Public health significance of inorganics in drinking water: which of the following statements are correct?

Introduction / Context:
Inorganic contaminants in potable water affect aesthetics and health. Some, like iron and manganese, mainly cause nuisance problems; others, like lead, barium, arsenic, and selenium, are toxic and strictly regulated. Understanding these effects is crucial for selecting treatment processes and ensuring compliance.

Given Data / Assumptions:

• Statements cover aesthetic staining and multiple toxic elements.
• The question seeks the comprehensive set of correct statements.

Concept / Approach:
Iron/manganese oxidize and precipitate, producing reddish/black stains on clothes and plumbing. Lead (from plumbing, corrosion) and barium (naturally occurring) are toxic. Arsenic and selenium are recognized poisons with chronic impacts at low levels. Elevated copper can cause gastrointestinal irritation and organ impacts at high doses; therefore, it is also health-relevant.

Step-by-Step Solution:
Map each contaminant to known effects (aesthetic vs. health). Confirm that all four individual statements describe true effects. Therefore, the combined answer “All the above” is correct.

Verification / Alternative check:
Standard water-quality references list iron/manganese as staining agents and classify lead, barium, arsenic, selenium, and copper among health-significant parameters with enforceable limits, confirming the statements collectively are true.

Why Other Options Are Wrong:

• Selecting any single statement ignores the other simultaneously true statements.

Common Pitfalls:

• Confusing aesthetic limits (iron/manganese) with health-based limits (Pb, Ba, As, Se, Cu).

Final Answer:
All the above.