Heavy metal levels and physico--chemical quality of potable water supply in Warri, Nigeria

The interaction between man's activities and the environment is gaining world wide attention. Warri an oil producing community in Delta State of Nigeria is faced with environmental oil pollution. Since open and underground water bodies are regarded as final recipients of most environmental pollutants, this study sought to provide data on the levels of the physico-chemical parameters and contaminants in Warri metropolitan water supply. This study investigated the cadmium, lead and chromium using Atomic Absorption Spectrophotometer, physico-chemical properties such as pH, temperature, total suspended solid TSS, total dissolved solid TDS, electrical conductivity EC, biological oxygen demand BOD, dissolved oxygen DO, chemical oxygen demand COD, and total coliform count of potable water sources in Warri. Ekpan River was found to have 1.2 mg/L of cadmium, 1.0 mg/L of chromium, 1.20 mg/L of lead and 2.0 mg/L of manganese. The heavy metals levels and the pollution parameters were lowest in the borehole water samples, except pH which is more acidic in borehole water samples and conductivity which is more in well water samples in all the sampling stations. Some of the parameters were above WHO standards.     

Iodine status and the effect of soil erosion on trace elements in Nanka and Oba towns of Anambra State, Nigeria

Iodine Deficiency Disorders (IDD) is common in all populations. Iodine and other trace elements naturally occur in the soil but erosion leaches off these elements from the soil. This results in a continued loss of trace elements from the soil. In the present study, the levels of iodine, selenium, zinc and lead in the environment (measured in soil, bitter leaves (Vernonia amygdalina), cassava roots (mannihot utilissima, staple food in Nigeria), and drinking water) and urinary iodine from school children (n=200), pregnant women (n=60) and women of child bearing age (n=60) were determined for Nanka prone to soil erosion and Oba all in Anambra State, Nigeria (used as control) to assess their risk to IDD. The levels of selenium, zinc and lead were analysed using Atomic Absorption Spectrophotometry while the levels of iodine in the environment and urinary iodine were estimated using the method of Dunn et al.,(1993). In this study there was a positive correlation between iodine and the metals. The results show that the mean concentrations of total soil zinc (0.69 +/- 0.16 ppm); lead (0.40 +/- 0.12 ppm) values in Oba were significantly (p < 0.05) higher than values from Nanka (Zn = 0.33 +/- 0.10 ppm; Pb = 0.21 +/- 0.09 ppm). However, total soil values for selenium and iodine in soil were not significantly different in the two communities. Mean concentration of total vegetable zinc (0.63 +/- 0.14 ppm) value in Oba is significantly (p < 0.05) higher than the value from Nanka (Zn = 0.31 +/- 0.07 ppm). However, total vegetable values for I, Se and Pb were not significantly different in the two communities. Also, mean concentration of total cassava zinc (0.65 = 0.15 ppm) in Oba was significantly (p < 0.05) higher than Zn (0.44 +/- 0.1l ppm) from Nanka. However, values for Se, Pb, and I were not significantly different in the two communities. Mean concentration of total water iodine (105.25 +/- 10.44 microg/L) in Oba was significantly (p < 0.05) higher than the value from Nanka (I = 89.8 +/- 6.42 microg/L). However, total water values for Se, Zn, and Pb were not significantly different in the two communities. The mean urinary iodine concentration of 170.65 +/- 27.17 microg/L in school children from Oba was significantly higher (p < 0.05) than the mean concentration of 156.12 +/- 16.48 microg/L found in school children from Nanka. However, the mean urinary iodine concentration of all the women (pregnant and non-pregnant) were not significantly different in the two communities but they are below the recommended daily intake. The results show that people living in Nanka and Oba, could be at risk of IDD.