The objective of the study reported in this paper was to assess the quality of harvested rainwater on the basis of the roofing materials used and the presence of lichens/mosses on the roofing surface. Four pilot structures with different roofing materials (i.e., wooden shingle tiles, concrete tiles, clay tiles [Gi-Wa] and galvanized steel) were installed in a field. The galvanized steel was found to be the most suitable for rainwater harvesting applications, with their resulting physical and chemical water quality parameters meeting the Korean guidelines for drinking water quality (e.g., pH (5.8–8.5), TSS <500 mg/L, NO₃ ⁻ < 10 mg/L, SO₄ ²⁻ < 200 mg/L, Al < 0.2 mg/L, Cu < 1 mg/L, Fe < 0.3 mg/L, Pb < 0.05 mg/L, Zn < 1 mg/L, and E. coli (No detection)). In the galvanized steel case, the relatively high water quality was probably due to ultraviolet light and the high temperature effectively disinfecting the harvested rainwater. It was also found that the presence of lichens and mosses may adversely affect the physical, chemical and microbiological quality of rainwater.

Antibiotic susceptibility, detection of sul gene types and presence of class 1, 2 and 3 integrons and gene cassettes using PCR assays were investigated in 3456 Escherichia coli isolates obtained from 38 sampling sites of the Dongjiang River catchment in the dry and wet seasons. 89.1% of the isolates were resistant and 87.5% showed resistance to at least three antibiotics. sul2 was detected most frequently in 89.2% of 1403 SXT-resistant isolates. The presence of integrons (class 1 and 2) was frequently observed (82.3%) while no class 3 integron was found. In these integrons, 21 resistance genes of 14 gene cassette arrays and 10 different families of resistance genes were identified. Three gene cassette arrays, aac(6')-Ib-cr-aar-3-dfrA27-aadA16, aacA4-catB3-dfrA1 and aadA2-lnuF, were detected for the first time in surface water. The results showed that bacterial resistance in the catchment was seriously influenced by human activities, especially discharge of wastewater.

We assessed the occurrence of pollution indicators and antibiotic resistant bacterial isolates from water and sediment samples of three different eco-regions of the Chennai coast between March – May of 2010. Total of 960 bacterial strains belonging to four genera were isolated which show the highest frequencies of resistance to vancomycin (53.6%) and penicillin (52.6%) (except Enterococcus sp., which is highly resistant to erythromycin) and lowest frequencies of resistance to chloramphenicol (3.43%), ciprofloxacin (3.95%), gentamicin (4.68%), and tetracycline (6.97%). The E. coli, Vibrio sp., Salmonella sp. and Enterococcus sp. show high frequency of resistance to 2–5 antibacterials of 60.4%, 45.83%, 69.16% and 46.6%, respectively. High pollution indices (PI – 6.66–14.06) and antibiotic resistance indices (ARI – 0.29–0.343) indicate that the coastal environment is highly exposed to antibiotic sources that suggesting to avoid direct contact.

The microbiological pollution of coastal waters is a major problem, especially in shellfish areas. This article shows the faecal contamination in bivalves from the Ria Formosa Lagoon (south coast of Portugal) along 20years (1990–2009). The highest values of Escherichia coli in bivalves were obtained during the 90s, related with the discharge of untreated wastewaters and agricultural runoff. In the 2000s contamination levels decreased, with 83% of the population already served by new or remodelled sewage treatment plants. The highest levels were found in bivalves close to the largest city, where punctual and diffuse contamination sources still exist. Bivalves from the less impacted site showed the lowest contamination, an area with more water renewal. Seasonally, the highest levels were in autumn and winter, due to the runoff of waters from rainfall. These were opposite to those in spring and summer, when the highest temperatures and salinity showed a bactericidal effect.

The aim of this study was to assess the impact of sewage discharge on coastal waters by evaluating the influence of physicochemical parameters on the presence of enteric microorganisms in seawater samples collected from 11 beaches in Florianopolis, Santa Catarina, Brazil, over a one-year period (August 2009 to July 2010). Samples were assessed for the presence of human adenoviruses (HAdV), polyomavirus (JCPyV), hepatitis A virus (HAV), and noroviruses (HuNoV GI and GII). Escherichia coli and physicochemical parameters (salinity, temperature, pH and dissolved oxygen) were also evaluated. From the 132 samples analyzed, 55% were positive for HAdV, 51.5% for HAV, 7.5% for HuNoV GI, 4.5% for HuNoV GII, and 3% for JCPyV. E. coli levels ranged from 8 to 1325CFU/100mL at all sites. The overall results highlight the problem of sewage discharge into coastal waters and confirm that there is no correlation between viral presence and bacterial contamination.

