An investigation of some water quality properties from different sources in Pelengana commune , Segou , Mali

An assessment of consumer quality perception, as well as some physical and chemical characteristics of water samples sourced from wells, boreholes, and rivers in the locality of Pelengana commune, in Mali, was carried out. The World Health Organization (WHO) Guideline (or other) Values (GVs) for drinking water quality was used as a benchmark. One-way analysis of variance (ANOVA) alongside Duncan’s multiple comparison tests for significant differences, and Principal Component Analysis (PCA) were used in analyzing differences and correlations regarding the parameters investigated. Results revealed that the majority of the households (61.2%) regarded wells and river water as unsafe for drinking. The physical and chemical quality of water was affected by climatic season. Also, with the exception of iron (average values), the parameters studied met the WHO GVs. Based on the analyzed parameters, the quality of these different water sources is chemically acceptable. This is an Open Access article distributed under the terms of the Creative Commons Attribution Licence (CC BY 4.0), which permits copying, adaptation and redistribution, provided the original work is properly cited (http://creativecommons.org/licenses/by/4.0/). doi: 10.2166/washdev.2018.172 s://iwaponline.com/washdev/article-pdf/8/3/449/484182/washdev0080449.pdf Amadou Toure Duan Wenbiao (corresponding author) School of Forestry, Northeast Forestry University, No.26 Hexing Road Xiangfang District, Harbin 150040, China E-mail: dwbiao88@126.com Zakaria Keita Department of Study and Research in Public Health of the Faculty of Medicine and Odontostomatology of Bamako, Bamako, Mali


