metal finishing wastes

This is incorrect. Acids are a common component of metal finishing wastewater.

This is incorrect. Caustics are a common component of metal finishing wastewater.

This is incorrect. Heavy metals are a common component of metal finishing wastewater.

This is the correct answer. Vitamins are not typically found in metal finishing wastewater.

This is incorrect. While some metal finishing processes can release air pollutants, the primary concern is water pollution.

This is the correct answer. Metal finishing wastewater can contaminate water sources with heavy metals and other toxic substances.

This is incorrect. Noise pollution is not a primary concern associated with metal finishing wastewater.

This is incorrect. Soil erosion is not a primary concern associated with metal finishing wastewater, although the wastewater could contribute to it indirectly.

This is incorrect. Using more toxic chemicals is the opposite of a sustainable practice.

This is incorrect. Releasing untreated wastewater is harmful to the environment and is not a sustainable practice.

This is the correct answer. Implementing closed-loop systems is a sustainable practice that reduces waste and resource consumption.

This is incorrect. Increasing the use of single-use disposable materials is not sustainable and contributes to waste generation.

This is incorrect. Advanced treatment is used for further purification, but not the initial removal of hazardous components.

This is incorrect. Source reduction focuses on preventing waste generation in the first place.

This is the correct answer. Pretreatment is used to remove or convert hazardous substances before discharge.

This is incorrect. Regulations and enforcement are important for ensuring compliance, but not a type of treatment.

This is incorrect. Cyanide-based plating baths are highly toxic and not a green chemistry approach.

This is the correct answer. Developing non-toxic alternatives is a key aspect of green chemistry in metal finishing.

This is incorrect. Increasing the use of hazardous solvents is the opposite of a green chemistry approach.

This is incorrect. Disposing of waste in landfills is not a green chemistry approach.

Here's a possible solution:

Environmental Impacts:

1. Water Contamination: Nickel, chromium, and cyanide are highly toxic to aquatic life. Their presence in the river would harm fish, plants, and other organisms.
2. Sediment Accumulation: Heavy metals like nickel and chromium can accumulate in river sediments, making them toxic to organisms that live in the sediment and those that ingest them.
3. Drinking Water Contamination: If the river is a source of drinking water, the contamination could pose a serious health risk to humans.

Proposed Solutions:

1. Pretreatment System: The company could install a pretreatment system to remove or convert the heavy metals and cyanide before the wastewater is discharged. This could involve techniques like chemical precipitation, ion exchange, or oxidation.
2. Closed-Loop System: The company could explore implementing a closed-loop system to recycle and reuse the plating solutions. This would significantly reduce the volume of wastewater generated and minimize the discharge of pollutants.

Sustainability Explanation:

• Pretreatment System: This reduces the direct discharge of toxic substances into the river, minimizing the risk to aquatic life and potential drinking water contamination. It also promotes resource conservation by removing valuable metals for potential reuse.
• Closed-Loop System: This significantly reduces the generation of wastewater, minimizing the environmental impact. It also promotes resource efficiency by reusing plating solutions and reducing the need for new materials.