Organic micro-pollutant profiles from urban, industrial, and rural soils and sediments from South Africa.

• Despite having the largest economy in Africa, very little is known about organic pollutants in soils and sediments from urban and industrial areas of South Africa. Here, we present the results of the first studies to investigate levels and distribution of organochlorine pesticides, PCBs, PAHs, chlorinated paraffins, and dioxin-like chemicals from the highly industrialised regions south of Johannesburg. Industries here include petro-chemicals, ferrous and non-ferrous metal production, paper and pulp, coking, mining, and coal-fired power plants.The concentration of PAHs ranged between 44-39 000 ng/g dw and the concentration of carcinogenic PAHs ranged between 19-19 000 ng/g dw. Pyrogenic processes were the most likely sources, with some petrogenic contributions. Carcinogenic PAHs at low-income residential sites were sufficient to potentially cause health effects such as cancer considering direct contact with soil. PCB concentrations ranged between 120‑4 700 ng/kg dw in soils and sediments with highest concentrations from industrial and associated residential areas. Concentrations of dioxin TEQWHO2005 ranged between 0.12 -32 ng/kg TEQ dw in sediments, and between 0.34-20 ng/kg dw in soils. Various combustion and high-temperature processes were likely sources of pollution at the majority of the sites. The polychlorinated paraffins had concentrations between 1.8‑1 200 ng/g dw. Levels of organochlorine pesticides were at or close to limits of detection.The sources, processes and threats that govern and the lesser concentrations in sediment and higher concentrations in soils need further investigation as it may affect human exposure. Bio-accumulation into humans and biota from terrestrial and aquatic food webs under developing-country conditions as examined here needs further investigation before conclusive statements about threats and the need for mitigating interventions can be made. These studies have contributed towards a much better understanding of organic chemical pollutants in sediments and soils from the largest industrial and urban area in South Africa.

Ämnesord

NATURVETENSKAP  -- Geovetenskap och miljövetenskap -- Miljövetenskap (hsv//swe)

NATURAL SCIENCES  -- Earth and Related Environmental Sciences -- Environmental Sciences (hsv//eng)

LANTBRUKSVETENSKAPER  -- Lantbruksvetenskap, skogsbruk och fiske -- Markvetenskap (hsv//swe)

AGRICULTURAL SCIENCES  -- Agriculture, Forestry and Fisheries -- Soil Science (hsv//eng)

NATURVETENSKAP  -- Kemi -- Analytisk kemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences -- Analytical Chemistry (hsv//eng)

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