Antimony in water: origin, risks, regulations, and treatment

Antimony is a metalloid naturally present in certain rocks and ores. It is also used in alloys, batteries, flame retardants, plastics, ceramics, solder, and certain industrial equipment. In drinking water, its presence can stem from geology, past mining or metallurgical activities, industrial discharge, and, more rarely, plumbing materials. Antimony is regulated due to its potential effects on the liver, the digestive system, and other organs following chronic excessive exposure.

Chemical symbol: Sb
Atomic number: 51
Common forms: Sb(III) and Sb(V)
EU limit: 10 µg/L

What is antimony?

Antimony is a chemical element with the symbol Sb and atomic number 51. Its symbol comes from the Latin stibium. It is generally classified as a metalloid because it exhibits properties intermediate between those of metals and non-metals.

In its natural state, free antimony is rare. It is mainly found in the form of mineral compounds, the most important being stibnite, an antimony sulfide with the formula Sb₂S₃. It can also be associated with arsenic, lead, copper, silver, and other metals in complex ores.

Antimony has no known essential biological role in humans. Exposure of the general population primarily comes from food, beverages, air, certain consumer products, and, to a lesser extent, drinking water.

Keep in mind: antimony is generally present at low concentrations in drinking water. However, a high value should be confirmed and investigated, as it may indicate a geological or industrial source, or may be related to certain materials.

What are the properties of antimony?

Characteristic	Information	Importance in water
Symbol	Sb	Group 15 element of the periodic table.
Atomic number	51	Identifies the chemical element.
Atomic mass	Approximately 121.76	Used in analytical and toxicological calculations.
Common oxidation states	+3 and +5	Sb(III) and Sb(V) forms behave differently.
Form in oxidizing environments	Sb(V)	Often the majority in aerated and chlorinated waters.
Form in reducing environments	Sb(III)	May be more strongly adsorbed and exhibit different toxicity.
Mobility	Depends on pH and iron or manganese oxides	Sorption to minerals strongly controls its presence in water.

The chemistry of antimony is complex. Its mobility depends on pH, redox potential, the presence of sulfides, organic matter, and iron or manganese oxides. These parameters also influence the effectiveness of treatment methods.

What is antimony used for?

Antimony and its compounds are used in many industrial sectors. Antimony trioxide, in particular, is used with other substances to provide flame retardant properties.

lead and tin alloys;
lead-acid batteries;
flame retardants;
plastics and synthetic resins;
manufacturing of polyethylene terephthalate (PET);
solder, brazing, and electrical components;
glass, ceramics, pigments, and enamels;
semiconductors and electronic equipment;
ammunition and certain friction materials;
pharmaceutical treatments for certain parasitic diseases.

These uses can lead to emissions into the air, soil, and water, particularly around mines, smelters, coal-burning facilities, and industrial sites.

How does antimony get into water?

Natural origin

The weathering of rocks and ores containing antimony can release this element into groundwater and surface water. The highest concentrations are generally observed near mineralized formations or old mining districts.

Mining and metallurgy

Mining activities, ore concentration, smelting, and refining can produce waste containing antimony. Drainage from waste rock piles, tailings, and settling ponds can cause long-term contamination of local water sources.

Coal combustion

Antimony can be released during the burning of coal and end up in ash, atmospheric dust, and wet deposition.

Industrial and urban discharge

Industries involved in plastics, batteries, metals, flame retardants, ceramics, and electronics can contribute to discharges. Road traffic can also produce particles containing antimony, notably through the wear of certain braking materials.

Drinking water networks

Antimony can enter water upon contact with certain lead-free solders, certain brass alloys, or deposits present in the network. This contribution is not systematic and depends heavily on the materials and water chemistry.

What is the difference between Sb(III) and Sb(V)?

Form	Favorable conditions	Behavior	Importance for treatment
Sb(III)	Reducing, oxygen-poor environments	Often present as neutral antimonite depending on pH	Can be strongly adsorbed, but its behavior varies with the media.
Sb(V)	Oxidizing environments, treated and chlorinated water	Often present as anionic antimonate	Can be more mobile and harder to remove depending on pH.
Particulate antimony	Associated with oxides and sediments	Transported with particles	Can be removed by clarification or appropriate filtration.
Total antimony	Sum of dissolved and particulate forms	Parameter used for compliance	Must be measured with proper sample preparation.

The distinction between Sb(III) and Sb(V) is important because electrical charge, mobility, adsorption, and response to treatment processes differ. In oxidized drinking water, Sb(V) is generally considered the dominant form.

Can antimony come from plumbing?

Yes, but this source generally remains secondary. Some plumbing materials may contain small amounts of antimony, including "lead-free" solder, certain brass alloys, and specific metal parts.

Migration depends on contact time, pH, temperature, alkalinity, and water composition. Prolonged stagnation can increase the concentration at the first draw.

To investigate a source linked to plumbing, compare a sample taken after several hours of stagnation with a sample taken after flushing. A clear drop after flushing points toward a contribution from internal piping.

Antimony can also adsorb onto iron and manganese deposits present in pipes. During an episode of colored water or hydraulic disturbance, these deposits can be resuspended and release multiple contaminants simultaneously.

