Heavy Metals Content in Laboratory Wastewater: A Case Study of Selected Units of Bayero University, Kano-Nigeria.

Abstract

Heavy metals are well-known environmental pollutants due to their toxicity, persistence in the environment and bio-accumulative in nature. They contribute immensely in the environmental pollution and their sources include weathering of metal bearing rocks, mining, industrial and agricultural activities. Laboratory is a major point of research activities. This study is aimed at accessing the level of heavy metals in some laboratories wastewater in Bayero University, Kano. Four different laboratories where selected (Biochemistry, Chemistry, Microbiology and Central Laboratory complex) from Bayero University Old Campus. The wastewater samples were collected four times with one week interval and some heavy metals were determined using microwave plasma atomic emission spectrometry (MP-AES). The average mean concentrations of Cd, Cr, Co, Mn, Ni and Pb in each laboratory were compared with WHO standard in wastewater. The Results obtained from Biochemistry Laboratory for Cd, Cr, Co, Mn, Ni and Pb are 0.0067±0.0001, 0.0000±0.0000, 0.000±0.0000, 0.010±0.001, 0.027±0.0001 and 0.106±0.0001 mg/L respectively. Similarly Central laboratory with 0.07±0.001, 0.47±0.002, 0.00±0.00, 0.31±0.003, 0.10±0.002 and 0.20±0.001 mg/L. While Microbiology Laboratory with 0.00±0.00, 0.00±0.00, 0.00±0.00, 0.063±0.001, 0.027±0.001 and 0.093±0.0001 mg/L respectively. And Chemistry laboratory with 0.000±0.00, 0.607±0.0001, 0.053±0.002, 2.183±0.001, 0.127±0.0001 and 0.263±0.0002 respectively. Among all the laboratories, chemistry laboratory was found to have higher average mean concentrations of Mn, Ni and Pb and are above WHO Standard. However some heavy metals like Cr and Cd were found to be lower compared to WHO Standard. Therefore the wastewater studied contained some heavy metals which contribute to the environmental pollution and measures should be taken by the management concerned to ensure good laboratory waste management.