Effects of Depths of Some Wells and Proximity to Rivers Niger and Benue on Water Quality in Lokoja, Nigeria.
Abstract
This reports the effects of depth on the physicochemical and microbial properties of hand-dug wells in villages close to Rivers Niger and in , Nigeria. up to 2.8 m deep and 300 m away from the rivers were studied in both the dry and wet seasons.
Analyses of samples of well water from the villages (Shintaku, Ganja, and Globe) and Lokoja metropolis showed that the total suspended solid (TSS), total dissolved solid (TDS), total solid (TS), alkalinity, total hardness (TH) and turbidity were in the ranges of 13 – 450, 57 – 905, 10 – 170, 11.5 – 18, 202 – 818 mgdm-3 and 0.611 – 140 NTU Respectively.
Biochemical oxygen demand (BOD), chemical oxygen demand (COD) and dissolved oxygen (DO), were in the ranges of 0.1 – 0.45, 108 – 346 and 0.08 – 0.75 mgdm-3 respectively. Also the ranges of electrical conductivity (EC) and ph recorded were: 53. 35 -98.5 µscm-1 and 5.9 – 7.5.
While those of ammonia, nitrate and phosphate in the water were in the ranges 0.01 – 0.3, 3.9 – 43 and 1.5 – 14.95 mgdm-3, respectively in the dry season of 2014. TSS, TDS, TS, alkalinity,
TH and turbidity of the well water samples showed the mean values of 13 – 450, 57 – 905, 10 – 170, 59 – 131, 130 – 404 mgdm-3 and 0.611 – 140 NTU respectively. BOD, COD and DO recorded the highest concentration ranges of 0.2 to 31, 60 to 818 and 0.9 to 1.2 mgdm-3 respectively.
However, the ranges of EC and ph of the sample were: 0.611 – 140 NTU and 5.8 – 7.15, respectively.
Ammonia, nitrate and phosphate were in the ranges of 3.1 – 14.5, 7.5 – 65 and 3.1-13.5 mgdm-3, respectively in the wet season of 2014.
The water samples had detectable levels of Cu, Cd, Ni, Mn, Pb and Zn, but all the samples have metal contents far below the permissible limits, except for the Cd content which was above in some of the water samples.
By using the multiple tube fermentation technique, the well water from all the sites had faecal contamination with bacteria pathogens such as Klebsiella spp, Escherichia coli, Enterobacter spp., Serantia spp. And Citrobacter spp.
During the wet season, it was found that the amounts of nitrate, turbidity, microbial isolate and ph values of the well water were found to increase with depth of the well.
And the value of TS and TDS also increases positively with the proximity of the wells to the rivers in wet season. Therefore, careful consideration and planning is needed in the construction of the wells. This suggests that wells must be up to 15 m deep and 300 m distance away from the river so as to be free from pollution.
Introduction
Water
Water, after air, is the most essential commodity to the survival of life. Human life depends, to a large extent, on water. It is used for an array of activities; chief among these being drinking, food preparation, as well as for sanitation purposes.
In as much as safe drinking water is essential to health, a community lacking in a good quality of this commodity will be saddled with a lot of health problems that could otherwise be avoided (miller and junior, 1997).
Water covers 70.9% of the earth’s surface and is vital for all known forms of life. On earth, it is found mostly in oceans and other large water bodies, with 1.6% of water below ground in aquifers and 0.001% in the air as vapour and precipitation.
Oceans hold 97% of surface water, 2.4% for glaciers and polar ice caps, and, 0.6% for other land surface water such as rivers, lakes and ponds.
A very small amount of the earth‘s water is contained within biological bodies and manufactured products (Wikipedia, 2010). Groundwater is of major importance and is intensively exploited for private, domestic and industrial uses. According to ajibade et al. (2011), 90% of the population in Nigeria depends largely on hand-dug wells and boreholes.
Water is necessary for sustainable economic development in a country like Nigeria. Hand-dug wells have been the source of water for people in Nigeria for ages. Some of these wells are dug close to rivers. And literature shows that rivers are the major transporting means for different contaminants into groundwater and lakes (sina et al., 2009).
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