Can PET bottles release antimony?

Antimony compounds are used as catalysts in the manufacturing of many polyethylene terephthalate (PET) plastics. Small amounts can migrate into beverages, especially when bottles are stored for a long time or exposed to high temperatures.

Migration depends on the type of material, storage time, temperature, and the liquid's composition. Available data generally show low levels in products that meet regulatory requirements.

Avoid storing water bottles for long periods in a hot vehicle, in direct sunlight, or near a heat source. This precaution applies to all migration phenomena from packaging, not just antimony.

What are the health effects of antimony?

Effects depend on the chemical form, solubility, dose, duration, and route of exposure. Data on chronic ingestion come primarily from experimental studies.

Gastrointestinal effects

Significant oral exposure to soluble antimony compounds can cause nausea, vomiting, abdominal pain, and diarrhea.

Hepatic effects

The liver is one of the main target organs identified in studies used to set health-based values. Histological and biochemical changes have been observed in animals at high doses.

Other studied effects

Renal, cardiovascular, metabolic, and developmental effects have also been reported in literature. Their significance depends on the compound, the dose, and the quality of the available data.

Health Canada has set a maximum acceptable concentration of 6 µg/L for total antimony. The Canadian document specifies that this value is meant to protect against the effects of lifetime exposure.

A concentration exceeding the regulatory value must be confirmed and investigated. Do not rely on taste, smell, or color, as antimony can be present without any perceptible signs.

Is antimony carcinogenic?

The answer strongly depends on the compound and the route of exposure. Some classifications mainly concern occupational inhalation of compounds such as antimony trioxide.

For oral exposure via drinking water, Health Canada indicates that the overall weight of scientific evidence does not lead to the conclusion that antimony and its compounds are carcinogenic via this route.

It is therefore important not to directly apply a classification related to the inhalation of industrial dust to the ingestion of drinking water. The doses, chemical forms, and exposure mechanisms are different.

Regulatory values for drinking water are primarily based on non-carcinogenic effects, particularly hepatic and biochemical ones.

What are the environmental effects of antimony?

Antimony can persist in soil and sediments. Its mobility depends on the chemical form, pH, redox conditions, and the presence of iron and manganese oxides.

Mining and metallurgical waste can cause long-term contamination of watersheds. Antimony can be transported in dissolved, colloidal, or particulate form, and subsequently accumulate in sediments.

Changes in pH or redox potential can remobilize a portion of the fixed antimony. Therefore, the restoration of contaminated sites must take into account geochemical conditions and not solely the total concentration in the soil.

What are the reference values for antimony in drinking water?

Organization or regulation	Value	Interpretation
World Health Organization	20 µg/L	Health-based guideline value for antimony in drinking water.
European Union – Directive (EU) 2020/2184	10 µg/L	Mandatory parametric value for water intended for human consumption.
France	10 µg/L	Quality limit aligned with the European regulatory framework.
United States – EPA	6 µg/L	Maximum Contaminant Level and health goal set at 0.006 mg/L.
Canada	6 µg/L	Maximum acceptable concentration for total antimony.
Australia	3 µg/L	National health-based guideline value.

Values differ between organizations due to toxicological choices, uncertainty factors, exposure assumptions, and treatment capabilities. For water distributed in France, the regulatory reference to be used is 10 µg/L.

How to analyze antimony in water?

Antimony is generally measured by Inductively Coupled Plasma Mass Spectrometry (ICP-MS), Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES), or atomic absorption with a graphite furnace.

Regulatory compliance is usually based on total antimony, including both the dissolved and particulate fractions. Sb(III)/Sb(V) speciation requires more specialized methods and an adapted preservation protocol.

use a container provided or approved by the laboratory;
follow the acidification and preservation instructions;
specify whether total or dissolved antimony is being sought;
optionally compare a first-draw sample with water after flushing;
also analyze for arsenic, lead, copper, iron, and manganese if the source is unknown;
have any value near or above the regulatory limit confirmed.

A speciation analysis must be interpreted with caution, as Sb(III) and Sb(V) can transform during sampling, storage, or sample preparation.

What technologies can reduce antimony?

Coagulation and filtration

Iron-based coagulants can promote the adsorption of antimony onto the formed hydroxides, followed by its removal via sedimentation and filtration. Effectiveness depends notably on the Sb(III) or Sb(V) form, pH, and dosage.

Adsorption onto metal oxides

Iron, aluminum, or manganese oxides and hydroxides can adsorb antimony. Performance varies depending on the medium, pH, competing ions, and speciation.

Reverse osmosis

Reverse osmosis is considered a potentially effective technology at the residential scale. However, performance must be verified by analysis before and after treatment.

Nanofiltration

Some nanofiltration membranes can reduce anionic species, but the result depends on the membrane charge and water composition.

Ion exchange

Anionic or selective resins can retain certain forms of antimony, notably Sb(V). The presence of sulfates, nitrates, and other anions can reduce useful capacity.

Distillation

Distillation can reduce non-volatile antimony, provided the system is properly designed, maintained, and protected against droplet carryover.

