil samples collected from the medium-/low-exposure and control villages. In the high-exposure village, the median blood arsenic concentration was 1.6 µg/L (range = 0.7 to 4.2 µg/L); 0.90 µg/L (range = < LOD to 2.5 µg/L) in the medium-/low-exposure village and 0.6 µg/L (range = < LOD to 3.3 µg/L) in the control village. Significant percentages of drinking water, soil and blood samples from the exposed sites were above the internationally recommended guidelines (namely, 10 µg/L, 20 mg/kg and 1 µg/L, respectively). Majority of participants (86%) relied on borehole water for drinking and there was a significant positive correlation between arsenic in blood and borehole water (p-value = 0.031). There was also a statistically significant correlation between arsenic concentrations in participants' blood and soil samples collected from gardens (p-value = 0.051). Univariate quantile regression found that blood arsenic concentrations increased by 0.034 µg/L (95% CI = 0.02-0.05) for each one unit increase in water arsenic concentrations (p < 0.001). After adjusting for age, water source and homegrown vegetable consumption in multivariate quantile regression, participants from the high-exposure site had significantly higher blood concentrations than those in the control site (coefficient: 1.00; 95% CI = 0.25-1.74; p-value = 0.009) demonstrating that blood arsenic is a good biomarker of arsenic exposure. Our findings also provide new evidence for South Africa on the association between drinking water and arsenic exposure, emphasising the need for the provision of potable water for human consumption in areas with high environmental arsenic concentrations.
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Affiliation(s)
- Thandi Kapwata
- Environment and Health Research Unit, South African Medical Research Council, Johannesburg, 2028, South Africa.
- Environmental Health Department, Faculty of Health Sciences, University of Johannesburg, Johannesburg, 2028, South Africa.
| | - Caradee Y Wright
- Environment and Health Research Unit, South African Medical Research Council, Pretoria, 0084, South Africa
- Department of Geography, Geoinformatics and Meteorology, University of Pretoria, Pretoria, 0001, South Africa
| | - Tarylee Reddy
- Biostatistics Research Unit, South African Medical Research Council, Durban, 4001, South Africa
- School of Mathematics, Statistics and Computer Science, University of KwaZulu Natal, Pietermaritzburg, 3201, South Africa
| | - Renee Street
- Environmental Health Department, Faculty of Health Sciences, University of Johannesburg, Johannesburg, 2028, South Africa
- Environment and Health Research Unit, South African Medical Research Council, Durban, 4001, South Africa
| | - Zamantimande Kunene
- Environment and Health Research Unit, South African Medical Research Council, Johannesburg, 2028, South Africa
- Environmental Health Department, Faculty of Health Sciences, University of Johannesburg, Johannesburg, 2028, South Africa
| | - Angela Mathee
- Environment and Health Research Unit, South African Medical Research Council, Johannesburg, 2028, South Africa
- Environmental Health Department, Faculty of Health Sciences, University of Johannesburg, Johannesburg, 2028, South Africa
- School of Public Health, University of the Witwatersrand, Johannesburg, 2028, South Africa
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Belle GN, Oberholster PJ, Fossey A, Esterhuizen L, Moodley R. Using pollution indices to develop a risk classification tool for gold mining contaminated soils. JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH. PART A, TOXIC/HAZARDOUS SUBSTANCES & ENVIRONMENTAL ENGINEERING 2022; 57:1047-1057. [PMID: 36469548 DOI: 10.1080/10934529.2022.2151283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Revised: 11/08/2022] [Accepted: 11/14/2022] [Indexed: 06/17/2023]
Abstract
The presence of potentially toxic elements (PTEs) in soil and plants is a risk factor to human well-being and the environment. Soil and leaves from a traditional medicinal plant, Vachellia karroo, known as the sweet thorn plant, were assessed to determine the extent of pollution by PTEs from gold mine tailings in a case study area of Matjhabeng Local Municipality, South Africa. A risk classification tool was developed using the different indicators of pollution quantified to describe the pollution risk at each sampling site. High concentrations of copper, cadmium, lead, nickel, and zinc were measured in the soil, which exceeded the maximum permissible soil quality limits. The enrichment factor and geoaccumulation index results also confirmed heavy soil pollution by copper, nickel, and zinc, with exceptionally heavy pollution by cadmium and selenium. The PTEs in the soil were in an exchangeable form, with the sweet thorn plant accumulating lead and selenium at toxic levels, which poses a risk to the health of the local people as the plant is used for medicinal purposes. The overall pollution risk classification tool of the sampling sites showed that 17% were high-risk areas, 53% were moderate-risk areas, and 20% of the sites were low-risk areas.
