James Odendaal

A review on sources of brominated flame retardants and routes of human exposure with emphasis on polybrominated diphenyl ethers

The presence of brominated flame retardants (BFRs) in various environmental matrices, including humans, has been well documented. Increasing levels of these emerging contaminants in various environmental compartments suggest the wide application of these chemicals in products of everyday use. The release of BFRs from treated products is generally believed to be the major source of these contaminants into the environment, particularly in indoor environments. The sources and pathways through which BFRs enter the human system are evaluated in this paper. Human exposure via consumption of contaminated food and water, inhalation and ingestion of dust, as well as dermal absorption, are important pathways for these contaminants. Consumption of fatty foods especially fish, meat, dairy products as well as human milk constitute important routes for human exposure to these contaminants. Although brominated diphenyl ether (BDE) 209 has been found to be less bioaccumulative due to its high molecular weight, its domina...

The possible effect of the bioaccumulation of disinfectant by-products on crops irrigated with treated wastewater

The shortage of potable water for irrigation of food crops in semi-arid developing countries led to the use of alternative sources of water. Wastewater is gaining importance for productive use in agriculture throughout the world. A widely used and efficient method to reduce the occurrence of waterborne diseases in numerous wastewater plants is water chlorination. In early 1970s, some volatile halogenated organic compounds such as chloroform were identified in chlorinated surface waters containing high levels of natural organic material. Generally, the trihalomethanes (THMs), including chloroform, bromodicholoromethane, dibromochloromethane and bromoform were the most prevalent in chlorinated surface water. Predominant research studies focused on the carcinogenic and mutagenic properties of these compounds in treated wastewater. But little attention was paid to how these compounds in treated wastewater could affect crop performance in agriculture, physiological changes amongst crop varieties and the build-up of these organic compounds in edible plant tissues with persistent use of treated waste-water. A probable reason for this was the absence of the practice of wastewater irrigation in food crop agriculture in the past. Current knowledge on the trihalomethanes and possible plant interactions with this group of volatile organic compounds are assessed in this review.

Identification of point sources of metal pollution in the Berg River, Western Cape, South Africa

The aim of this study was to statistically compare sampling sites identified along the Berg River system to identify the major point sources of metal pollution from June 2004 to May 2005. Three sites were selected [site A—agricultural farming area, site B—Plot 8000 (close to the informal settlement), and site C—the Newton pumping station] representing different sectors which the river services. Aluminium (Al), iron (Fe), manganese (Mn), and lead (Pb) concentrations were determined using Inductively Coupled Plasma Atomic Emission Spectrometry and were statistically compared and analysed with one-way ANOVAs. For all the metals analysed, site C (industrial area) proved to be the site where the highest average metal concentrations were recorded. Generally, the concentrations recorded at site A (site furthest from the industrial area) were significantly (p < 0.05) lower than the concentrations recorded at both sites B and C. While the Al and Fe concentrations were consistently higher than any of the other metals analysed for, site C was identified as the primary source of metal contamination in the Berg River, resulting from the runoff from industrial activities at this particular site.

The halogen effects of disinfectant by-products on nutrient concentration, oxidative stress, fatty acids and α-tocopherol concentrations in membrane lipids of two Solanum lycopersicum cultivars

Abstract A 30-day exposure time experiment was designed to investigate whether the extent of physiological impacts of trihalomethane exposure on two Solanum lycopersicum cultivars correlated with either the number of bromine or chlorine atoms in the trihalomethane molecules, focusing on biomass gain, nutrient concentration, oxidative stress, fatty acids and α-tocopherol contents in membrane lipids. The gain of biomass in tomato seedlings decreased with an increase in the degree of bromination. Concentrations of essential nutrients required for plant growth such as nitrogen, phosphorus, potassium, sulphur and boron decreased in plant dry matter that correlated with the increasing number of chlorine atoms in the trihalomethane molecules. Trihalomethane exposure resulted in an increase in oxidative stress response in both tomato cultivars with parameters such as total phenolic content, ferric reducing antioxidant power, oxygen radical absorbance capacity and the activities of antioxidant peroxidase enzymes, all correlating with an increasing number of chlorine atoms in the trihalomethane molecule; hence, oxidative damage increased with a higher degree of chlorination. However, no such correlations were observed in superoxide dismutase activity, general lipid peroxidation, α-tocopherol content and total soluble proteins. In plant membrane lipids, an increase in the saturated fat hexadecanoic acid was observed in both tomato cultivars that correlated with the degree of chlorination in the trihalomethane molecule. The increase in α-linolenic acid stress signaling correlated with an increase in the degree of chlorination in only one tomato cultivar suggesting variable tolerance between cultivars to chemical action.

Health risk assessment of plasticizer in wastewater effluents and receiving freshwater systems

Health risk assessment of plasticizer in wastewater effluents and receiving freshwater systems Luqman M (ed): Recent Advances in Plasticizers Rijeka, Croatia: InTech Online Publishers, 2012, pp 191-212, ISBN 978-953-51-0363-9