INTRODUCTION
Groundwater from captive and superficial aquifers are water resources that are exploited by man for various uses (Prasad & Narayana ). The chemical composition of natural water is variable. This could be due to the geological nature of the soil from which it originates and also the reactive substances that it may have encountered during flow (Matini et al. ). Thus, the quantitative and qualitative composition of groundwater in suspended and dissolved materials, of mineral or organic nature, determines its quality (Jain et al. ). However, this quality can be altered when external substances come into contact with the aquifer. Undesirable or even toxic substances make groundwater unsuitable and toxic for various uses, especially for human consumption. The intensive use of natural resources and increased human activities have caused serious issues with respect to groundwater quality (Mor et al. ). In developing countries, obtaining safe water for human consumption is challenging due to a lack of environmental protection. The bacteriological and physicochemical quality of water for public consumption requires constant assessment. Nowadays, in rural areas, especially in underdeveloped countries, waterborne diseases constitute the most health issues (Arnold & Colford ). Thus, access to safe drinking water is of essential need.
The supply of drinking water of sufficient quality and quantity remains a crucial public health challenge in most African countries ( Healy Profitós et al. ). Some noteworthy statistics from the WHO/UNICEF Joint Monitoring Program 2017 (JMP) for Water and Sanitation reveal that about 2.1 billion human beings lack good quality water, 4.5 billion do not have access to adequate sanitation and roughly 1.5 million deaths every year are attributed to diarrheal disease (WHO & UNICEF a, b). Additionally, it is estimated that 58% of the latter figure (842,000 deaths per year), is due to unsafe water supply, insufficient hygiene, and sanitation, and includes 361,000 deaths of children below five years, especially in developing countries (WHO ). Water for human consumption must not contain organisms and chemical substances in concentrations sufficiently high to affect health (Brian ).
Over the past decade, a rebellion linked with terrorism in the northern part of Mali has resulted in the migration of thousands of people into the peripheral areas of Pelengana commune in Segou region. Currently, the rural settlements in that area are overpopulated, thus leading to poor living conditions such as inadequate water, poor hygiene, and sanitation. Moreover, under such conditions, waterborne diseases (diarrhea, typhoid and paratyphoid fever, amoebic dysentery, etc.) are the principal class of diseases that may stricken the majority of such a population (Pelengana commune) living in such precarious conditions (Baig et al. ). During this study, it was noted that approximately 66.8% of that population source water from unimproved sources (unprotected dug wells, traditional wells, and rivers) and 33.2% from improved sources (such as boreholes and protected dug wells). Also, these waters are more often than not consumed without physical, chemical and biological treatment. Although microbiological contamination is a leading preoccupation of the Pelengana commune, inorganic contaminants of health and aesthetic concern may be present in such waters. Residents of the area practice agro-pastoralism. In order to increase agricultural yield, chemical fertilizers are often utilized which are rich in nitrate, ammonium, phosphate, and zinc, and are more often used above the accepted amounts. If nitrate is not absorbed by plant roots, it leaches into the soil or can be run off into water reservoirs during wetting or rainfall (Tamme et al. ). Consuming contaminated groundwater or crops with a high concentration of nitrate has negative effects on human health (Ikemoto et al. ). In surface and groundwater, zinc enters the environment from various sources but predominantly from the erosion of soil particles containing zinc (Noulas et al. ). Also, water sources are susceptible to contamination by fluoride due to minerals in the aquifer rocks, anthropogenic activities and fecal pollution originating from animals and the poor protection of these sources (Chidambaram et al. ; Manikandan et al. ).
This work investigates some physical and chemical qualities of water from three sources, namely river, well and borehole, situated at three sites within the commune of Pelengana. These sites are Pelengenewere, Pelengana Primary School, and Koukoun. The present work is justified by the fact that there is lack of scientific information with respect to water quality from the region concerned. A preliminary field investigation was carried out to evaluate the common source of drinking water for most households. Also, interviews were conducted to estimate perceptions of water taste issues, odor, color, turbidity, and health problems. Forty randomly selected people per site (480 people) were used for the interview. Water samples were collected each month from July 2016 to April 2017 from three different water sources: (1) a well from Pelenganawere (unprotected dug well with used wood acting as a curb, no perimeter of protection, animals nearby, farms all around), (2) a borehole (hand pump from Pelengana Primary School where water is sold to the population; practices of agriculture around), and (3) a river (the only river crossing Koukoun village) in Pelengana commune. These sites were selected for sampling in such a way that they represented a large cross-section of users who could be at risk of waterborne diseases, assuming the water is of poor quality due to the vicinity of pollution sources. The sources were chosen following a preliminary field investigation that assessed the proximity of wells and boreholes to pollution sources, nature of the environment, and depth of the water table. It is worth noting that testing of water from each collection site was carried out each month. In addition, ten repetitions were performed in order to ensure even representation, thus, a total of 30 water samples were collected for analyses. Water samples were collected in 1 L polyethylene bottles. These bottles were previously washed with detergent, rinsed with tap water and then with distilled water, and finally rinsed three times with water from the sampling source. The water samples were labeled and kept between 0 and 4 C in a cooler. They were then sent for laboratory tests with sample sheets containing all the required information.

Study area and sampling sites
It is worth noting that some field tests were also conducted.

Methods
In order to ascertain the level of drinking water contamination with respect to the various parameters and the risks to human health associated with the ingestion of contaminated water in the study area, it is therefore necessary to consider the physical, chemical and bacteriological quality, as well as heavy metals contamination. However, in this work, only 10 parameters (physical and chemical) under the recommendation of the communal hygiene office of Pelengana commune were studied. These parameters are: temperature, electrical conductivity (EC), pH, nitrate (NO 3 À ), nitrite (NO 2 À ), phosphate (PO 4 À P), fluoride (F À ), ammonium (NH 4 þ ), iron (Fe) and zinc (Zn 2þ ). The physical parameters, such as temperature, pH, and EC, were measured in situ using a digital thermometer, pH meter WTW, and a conductivity meter WTW, respectively, while the chemical analyses were achieved according to the manual of Rodier et al.
(). The nitrate and nitrite concentrations were measured employing the sodium salicylate and N-1 naphthylethylenediamine method, respectively. Ammonium was measured using the indophenol blue method. Phosphate (PO 4 À P) was measured using the phosphomolybdate method. Fluoride was measured by the potentiometric method using an Ionometer WTW (pH/ION 340i and probe F800). Finally, zinc and iron were measured using a Photometer WTW, model Photoflex Turb Set by the Photometric method.

