“Treated wastewater-irrigated produce exhibited substantially higher carbamazepine levels than fresh water-irrigated produce.”
Eating fresh produce grown in soil irrigated with reclaimed wastewater exposes people to tiny quantities of carbamazepine, an anti-epileptic drug commonly detected in wastewater effluents, according to research at the Hebrew University and Hadassah Medical Center in Jerusalem.

The study, published in Environmental Science and Technology, addresses the link between exposure to pharmaceutical contaminants and consumption of fresh fruits and vegetables grown in reclaimed wastewater-irrigated soil.

The global scarcity of fresh water has led to increased use of reclaimed wastewater for crop irrigation. But as there are so many drugs excreted by the body into the environment and released by treated effluents, there has been much concern over the exposure for consumers to drug contaminants via treated wastewater.

“Israel is a pioneer and world leader in reuse of reclaimed wastewater in the agriculture sector, providing an excellent platform to conduct such a unique study,” said research co-author Prof. Benny Chefetz from HU’s Faculty of Agriculture, Food and Environment and the director of HU’s Center of Excellence in Agriculture and Environmental Health.

“In a randomized controlled trial, we have demonstrated that healthy people consuming reclaimed wastewater-irrigated produce excreted carbamazepine and its metabolites in their urine, while subjects consuming fresh water-irrigated produce excreted undetectable or significantly lower levels of carbamazepine,” said Prof. Ora Paltiel, director of the Hebrew University-Hadassah Braun School of Public Health and Community Medicine, who led the research.

The study followed 34 men and women divided into two groups. The first group was given reclaimed wastewater- irrigated produce for the first week and freshwater-irrigated vegetables in the following week. The second group consumed the produce in reverse order. The volunteers consumed the vegetables, which included tomatoes, cucumbers, peppers and lettuce, according to their normal diet and drank bottled water throughout the study to neutralize water contamination.

“Treated wastewater-irrigated produce exhibited substantially higher carbamazepine levels than fresh water-irrigated produce,” said Paltiel. “It is evident that those who consume produce grown in soil irrigated with treated wastewater increase their exposure to the drug. Though the levels detected were much lower than in patients who consume the drug, it is important to assess the exposure in commercially available produce,” Paltiel said.

“This study demonstrates ‘proof of concept’ that human exposure to pharmaceuticals occurs through ingestion of commercially available produce irrigated with treated wastewater, providing data that could guide policy and risk assessments,” said Chefetz.