40 research outputs found
Heavy metals in the irrigation water, soils and vegetables in the Philippi horticultural area in the Western Cape Province of South Africa
The aims of this study were to investigate the
extent of heavy metal contamination in the Philippi
horticultural area in the Western Cape Province, South
Africa. Concentrations of Cd, Cr, Cu, Mn, Ni, Pb and Zn
were determined in the irrigation water, soils and vegetables
in both winter and summer cropping seasons with
an ICP-AES and tested against certified standards.
Differences were found in heavy metal concentrations
between the winter and summer cropping seasons in the
irrigation water, soils and vegetables. Certain heavy
metals exceeded the maximum permissible concentrations
in the irrigation water, soils and vegetables produced
in South Africa. These toxic concentrations were
predominantly found in the summer cropping season for
the soils and in the crops produced in winter. It is thus
suggested that further studies are carried out in the
Philippi horticultural area to determine the sources of
the heavy metals to try and mitigate the inputs thereof
and therefore reduce the amount of heavy metals entering
the human food chain.ISI & Scopu
Treatment of heavily contaminated storm water from an industrial site area by filtration through an adsorbent barrier with pine bark (Pinus Silvestris), polonite and active carbon in a comparison study
Abstract: This study aims to evaluate a simple and robust filtration method for separation of heavy metals from storm water. The storm water, collected at a metals manufacturing site, is heavily contaminated with heavy metals. A first analysis showed exceptionally high concentrations of Zn, which was present in concentrations exceeding 200 mgL -1 . The basic idea is to filter the water as it flows out of the industry area through a passive barrier in the storm water well pipeline. Pine bark was in this study compared to two other materials; polonite and the conventional adsorbent active carbon. The forestry by-product pine bark (Pinus silvestris) consists of approximately 85-90 % dried and granulated pine bark and 10-15 % wood fibres. Polonite is a manufactured product originating from the cretaceous rock opoka. A laboratory experiment was set up, where the storm water from the industrial site was filtered through all three filter materials in a pilotscale model of the proposed installation. The filter cartridge model could be filled with approximately 2.2 L filter material. 3 L of the storm water was poured through the material through natural percolation, approximately 0.35 Lmin -1 . Treated and untreated storm water was analyzed for heavy metals, suspended solids, electric conductivity and pH. Active carbon showed the highest level of adsorption, with nearly 100 % of all metals adsorbing to the filter. However, significant concentrations of As was desorbed from the material into the filtered water. Pine bark retained 90 % of the metals, even the Zn which was present in high concentrations. Polonite could only adsorb 70 % of the heavy metals and released Cr from the material
Treatment of high ethanol concentration wastewater by constructed wetlands: enhanced COD removal and bacterial community dynamics
International Water Association: Microbes in wastewater and waste treatment, bioremediation and energy productio