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Affiliation(s)
- Gladys Nyoh Belle
- Centre for Environmental Management, University of the Free State, Bloemfontein, South Africa
| | - Paul Johan Oberholster
- Centre for Environmental Management, University of the Free State, Bloemfontein, South Africa
| | - Annabel Fossey
- Graduate Mastery, Boskruin View Office Park, Randburg, South Africa
| | - Leana Esterhuizen
- Department of Life Sciences, Central University of Technology, Bloemfontein, Free State, South Africa
| | - Roshilia Moodley
- School of Chemistry and Physics, University of KwaZulu-Natal, Durban, KwaZulu-Natal, South Africa
- Department of Chemistry, University of Manchester, London, UK
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Shezi B, Street RA, Webster C, Kunene Z, Mathee A. Heavy Metal Contamination of Soil in Preschool Facilities around Industrial Operations, Kuils River, Cape Town (South Africa). INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:4380. [PMID: 35410061 PMCID: PMC8998666 DOI: 10.3390/ijerph19074380] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Revised: 03/30/2022] [Accepted: 03/31/2022] [Indexed: 12/03/2022]
Abstract
The contamination of soil by heavy metals is a potential health risk, especially among susceptible populations. The aim of this study was to measure the levels of heavy metals, identify the contamination levels and possible sources of heavy metals, and evaluate the health risk caused by heavy metals to the children living in Kuils River. Composite samples of soil were collected at 34 preschools. A portable X-ray fluorescence spectrometer was used to measure the levels of metals. Contamination levels were evaluated using a geoaccumulation index (Igeo), enrichment factor (EF), contamination factor (CF) and pollution load index (PLI). The spatial distribution of the Igeo contamination levels was assessed using ArcGIS. Sources of heavy metals and the correlation among metals were assessed using factor analysis and Pearson correlation, respectively. The measured concentrations of metals were used to estimate the health risk for children. The average levels of the metals were 16, 4469, 137, 30, 176, 1547 and 232 mg/kg for arsenic (As), iron (Fe), manganese (Mn), lead (Pb), strontium (Sr), titanium (Ti) and zinc (Zn), respectively. According to Igeo, EF, CF and PLI contamination exist in the study area. The health index (HI) for non-carcinogenic effects showed the ingestion route as the main contributor to the total risk, with the accumulative carcinogenic risk exceeding the maximum acceptable level. To protect the affected communities, and children in particular, this study provides evidence of the need for action, including the institution of mandatory buffer zones between pollutant-generating activities and human settlements.
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Affiliation(s)
- Busisiwe Shezi
- Environment and Health Research Unit, South African Medical Research Council, Johannesburg 2094, South Africa; (C.W.); (Z.K.); (A.M.)
- Department of Environmental Health, Faculty of Health Sciences, University of Johannesburg, Johannesburg 2094, South Africa;
| | - Renée Anne Street
- Department of Environmental Health, Faculty of Health Sciences, University of Johannesburg, Johannesburg 2094, South Africa;
- Environment and Health Research Unit, South African Medical Research Council, Durban 4001, South Africa
| | - Candice Webster
- Environment and Health Research Unit, South African Medical Research Council, Johannesburg 2094, South Africa; (C.W.); (Z.K.); (A.M.)
| | - Zamantimande Kunene
- Environment and Health Research Unit, South African Medical Research Council, Johannesburg 2094, South Africa; (C.W.); (Z.K.); (A.M.)
| | - Angela Mathee
- Environment and Health Research Unit, South African Medical Research Council, Johannesburg 2094, South Africa; (C.W.); (Z.K.); (A.M.)
- Department of Environmental Health, Faculty of Health Sciences, University of Johannesburg, Johannesburg 2094, South Africa;
- Department of Environmental Health, School of Behavioural and Lifestyle Sciences, Faculty of Health Sciences, Nelson Mandela University, Port Elizabeth 6019, South Africa
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Githaiga KB, Njuguna SM, Gituru RW, Yan X. Assessing heavy metal contamination in soils using improved weighted index (IWI) and their associated human health risks in urban, wetland, and agricultural soils. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2021; 28:66012-66025. [PMID: 34327642 DOI: 10.1007/s11356-021-15404-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Accepted: 07/08/2021] [Indexed: 06/13/2023]
Abstract
Contamination of nine heavy metals (HMs) Zn, Pb, Cu, Cd, As, Co, Cr, Mo, and Ni in agricultural, urban, and wetland soils from Western and Rift Valley parts of Kenya was assessed using improved weighted index (IWI) and pollution loading index (PLI). Non-carcinogenic risks posed by the HMs were assessed using hazard quotients (HQ) and hazard index (HI), while carcinogenic risks were assessed using cancer risks (CR) and total cancer risks (TCR). The average concentration of Zn, Cr, Ni, Pb, Co, Cu, As, Mo, and Cd was 94.7 mg/kg, 43.6 mg/kg, 22.3 mg/kg, 21.0 mg/kg, 19.8 mg/kg, 18.0 mg/kg, 16.3 mg/kg, 1.83 mg/kg, and 1.16 mg/kg, respectively. IWI ranged from 0.57 to 6.04 and categorized 6.82% of the study sites as not polluted, 27.3% as slightly polluted, 43.2% as moderately polluted, and 22.7% as seriously polluted. PLI ranged from 0.38 to 3.95 and classified 15.9% of the sites as not polluted, 61.4% as slightly polluted, 20.5% as moderately polluted, and only 2.3% as seriously polluted. Wetlands retained more HMs from both urban and agricultural runoff and were therefore the most polluted. The heavy metals did not pose any risks via inhalation and dermal contact, but HQingestion for As for children was >1 in 2.3% of the sites studied. CR via ingestion and TCR for As were above the allowable limits for children and adults indicating high risks of cancer. Intensive agriculture and urbanization should be closely monitored to prevent further HM pollution.
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Affiliation(s)
- Kelvin Babu Githaiga
- Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, 430074, China
- Sino-Africa Joint Research Center, Chinese Academy of Sciences, Wuhan, 430074, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Samwel Maina Njuguna
- Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, 430074, China
- Sino-Africa Joint Research Center, Chinese Academy of Sciences, Wuhan, 430074, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Robert Wahiti Gituru
- Botany Department, Jomo Kenyatta University of Agriculture and Technology, P. O Box 62000, Nairobi, 00200, Kenya
| | - Xue Yan
- Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, 430074, China.
- Sino-Africa Joint Research Center, Chinese Academy of Sciences, Wuhan, 430074, China.
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Bech J. Soil contamination and human health: part 3. ENVIRONMENTAL GEOCHEMISTRY AND HEALTH 2020; 42:4065-4071. [PMID: 33123931 DOI: 10.1007/s10653-020-00741-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Affiliation(s)
- Jaume Bech
- Emeritus Professor University of Barcelona (UB), Barcelona, Spain.
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