Ultrafiltration

Ultrafiltration alone primarily retains the particulate or colloidal fraction. For dissolved antimony, it is more effective when preceded by coagulation or adsorption.

Health Canada indicates that no residential units were specifically certified for the removal of antimony at the time of publication of its 2024 technical document. Analysis before and after treatment is therefore essential.

How to evaluate a filter's performance for antimony?

A general "heavy metals" claim does not allow for the conclusion that antimony is reduced. It is necessary to have a test where this contaminant is named and measured.

Element to verify	Why is it important?
Total or specified form of antimony	Performance can differ between Sb(III), Sb(V), and the particulate fraction.
Inlet concentration	It must be representative of the water to be treated.
Outlet concentration	It verifies compliance with the regulatory value.
Volume treated	An initial result does not demonstrate effectiveness throughout the entire service life.
pH and water composition	They influence adsorption, ion exchange, and membrane rejection.
Flow rate and contact time	A flow rate that is too high can reduce the performance of adsorbent media.
Laboratory and analytical method	They determine the reliability and detection limit of the result.

The performance of a filtration system must be evaluated based on specific tests conducted by its manufacturer. In the absence of published results concerning this contaminant, no numerical reduction can be claimed.

The most relevant verification involves having the water analyzed before and after the device under actual conditions of use, and then repeating the check as the media approaches the end of its advertised service life.

Consult Monderma certifications and analyses

Frequently asked questions about antimony in water

Is antimony dangerous in water?

Excessive chronic exposure can primarily affect the liver and the digestive system. This is why antimony is subject to health-based values in drinking water.

What is the European limit?

The European directive sets a parametric value of 10 µg/L for antimony in water intended for human consumption.

What is the WHO value?

The WHO uses a guideline value of 20 µg/L. National or regional regulations may adopt a lower value.

Can antimony be detected by taste?

No. Regulatory concentrations are too low to be identified by taste, odor, or color.

Does antimony always come from industrial pollution?

No. It can also be naturally present in certain geological formations. An analysis of the resource and the local context is necessary.

Can pipes release it?

Certain solders and alloys can contribute to its presence, especially after stagnation. However, this source is generally limited.

Do plastic bottles contain antimony?

Antimony compounds can be used as catalysts in the manufacture of PET. A slight migration may occur, especially with heat and prolonged storage.

Does boiling water remove antimony?

No. Boiling is not a reliable treatment and can concentrate non-volatile substances if part of the water evaporates.

Does a sediment filter remove antimony?

It may retain the fraction associated with particles, but not necessarily dissolved antimony.

Does activated carbon remove antimony?

Standard activated carbon offers no specific guarantee. Effectiveness depends on the media, any potential modification, and the chemical form of the antimony.

Is reverse osmosis effective?

It is considered a potentially effective technology, but the actual reduction must be verified for the device in question.

What analysis should be requested?

For regulatory testing, request total antimony. Sb(III)/Sb(V) speciation analysis is reserved for specialized investigations.

What to do if the result exceeds 10 µg/L?

Have the result confirmed, identify the source, follow the health authority's guidelines, and use alternative drinking water if recommended.

Can antimony be associated with arsenic?

Yes. Both elements can be present in similar ores and share certain mobility and adsorption mechanisms.

Is antimony carcinogenic via ingestion?

Health Canada considers that the overall weight of evidence does not support classifying antimony and its compounds as carcinogenic via the oral route. Some classifications pertain primarily to occupational inhalation.

Associated contaminants

Antimony can be associated with other metalloids and metals present in ores, distribution networks, and corrosion deposits.

Arsenic Lead Cadmium Iron Manganese Copper Nickel Zinc

Scientific and administrative sources

This factsheet is based on public organizations, regulatory texts, and government scientific databases. No commercial blog or affiliate site is used as a primary health source.

World Health Organization – Antimony Official factsheet dedicated to the presence, health effects, analysis, and treatment of antimony in drinking water.
Consult the official WHO factsheet
WHO – Thematic page dedicated to antimony Reference documents and history of recommendations.
Consult the WHO thematic page
European Union – Directive (EU) 2020/2184 Parametric value of 10 µg/L for antimony.
Consult the directive on EUR-Lex
Légifrance – Order of January 11, 2007 Quality limits and references applicable in France for water intended for human consumption.
View the text on Légifrance
Environmental Protection Agency – Antimony U.S. MCL and MCLG set at 0.006 mg/L.
View EPA regulations
Health Canada – Technical document on antimony Maximum acceptable concentration of 0.006 mg/L and detailed summary of health, analytical, and treatment data.
View the Health Canada document
PubChem – Antimony Official data on the identity, properties, and compounds of antimony.
View the PubChem record
Monderma – Certifications and laboratory analyses Reports and information available regarding the performance of Monderma filtration systems.
View Monderma certifications and analyses

Health disclaimer: this fact sheet is provided for informational purposes only. It does not replace a laboratory analysis, the recommendations of the competent health authority, or the advice of a healthcare professional. In the event that regulatory limits are exceeded or if well contamination is suspected, confirm the results and use water that complies with the recommendations of the competent authorities.