Documenting Human Health Impacts Of Exposure To Microbial And Chemical Hazards In Reclaimed Wastewater Used In Urban Agriculture, Cache Valley

Diminished water supplies have resulted in an increased use of alternative water sources for agriculture, including treated municipal wastewater (hereafter reclaimed water). A total of 20 million hectares in 50 countries worldwide was irrigated with reclaimed water in 2010 (Winpenny et al., 20100. Studies have shown that manmade chemicals including pharmaceuticals and personal care products (PPCPs) (Ternes et al., 2004; Xu et al., 2009) and pathogens may be present in reclaimed water (Li et al., 2016). When reclaimed water is used for agricultural irrigation it has been documented that some of these compounds are taken up into food (Wu et al., 2014; Wu et al., 2013) (e.g., antiseizure medication in produce (Paltiel et al., 2016)). Further, enteric pathogens have also been shown to adhere to plants irrigated with reclaimed water (Hamilton et al, 2006; Hirnesen et al., 2012). While advanced treatment methods exist to remove nearly all the constituents of concern from municipal water, these technologies are cost prohibitive. With the increasing need for non-traditional water supplies for agriculture there is a critical need to identify which contaminants in reclaimed water used for agriculture present the greatest human health risk.Therefore, the goal of this research is to determine which constituent(s) or combination of constituents of concern represent the greatest risk to humans exposed to the reclaimed water used in agriculture. Our central hypothesis is that the additive risk of PPCPs and microbial pathogens in reclaimed water exceed acceptable risk levels when all exposure routes are considered.Our second hypothesis is that most pathogens (bacterial, eukaryotic, viral) in reclaimed water can be detected via a custom microarray that can detect >430 waterborne pathogens and indicator bacteria. We propose that our microarray, when coupled with quantitative microbial risk assessment and Bayesian statistics will allow for more accurate estimation of human health risk from reclaimed water for agriculture than the fecal indicator bacteria paradigm. Our final hypothesis is that in a community already accepting of reclaimed water use, when educated on the health risks of reclaimed water for agriculture will modify their practices for the most protective use of the resource. From these hypotheses, several objectives for the study are proposed as follows:Objective 1. Quantify select PPCPs and a wide range of microbial pathogens, using culture-based, quantitative polymerase chain reaction (qPCR), and novel microarray techniques, in three reclaimed wastewater sources currently being used for agricultural irrigation in the Cache Valley watershed. With this reclaimed source water, quantify human exposure to these PPCPs and microbial pathogens at field sites as a function of irrigation delivery methods via a range of exposure pathways.Objective 2. Carry out a quantitative risk assessment using field exposure and transport data, coupled with PPCP and pathogen concentrations in reclaimed wastewater, to improve estimates of human health risks from multiple hazards in reclaimed wastewater, and to identify minimum wastewater treatment (reclaimed wastewater hazard source characteristics) and irrigation delivery methods that yield minimal human health risks.Objective 3. Evaluate risk perceptions and attitudes of key informants and residents in a community using reclaimed wastewater for agriculture, contrast these results with those from a community where reclaimed wastewater use and exposure are limited, and assess how community education and outreach may impact modifications in recommended water reuse practices to manage perceived and actual human risks.Long-Term Goals and Objectives of ProjectOur long term goals and objectives of the project are to understand additivity in human health risks from reclaimed water use for agriculture, evaluate methods to mitigate those risks, and determine methods for effective communication about those risks with reclaimed water end users. To achieve these goals and address the hypotheses proposed herein we will use three existing water reclamation systems in urban, peri-urban and rural settings in Cache Valley, Utah (representing 85% of the Valley's population) as a model watershed to address Objectives 1 and 2. Further, we will leverage existing research through the NSF-sponsored EPSCoR iUtah project on water use perceptions in the Valley to address Objective 3. The results generated in the proposed study could be broadly applied to other regions with water scarcity issues such as California, Texas, and Florida.ReferencesHamilton, A. J., F. Stagnitti, R. Premier, A.-M. Boland, and G. Hale. 2006. Quantitative Microbial Risk Assessment Models for Consumption of Raw Vegetables Irrigated with Reclaimed Water. Applied and Environmental Microbiology 72:3284-3290.Hirneisen, K. A., M. Sharma, and K. E. Kniel. 2012. Human Enteric Pathogen Internalization by Root Uptake into Food Crops. Foodborne Pathogens and Disease 9:396-405.Li, X., V. J. Harwood, B. Nayak, and J. Weidhaas. 2016. Ultrafiltration and Microarray Detect Microbial Source Tracking Marker and Pathogen Genes in Riverine and Marine Systems. Applied and Environmental Microbiology 82:1625-1635.Paltiel, O., G. Fedorova, G. Tadmor, G. Kleinstern, Y. Maor, and B. Chefetz. 2016. Human Exposure to Wastewater-Derived Pharmaceuticals in Fresh Produce: A Randomized Controlled Trial Focusing on Carbamazepine. Environmental Science & Technology 50:4476-4482.Ternes, T. A., A. Joss, and H. Siegrist. 2004. Peer Reviewed: Scrutinizing Pharmaceuticals and Personal Care Products in Wastewater Treatment. Environmental Science & Technology 38:392A-399A.Winpenny, J., I. Heinz, and S. Koo-Oshima. 2010. The wealth of waste: The economics of wastewater use in agriculture. Food and Agriculture Organization of the United Nations, available at: http://www.fao.org/docrep/012/i1629e/i1629e.pdf.Wu, X., F. Ernst, J. L. Conkle, and J. Gan. 2013. Comparative uptake and translocation of pharmaceutical and personal care products (PPCPs) by common vegetables. Environment International 60:15-22.Wu, X., J. L. Conkle, F. Ernst, and J. Gan. 2014. Treated Wastewater Irrigation: Uptake of Pharmaceutical and Personal Care Products by Common Vegetables under Field Conditions. Environmental Science & Technology 48:11286-11293.Xu, J., L. Wu, and A. C. Chang. 2009. Degradation and adsorption of selected pharmaceuticals and personal care products (PPCPs) in agricultural soils. Chemosphere 77:1299-1305.