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Contaminants of Emerging Concern (CECS): From Treated Wastewater and Biosolids to Fresh Produce

Gan, Jianying
University of California - Riverside
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The overall objective of this project is to obtain new information and knowledge on the uptake, accumulation and potential human dietary exposure of CECs in fresh produce including vegetables and fresh fruits when reclaimed water irrigation and biosolids are used in crop production, and to develop guidelines and science-based educational and outreach materials to inform stakeholders and end-users, thus minimizing the potential risks from such practices. Specifically, we will:

  1. Conduct whole-plant and plant cell experiments to evaluate the uptake, translocation, metabolism, and accumulation of a comprehensive list of CECs and to identify "priority" CECs that have a high potential for plant accumulation;
  2. Carry out field-plot studies in Southern California on uptake of CECs by vegetables, strawberries, melons and tree fruits grown with reclaimed water irrigation or biosolids amendment under representative agronomic conditions to determine levels of CECs in raw edible tissues at harvest;
  3. Evaluate the thepotential human health risjsby calculating the human exposure to CECs from dietary intakes of vegetables and fruits that are grown with reclaimed wastewater or biosolids; and
  4. Produce outreach and education materials, including fact sheets, publications in non-technical venues, web postings, carrying out information dissemination and training workshops and field tours to extend scientific findings to sanitation and water districts, regulators, commodity groups, growers, and the general public.
More information
The use of reclaimed water and biosolids in agriculture has increased drastically due to worsening water scarcity and rising need for waste disposal. Reuse of such previously under-utilized resources has important economic and environmental benefits, but also poses unknown risks to consumers due to the potential introduction of many contaminants of emerging concern (CECs) into food products. The perceived risks are the greatest for fresh produce such as vegetables and fruits that are often consumed raw. However, the occurrence and levels of CECs in vegetables and fruits under field conditions are essentially unknown, preventing assessment of the associated food safety. This project aims to improve food safety by evaluating emerging and under-researched chemical hazards in fresh produce. Specifically, we will first conduct greenhouse and cell-based experiments to develop a short list of CECs that have a high tendency for plant accumulation, and then measure the actual levels of these priority CECs in edible parts of common vegetables (lettuce, spinach, cabbage, celery, tomato, pepper, cucumber, radish, carrot, onions) and fruits (strawberries, melons, apple, citrus, avocado, plum) grown with treated wastewater irrigation or biosolid amendment in fields in Southern California. We will further use typical consumption values to estimate dietary intakes of CECs for different age groups and predict potential human exposure risks. Working with county-based farm advisors in California, we will actively extend science-based information to growers and the general public to promote safe reuse. This project contributes to a sustainable U.S. agriculture by promoting the use of treated wastewater and biosolids as valuable resources while safeguarding consumers.
Funding Source
Nat'l. Inst. of Food and Agriculture
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Bacterial Pathogens
Natural Toxins