Taming food security through wastewater irrigation practices

Abstract

Water scarcity, deteriorating water quality and wastewater irrigation is a regional as well as global problem affecting human livelihood and economic prosperity in developing countries. Pakistan’s economy is based on agriculture, which supports livelihood of more than 50 % people relying heavily on available fresh water supplies. Around 90 % of the food and fi ber requirements of the country are met from irrigated areas (86.25 % of the total cultivated area) and remaining 10 % from rain-fed areas (13.75 % of the area under cultivation). Water availability is maximum in the Kharif (summer) season and lowest in the Rabi (winter) season. Since Pakistan’s creation water availability has reduced from 5600 m3 to <1000 m3 placing immense pressure on the domestic, industrial and agricultural sectors. Reduction in available fresh water supplies has attracted farmers in rural, urban and peri-urban areas to harvest untreated wastewater in agriculture. Wastewater is a complicated mixture of chemical pollutants in which heavy metals are of signifi cant concern. Heavy metals laden wastewaters have adverse impacts on the plants, soils, humans and livestock health. Grave food safety issues arise from the consumption of metal polluted agricultural produce leading to serious clinical conditions. Around 4369 million m3 of wastewater is generated per annum in Pakistan, which is roughly equivalent to standing wheat crop water requirements. Wheat is grown in the Rabi season (November to May), the season, which is already facing serious water defi - cit. Voluminous amounts of wastewater generated from municipal and industrial sectors can be effi ciently utilized in safer crop (wheat) production on treatment. As raw wastewater irrigation can result in serious toxicological conditions in the wheat crop therefore diverse wheat genetic makeup (different wheat varieties/advanced lines) may be used to determine the extent of adverse impacts of heavy metal containing municipal/industrial wastewater on growth/metabolism of different Pakistani wheat cultivars. Identifi ed tolerant wheat varieties then can be recommended for areas where wastewater irrigation is common or fresh water is scarce that will also minimize contaminants (metals) exposure to human and livestock through wheat consumption. Related information on wastewater antagonistic impacts on different wheat varieties is not available from Pakistan. Food safety issues arising from consumption of metal contaminated wheat grains/fl our irrigated with municipal/industrial wastewater have only been explored on one of the most commonly growing wheat varieties in various studies. Wheat is the conduit to food security, so harvesting precious wastewater with its potential reuse in wheat irrigation can be of great competitive advantage in achieving food security in rapidly populating country i.e. Pakistan, where growing population needs continuous food supplies with an ever growing water needs. Future research endeavors if focused on gauging impact of wastewater irrigation practices on different wheat cultivars, information generated would be helpful in combating water scarcity, food safety and food security related issues in Pakistan.