Manganese in water: origin, discoloration, risks and filtration
Manganese is an element naturally present in many rocks, soils and sediments. It is also essential for the body's functioning in very small quantities. However, in drinking water, high concentrations can cause brown or black discoloration, deposits and stains on laundry or equipment. Excessive and prolonged exposure is also a health concern, particularly regarding the neurological development of infants and young children.
- Chemical symbol
- Mn
- Atomic number
- 25
- Family
- Metal and trace element
- EU Value
- 50 µg/L
What is manganese?
Manganese is a chemical element with the symbol Mn and atomic number 25. It is a transition metal frequently associated with iron in rocks, soils and ores.
In nature, it can exist in several oxidation states. The most common forms in natural water are generally divalent manganese Mn(II), often dissolved, and tetravalent manganese Mn(IV), more often associated with oxides and particles.
Key point: clear water can contain dissolved manganese. Discoloration may appear later when the manganese oxidizes upon contact with air, a disinfectant, or within the plumbing system.
What is the role of manganese in the body?
Manganese is an essential trace element. It contributes to the functioning of several enzymes necessary for metabolism and cell protection.
It is involved in particular in:
- the metabolism of carbohydrates, lipids and proteins;
- the formation and maintenance of bones;
- the protection of cells against oxidative stress;
- the functioning of certain enzymes;
- healing and the formation of connective tissue.
Diet is generally the main source of manganese. Whole grains, nuts, legumes, tea and certain vegetables contain it naturally.
The essential nature of manganese does not mean that high concentrations in water are risk-free. As with many elements, the effects depend on the dose absorbed and the duration of exposure.
What is manganese used for?
Manganese is widely used in industry, primarily to improve metal properties and manufacture various chemical compounds.
- manufacturing steel and metal alloys;
- production of cells and batteries;
- manufacturing pigments, glass and ceramics;
- production of fertilizers and animal feed;
- manufacturing of certain chemical products;
- use of potassium or sodium permanganate for oxidation, cleaning, disinfection or water treatment;
- metallurgical and electronic applications.
How does manganese get into water?
Natural geological origin
The weathering of rocks and soils is generally the main source of manganese in groundwater and surface water. Some geological formations can release more than others.
Oxygen-poor groundwater
In reducing conditions, particularly when the water contains little oxygen, manganese oxides present in soils and sediments can dissolve. The manganese then becomes a soluble form in the water.
Lakes and reservoirs
In the deep layers of a lake or reservoir, the lack of oxygen can cause the release of manganese from sediments. Seasonal variations can therefore change the concentration in the captured water.
Mining and industrial activities
The extraction and processing of ores, metallurgy, battery production and certain chemical industries can contribute to local contamination.
Products used for water treatment
Certain chemical products used in water treatment facilities may contain manganese as an impurity. Manganese compounds can also be intentionally used as oxidizing agents.
In what forms is manganese present in water?
| General form | Description | Consequence for treatment |
|---|---|---|
| Dissolved manganese | Often present in Mn(II) form, especially in oxygen-poor groundwater. | Can pass through simple mechanical filtration and generally requires oxidation, adsorption or ion exchange. |
| Colloidal manganese | Small particles or aggregates that can remain in suspension for a long time. | May require coagulation, adsorption or fine filtration. |
| Particulate manganese | Black or brown oxides formed after oxidation of dissolved manganese. | Can generally be removed by appropriate filtration, depending on particle size. |
Measuring total manganese does not always distinguish between dissolved and particulate forms. This distinction is, however, important for choosing the appropriate treatment process.
Why does manganese discolor water and stain laundry?
When dissolved manganese oxidizes, it can form brownish or black particles. These particles can settle in pipes, water heaters, filters, sanitary fixtures and household appliances.
A significant presence can cause:
- brown, gray or black water;
- visible black particles;
- stains on laundry;
- deposits on sinks, bathtubs and toilets;
- a metallic or unpleasant taste;
- an accumulation of deposits in the piping network;
- the sudden re-suspension of particles after maintenance work or a change in flow.
Black stains are often associated with manganese, while orange-red deposits are more frequently associated with iron. Both elements can, however, be present simultaneously.
What are the health risks of manganese?
The nervous system is the primary concern in the event of excessive and prolonged exposure. The effects depend on the dose, duration of exposure, age and the body's ability to eliminate manganese.
Infants and young children
Infants can absorb and retain more manganese than adults, particularly because their biliary elimination system is still developing. Water used to prepare baby bottles can add to the manganese already contained in certain infant formulas.
Epidemiological studies have reported associations between exposure to manganese in water and certain neurological or cognitive effects in children. These studies contain uncertainties, but they reinforce the need for caution for the most sensitive populations.
Prolonged exposure in adults
Very high or prolonged exposure can affect the nervous system and cause movement, coordination, memory or behavioral disorders. Occupational exposure via inhalation should not, however, be directly equated with exposure via water ingestion.
Sensitive individuals
People with liver disease or reduced ability to eliminate manganese may be more sensitive to accumulation in the body.
The presence of manganese should not lead to abandoning a microbiologically safe source in favor of an uncontrolled water supply. In case of exceedance, it is advisable to follow the recommendations of health authorities and use a replacement solution recognized as safe when requested.
What are the effects of manganese on the environment?
Manganese is naturally present in ecosystems and is an essential element for many organisms. At high concentrations, however, it can alter the quality of water and sediments.
Its behavior depends heavily on oxygen, pH, organic matter and microbial activity. It can alternate between dissolved and solid forms depending on environmental conditions.
Manganese oxides can also bind other contaminants, notably certain metals and metalloids. A change in water chemistry can subsequently cause their re-circulation.
What is the regulation for manganese in drinking water?
