Abstract

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.

Key words: Antioxidants, biomagnification, chlorophyll, metabolites, oxidative-stress, photosynthesis, phytotoxicity, seed germination, trihalomethanes.