March 19, 2020

Study finds treated wastewater may be safe for aquaculture

Researchers at Ben-Gurion University of the Negev, Israel has found that organic micropollutants (OMPs) in treated water are minimally accumulated in fish.

OMPs include trace elements of heavy metals, pharmaceuticals and personal care products as well as pesticides, solvents, and detergents.

While inorganic compounds and substances such as nitrogen and phosphorus are removed in tertiary wastewater treatment (TTWW), the last stage of the wastewater cleaning process, it is unable to remove organic compounds.

In the study, juvenile Carp (Cyprinus carpio) were raised in 0%, 50% and 100% TTWW for five months, with seven out of 40 screened OMPs were detected in the water samples at least once.Out of the 19 analysed OMPs in fish tissues, four were detected in exposed fish.

Carbamazepine, an anticonvulsant and diclofenac, an anti-inflammatory, were detected in the muscle and liver of fish grown in 50% and 100% TTWW at measurable concentrations. Carbamazepine-epoxide and Benadryl (diphenhydramine) concentrations were below the limit of quantification (LOQ) in the muscle of the exposed fish, while diphenhydramine was detected above the LOQ level in two liver samples of fish grown in 100% TTWW.

Based on the findings, Prof. Dina Zilberg, a researcher in the BGU French Associates Institute for Agriculture and Biotechnology of Drylands, Jacob Blaustein Institutes for Desert Research said TTWW can be used for raising fish, meeting all existing standards for heavy metal accumulation.

The professor added that further investigation is required on OMPs accumulation in different species of edible fish with different feeding habits to ensure public health when using TTWW for aquaculture.