Nutrient Loads and Heavy Metals assessment along Sosiani River, Kenya.

Abstract

Pollution loads were investigated to obtain data on nature and level of contaminations. Soil, sediment and water were collected from five sites and analyzed. Nitrates were determined using UV spectrophotometric screening and colorimetric methods. Phosphates were determined using ascorbic acid and Olsen methods. Nitrates and Phosphates were below EMC and Kenya Bureau of Standards (KEBS) recommended values of 3.0 ppm and 10.0 ppm respectively. Heavy metals were analyzed using wet digestion method and values obtained were above the set limits. At site 3 values obtained were: for Iron (3.562±0.012, 3.033±0.131, 0.033±0.013 ppm), Lead (4.891±0.030, 1.39±0.030, 1.89±0.000 ppm), Cadmium (0.065±0.003, 0.103±0.002, 0.013±0.002 ppm), Zinc (2.372±0.031, 0.410±0.003, 0.310±0.033 ppm) and Copper (0.728±0.000, 0.113±0.000, 0.213±0.000 ppm) for soil, sediment and water, respectively. Concentrations exceeded KEBS permitted levels. Zinc values were above WHO standards of 0.50 ppm for drinking water. It can be concluded that river Sosiani water is not safe for domestic use.

Key words: Contamination, Heavy metals, Water, Soil, Sediment.