Which heavy metal is commonly found in industrial wastewater?

Lead is commonly found in industrial wastewater due to its extensive use in various industries, particularly in battery manufacturing, metal processing, and construction. It is a heavy metal that can be released into the environment through improper disposal of industrial waste, corrosion of lead-containing pipes, and mining activities. The presence of lead in wastewater is concerning because of its toxic properties and potential to contaminate water supplies, posing serious health risks to humans and aquatic life.

In contrast, calcium, potassium, and magnesium are essential nutrients and are typically found in higher concentrations in natural waters and agricultural runoff rather than as contaminants in industrial wastewater. Their presence is more related to biological processes and less to the toxic effects associated with heavy metals like lead. Therefore, lead stands out as the relevant answer to this question.