Using tertiary treated wastewater for aquaculture purposes has minimal effects on fish survival, growth, or immune function, and could potentially be used in commercial aquaculture operations, according to a new study.
A team of researchers from Ben-Gurion University of the Negev in Beersheba, Israel, have determined that that organic micropollutants (OMPs) in water – trace elements of heavy metals, pharmaceuticals, and personal care products as well as pesticides, solvents, and detergents – result in minimal accumulation in fish. These findings were recently published in the journal Aquaculture.
Although aquaculture in treated wastewater is practiced worldwide, there is little scientific research concerning whether organic micropollutants are present at safe levels for consumption, the researchers wrote in the study’s abstract.
Tertiary wastewater treatment is the third and final stage of the cleaning process that improves wastewater quality before it is reused, recycled, or discharged to the environment. The treatment removes remaining inorganic compounds and substances, such as the nitrogen and phosphorus, but not the organic compounds.
"The presence of micropollutants in water can lead to toxic biological effects in fish including mutations, and feminization of male fish from being exposed to endocrine disrupting OMPs," wrote Dina Zilberg, a researcher at the BGU French Associates Institute for Agriculture and Biotechnology of Drylands.
In the study, juvenile carp were raised in zero percent, 50 percent, and 100 percent tertiary-treated wastewater for five months. The team found that exposure to tertiary-treated wastewater had no effect on fish health, with the presence of heavy metals in the fish muscle below maximal levels permitted by the E.U. and United Nationas Food and Agriculture Organization. Seven of 40 screened OMPs were detected in the fish at least once. Out of the 19 analyzed OMPs in fish tissues, four were detected in exposed fish.
"Based on the findings, tertiary treated wastewater can be successfully used for growing fish, and TTWW-grown fish met all the existing standards for heavy metals accumulation," wrote Zilberg. "However, further investigation on OMPs accumulation in different species of edible fish with different feeding habits is required to ensure public health when using TTWW for aquaculture."
Photo courtesy of Ben-Gurion University of the Negev
