Aluminum in water: origin, water treatment, risks, and filtration
Aluminum is the most abundant metal in the Earth's crust. It is naturally present in many soils, rocks, and minerals and can enter surface or groundwater through natural weathering. Aluminum salts are also used in drinking water treatment plants as coagulants to remove turbidity, certain organic matter, and microorganisms. When treatment is not perfectly optimized, a residual concentration of aluminum may remain in the distributed water.
- Chemical symbol
- Al
- Atomic number
- 13
- Family
- Metal
- EU Value
- 200 µg/L
What is aluminum?
Aluminum is a chemical element with the symbol Al and the atomic number 13. It is a lightweight, malleable metal that is corrosion-resistant when a thin oxide layer forms on its surface.
In nature, aluminum is generally not present in its pure metallic form. It is found combined with oxygen, silicon, fluorine, sulfates, and other elements in many minerals.
Its solubility and mobility in water strongly depend on pH, temperature, organic matter, and other substances present.
Remember: Aluminum present in water can have a natural origin, come from purification treatment, or be released by certain materials and products used in the network.
What is aluminum used for?
Aluminum is very widely used due to its lightness, conductivity, resistance to corrosion, and ease of forming.
- construction of buildings and infrastructure;
- manufacturing of vehicles, trains, boats, and aircraft;
- food packaging, cans, and metal foils;
- electrical cables and equipment;
- electronic devices and household appliances;
- kitchen utensils and equipment;
- pharmaceuticals and certain antacids;
- cosmetics and personal care products;
- additives and materials intended for food contact;
- coagulants used in water treatment.
The industrial or sanitary utility of aluminum compounds does not mean that all forms or all concentrations have the same characteristics.
How does aluminum get into the water?
Natural weathering of rocks
The erosion and weathering of rocks and soils containing aluminum can release it into surface water and groundwater. Acidic water can promote its mobilization.
Drinking water treatment
Aluminum salts, such as aluminum sulfate or certain aluminum polychlorides, are commonly used as coagulants. A residual portion may remain in the water when the dosage, pH, or coagulation conditions are not optimized.
Cement-based materials
Certain cementitious materials in contact with water can contribute to the presence of aluminum, particularly depending on their composition and the physicochemical characteristics of the water.
Chemicals used in facilities
Aluminum can be present as an impurity in certain chemical products used to adjust pH, treat water, or control corrosion.
Activated alumina
Activated alumina can be used to reduce certain contaminants, notably arsenic or fluorides. Improper use or adjustment can lead to residual release of aluminum.
Why are aluminum salts used to treat water?
In raw water, many particles are too small to settle naturally. The addition of an aluminum-based coagulant allows destabilizing these particles and promoting their grouping into larger flocs.
This step facilitates, in particular, the reduction of:
- turbidity;
- color;
- a portion of natural organic matter;
- certain disinfection by-product precursors;
- microorganisms associated with particles;
- certain metals and contaminants fixed on suspended matter.
After coagulation and flocculation, the flocs are separated by settling, flotation, or filtration.
Trying to minimize residual aluminum should not lead to excessively reducing the coagulant dosage. Under-dosing can degrade the removal of turbidity and microorganisms. The treatment must be optimized as a whole.
In what forms can aluminum be present in water?
Aluminum can be found in dissolved, colloidal, or particulate form. It can also be linked to hydroxides, fluorides, sulfates, phosphates, or organic matter.
| General form | Description | Possible influence |
|---|---|---|
| Dissolved aluminum | Ions and complexes small enough to pass through certain analytical filters. | Its concentration strongly depends on pH and the ligands present. |
| Colloidal aluminum | Very small particles or aggregates remaining in suspension. | Can contribute to turbidity and complicate the interpretation of analyses. |
| Particulate aluminum | Aluminum fixed on suspended matter or present in flocs. | Can be reduced by mechanical separation when particles are large enough. |
pH plays an essential role. Under certain acidic conditions, aluminum can become more soluble. It can also be remobilized when water conditions change in the network.
What are the health risks of aluminum?
Aluminum is not considered an essential element for the human body. Food generally constitutes the main source of exposure, while the contribution of drinking water is usually minor.
The WHO has not set a formal health-based guideline value for aluminum in drinking water. It indicates that a theoretical health value could be calculated, but that the concentrations targeted in practice are mainly determined by the optimization of the coagulation treatment.
Studied neurological effects
Certain studies have looked for an association between ingested aluminum and neurological diseases. The available human data, however, have significant methodological limitations and do not allow for a clear establishment of a direct causal relationship between aluminum in drinking water and Alzheimer's disease.
Neurological effects have been observed in animals exposed to high doses. Health Canada considers the nervous system a sensitive organ in its toxicological assessment.
People with severe renal insufficiency
The elimination of absorbed aluminum occurs primarily through the kidneys. People with severe renal insufficiency may be more sensitive to accumulation, particularly in certain specific medical contexts.
A concentration higher than the European indicator value of 200 µg/L does not automatically mean immediate intoxication. However, it can reveal an insufficiently optimized treatment, an accumulation in the network, or a change in water quality that must be investigated.
What are the effects of aluminum on the environment?
Aluminum is naturally very abundant, but its mobility and toxicity to organisms depend on its chemical form and pH.
In acidified waters, certain dissolved forms can become more available and affect fish, invertebrates, and microorganisms. Aluminum can notably disrupt the gills of certain fish and their ability to regulate ionic exchanges.
In less acidic conditions, it can precipitate or fix onto particles and sediments.
What is the value for aluminum in drinking water?
