Assessment of microbiological quality of groundwater in the Saïs plain (Morocco) (original) (raw)
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Environmental Monitoring and Assessment, 2008
This study scrutinized bacteriological and chemical quality of groundwater supplies of Marrakesh (Morocco) within a year. It assessed the influence of some chemical factors on fecal and opportunistic pathogenic bacterial communities. The annual average densities of fecal coliforms, fecal streptococci and Pseudomonas aeruginosa were respectively: 1891 colony forming units (CFU)/100 mL, 1246 CFU/ 100 mL and 206 CFU/100 mL. The total occurrence of these bacteria during the period of study was 94%. Detectable non-O1 Vibrio cholerae was present in 81% of samples and the mean abundances ranged from 0 to 11100 MPN/100 mL. Significant correlations between fecal coliforms and streptococci and between fecal coliforms and non-O1 V. cholerae (p<0.01) were found. Fecal coliforms can be used to detect the presence of non-O1 V. cholerae in this groundwater. These well waters were greatly mineralized, hard, salt with high concentrations of nitrogenous ions and major elements (Ca 2+ , Na + , Cl − , SO 2À 4 and K +). Most of chemical parameters were relatively steady with time except for calcium, ammonium, nitrites and organic matter which were seasonally influenced. The degree of correlation between chemical parameters and the abundances of isolated bacteria is heterogeneous. The concentrations of calcium and nitrites favored (p< 0.01) the abundance of fecal coliforms and streptococci, but reduced P. aeruginosa abundances. Calcium, salinity, chlorides, nitrites and nitrates tests can be used for screening in situ when the laboratory facilities are limited. This work is expected to assist local authorities in developing plans and actions to reduce the pollution to acceptable levels.
Quaternary aquifer and water streams of Sohag, Egypt are currently under contamination stress due to agricultural and urbanization activities. In addition, wastewater represents a potential environmental hazard, where bacteriological pollution of water resources was occurred. In order to develop strategies to diminish or eliminate contamination in water resources, groundwater and surface water samples from Sohag were investigated for the presence of indicator bacteria; heterotrophic plate count (HPC), total coliform (TC), fecal coliform (FC) and fecal streptococci (FS) repeatedly measured during October 2010 and June 2011. In addition to Fe, Mn, Zn, Cd and Pb were determined at the same times for biological measurements. TC, FC, and FS were found in all surface samples indicating the contamination of stream with human and animal fecal material. The cause of contamination could be linked to the easy access of domestic wastes to the streams. Generally, the quality of surface water was very poor as compared to groundwater in terms of microbial content, where groundwater is free from TC, FC, and FS. On the other hand both of surface and groundwater are contaminated with Cd and Pb. The soil provides a natural filtering action and adsorption site for the removal of bacteria. Also, Fe, Mn, Zn, Cd and Pb of water have a major influence on bacterial population content in surface water and show no discernible relationship with groundwater.
Quaternary aquifer and water streams of Sohag, Egypt are currently under contamination stress due to agricultural and urbanization activities. In addition, wastewater represents a potential environmental hazard, where bacteriological pollution of water resources was occurred. In order to develop strategies to diminish or eliminate contamination in water resources, groundwater and surface water samples from Sohag were investigated for the presence of indicator bacteria; heterotrophic plate count (HPC), total coliform (TC), fecal coliform (FC) and fecal streptococci (FS) repeatedly measured during October 2010 and June 2011. In addition to Fe, Mn, Zn, Cd and Pb were determined at the same times for biological measurements. TC, FC, and FS were found in all surface samples indicating the contamination of stream with human and animal fecal material. The cause of contamination could be linked to the easy access of domestic wastes to the streams. Generally, the quality of surface water was very poor as compared to groundwater in terms of microbial content, where groundwater is free from TC, FC, and FS. On the other hand both of surface and groundwater are contaminated with Cd and Pb. The soil provides a natural filtering action and adsorption site for the removal of bacteria. Also, Fe, Mn, Zn, Cd and Pb of water have a major influence on bacterial population content in surface water and show no discernible relationship with groundwater.
