Manganese
Common in groundwater and in reservoirs that stratify in summer. Long treated as an aesthetic nuisance because it stains laundry and fittings black, manganese has attracted increasing attention as a neurotoxicant at elevated concentrations.
Key facts
- Contaminant group
- Metal
- World Health Organization — guideline
- 80 µg/lHealth-based; the earlier value was aesthetic.
- European Union — legal limit
- 50 µg/lAn indicator parameter, set for acceptability rather than health.
- United Kingdom — legal limit
- 50 µg/l
- United States — guideline
- 50 µg/lA secondary standard, not federally enforceable.
Where it comes from
- Natural dissolution from soils and rock under reducing conditions
- Release from reservoir sediments during summer stratification
- Mining discharge
- Accumulated deposits within distribution mains, released by flow changes
How it behaves in water
Soluble in its reduced form and precipitates as a black oxide when oxidised. Deposits build up inside water mains over years and can be mobilised suddenly by a change in flow direction, producing discoloured water complaints with no change at the treatment works.
How it is measured
Measured in micrograms per litre. Visible staining occurs well below the concentrations of health interest.
Regulatory position
| Jurisdiction | Value | Status | Notes |
|---|---|---|---|
| World Health Organization | 80 µg/l | guideline | Health-based; the earlier value was aesthetic. |
| European Union | 50 µg/l | legal limit | An indicator parameter, set for acceptability rather than health. |
| United Kingdom | 50 µg/l | legal limit | — |
| United States | 50 µg/l | guideline | A secondary standard, not federally enforceable. |
Table sources
- World Health Organization — Guidelines for Drinking-water Quality. Public but restricted · CC BY-NC-SA 3.0 IGO
- European Commission — Drinking Water Directive (EU) 2020/2184 and reporting. Open — attribution required · European Commission reuse policy (Decision 2011/833/EU)
- Drinking Water Inspectorate — Drinking water quality in England and Wales. Open — attribution required · Open Government Licence v3.0
- United States Environmental Protection Agency — Safe Drinking Water Information System. Open · US Government work — public domain
Health context
Manganese is an essential nutrient at low intake. Evidence for neurodevelopmental effects at elevated drinking water concentrations has grown, which is why WHO restored a health-based guideline value.
What removes it
| Row | Effective | Not reliably effective |
|---|---|---|
| 1 | Oxidation followed by filtration | Boiling |
| 2 | Greensand or catalytic media filtration | Carbon filtration alone |
| 3 | Ion exchange softening at low concentrations | Sediment filters for dissolved manganese |
| 4 | Reverse osmosis | — |
Relationships
Related intelligence
Sources
- World Health Organization — Guidelines for Drinking-water Quality. Public but restricted · CC BY-NC-SA 3.0 IGO
- Peer-reviewed scientific literature — Open-access hydrology, water chemistry and water use research. Public but restricted · Publisher terms — public access, reuse not clearly granted