Statistical analysis
The statistical analysis was been carried out using SPSS soft-

RESULTS AND DISCUSSION
The drinking water sources and perception on water quality In this study, it was noted that 66.8% of the population surveyed sourced water from unimproved sources (unprotected dug wells, traditional wells, and rivers) and 33.2% from improved sources (such as boreholes and protected dug wells).
Regarding the perception of the water quality and other water source attributes, approximately 39% of respondents assessed their drinking water as safe for consumption, whereas the remaining respondents (61.2%) had concerns with safety, particularly from wells and river water. It was also discovered that in more than 28% of households in the commune mentioned previously, at least one household member had suffered some water-borne disease during the last three years. Respondents were asked to rate water quality based on four sensory characteristics of drinking water. turbidity, and safety against contamination. In terms of river water, many respondents judged odor (48.3%), taste (31.1%), color (9.3%), and turbidity (11.2%). It is important to note that the respondents had poor knowledge about the sensory attributes of water because they most often misconstrued visual and organoleptic characteristics decisively in the quality of water consumed.

Physico-chemical parameters
The results of physico-chemical analysis (average ± standard deviation, minimum, maximum values) are presented in Tables 1 and 2. The number of samples analyzed (N), the guideline values (GVs) for drinking water are also indicated.
In some cases, no WHO GV, but other values (GVs) have been used for clarity. Table 3 compares the average values of the water quality parameters for the different seasons (dry and rainy) at the different water sources.
The optimum acceptable pH range for drinking water varies from 6.5 to 8.5, although there is no health-based guideline. Three borehole water samples (30%), one river water sample (10%) and seven well water samples (70%) fell outside the recommended pH range, being acidic in nature.
The minimum and maximum pH values (5.17 and 7.90) were observed respectively in the well water and river water with significantly lower average values observed in the dry season. A significant difference (p < 0.05) was noted among the well, borehole and river which had average pH values of 6.03, 6.58, 7.17, respectively (Table 1). The well water value was below the WHO range (6.5-8.5). The pH of the well water may be attributed to the discharge of acidic products into this source by agricultural and domestic activities. This is supported by the fact that studies have shown that 98% of all groundwater worldwide is related to the geological nature of the aquifer formations and the lands   The temperature of the three water sources varied according to the sampling period (rainy or dry). The highest temperature was observed from May to October, corresponding to the rainy season (Table 3). The ideal water temperature is between 6 and 12 C (Degbey et al. ).
The temperature of the borehole water (31.43 C) differed significantly (p < 0.05) from that of the river (28.24 C).
On the other hand, there was no significant difference (p > 0.05) between the borehole and well water (29.90 C) and also between the river and well water (  well water (32.01 mg/L) was significantly lower (p < 0.05) than the borehole (41.94 mg/L) and rivers (46.64 mg/L) ( Table 2). The minimum and maximum nitrates values (21.20 and 65.23 mg/L) were observed, respectively, in the well water and in the river water. In addition, the highest average value for nitrate (63.80 mg/L) was noticed in the river water which was taken during the rainy season (Table 3). In our study, the increase in nitrate levels observed is particularly related to human activities and intensive farming practices. This is consistent with the findings of Hanis et al.
(), who noted that significant contamination of well waters by nitrates was due to intensive agriculture.
Nitrites are mostly absent from surface waters, but their presence is possible in groundwater, mainly because nitrogen will tend to exist as ammonia or more oxidized (nitrate) forms. WHO GV retains 3 mg/L as a limit value for drinking water quality (GDWQ ). The average value for river water differed significantly (p < 0.05) from borehole and well water (Table 2). However, they are all below the WHO GV for drinking water, but these sources may not be safe for domestic and livestock use. Lagnika The concentration of fluoride was found to be between 0.01 and 0.84 mg/L respectively in the borehole and river waters. High average values of fluoride were noticed in the rainy season compared to that of the dry season (Table 3).
There was a significant difference (p < 0.05) between the mean value of river waters and those of wells and boreholes (Table 2). However, all these values are below the WHO GV The average load of contamination of NH 4 þ in the different sources were 0.25 mg/L (well water), 0.26 mg/L (borehole water) and 0.97 mg/L (river water). It appears that there are significantly more concentrations of NH 4 þ (p < 0.05) in the river water samples than in the well and boreholes waters (Table 2). No health-based guideline value is proposed for NH 4 þ , although GDWQ does note that at alkaline pH, the odor threshold is approximately 1.5 mg/L. A high average value for NH 4 þ was noticed in the rainy season in river water compared to that of the borehole and well water ( Table 3) Table 2). The highest average value for phosphate (1.84 mg/L) during this study was from well water which was obtained in the rainy season, whereas the lowest value (0.07 mg/L) was observed in borehole water which was taken during the dry season (Table 3) (Table 3). This may be due to soil leaching phenomenon as well as the result of the water-rock interaction.
Zinc is of benefit for human health, but if ingested in large amounts it can cause emesis (Roohani et al. ).
However, zinc is one of the least toxic metals and deficiency problems are more frequent and more serious than those of toxicity (Ricardo ). Of water intended for human consumption, WHO GDWQ notes that water with zinc concentrations greater than 3 mg/L may cause consumer acceptability issues (appearance, taste). Two river water samples (20%) and three well water samples (30%) were all above the WHO GV. There is a significant difference (p < 0.05) between the average value of well waters and those of river and boreholes (

