Ontario Operator-in-Training (OIT) Practice Exam

What can heavy metals in inadequately treated sewage lead to?

1. Enhanced aquatic life

2. No significant environmental impact

3. Severe environmental damage

4. Increased soil fertility

The correct answer is: Severe environmental damage

Heavy metals in inadequately treated sewage can lead to severe environmental damage due to their toxic nature. These metals, which include lead, mercury, cadmium, and arsenic, can accumulate in the sediment of water bodies and bioaccumulate in aquatic organisms. As these metals build up through the food chain, they pose a threat not only to aquatic life but also to birds, mammals, and humans that rely on these ecosystems for food and water. The toxicity of heavy metals can disrupt biological processes in wildlife, leading to reproductive issues, developmental problems, and even death in extreme cases. Additionally, when these metals enter the soil, they can contaminate plants, further affecting agricultural productivity and food safety. Therefore, the presence of heavy metals in sewage has far-reaching consequences that affect biodiversity, ecosystem health, and human safety, highlighting the pressing need for effective sewage treatment processes to mitigate these risks.