Assessment of Microbial Contamination of Groundwater in Oualidia Area, Morocco
2014
In rural Africa, scientific evidence is often lacking to guide the scaling-up of groundwater as the safest source of potable water. An investigation was conducted in the Upper Limphasa Catchment in northern Malawi to determine the safety of groundwater sources and to explore factors influencing water quality. Water samples from 17 boreholes, 6 hand-dug wells and 90 households were analysed for selected parameters. Portable incubators, multi-parameter probe and colorimetric standard methods were used for field measurements, and standard methods were used for laboratory water analysis. Results were compared to specified guidelines of the World Health Organization and Malawi Bureau of Standards to establish the potability of water. Statistical results using non-parametric t-tests indicated that the wells were more contaminated with E. coli bacteria than boreholes (p=6.2x10-6), suggesting non-consideration of local hydrogeologic factors in groundwater development. Water from boreholes that tested negative for pathogens at source tested positive at some households (total coliform: p=0.0042 and E. coli p=7.8x10-7) suggesting the effect of handling practices. Water from wells that was not treated with chlorine showed higher levels of E. coli than treated water from the same sources, confirming the effectiveness of chlorine in reducing pathogenic bacteria in households' stored drinking-water, reinforcing the scientific basis for scaling up chlorine as effective disinfectant. However, this study demonstrated that chlorine failed to effectively eliminate all pathogens in drinking water. As a case study in tropical rural environments in Africa, these findings on the suitability of using chlorine as disinfectant and on factors explaining groundwater contamination, though provisional, provide a scientific basis for assessing cost-effectiveness and sustainability of scaling-up the use of chlorine as a curative remedy and of systematically investigating local hydrogeologic factors in order to implement measures to protect groundwater quality in povertyprone rural communities.
Pollution of Surface and Ground Water by Sources Related to Agricultural Activities
Frontiers in Sustainable Food Systems
The objective of this study was to monitor the quality of ground water supplied to animal farms and 2 villages and of surface water (rivers) in the same area (Košice basin, eastern Slovakia) with the aim to assess contamination of water by potential sources in this area. Samples for physico-chemical and microbiological examination were collected at 12 sampling points (6-surface water; 6-ground water) from May 2014 up to March 2015, covering all four seasons. The examination and evaluation of individual parameters was carried out according to relevant Slovak legislation compatible with EU Drinking water directive. The physico-chemical evaluation focused on parameters that indicate pollution of water resulting from human activities and farming. Microbiological examination included determination of counts of bacteria cultivated at 22 • C and 37 • C (BC22 and BC37), total coliforms, E. coli and fecal streptococci. Ground water intended for mass consumption (farms, villages) is abstracted from wells, collected in storage reservoirs and disinfected before brought to consumers. Some families in the villages use their own wells. Water for individual consumption (individual households) originates directly from individual wells. Examination of potable water used on agricultural farms showed some possibility of contamination of sources by runoff and inappropriate manipulation with excrements. Surface water in in the area close to both farms was polluted with organic substances (COD Mn), however they did not exceed the limit set for surface water. At many samplings we detected in surface water presence of total coliforms, E. coli and occasionally also fecal enterococci indicating fecal pollution that could eventually affect ground water in individual wells. Our investigations showed that protection zones of water sources were not always sufficient. There were considerable variations in the quality of surface water during the year but no clear relationship between microbial contamination and seasons was observed. Quality of ground water supplied for mass consumption complied with legislative regulations except for BC 22 (heterotrophic count at 22 • C) in summer and autumn). Water from individual wells contained occasionally presence of total coliforms, E. coli and enterococci and higher heterotrophic counts.
Seasonal Bacterial Contamination of Groundwater in the Zagora Area, Morocco
Ecological Engineering & Environmental Technology
The assessment of the bacterial quality of groundwater is a critical step in ensuring safe drinking water. A total of nine (9) water samples were obtained from wells located within the study area, during the wet and dry seasons between December 2020 and December 2021. The parameters measured in this study include total germs at 22 °C (TG-22 °C) and 37 °C (TG-37 °C), total coliforms (TC), fecal coliforms (FC), fecal streptococci (FS), and the sulfito-reductor clostruim (SRC). The results show that the contamination levels vary widely between the different wells and between seasons. The highest levels of contamination were found in W6, with the highest values of all parameters measured except for TC. W1 and W7 were the only wells that were protected, and they had lower levels of contamination compared to unprotected wells. The sources of pollution were mainly related to agricultural activities, such as animal waste and metal waste. The findings of this study suggest the need for improved management practices to reduce contamination and protect the groundwater resources in the study area.