The European Union sets a value of 50 micrograms per liter for manganese. It is classified among the indicator parameters.
| Reference | Value | Nature or detail |
|---|---|---|
| European Union | 50 µg/L | Indicator parameter intended in particular to monitor water quality, discoloration and treatment functioning. |
| World Health Organization | 80 µg/L | Provisional guideline value intended in particular to protect bottle-fed infants against neurological effects. |
| United States – EPA | 50 µg/L | Federal secondary standard that is not mandatory at the national level, based primarily on aesthetic effects such as discoloration and staining. |
50 µg/L corresponds to 0.05 mg/L and 80 µg/L to 0.08 mg/L.
An indicator or aesthetic value and a health-based guideline value do not have exactly the same purpose. Water can cause stains and discoloration at a concentration lower than a value based on health effects.
How can I know if my water contains manganese?
A laboratory analysis is necessary to precisely measure the concentration. Transparent water does not exclude the presence of dissolved manganese.
Depending on the context, the laboratory may measure:
- total manganese;
- dissolved manganese;
- particulate manganese;
- iron, often present in the same water;
- pH, dissolved oxygen and redox potential;
- turbidity and color;
- concentration before and after treatment.
Sampling must be carried out according to the laboratory's instructions, because dissolved manganese can oxidize and form particles after sampling.
What technologies can reduce manganese in water?
The choice of treatment depends on the form of the manganese, its concentration, pH, dissolved oxygen, and the presence of iron or organic matter.
Technologies used include, in particular:
- oxidation followed by filtration;
- filtration using green sand or suitable catalytic media;
- combined adsorption and oxidation;
- biological filtration;
- certain suitable ion exchangers or water softeners;
- point-of-use reverse osmosis;
- mechanical filtration when the manganese is already in particulate form;
- network cleaning when accumulated deposits are regularly resuspended.
A simple mechanical cartridge does not necessarily reduce dissolved manganese. It generally must be oxidized, adsorbed, or exchanged before it can be effectively retained.
After installing a treatment system, a control analysis of the treated water is recommended. The media must be maintained, regenerated, or replaced according to the manufacturer's instructions.
Result of Imperial tests for manganese
Manganese appears in the performance analysis table published for the Monderma Imperial GF and Imperial AMB filters. The tests were carried out by Envirotek Laboratories in the United States.
Manganese: result indicated in the Envirotek table
Verification of result: the change from 1,010 µg/L to 24.69 µg/L mathematically corresponds to a reduction of approximately 97.56%, consistent with the rounded value of 97.6% indicated in the report.
The final concentration declared in the test is lower than the European indicator value of 50 µg/L and the WHO provisional guideline value of 80 µg/L. This comparison concerns only the conditions of the laboratory test.
Limitation of interpretation: the summary table does not on its own specify the proportion of dissolved, colloidal, and particulate manganese, nor its exact oxidation state.
The performances obtained in the laboratory correspond to the conditions of the test protocol. Actual results may vary according to pH, dissolved oxygen, initial concentration, flow rate, contact time, maintenance, and the duration of use of the cartridges.
A test carried out according to an NSF/ANSI protocol does not necessarily mean that the complete filter is NSF certified for the reduction of manganese. Official certifications and performance tests must be distinguished.
Consult Monderma certifications and analysesFrequently asked questions about manganese in water
Why does water containing manganese turn black?
Dissolved manganese can oxidize and form brown or black oxide particles. These particles can color the water and deposit in equipment.
Is manganese useful to the body?
Yes. It is an essential trace element that participates in the functioning of several enzymes. Excessive and prolonged exposure may, however, become undesirable.
What is the European value for manganese in water?
The European Union sets an indicator value of 50 µg/L, or 0.05 mg/L.
What is the value recommended by the WHO?
The WHO has established a provisional guideline value of 80 µg/L, primarily to protect bottle-fed infants.
Does boiling water eliminate manganese?
No. Domestic boiling is not a reliable method for removing manganese. It can promote certain transformations, but does not guarantee its reduction.
Can clear water contain manganese?
Yes. Dissolved manganese can be invisible. Coloration may only appear after its oxidation.
Is a mechanical filter sufficient to remove manganese?
It can retain manganese already present in particulate form, but not necessarily dissolved manganese. Oxidation or a specific medium may be necessary.
Can manganese accumulate in pipes?
Yes. Manganese oxides can form deposits in the network, which are then released during work, flushing, or changes in water pressure and composition.
Associated contaminants
Manganese belongs to the category of metals and trace elements. It is frequently tested for along with iron and may be associated with other metals present in groundwater.
Scientific and administrative sources
This factsheet is based on public organizations, international institutions, and government scientific databases. No commercial blog, comparator, or affiliate site is used as a primary health source.
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World Health Organization – Manganese in drinking water
Factsheet presenting the 80 µg/L provisional guideline value,
neurological effects, sensitive populations, and main treatment methods.
Consult the official WHO factsheet -
WHO – Scientific document on manganese in water
Detailed document used for the revision of World Health Organization
recommendations.
Consult the WHO reference document -
European Union – Directive (EU) 2020/2184
Official text classifying manganese among indicator parameters with a
value of 50 µg/L.
Consult the directive on EUR-Lex -
Environmental Protection Agency – Secondary standards
Official list of US secondary standards, with a value of 0.05 mg/L for
manganese.
Consult the official EPA page -
EPA – Health documents on manganese
Official health assessment documents and non-regulatory notices
relating to manganese in drinking water.
Consult EPA documents -
PubChem – National Institutes of Health
Data on manganese, its symbol Mn, atomic number, and general chemical
properties.
Consult the PubChem factsheet -
Monderma – Certifications and laboratory analyses
Certifications, reports, and analysis table for Imperial filters.
Consult Monderma certifications and analyses
