Analyzing Water and Fish from an Artificial Lake Receiving Treated Wastewater

Inbal Zaibel, The Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boker, Israel
Ludmila Groisman, National Public Health Laboratory, Ministry of Health, Tel-aviv, Israel
Shai Arnon, The Jacob Blaustein Institutes for Desert Research, Ben-gurion University of The Negev, Sede Boker, Israel
Dina Zilberg, The Jacob Blaustein Institutes for Desert Research, Ben-gurion University of The Negev, Sede Boker, Israel

Chronic water shortage in Israel led to enhanced utilization (85%) of treated wastewater (TWW) for agriculture, public gardens and parks, and recently for feeding of artificial lakes.  TWW quality standards in Israel are well defined for nutrients, heavy metals and bacterial contamination. Different countries (excluding Israel) use TWW for fish culture, yet this activity is scarcely supported by research. The few published studies address bacterial contamination and heavy metal accumulation.

There is recognition that TWW contains low concentrations of various organic micropollutants (OMPs) that may carry a risk to public health and the aquatic ecosystems. OMPs are not regulated in water quality standards in Israel or elsewhere around the world. Our objective is to evaluate the feasibility of use of tertiary TWW (TTWW) for aquaculture.

A project which included monthly monitoring of artificial TTWW-fed Lake Yeruham, over two years provides information on the feasibility of the use of this water for aquaculture. Monthly analysis of TTWW chemistry revealed good quality which can support aquaculture. Of sixteen tested OMPs, only 6 were found in the TTWW and 4 in the lake water samples. Levels were mostly much lower than the predicted no effect concentration (PNEC), except for estrone, which was found to be higher by 40% in one out of four measurements. Fish grown in Lake Yeruham appeared to be healthy and histopathological analysis revealed moderate infection levels with commonly occurring parasites. Concentrations of OMP's in fish tissues were lower by 25-30 folds from the permitted levels in food products, according to EU standards.

A preliminary lab-based study maintaining guppies in TTWW revealed no apparent abnormalities in the fish. Further lab-based and field research with guppies and food fish will be carried out to provide fundamental data on the feasibility of using TTWW for aquaculture.