Microbial quality assessment of Beni Aamir and Beni Moussa groundwater (Tadla plain-Morocco)
Desalination and Water Treatment, 2020
The groundwaters from the deep aquifers of the Tadla are mainly used for agriculture, industry, and drinking water. To assess the state of microbial contamination of the groundwater in the irrigated area, a study has been carried out over a 1 y period from March 2017 to May 2018. A total of 43 wells are selected and the water has been analyzed every 3 months to quantify the coliforms (TC), fecal coliforms (FC), and fecal streptococci (FS) using the membrane filter (MF) method, and also to perform a spatial-temporal mapping in order to clarify the concentration of pollution using the Surfer software. The result has revealed significant groundwater contamination by microbial agents. The analyzes of TC, FC, and FS indicated that 95.34%, 86.04%, and 55.81% of the wells tested to exceed 1,000 CFU/100 mL respectively, for each TC, FC, and FS group, where 100% of the wells have positive results, that is, having more than one colony-forming unit (CFU). However, spatial variation maps show c...
Groundwater bacteriological quality assessment: impact of urbanization and agricultural activity
Water Supply, 2021
Groundwater from boreholes is the major source of bottled water in Algeria. The aim of this study is to determine the bacteriological quality of groundwater that serves bottled water production. A total of 73 groundwater boreholes were sampled and analyzed for the required bacteriological parameters. The analysis was performed in accordance to ISO standards methods. There should be no bacteria growth for each bacteriological parameter to qualify the groundwater of good bacteriological quality. The bacteriological analysis highlighted that 37 of the 73 groundwater samples (51%) were of poor bacteriological quality while 36 of them (49%) were of good bacteriological quality. Total coliforms and E. coli were the major sources of contamination with respectively 35 and 24 contaminated samples, followed in order by Pseudomonas aeruginosa, enterococci and sulfite reducing anaerobic bacteria spores with respectively 8, 7 and 2 contaminated samples. Bacteriological quality was strongly and n...
Ecological Engineering & Environmental Technology
Groundwater is crucial for meeting the water needs of rural communities, serving both domestic and agricultural purposes. However, its quality in our study area remains unclear. Therefore, the primary objective of the current study is to evaluate the groundwater quality and ascertain the level of contamination risk associated with the use of septic tanks in rural communities within the Al Hoceima province. This will be achieved by conducting a comprehensive analysis of physicochemical parameters and employing effective indices, including the Water Quality Index (WQI), Nitrate Pollution Index (NPI), and Chronic Health Risk (CHR). In February 2023, we collected samples from 33 wells, spanning densely and sparsely populated regions, to account for potential variations in water quality. The analyzed parameters included pH, total dissolved solids (TDS), electrical conductivity (EC), ammonium (NH 4 +), nitrates (NO 3-), nitrites (NO 2-), sodium (Na +), potassium (K +), calcium (Ca 2+), magnesium (Mg 2+), chloride (Cl-), sulfate (SO 4 2-), bicarbonate (HCO 3-), phosphate (PO 4 3-), and silica (SiO 2). Our findings revealed slightly alkaline groundwater with TDS levels ranging from 1508.63 mg/l to 8289.8 mg/l, with an average of 3223.19 mg/l. The cation dominance sequence observed was Na + > Ca 2+ > Mg 2+ > K + > NH 4 + , while for anions, it followed as SO 4 2-> Cl-> HCO 3-> NO 3-> PO 4 3-> NO 2-. The Water Quality Index (WQI) indicated contamination in 54.55% of the wells, with notably higher NPI values in densely populated regions. This suggests anthropogenic nitrate contamination, likely originating from septic tanks. The assessment of Chronic Health Risk (CHR) revealed non-carcinogenic health risks in 27.27% of samples for children and 15.15% for adults. Given these findings, it is imperative for Moroccan authorities, despite the efforts of the Loukkos Hydraulic Basin Agency (LHBA), to implement strategic measures to protect groundwater quality in densely populated rural regions.