What is the major pollutant found in the wastes and wastewater generated by the chlor-alkali industry?

In the chlor-alkali industry, mercury is a significant pollutant associated with the production process, particularly in the electrolysis of brine to produce chlorine and sodium hydroxide. Historically, mercury was used in some production methods, such as the mercury cell process. During this process, mercury can leak into wastewater and waste products, leading to severe environmental contamination.

Mercury is a heavy metal that poses substantial health risks to humans and aquatic life. It can accumulate in the food chain, leading to toxic effects on organisms and potential neurotoxic effects in humans who consume contaminated fish. Because of its significant environmental and health impacts, regulatory agencies have established stringent guidelines for managing and reducing mercury emissions and discharges from chlor-alkali plants.

Other metals like zinc, nickel, and copper can also be found in industrial processes but are not characteristic pollutants of the chlor-alkali industry specifically. In the context of this question, mercury stands out as the major pollutant directly linked to the unique processes of the chlor-alkali manufacturing environment.