Environmental and public health risks associated with chemical waste from research and educational laboratories in Dar es Salaam, Tanzania

This study presents a preliminary assessment of waste management practices in eleven laboratories of six educational and research institutions in Dar es Salaam, Tanzania. Categorical questionnaires were administered to 52 laboratory personnel to assess their awareness of health and environmental risks of chemical waste and the waste management practices. A chemical analysis was carried out to determine the nature, amount and composition of waste so as to assess the associated risk of environmental contamination and human exposure. The study found that liquid waste generated by the surveyed laboratories was mostly acidic in nature (pH = 1.2–3.4) and contaminated by elements such as Cu (0.02–3.44 mg/L), Cr (0.01–0.19 mg/L) and Pb (0.12–2.33 mg/L), in some cases above the safety limits. Generally, improper waste handling procedures were observed in terms of unlabeled waste containers (72.3%), lack of proper collection plan (75.0%), unsuitable means of disposal that included direct discharge into the drainage system (53.8%) and open dumping (42.4%) as well as lack of proper records of the waste quantities (55.8%). Regarding personnel awareness, >90% of the contacted personnel indicated that they were knowledgeable about pollution prevention concepts and impacts associated with chemical waste, while 25% had formal training on chemical waste management. The findings of this study raise awareness of the risks associated with chemical waste from this potential source and call for proper management of chemical waste, particularly to laboratory scientists and policy makers. It may also motivate a new generation of environmentally conscious scholars.