Physicochemical and Microbiological Quality of Shallow Groundwater in Lomé, Togo

The present study aimed to assess the physicochemical and microbiological quality of shallow groundwater tapped by private boreholes for water sale in Togo’s most urbanized coastal areas. Ninety-six (96) groundwater samples were collected at the water sale points for chemical and microbiological analyses using standard methods. The results showed that groundwater is predominantly acidic with fresh and brackish water of Na-Cl type. High concentrations of dissolved inorganic nitrogen (NO3- , NH4+and NO2-) and permanganate indices indicating potential organic matter were found. Among the major ions, Na+ (46.9%), Cl- (51.0%) and NO3- (50.0%) present the highest percentages of unsuitable concentrations compared to WHO guidelines. These findings indicate the control of the natural impact of seawater and lagoon system and anthropogenic pollution from domestic and urban wastes on groundwater’s physicochemical quality. About 65% of groundwater samples did not comply with the drinking water guidelines for microbial indicators, including total mesophilic flora, thermotolerant coliforms, and sulfite-reducing anaerobes. The results showed the failure of sanitation and hygiene conditions around sampling points and fecal contamination from sewage, pit latrines, septic tanks, and refuse and waste disposal. The degradation of physicochemical quality is higher in the old and high-density built-up areas. Simultaneously, microbial contamination represents a high risk of contracting waterborne or hygiene-sanitation-related diseases in the whole study area. This study provides a global view of shallow groundwater’s physicochemical and microbiological quality in the study area. Limitations and suggestions for future research are discussed.

Prevalent fecal contamination in drinking water resources and potential health risks in Swat, Pakistan

Fecal bacteria contaminate water resources and result in associated waterborne diseases.This study assessed drinking water quality and evaluated their potential health risks in Swat, Pakistan. Ground and surface drinking water were randomly collected from upstream to downstream in the River Swat watershed and analyzed for fecal contamination using fecal indicator bacteria（Escherichia coli） and physiochemical parameters（potential of hydrogen, turbidity, temperature, electrical conductivity, total dissolved solid, color, odor and taste）. The physiochemical parameters were within their safe limits except in a few locations, whereas, the fecal contaminations in drinking water resources exceeded the drinking water quality standards of Pakistan Environmental Protection Agency（Pak-EPA）,2008 and World Health Organization（WHO）, 2011. Multivariate and univariate analyses revealed that downstream urbanization trend, minimum distance between water sources and pit latrines/sewerage systems, raw sewage deep well injection and amplified urban,pastures and agricultural runoffs having human and animal excreta were the possible sources of contamination. The questionnaire survey revealed that majority of the local people using 10–20 years old drinking water supply schemes at the rate of 73% well supply,13% hand pump supply, 11% spring supply and 3% river/streams supply, which spreads high prevalence of water borne diseases including hepatitis, intestinal infections and diarrhea, dysentery, cholera, typhoid fever, jaundice and skin diseases in children followed by older and younger adults.

Occurrence and infection risk of waterborne pathogens in Wanzhou watershed of the Three Gorges Reservoir, China

The Three Gorges Reservoir （TGR）, formed by China＇s Yangtze Three Gorges Project, is the largest lake in the world, but there is too little information available about fecal contamination and waterborne pathogen impacts on this aquatic ecosystem. During two successive 1-year study periods （July 2009 to July 2011）, the water quality in Wanzhou watershed of the TGR was tested with regard to the presence of fecal indicators and pathogens. According to Chinese and World Health Organization water quality standards, water quality in the mainstream was good but poor in backwater areas. Salmonella, Enterohemorrhagic Escherichia coli （EHEC）, Giardia and Cryptosporidium were detected in the watershed. Prevalence and concentrations of the pathogens in the mainstream were lower than those in backwater areas. The estimated risk of infection with Salmonella, EHEC, Cryptosporidium, and Giardia per exposure event ranged from 2.9 × 10 -7 to 1.68 × 10-5 , 7.04 × 10-10 to 2.36 × 10-7 , 5.39 × 10-6 to 1.25 × 10-4 and 0 to 1.2 × 10-3 , respectively, for occupational divers and recreational swimmers exposed to the waters. The estimated risk of infection at exposure to the 95% upper confidence limit concentrations of Salmonella, Cryptosporidium and Giardia may be up to 2.62 × 10-5 , 2.55 × 10-4 and 2.86 × 10-3 , respectively. This study provides useful information for the residents, health care workers and managers to improve the safety of surface water and reduce the risk of fecal contamination in the TGR.