Detection of non-CPE producing enteric viruses via ICC-PCR at wastewater land application sites in Arizona and California; endocrine disruption activity after wetland, pond, and soil aquifer treatment of wastewater

Abstract

In the arid Southwest where groundwater levels are rapidly declining, reuse of wastewater for groundwater recharge is currently being practiced. Since this practice is known to improve the chemical and biological quality of wastewater, it has been referred to as Soil Aquifer Treatment (SAT). This study investigated the fate of enteric viruses during SAT in Los Angeles, California, and Tucson, Arizona. The sites differed by both the quality and quantity of wastewater applied to spreading basins. At the Tucson site, secondary treated wastewater was applied. In Los Angeles, some sites received stormwater run-off combined with tertiary treated wastewater and others received only tertiary treated wastewater. A major concern with recharge of groundwater is the possible introduction of disease-causing organisms from inadequately treated wastewater. Although harmful bacteria, viruses, and protozoa may be present in wastewater, viruses cause the greatest concern regarding groundwater contamination due to their small size and long-term survival capabilities in the environment--making them less likely to be removed by the process of soil filtration. Integrating the DNA amplification method Polymerase Chain Reaction (PCR) with cell culture, a new technique called Integrated Cell Culture-Polymerase Chain Reaction (ICC-PCR) was adopted to study the occurrence of viruses after SAT. ICC-PCR was used in this study for the detection of non-cytopathogenic effect (CPE) producing enteroviruses in cell culture lysates. Primers had a sensitivity of 1 PFU/mul in cell culture lysate fluid. ICC-PCR products were confirmed with semi-nested PCR and sequencing of the viral nucleic acid. Two hundred eighty-two CPE negative cell culture lysates were analyzed via ICC-PCR. Twenty-seven of these cell culture lysates were found to be positive by ICC-PCR. These twenty-seven cell culture lysates encompassed four tertiary treated wastewater samples, three reclaimed groundwater monitoring well samples, three deep potable groundwater well samples from the Los Angeles area, two secondary wastewater effluent samples, and one reclaimed groundwater monitoring well sample from Tucson, AZ. Coliphages were detected in the groundwater at the Tucson SAT site more often than indicator bacteria. There was no evident relationship between the occurrence of indicators and isolation of non-CPE producing enteroviruses at the Tucson site.