How Aluminium Hydroxide Affects the Environment

Aluminium hydroxide isn’t just a medication you swallow for heartburn. It’s also in your toothpaste, your antiperspirant, your vaccines, and the chemicals used to clean your local wastewater. But what happens when all that aluminium hydroxide ends up in rivers, soil, or the air? Most people never think about it-until they see a lake with strange white sediment or hear that fish are disappearing from a stream near a factory.

Where aluminium hydroxide comes from

Aluminium hydroxide, or Al(OH)₃, is a white, powdery compound made by reacting aluminium salts with alkalis. It’s cheap, stable, and non-toxic to humans at low doses-which is why it’s used in everything from antacids to flame retardants. But its environmental footprint starts long before it reaches your medicine cabinet.

Most aluminium hydroxide comes from the Bayer process, which extracts aluminium from bauxite ore. This process generates millions of tons of red mud every year-a toxic sludge packed with heavy metals and residual aluminium compounds. In 2023, global bauxite mining produced over 400 million tons of red mud. Only a fraction of it is safely stored; the rest leaks into groundwater or gets washed into rivers during heavy rains.

How it enters water systems

Wastewater treatment plants use aluminium hydroxide to remove phosphorus and suspended solids. It binds to pollutants and sinks to the bottom as sludge. That sounds helpful-until you realize that sludge often gets spread on farmland as fertilizer. In the UK alone, over 1.2 million tons of sewage sludge are applied to agricultural land each year. Studies from the University of Birmingham in 2024 found aluminium levels in these soils increased by 18% over five years, especially near urban runoff zones.

When rain hits these fields, aluminium hydroxide dissolves slightly and flows into nearby streams. Unlike natural aluminium, which is tightly bound to soil minerals, the aluminium from industrial sources is more soluble and bioavailable. That means aquatic life absorbs it more easily.

Effects on aquatic ecosystems

Aluminium hydroxide itself isn’t deadly to fish-but its breakdown products are. In acidic water (pH below 5.5), aluminium hydroxide breaks down into aluminium ions (Al³⁺). These ions coat fish gills, suffocating them by blocking oxygen exchange. A 2023 study in Norway’s River Glomma showed a 62% drop in trout populations in areas where aluminium levels exceeded 0.1 mg/L. That’s below the EU’s safety limit of 0.2 mg/L for drinking water, but deadly for sensitive species.

Aluminium also disrupts plankton and algae, the base of the aquatic food chain. Research from the University of Brighton in 2025 found that even low concentrations of aluminium hydroxide reduced phytoplankton growth by 30% in lab conditions. That’s not just a numbers game-it means fewer insects, fewer small fish, and eventually, fewer birds and mammals that depend on them.

Soil damage and plant growth

Plants don’t need aluminium. In fact, most crops-including wheat, potatoes, and beans-are highly sensitive to it. Aluminium hydroxide in soil lowers pH and releases toxic aluminium ions that attack root tips. Roots stop growing, plants can’t take up water or nutrients, and yields drop.

Fields near aluminium refineries in Brazil and Australia have seen up to 70% crop failure in aluminium-rich zones. Even in the UK, soil tests in East Sussex showed aluminium concentrations above 100 mg/kg in areas where sewage sludge had been applied for over a decade. That’s above the EU’s recommended threshold of 80 mg/kg for sensitive crops.

Some plants, like blueberries and rhododendrons, actually prefer acidic soil-but even they struggle when aluminium spikes too high. In one garden experiment in Sussex, blueberry bushes planted in soil treated with aluminium hydroxide-based sludge produced 45% fewer berries than those in untreated soil.

Airborne aluminium and dust

Aluminium hydroxide isn’t just a water problem. When it’s used in fireproofing materials or industrial powders, fine dust can become airborne. In factories in Germany and Poland, workers are exposed to aluminium hydroxide particles daily. But the bigger concern is wind-blown dust from storage piles and waste sites.

A 2024 air quality study near a Bayer plant in Greece found aluminium hydroxide dust particles up to 15 km downwind. While not immediately toxic, these particles settle on leaves, blocking sunlight and reducing photosynthesis. In urban areas, they mix with other pollutants and contribute to smog formation.

What’s being done-and what’s not

Some countries are trying to fix this. The Netherlands banned the land application of aluminium-based sludge in 2022. Sweden now requires wastewater plants to recover aluminium from sludge before disposal. In the UK, the Environment Agency has started monitoring aluminium levels in 37 high-risk rivers, but there’s no national limit for aluminium in agricultural soils.

Companies are also exploring alternatives. Magnesium hydroxide is gaining traction in wastewater treatment because it’s less harmful to aquatic life. In vaccines, some manufacturers are switching to adjuvants like squalene or polysorbate 80. But these alternatives are more expensive-and aluminium hydroxide is still the default choice in most places.

What you can do

You won’t stop aluminium hydroxide pollution by refusing antacids. But you can push for change. Ask your local council: Where does our sewage sludge go? Is it being tested for aluminium? Support policies that ban sludge dumping on farmland and fund recycling tech for industrial waste.

At home, reduce your use of products with aluminium hydroxide. Check labels on antiperspirants, toothpaste, and sunscreens. Look for brands that use zinc oxide, titanium dioxide, or natural clay instead. Small choices add up.

Aluminium hydroxide isn’t evil. It’s a useful chemical that helps people every day. But like any tool, it becomes dangerous when used carelessly. The environment doesn’t have a voice-but we do. And if we don’t start asking the right questions, the next generation will inherit a world where rivers run white and soil can’t grow food.