18-Env-B5 Industrial & Hazardous Waste Management · December 2017
Nivaar worked solution (AI-drafted; not reviewed by a licensed engineer)
Reference texts: Nemerow & Dasgupta, Industrial and Hazardous Waste Treatment, 2nd ed.; Metcalf & Eddy, Wastewater Engineering: Treatment and Resource Recovery, 5th ed.; Davis & Cornwell, Introduction to Environmental Engineering, 6th ed.; LaGrega, Buckingham & Evans, Hazardous Waste Management, 2nd ed.; CCME, Guidelines for the Management of Biomedical Waste in Canada (1992); Canadian Environmental Protection Act (CEPA), 1999; Basel Convention on the Control of Transboundary Movements of Hazardous Wastes (1989); Canadian Nuclear Safety Commission (CNSC) regulations on radioactive waste; provincial hazardous waste regulations (e.g. BC's Environmental Management Act and Hazardous Waste Regulation).
Question text not reproduced: the examination questions are © Engineers and Geoscientists BC. Open the official past paper (linked at the top of this page) to read the question, then follow the worked solution below.
A carcinogen is a substance or agent capable of causing cancer by itself — typically by damaging DNA (a genotoxic mechanism) or by promoting uncontrolled cell division, with the effect often appearing only after a long latency period and at very low exposure thresholds (many regulators treat carcinogens as having no safe threshold). Example: benzene, a known human carcinogen linked to leukemia, and found in petroleum-industry wastewaters.
A cocarcinogen is a substance that is not itself carcinogenic but enhances the carcinogenic effect of a true carcinogen when the two are present together — it may act by increasing the primary carcinogen's uptake, activating it metabolically, or suppressing the body's repair/immune response. Example: certain phorbol esters (e.g. from croton oil) act as tumour promoters/cocarcinogens that amplify the effect of a genotoxic initiator such as a polycyclic aromatic hydrocarbon (PAH).
