Question

Which of the following human activities is a significant source of anthropogenic trace metal contamination in soils?

• A. Organic farming
• B. Mining and industrial activities
• C. Reforestation projects
• D. Environmental conservation efforts

Hint:

• Anthropogenic trace metal (heavy metal) contamination in soils is a serious environmental issue.
• Key human activities responsible include:
  • Mining operations and smelting (releases metals like Pb, Cd, As, Cu).
  • Industrial discharges and emissions (from manufacturing, power generation).
  • Use of some agricultural inputs (certain fertilizers, pesticides, sewage sludge).
  • Improper waste disposal.
• Organic farming, reforestation, and conservation efforts aim to reduce or prevent pollution.

Answer 1

The Correct Option is B

Anthropogenic (human-caused) trace metal contamination in soils refers to the introduction of heavy metals and other trace elements into the soil at levels that can be harmful to plants, animals, and humans. Significant sources include:

• Mining and Industrial Activities (option b):
  • Mining and Smelting: Extraction and processing of ores (e.g., for lead, zinc, copper, cadmium, arsenic) can release large quantities of trace metals into the surrounding soil and water through dust, tailings, and wastewater.
  • Industrial Processes: Various industries, such as metal plating, battery manufacturing, tanneries, chemical plants, and fossil fuel combustion (e.g., coal burning releases mercury, arsenic), can discharge trace metals as waste products or emissions that deposit on soil.
• Agriculture: Application of certain pesticides (e.g., older arsenical or copper-based pesticides), phosphate fertilizers (which can contain cadmium), and sewage sludge can introduce trace metals.
• Waste Disposal: Improper disposal of municipal solid waste, industrial waste, and e-waste can lead to leaching of trace metals from landfills or dumpsites.
• Atmospheric Deposition: Emissions from industries and vehicles can deposit trace metals over wide areas.

Let's evaluate the other options:

• Organic farming (option a): This practice aims to minimize synthetic inputs and typically reduces the risk of trace metal contamination compared to conventional farming that might use certain synthetic pesticides or fertilizers with higher metal content. It is not a source of contamination.
• Reforestation projects (option c): These are efforts to restore forests and are generally beneficial for the environment. They are not sources of metal contamination.
• Environmental conservation efforts (option d): These activities are aimed at protecting and improving the environment, not contaminating it with trace metals.

Therefore, mining and industrial activities are major and well-documented significant sources of anthropogenic trace metal contamination in soils. \[ \boxed{\text{Mining and industrial activities}} \]