खालीलपैकी कोणते विधान बरोबर आहे ?
(a) सिंचनासाठी नगरपालिका सांडपाण्याचा वापर केल्याने जमिनीत उपलब्ध झिंक आणि तांबे जमा होण्यात लक्षणीय वाढ होते.
(b) सिंचनासाठी नगरपालिका सांडपाण्याचा वापर केल्याने जमिनीत कॅडमियम (Cd) जमा होण्यात लक्षणीय वाढ होते.

The correct answer is Option C (Both (a) and (b) statements are correct).

Key Points:
• Heavy Metal Contamination from Municipal Wastewater Irrigation:
• Untreated or semi-treated municipal and urban wastewater contains high concentrations of industrial effluents, domestic detergents, corroded piping residues, and heavy metals.
• Statement (a) is CORRECT: Prolonged irrigation with sewage and municipal wastewater leads to significant build-up and toxic accumulation of heavy micronutrients like Zinc (Zn) and Copper (Cu) in the surface soil profile.
• Statement (b) is CORRECT: Municipal wastewater is a notorious carrier of non-essential, highly hazardous toxic heavy metals such as Cadmium (Cd), Lead (Pb), and Nickel (Ni), which accumulate in the soil and enter the food chain via plant uptake.
• Therefore, both statements (a) and (b) are scientifically correct (Option 3).
• Key Takeaway: Municipal wastewater irrigation causes dangerous soil accumulation of heavy metals including Zinc, Copper, and Cadmium.