Assessment of Water Quality From Shallow Wells in Informal Settlements in Kenya: a Case of Nyalenda Estates, Kisumu County, Kenya

Abstract

The study assessed the physico-chemical and bacteriological water quality parameters from shallow wells in Nyalenda A and B Estates in Kisumu County. The purpose was to evaluate the quality of water used by the residents of these estates. Water samples were collected in February and April 2017 representing the dry and wet seasons respectively. Ten sampling sites were randomly selected for the study based on their closeness to pit latrines or domestic solid waste disposal sites. The parameters analyzed were colour, pH, turbidity, total dissolved solids (TDS) and electrical conductivity, nitrates, nitrites, fluoride, sulphate and phosphates, alkalinity, total hardness, calcium hardness, magnesium hardness and salinity, total and feacal coliforms bacteria. The metals ions analysed were copper, lead, cadmium, zinc and chromium. Colour was recorded at below 4 Hazen units in all the ten sampling sites. pH ranged from 6.8 ± 0.1 to 9.2 ± 0.04, turbidity was between 0.344 ± 0.02 mg/L and 23.7 ± 0.1 mg/L; alkalinity values were between 40 ± 4.0 mg/L and 550 ± 4.0 mg/L; total hardness ranged from 85.0 ± 3.0 mg/L to 600.0 ± 5.0 mg/L; electrical conductivity was recorded at a minimum of 328.0 ± 1.0 μScm-1 and a maximum of 2820.0 ± 6.00 μScm-1. TDS ranged between 156.0 ± 2.0 mg/L and 1,356.0 ± 3 mg/L as magnesium concentration was recorded at between 0.2 ± 0.01 mg/L and 2.7 ± 0.1 mg/L. Calcium values ranged from 1.4 ± 0.1 mg/L to 25.7 ± 0.1mg/L as chloride minimum value was 5.00 ± 1.0 mg/L with a maximum of 190.0 ± 4.0 mg/L. The highest phosphate level was recorded at 1.61 ± 0.01 mg/L while the lowest was 0.5 ± 0.01 mg/L. Nitrates minimum concentration was 0.2 ± 0.01 mg/L with a maximum of 5.16 ± 0.04 mg/L. Nitrite’s concentration ranged between 9.0 ± 1.0 μg/L and 290.0 ± 10.0 μg/L. Fluoride’s concentration ranged between 720.0 ± 10.0 μg/L and 1,650.0 ± 50.0 μg/L. Total coliform count was recorded at a minimum of 78 c.f. u /100 with a maximum of TNTC/100 (too numerous to count/100 ml). Minimum feacal coliform count in the shallow wells was recorded at nil with a maximum of 68.0 ± 5.0 c.f. u /100 ml. Zinc ion concentration ranged from 0.20±? μg/L to 1.438.3 ± 0.4 1 μg/L. Cadmium was recorded at below 0.2 ± 0 μg/L in all the sampling sites; manganese levels ranged from < 0.1 μg/L and 440.0 ± 0.2 μg/L while lead was recorded at > 0.3 μg/L maximum of 1,383.0± μg/L, a value beyond the WHO stipulated limit of 50 μg/L). Nickel minimum concentration was 12.0 ± 1.0 μg/L with a maximum of 694.0 ± 1.0 μg/L Copper minimum value recorded was 1.1 ± 0.2 μg/L and a maximum of 438.0 ± 1.0 μg/L The shortest distance between a water well and a latrine was 12 metres while the longest was 18 metres away. The wells were protected using concrete and metal plate covers of iron sheets while only one well was left open. Eighty percent of well owners chlorinated their water before drinking. Disposal of domestic solid and animal waste were done at dumping sites twenty metres or less away from the water well at a frequency of eighty percent. Sixty percent of the respondents agreed that a member of their family had suffered from diarrheal disease in the past six months. Seasonal flooding was the main challenge to the provision of safe well water quality, followed by the contamination of vessels for drawing water, poor siting of pit latrines and dumpsites by neighbours. Stringent management and public awareness are required to enforce the protection of shallow well in order to safeguard water quality and environment pollution in Kisumu City