The European Union sets a value for aluminum of 200 micrograms per liter. This is an indicator parameter and not a health-based parametric value equivalent to those provided for lead, arsenic, or cadmium.
| Reference | Value | Nature or precision |
|---|---|---|
| European Union | 200 µg/L | Indicator parameter used in particular to monitor treatment efficiency and network quality. |
| World Health Organization | No formal health guideline value | The WHO mentions practicable levels of about 0.1 mg/L in large facilities and 0.2 mg/L in properly operated small facilities. |
| Canada | 2.9 mg/L | Maximum acceptable concentration based on neurological effects observed in animals. |
| Canada – operational recommendation | 0.1 mg/L | Value intended to optimize treatment and limit accumulation in the network. |
200 µg/L corresponds to 0.2 mg/L.
The differences between international values are explained by their objective. Some are based on a health assessment, while others serve primarily to monitor the functioning of the treatment, the appearance of the water, and deposits in the network.
How to know if water contains aluminum?
A low concentration cannot be reliably detected by taste or smell. When the concentration is higher or when flocs are present, cloudy, whitish water or water with deposits can sometimes be observed, but these signs are not specific to aluminum.
An analysis can measure:
- total aluminum;
- dissolved aluminum;
- particulate aluminum, calculated or measured separately;
- pH and turbidity;
- organic matter;
- iron, manganese, and other associated metals;
- variations between plant outlet and the tap.
The sampling protocol must be defined according to the objective: monitoring of produced water, investigation of a deposit in the network, or study of quality at the tap.
What technologies can reduce aluminum in water?
The choice of treatment mainly depends on the form of aluminum, pH, concentration, turbidity, and composition of the water.
Processes that can be used include, in particular:
- optimization of coagulant dosage and pH in treatment plants;
- coagulation, flocculation, sedimentation, and filtration;
- mechanical filtration of particulate or colloidal forms;
- certain suitable adsorbent media or ion exchangers;
- properly sized reverse osmosis;
- flushing and network management when deposits are remobilized;
- correction of chemical conditions favoring the dissolution or precipitation of aluminum.
Not all activated carbon filters automatically reduce dissolved aluminum. Mechanical filtration can retain particles, but it does not guarantee the reduction of ionic or complexed forms. One must consult a test specific to the system concerned.
When a high concentration is confirmed, an analysis before and after treatment makes it possible to verify performance under actual conditions of use.
Imperial test results for aluminum
Aluminum is included in the performance analysis table published for Monderma Imperial GF and Imperial AMB filters. The tests were conducted by Envirotek Laboratories in the United States.
Aluminum: result indicated in the Envirotek table
Result verification: the transition from 200 µg/L to 2.13 µg/L corresponds mathematically to a reduction of approximately 98.94%, consistent with the rounded value of 98.9% displayed in the table.
Interpretation limit: the summary table does not by itself specify the proportion of dissolved, colloidal, and particulate aluminum, nor the chemical complexes present in the test water. The result should therefore not be automatically extrapolated to all forms of aluminum and all types of water.
The performances obtained in the laboratory correspond to the test protocol conditions. Actual results may vary depending on pH, turbidity, water composition, initial concentration, flow rate, contact time, maintenance, and duration of cartridge use.
A test carried out according to an NSF/ANSI protocol does not necessarily mean that the complete filter is NSF certified for aluminum reduction. Official certifications and performance tests must be distinguished.
Consult Monderma certifications and analysesFrequently asked questions about aluminum in water
Why is aluminum found in drinking water?
It can originate naturally from rocks and soil. It can also be linked to the use of aluminum salts as coagulants during the production of drinking water.
Is aluminum actually used to purify water?
Yes. Aluminum salts are used to group small particles into flocs, which facilitates their sedimentation and filtration. This technique is used, in particular, to reduce turbidity and some microorganisms.
What is the European value for aluminum in water?
The European Union sets a value of 200 µg/L. Aluminum is classified as an indicator parameter, particularly for monitoring treatment and network operation.
Does aluminum in water cause Alzheimer's disease?
Available human studies do not clearly establish a direct causal link between aluminum in drinking water and Alzheimer's disease. Health organizations highlight the limitations and confounding factors of these studies.
Does boiling water remove aluminum?
No. Domestic boiling is not a reliable method for removing dissolved aluminum. Evaporation can even concentrate non-volatile substances in the remaining volume.
Is a mechanical filter enough to remove aluminum?
It can retain some particulate or colloidal forms, but it does not guarantee the removal of dissolved aluminum. Performance depends on the chemical form and the technology used.
Does whitish water necessarily contain aluminum?
No. A whitish appearance can be caused by microbubbles, limescale, or other particles. Only an analysis can identify aluminum.
Associated contaminants
Aluminum belongs to the category of metals and trace elements. You can also consult the pages dedicated to other metals likely to be present in water.
Scientific and administrative sources
This sheet is based on public organizations, international institutions, and governmental scientific databases. No commercial blog, comparison site, or affiliate site is used as a primary health source.
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World Health Organization – Aluminum in drinking water
Information on the origin of aluminum, its use as a coagulant, and
achievable levels after treatment.
Consult the official WHO fact sheet -
World Health Organization – Scientific document on aluminum
Reference document dedicated to the presence, effects, and management of
aluminum in water.
Consult the official WHO page -
European Union – Directive (EU) 2020/2184
Official text classifying aluminum among indicator parameters with a
value of 200 µg/L.
Consult the directive on EUR-Lex -
Health Canada – Aluminum in drinking water
Comprehensive assessment of sources, health effects, analytical methods,
and aluminum treatment.
Consult the official Health Canada document -
PubChem – National Institutes of Health
Data on the element aluminum, its symbol, atomic number, and general
properties.
Consult the PubChem entry -
Monderma – Certifications and laboratory analyses
Certifications, reports, and analysis table for Imperial filters.
Consult Monderma certifications and analyses
