A new study has found that eating vegetables and fruits grown in soils irrigated with reclaimed wastewater exposes consumers to trace quantities of carbamazepine, an anti-epileptic drug commonly detected in wastewater. The “proof of concept” study points to the possibility that other pharmaceuticals may contaminate produce in a similar fashion.
Fresh water scarcity worldwide has led to increased use of reclaimed wastewater as an alternative source for crop irrigation. But the ubiquity of pharmaceuticals in treated water has raised concerns over the potential exposure to drug contaminants via treated wastewater.
The study out of Israel was published in Environmental Science and Technology.
“In a randomized controlled trial we have demonstrated that healthy individuals 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 researchers measured carbamazepine levels in the fresh produce and in the participants’ urine. To begin with, the urinary levels of carbamazepine differed in their quantifiable concentration, with some participants having undetectable levels. Following seven days of consuming reclaimed water-irrigated produce, all members of the first group exhibited quantifiable levels of carbamazepine, while in the second group the distribution remained unchanged from baseline. Levels of carbamazepine excretion were markedly higher in the first group versus the second.
“Treated wastewater-irrigated produce exhibited substantially higher carbamazepine levels than fresh water-irrigated produce,” said Prof. 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,” Prof. 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 which could guide policy and risk assessments,” said Prof. Chefetz.