Drinking water quality is determined by the water’s biological, chemical, and physical features. Water sampling was carried out in 20 villages in the Pune and Satara districts of Maharashtra, with 15 falling in a low rainfall zone. Samples were collected from rivers, open wells, and bore wells, four times in a period of a year covering all seasons. A total of 206 water samples were analyzed for their physical, chemical, and bacteriological properties. Physical and chemical properties were expressed in the form of a modified Water Quality Index (WQI). Additionally, the modified WQI was compared to an Overall Pollution Index (OIP) for rivers. The present investigation is an attempt to analyze the impact of seasonal changes on water quality of different water bodies using two different WQIs. To understand the degree to which water quality is affected by faecal bacteria, modified WQI with exclusion of faecal coliforms (FC) and OIP with inclusion of FC were compared with each other in river water bodies. Modified WQI values and bacterial counts were at a maximum during the onset of the monsoon. In terms of bacteriological contamination, the number of FC and intestinal enterococci (IE) in the water bodies was of major concern since it would impact human health.

In laboratory experiments we added Vibrio cholerae and Vibrio parahaemolyticus to bottles with seawater previously treated by filtration, UV, chlorine or ozone. The purpose was to investigate the influence of different treatment techniques on the growth potential of these bacteria in simulated ballast water tanks. Residual oxidants were removed before inoculation, and the bottles were incubated at 21 ± 1 °C. The growth potential of the vibrios was investigated in two different experimental setups, i.e. in presence and absence of added natural microorganisms. In general, V. cholerae and V. parahaemolyticus rapidly lost their culturability after inoculation and storage in untreated seawater, but showed increased survival or growth in the treated water. Highest growth was observed in water previously exposed to high concentrations of ozone. Addition of natural microorganisms reduced the growth of V. cholerae and V. parahaemolyticus.

Surface water is used for irrigation of food plants all over the World. Such water can be of variable hygienic quality, and can be contaminated from many different sources. The association of contaminated irrigation water with contamination of fresh produce is well established, and many outbreaks of foodborne disease associated with fresh produce consumption have been reported. The objective of the present study was to summarize the data on fecal indicators and selected bacterial pathogens to assess the level of fecal contamination of a Norwegian river used for irrigation in an area which has a high production level of various types of food commodities. Sources for fecal pollution of the river were identified. Measures implemented to reduce discharges from the wastewater sector and agriculture, and potential measures identified for future implementation are presented and discussed in relation to potential benefits and costs. It is important that the users of the water, independent of intended use, are aware of the hygienic quality and the potential interventions that may be applied. Our results suggest that contamination of surface water is a complex web of many factors and that several measures and interventions on different levels are needed to achieve a sound river and safe irrigation.

Simple, automated methods are required for rapid detection of wastewater contamination in urban recreational water. The activity of the enzyme β-d-galactosidase (GAL) can rapidly (5 LOG₁₀. Furthermore, the GAL-activity per gram feces from birds, sheep and cattle was 2–3 LOG₁₀ lower than the activity from human feces, indicating that high GAL-activity in water may reflect human fecal pollution more than the total fecal pollution. The rapid method can only be used to quantify high levels of human fecal pollution, corresponding to about 0.1 mg human feces/liter (or 10³ E. coli/100 mL), since below this limit GAL-activity from non-fecal environmental sources may interfere.

The recommended test for assessing if a chemical can be biodegraded in the marine environment is performed according to the Organisation for Economic Cooperation and Development Marine biodegradation test guideline (OECD 306). However, this test is known to generate highly variable test results when comparing interlaboratory test results for the same compound. One reason can be the relatively low bacterial content compared to the inoculum used for OECD readily biodegradation tests (OECD 301). Some of the variability in data obtained from OECD 306 tests can also be due to the flexibility on how to store the seawater inoculum before starting a test. Another variable in the seawater inoculum is the source of seawater used by different laboratories, i.e., geographical location and anthropogenic activities at the source. In this study, the effect of aging seawater and the source of seawater (sample time and depth) were investigated to determine differences in the biodegradation of the reference compound aniline. Aging the seawater before starting the test is recommended in OECD 306 to reduce the background levels of organic carbon in the water. However, it also functions to acclimatize the bacterial community from the environmental source temperature to the test temperature (normally 20 °C). Herein, the microbial community was monitored using flowcytometer during the aging process. As expected, the microbial community changed over time. In one experiment, aging significantly improved the biodegradation of aniline, while in two experiments, there was no significant difference in biodegradation. Interestingly however, there was significant variability in the biodegradation of aniline between sampling seasons and depths, even when all experiments were performed in the same lab, by the same operator and seawater obtained from the same source. This highlights the need for a more robust and consistent microbial inoculum source to reduce variability in seawater biodegradation tests.

Persistent chemicals discharged into the sea can pose long-term, irreversible risks. New approaches are needed to elucidate the number and type of persistent chemicals, particularly in complex mixtures and high-volume discharges. We introduce a novel "Persistence-Directed Testing" approach that combines environmentally relevant biodegradation tests with nontarget analytical methods. Complex produced waters from two offshore oil platforms in the North Sea served as case studies. In the biodegradation tests, produced waters were diluted 1:200 with seawater from the site of discharge (inoculum). Biotic test systems and abiotic controls were incubated at 9 °C. At day 60 nontarget analyses were performed by Solid Phase Microextraction coupled to GC-MS and Solid Phase Extraction coupled to LC-HRMS. Primary biodegradation and persistence were determined based on biotic/abiotic peak area ratios. Over 600 chemicals passed the quality control filtering criteria, and the persistent fraction of chemicals discovered by GC-MS was 4% and that discovered by LC-HRMS was 32-44%. Spectral library matches and computational modeling of the LC-HRMS data annotated several persistent chemicals as N-substituted aromatic ring structures. These findings demonstrate the value of a persistence-directed approach in uncovering the hidden burden of unidentified persistent chemicals in environmental discharges and highlight the urgent need for enhanced treatment of produced water discharges.