Comparative Study of Two Methods of Enteric Virus Detection and Enteric Virus Relationship with Bacterial Indicator in Poyang Lake, Jiangxi, China.

Currently, water contaminated with fecal matter poses a threat to public health and safety. Thus, enteric viruses are tested for as a part of water quality indicator assays; however, enteric viruses have not yet been listed in the criteria. Effective and sensitive methods for detecting enteric viruses are required in order to increase water safety. This study utilized enteric viruses as possible alternative indicators of water quality to examine fresh water in six sites in Poyang Lake, Nanchang, Jiangxi Province. The presence of norovirus geno-groups II (NoV GII), enteroviruses (EoV) and adenoviruses (AdV) were determined using Tianjin's protocol and Hawaii's protocol during a six month period from 2016-2017. The former used an electropositive material method for viral concentration and Taqman-q reverse transcription polymerase chain reaction (RT-PCR) to detect enteric viruses; while the latter used a filtration-based method for viral concentration and RT-PCR for enteric virus detection. There is a statistically significant difference between Tianjin's method and Hawaii's method for the detection of enteric viruses, such as NoV GII, EoV, and AdV (n = 36, p < 0.001). The enteric viruses showed no significant positive correlation with bacteria indicators (n = 36, p > 0.05). These data stress the need for additional indicators when establishing water quality systems, and the possibility of using enteric viruses as water quality indicators. It has become essential to improve shortcomings in order to search for an adequate method to detect enteric viruses in water and to implement such method in water quality monitoring.

Probabilistic health risk assessment of nitrosamines in drinking water of Shaoxing, Zhejiang, China.

Nitrosamines (NAms) are potent genotoxic and carcinogenic but widely detected in drinking water. This study aimed to investigate the occurrence of major types of NAms in drinking water in Shaoxing, China, and to conduct multi-pathway probabilistic cancer risk (CR) assessment to residents based on age-dependent adjustment Chinese exposure factors. Results showed that concentrations of NAms in water varied from not detected (ND) to dozens of nanograms per liter level. N-Nitrosodimethylamine (NDMA) was detected most frequently (93.06%), followed by N-nitrosodiethylamine (NDEA) (64.08%)-with the highest cancer risk among NAms. The CR of NAms came mainly through the oral exposure pathway. The 95th percentile of the total CR of five major NAms was 1.06 × 10-4, exceeding the maximum acceptable lifetime CR (1 × 10-4) recommended by US EPA. Exposure to NDEA contributed the highest to the total CR. The CR of the five NAms through ingestion was 2.5 times higher using the Chinese exposure factors than that of the Americans. The most important variables related to CRs were concentrations of NAms in drinking water, exposure duration, drinking water ingestion rate, and exposure time during bathing. Our findings suggest the urgent need to develop and enforce effective regulatory policies to control the contamination of NAms in drinking water in China. Graphical abstract.