Presentations 2016

Approach to Reduce Drought in California

California Department of Public Health

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Drought has been projected as the biggest threat from climate change and its impacts are global. Drought occurs in all continents of the world including Africa, Australia, Asia, and North America. A drought can be defined in various ways. A meteorological drought, for example, is when the rains fail. A hydrological drought is when the lack of rainfall goes on long enough to empty rivers and lower water tables. Agricultural drought begins when the lack of water starts killing crops and livestock. And after that, people may start dying too as a result of insufficient food and water supply. Droughts have significant economic, environmental, direct and indirect social impacts. Beyond direct economic impacts, drought can threaten drinking water supplies and ecosystems, and often contributes to increased food costs. Within the last decade, drought conditions have hit the Southeastern U.S, the Midwest, and the Western U.S. In 2013, California had the driest year on record. The 2011 U.S. drought covered the southern states where Texas, Oklahoma and New Mexico were most adversely affected. Drought also affected parts of Arizona, Kansas, Arkansas, Georgia, Florida, Mississippi, Alabama, South and North Carolina. Now is the time to find some approach that might mitigate the drought issue in California. FDB is now initiated several research efforts to evaluate use of recycled water from several sources to provide new insight and timely solutions for amelioration of projected irrigation water deficits in California agriculture. Recycled water has the added benefit of high nutrient content and has the potential of being both a good resource for irrigation and soil nutrient supplementation. Although recycled water is potentially a good resource, it may also have possible negative impacts on food crops and public health due to microbial and heavy metal contamination. The new FDB studies are intended to identify and categorize these public health risks. The greatest concern is that recycled water may be contaminated with human pathogens which could be absorbed by food plants irrigated with recycled water. These pathogens, if present in the edible parts of the vegetables, have the potential to cause human and animal illness when consumed. Research and epidemiological follow-up has detected Escherichia coli, other fecal coliforms, fecal streptococci, Salmonella spp. and helminth eggs in vegetables irrigated with tertiary-treated municipal wastewater. Lonigro et. al. 2015, reported that Escherichia coli and Salmonella were found, at harvesting time, on edible parts of crops like cucumber, lettuce and melon irrigated with treated municipal wastewater. Rai and Tripathi, 2007, reported that vegetables irrigated with partially treated wastewater had coliform counts higher than the recommended standards, with highest amounts detected in spinach and cabbage. Consumption of such contaminated vegetables has been epidemiologically linked to disease outbreaks with associated serious health risks to vulnerable human populations. In summary, our studies will contribute significant and timely data evaluating the use of recycled water from organic waste for irrigation of leafy greens.