What is a common impact of waste from metal-plating industries on influent?

The choice highlighting increased toxicity as a common impact of waste from metal-plating industries on influent is accurate because the effluents from these industries often contain heavy metals and other hazardous substances. These agents are toxic to aquatic life and can pose serious health risks to humans who may be exposed to contaminated water sources. Heavy metals such as lead, cadmium, or chromium can disrupt biological processes in living organisms and may cause acute or chronic effects including organ damage and genetic mutations.

In contrast, increased pH levels would not typically be a direct result of metal plating waste; rather, the effluent usually has a lower pH due to acidic cleaning processes used in plating. Decreased odor is unlikely because chemical processes often contribute to foul odors rather than mitigate them. Additionally, wastewater from metal-plating industries usually has higher inorganic content compared to organic matter, so the suggestion that organic matter is reduced doesn't align with the typical characteristics of this type of industrial waste. Understanding the toxicity of industrial effluents is crucial for designing appropriate treatment and management strategies to protect water quality and public health.