PCA profiles of correlation between different parameters
The correlation between physico-chemical parameters was developed using the PCA. A total of 10 variables were used, namely pH, EC, temperature, NO 3 À , NO 2 À , NH 4 þ , PO 4 À P, F À , Fe and Zn 2þ . Figure 2(a) projects the correlation circle of the aforementioned water quality parameters. Figure 2( and positively correlated to axis F2. These results reveal that the mineral composition of the water is almost identical throughout the sampling locations. However, the extent of this mineralization differed according to seasonal variability.

CONCLUSIONS
The physical and chemical quality parameters of water from different water sources (well, borehole and river) in Pelengana commune were studied. This work therefore affords baseline water quality data in the region concerned. In addition, it helped to identify the main concerns regarding the quality of drinking water, in order to suggest appropriate solutions to reduce the observed contaminations and to motivate the local public authorities to plan future interventions in this sector.
It was revealed that the physical and chemical quality of water was affected by climatic season. Generally, the average values of all the parameters measured were higher in the rainy season than in the dry season. The parameters investigated, with the exception of iron, had average values that met the guideline (or other) values included in the WHO Guidelines for Drinking-water quality. It is worth mentioning that the different water sources considered in this work are prone to contamination due both to the water-rock interaction and the prevalence of agricultural practices in that region.
Although the average values of the parameters measured did comply with the WHO GV, the different water sources considered constitute potential sources of contamination. It is also worth noting that this work is not an exhaustive or complete analysis of drinking water quality. For this reason, it is recommended that groundwater for human consumption is treated in the same manner as surface water sources before distribution to users. Detailed and continuous monitoring and assessment of other chemical species in the area is highly recommended. Furthermore, population involvement through protection of drinking water sources from contamination could contribute to improving the water situation throughout the region, thus ensuring a healthy environment, for instance, rules governing activities within the area, particularly pit latrine siting, best management practices for farming, general hygiene and adequate storage practices at the household level.