Marine waters from six sites around Hong Kong with varying levels of sewage pollution were examined for noroviruses (NoVs) by PCR cloning and sequencing of a highly-variable N-terminal region of the VP1 capsid gene, at the ORF1-ORF2 junction of NoV. Phylogenetic analysis of genogroups GI- and GII-specific PCR clones obtained from different marine sites indicated that human NoV GI.1 and GII.4 strains are the most prevalent genotypes circulating in Hong Kong waters. GI- and GII-specific TaqMan-based real-time PCR assays targeting the ORF1-ORF2 junction of NoVs were used to quantify NoV particles in marine water samples in parallel with total Escherichia coli counts which were enumerated on TBX medium. No correlation of any significance between NoV and E. coli counts was observed which highlighted the inadequacy in using E. coli as a fecal indicator to predict the level of NoVs in marine waters to protect public health.

The attenuation of Escherichia coli and total coliform from secondary treated wastewater effluent under two “at-grade” effluent distribution systems was evaluated in a sandy silt vadose zone in a cold climate. The two at-grade distribution lines had different designs and hydraulic loading rates. Effluent transport was examined using chloride as a tracer. Coliform fate was evaluated relative to the chloride using a combination of in situ pore water sampling and destructive soil sampling, combined with the observation of a dye tracer along excavation sidewalls. Although bacteria attenuation in the subsoil appeared to decrease during colder, winter temperatures (likely due to decreased viability and decreased predation), the subsoil provided about a four log reduction in E. coli over 90 cm of vertical transport. Horizontal transport of bacteria (up to 1.5 m from the line) was likely aided by flow on top of a microbial biomat observed at the soil surface. Both the subsurface dye patterns and the E. coli sampling suggested less preferential flow occurred below the lower loading rate design. At-grade distribution of secondary treated wastewater appears to be a viable alternative to conventional distribution fields at sites with similar climate and soils.

Faecal contamination of drinking water extracted from alluvial aquifers can lead to severe problems. River water infiltration can be a hazard for extraction wells located nearby, especially during high discharge events. The high dimensionality of river–groundwater interaction and the many factors affecting bacterial survival and transport in groundwater make a simple assessment of actual water quality difficult. The identification of proxy indicators for river water infiltration and bacterial contamination is an important step in managing groundwater resources and hazard assessment. The time resolution of microbial monitoring studies is often too low to establish this relationship. A proxy-based approach in such highly dynamic systems requires in-depth knowledge of the relationship between the variable of interest, e.g. river water infiltration, and its proxy indicator. In this study, continuously recorded physico-chemical parameters (temperature, electrical conductivity, turbidity, spectral absorption coefficient, particle density) were compared to the counts for faecal indicator bacteria, Escherichia coli and Enterococcus sp. obtained from intermittent sampling. Sampling for faecal indicator bacteria was conducted on two temporal scales: (a) routine bi-weekly monitoring over a month and (b) intense (bi-hourly) event-based sampling over 3 days triggered by a high discharge event. Both sampling set-ups showed that the highest bacterial concentrations occurred in the river. E. coli and Enterococcus sp. concentrations decreased with time and length of flow path in the aquifer. The event-based sampling was able to demonstrate differences in bacterial removal between clusters of observation wells linked to aquifer composition. Although no individual proxy indicator for bacterial contamination could be established, it was shown that a combined approach based on time-series of physico-chemical parameters could be used to assess river water infiltration as a hazard for drinking water quality management.

Mechanistic models of enteric bacteria fate and transport in surface waters are important tools for research and management. The existing modeling approach typically assumes that bacteria die in a first-order fashion, but a recent study suggests that bacteria can mutate relatively rapidly to a strain better adapted to the surface water environment. We built an agent-based model that simulates individual wild-type and mutant Escherichia coli cells. The bacteria die, grow on the natural assimilable organic carbon available to E. coli, divide and mutate. We apply the model to laboratory experiments (from the literature and new ones) and the Charles River in Boston. Laboratory applications include decay, growth, and competition (between wild-type and mutant) in various types of surface water. For decay experiments, the stochastic mutation process in the model can produce both first-order and biphasic decay patterns, which is consistent with observations in the literature. For the Charles River, the model can reproduce the main patterns observed in the field data. The model applications provide evidence in support of the mutation mechanism. However, the mutation model does not produce better predictions for the Charles River than a previous model based on labile and resistant subpopulations.

Animal wastes are commonly used in a sustainable manner to fertilize crops. However, manures contain numerous pathogenic bacteria that can impact animal and human health. Treatment of animal waste by anaerobic digestion has the potential to reduce pathogen loading to land. This study was conducted to determine the fate of bacteria applied in raw and anaerobically digested dairy slurries that were broadcast and subsurface applied in a field of forage grasses. Digested slurry had significantly fewer indicator bacteria, Escherichia coli and fecal coliform at time of application. Anaerobic digestion did not increase the survivability of indicator bacteria. Waste treatment and application method did not affect the rate of bacteria die-off. There were fewer E. coli and fecal coliform at the end of each trial in the soils that received digested slurry. Anaerobic digestion of dairy waste has the potential to reduce pathogenic bacteria loading to cropland.