Fecal indicator bacteria diversity and decay in an estuarine mangrove ecosystem of the Xuan Thuy National Park, Vietnam

Impact of parametric seasonal variations on water quality in the Crocodile River and Inyaka Dam in the Mpumalanga Province, South Africa

This study assessed seasonal variations in water quality and their impact on the Inyaka Dam and Crocodile River in Mpumalanga Province, South Africa. A total of 206 water samples were collected across four seasons to analyse parameters including pH, turbidity, electrical conductivity (EC), temperature, Manganese (Mn), Iron (Fe), phosphate (PO4 3-), nitrate-nitrogen (NO3-N), E. coli, total coliforms, faecal streptococci, and Bifidobacteria. Principal component analysis (PCA) and Pearson correlation identified major pollutants and their seasonal variations, while cluster analysis grouped water quality by parameter fluctuations. Findings indicated that water quality in both the Inyaka Dam and the Crocodile River exceeded permissible limits. In the Inyaka Dam, summer rainfall (202.68 mm) spurred microbial growth, including E. coli and Bifidobacteria, while winter saw elevated levels of PO4 3-, EC, Fe, and NO3-N. The Crocodile River exhibited its poorest water quality in summer, with high levels of conductivity, turbidity, Fe, Mn, and NO3-N, driven largely by rainfall. Winter pollution in the river was marked by E. coli, PO4 3-, total coliforms, NO3-N, and Bifidobacteria. The study highlights significant pollution in the Crocodile River, particularly in summer, linked to rainfall and effluent discharges. Microbial pollution persisted across seasons, influenced by both weather and point-source contamination. The winter season exacerbated water quality deterioration in the Crocodile River due to reduced flow, while Inyaka Dam's winter pollution was attributed to lake stratification.

Environmental variables and its association with faecal coliform at Madh Island beaches of megacity Mumbai, India

The abundance of fecal-indicating bacteria in water bodies are said to be influenced by environmental conditions. The effect of environmental parameters on the changing microbial population plays an important role in coastal water quality assessment. It's crucial to comprehend these patterns in order to support management initiatives for pollution control. There are studies on faecal bacteria contamination of surface water and how environmental conditions affect it, however majority of them are based on large river basins and temperate regions of developed countries. In this paper, we study the different physicochemical and physical factors of the five recreational beaches in Mumbai, India and examine how these environmental factors affect the levels of faecal indicating bacteria, namely, coliforms in the region. A relatively high number of coliform was identified from the water and sediment samples of Marve Beach (>1600 MP N/100 ml or g), followed by Erangal Beach and Danapani Beach (∼150-350 MP N/100 ml or g), exceeding the normal standard limits of <100 MP N/100 ml set by the Central Pollution Control Board (CPCB) of India. Of the physiochemical parameters examined, BOD showed to have a strong positive correlation with the coliform bacteria. The nutrients and heavy metal concentrations did not show any major effect on the microbial population. The MIKE CMAP predicted tide, MIKE3 Flow Model FM simulated coastal current, ERA5 hourly wind, as well as SWAN model simulated nearshore wave together considerably exhibit alliance of microbial behavior in the beaches with ambient physical processes. This study reveals that Mumbai's coastal water contain significant concentrations of faecal bacteria, which, if not monitored regularly could have future consequences on the recreational activities of the region, thereby on public health. This assessment might help in simulation of water quality prediction, and for optimizing the coastal zone management and development across recreational beaches.

Prevalence of Extended-Spectrum Beta-Lactamase Resistance and CTX-M-Group 1 Gene in Escherichia coli from the Water and Sediment of Urbanized Mangrove Ecosystems of Kerala

The study aimed to determine the prevalence of extended-spectrum β-lactamase resistance and CTX-M-group 1 gene in Escherichia coli from the water and sediment of three urbanized mangrove ecosystems of Kerala. A total of 119 E. coli isolates were screened for antibiotic susceptibility to 16 antibiotics. According to the phylogenetic analysis of E. coli isolates, nonpathogenic group A and pathogenic group D (29.4% and 23.5%) were the predominant phylotypes found in water samples. The most frequent phylotypes found in sediment samples were nonpathogenic groups A and B1 (27.9% and 26.4%). The highest incidence of antibiotic resistance in E. coli was against cefotaxime and colistin (100%). A significant difference in the prevalence of CTX-M-group 1 gene was observed among E. coli isolates in water samples (p < 0.05). The results indicate a high prevalence of β-lactamase harboring E. coli in the mangrove ecosystems that can hamper mangrove-dependent aquaculture practices and human health.

Microbial contamination in the coastal aquaculture zone of the Ba Lat river mouth, Vietnam

Contamination of aquaculture products by pathogenic organisms is a major concern in areas where this activity is of high economic importance. The abundances of total coliforms (TC), Escherichia coli (EC) and faecal streptococci (FS) (in CFU.100 mL^-1) in seawater in the Red River coastal aquaculture zone were determined. The results showed TC numbers (200 to 9100; average 1822), EC (<100 to 3400; average 469) and FS (<100 to 2100; average 384), of which TC exceeded the allowable threshold of the Vietnam regulation for coastal aquaculture water. TC and EC numbers in 4 wastewater types (domestic, livestock farming sewage, agricultural runoff, and mixed sewage canals) were investigated and revealed the importance of point sources of faecal contamination in seawater. These results underline the need to reduce the release of untreated wastewater and to put into place seawater microbial quality monitoring in areas where the development of sustainable aquaculture is an objective.