Surface Water Quality in Punjab, India: Tracking Human and Farm Animal-Specific Adenoviral Contamination and Correlation with Microbiological and Physiochemical Parameters

Abstract

The capability of faecal indicator bacteria (FIB) to be environmental in origin and the deficient specificity of markers can mean uncertain outcomes when just a single marker is distinguished. This can give a bogus thought regarding water quality. A water quality analysis and the correlation between FIB, multiple physiochemical parameters and a viral marker in recreational waters were studied. For water concentration, carefully validated virus filtration techniques were used coupled with PCR-based assays for virus quantification. Around 32.0% of analysed surface water samples were positive for human adenovirus (HAdV, qPCR), 16.0% for bovine adenovirus (BAdV, nested PCR) and 11.0% for porcine adenovirus (PAdV, qPCR). For all the types of the adenoviruses, detection frequencies were not significantly different except for HAdV that showed higher frequency in water samples from tehsil Ludhiana. Only a sporadic significant correlation was observed with the few components; there was no constant, stable correlation between the microbiological and physiochemical parameters. Although both canals and river showed a stable and significant positive correlation between bacteriological parameters (coliform and enterococci) and between biological oxygen demand (BOD) and chemical oxygen demand (COD), regression analysis revealed no significant correlations between concentration of enterococci count to a concentration of AdVs, unlike coliform that showed sporadic but significant correlation with PAdV and no correlation with HAdVs/BAdVs. On principal component analysis, the first factor had strong positive loadings on BOD, COD, total dissolved solids (TDS), turbidity and PAdV and is largely a pollution loading factor which is also supported by their mutual cluster in cluster analysis. Factor 2 had strong loading on enterococci/coliform count due to the natural quality of water and domestic waste and factor 3 had loading on HAdV. This factor shows the impact of human activities overwhelmed in the catchment area of the canals and river. Hence, a significant level of certainty on the contamination source can be acquired if more than one marker is distinguished. Our study thus gives a case of how quantifying both physiochemical, FIB and adenoviral markers in surface water can improve water quality evaluation and help tailor CPCB -India programs for impaired water bodies in the future.