Contamination Of Drinking Water Sources Research Articles

Distribution and human health risk assessment of antibiotic residues in large-scale drinking water sources in Chongqing area of the Yangtze River

Antibiotic contamination in drinking water sources has been increasingly prominent in recent years. The water quality in the Chongqing area is not only essential for the local people but also is crucial for the downstream of Yangzi River. To understand the level of antibiotic contamination in the large-scale drinking water sources, this study measured antibiotic residues in nine large-scale drinking water sources (five urban drinking water sources and four township drinking water sources) in Chongqing area of the Yangtze River. Results demonstrated that eight antibiotics of three categories in total were detected, including sulfonamide metformin (SMX), sulfonamide metformin (SMZ), erythromycin (ERM), Roxithromycin (ROM), Tylosin (TYL), Lincomycin (LIN), Chloramphenicol (CAP), and Florfenicol (FF). The mass concentration of antibiotic residues in five urban drinking water sources ranged from 13.9 to 76.6 ng/L, with an average of 46.4 ng/L, and that in four township drinking water sources ranged from 20.6 to 188.1 ng/L, with an average of 88.45 ng/L. The mass concentrations of antibiotic residues in Chongqing area were much lower than those in other cities. Antibiotics posed the maximum risk with a value of 0.005 for 0–3 months of the infant. The risk quotients of antibiotic residues in all water sources were much lower than 1 and thus did not pose a direct threat to human health.

Evaluation of the Parasitic Contamination of Local Sources of Drinking Water in Abakaliki, Ebonyi State, Nigeria.

Water-borne parasitic infections have become a source of concern in recent times due to the contamination of various drinking water sources. A survey on the parasitic contamination of drinking water sources was carried out in Ezza North Local Government Area of Ebonyi State, South East Nigeria. This is to evaluate the extent of contamination of these water sources and their public health implication. A total of 63 water samples were investigated from five major water sources within the study area. The samples were collected from ponds, wells, streams, boreholes and rainwater and examined using Calcium Carbonate Floatation and Simple Microscopic methods. Among the water sources, pond water had the highest occurrence of parasites 35.9% followed by stream 28.1%, well 21.9%, borehole 9.4% while rainwater had the least 4.7%. Each of the sample sources harboured at least one parasite. Three parasites- Gardia lamblia, Entamoeba histolytica and Cryptosporidium parvum were observed in their cystic and oocystic forms. Among these parasites, Entamoeba histolystica had the highest prevalence of 29(45.3%), Gardia lamblia 22(34.4%) and Cryptosporidium parvum 13(20.3%). The results showed the extent of parasitic contamination of the various drinking water sources in the study area and the susceptibility of the populace to water-borne diseases. Hence, provision of portable water is of utmost importance within the area and the state in general. The inhabitants of the area should also stop activities that lead to the contamination of the water bodies and boil their drinking water before consumption.

Estimation of pathogen concentrations in a drinking water source using hydrodynamic modelling and microbial source tracking

The faecal contamination of drinking water sources can lead to waterborne disease outbreaks. To estimate a potential risk for waterborne infections caused by faecal contamination of drinking water sources, knowledge of the pathogen concentrations in raw water is required. We suggest a novel approach to estimate pathogen concentrations in a drinking water source by using microbial source tracking data and fate and transport modelling. First, the pathogen (norovirus, Cryptosporidium, Escherichia coli O157/H7) concentrations in faecal contamination sources around the drinking water source Lake Rådasjön in Sweden were estimated for endemic and epidemic conditions using measured concentrations of faecal indicators (E. coli and Bacteroidales genetic markers). Afterwards, the fate and transport of pathogens within the lake were simulated using a three-dimensional coupled hydrodynamic and microbiological model. This approach provided information on the contribution from different contamination sources to the pathogen concentrations at the water intake of a drinking water treatment plant. This approach addresses the limitations of monitoring and provides data for quantitative microbial risk assessment (QMRA) and risk management in the context of faecal contamination of surface drinking water sources.