Is Barley High in Heavy Metals? Understanding Contamination and Safety

December 4, 2025 •

4 min read

Research in Ethiopia found that the concentration of heavy metals like lead and cadmium in locally grown barley can, in some cases, exceed safe levels set by the FAO/WHO. The question of whether barley is high in heavy metals requires a nuanced understanding of environmental factors, agricultural practices, and the plant's unique biology.

Quick Summary

Barley's heavy metal content is not inherently high but is influenced by external factors like soil quality and irrigation water. The risk of contamination varies geographically, and regulatory standards help ensure safety for consumers. The grain's processing can also impact heavy metal levels.

Key Points

Source of Contamination: Barley's heavy metal levels are primarily dependent on environmental factors, such as contaminated soil, polluted irrigation water, and atmospheric pollution.
Cadmium and Lead Levels: While barley typically has low lead levels, and generally lower cadmium levels than wheat, contamination can occur in polluted areas.
Accumulation Varies by Crop: Comparative studies show barley is generally a less effective accumulator of arsenic in its grain compared to oats, indicating selective uptake.
Agricultural Management: Practices like soil pH management, avoiding contaminated water sources, and carefully selecting fertilizers can minimize heavy metal uptake by barley.
Consumer Safety Measures: Consumers can minimize heavy metal exposure by sourcing barley from reputable suppliers and through food preparation methods like malting and washing.
Processing Impact: Malting has been shown to reduce surface contamination of heavy metals like cadmium and lead in barley, potentially lowering overall levels in the final product.

Sources of Heavy Metal Contamination in Barley

Heavy metal accumulation in barley is not a random process but is directly linked to its growing environment. The primary sources of this contamination are agricultural inputs and environmental pollutants.

Contaminated Soil and Water

Soil contamination: Agricultural land can become contaminated through the long-term application of certain chemical fertilizers, pesticides, and livestock manures, which can contain trace amounts of heavy metals like cadmium (Cd), lead (Pb), and arsenic (As). For instance, a study noted that phosphate fertilizers often contain cadmium impurities, which can build up in the soil over time.
Wastewater irrigation: In some regions, agricultural lands are irrigated with urban wastewater that contains heavy metals from industrial and municipal waste. This practice can lead to a significant uptake of metals by plants. One study found that barley irrigated with treated wastewater had cadmium and lead levels higher than WHO permissible limits.
Atmospheric deposition: Proximity to industrial sites, heavy traffic, and other sources of pollution can deposit heavy metal particles onto the soil and plant surfaces.

Other Factors Influencing Uptake

Several other factors beyond the source of contamination affect how much heavy metal a barley plant absorbs and translocates to its grain:

Soil pH: Lower, more acidic soil pH increases the bioavailability of many heavy metals, including cadmium, making them more easily absorbed by the plant's roots.
Barley variety: Different cultivars and varieties of barley exhibit varying abilities to absorb and accumulate heavy metals. Some varieties are more efficient at preventing metals from reaching the grain, while others may accumulate higher concentrations.
Plant growth stage: The uptake and accumulation of heavy metals can vary at different stages of the plant's life cycle.

The Accumulation of Specific Heavy Metals

Barley's accumulation of heavy metals is selective, with some metals being more readily absorbed than others.

Cadmium (Cd) and Lead (Pb)

While barley typically has low concentrations of lead, some studies have found levels exceeding maximum permissible limits in certain contaminated areas. The accumulation of cadmium varies by cultivar, but researchers found that barley generally accumulates less cadmium in its grain than wheat under comparable soil conditions. Cadmium and lead are particularly concerning due to their toxicity and tendency to accumulate in the body over time.

Arsenic (As)

Studies comparing barley and oats have shown that barley is generally a less effective accumulator of arsenic in its grain. Arsenic is primarily taken up in the roots, with lower translocation to the grain.

Beneficial Metals (Copper and Zinc)

Barley naturally contains essential trace minerals like copper (Cu) and zinc (Zn). However, if these metals are present at high concentrations in the soil due to excessive fertilizer application or other pollution, the barley can accumulate them to levels that exceed safe limits.

Comparison of Heavy Metal Accumulation in Cereal Grains

Not all cereal grains absorb and store heavy metals in the same way. The following table compares the accumulation of some key heavy metals in different grains.


Feature	Barley	Oats	Rice	Wheat
Arsenic Accumulation	Low accumulation in grain.	Higher accumulation in grain than barley.	High accumulator, especially in flooded conditions.	Relatively low accumulation.
Cadmium Accumulation	Generally lower in grain than wheat.	Accumulation varies by growth conditions.	Can accumulate significant levels depending on variety.	Accumulates higher levels in grain than barley.
Lead Accumulation	Low accumulation in grain.	Can show higher accumulation in leaves and roots in contaminated areas.	Accumulates lead, though mechanisms differ from barley.	Accumulates lead, but usually at low concentrations.
General Takeaway	Lower risk for As, Cd, and Pb in grain compared to some other cereals under similar conditions.	Better accumulator of As than barley, but varies by growth condition.	Known for higher As and Cd accumulation in grain depending on variety and water management.	Often accumulates more cadmium than barley.

Minimizing Your Exposure to Heavy Metals from Barley

For consumers, it is possible to take steps to minimize the intake of heavy metals when consuming barley products.

Choose Responsibly Sourced Products

Look for barley and other grains from reputable sources that adhere to strict food safety regulations and monitor heavy metal levels in their crops. When possible, choose products grown in regions with a low risk of soil or water contamination. Certified organic products often undergo testing for contaminants, though this is not a universal guarantee of zero heavy metals.

Processing and Preparation

Studies suggest that malting barley can reduce certain heavy metal concentrations, such as cadmium and lead, as much of the contamination is found on the surface of the grain. Thoroughly rinsing or washing barley before cooking may also help remove some surface-level contamination. Incorporating high-fiber foods into your diet can help bind heavy metals in the digestive tract and aid in their elimination from the body.

A Balanced Diet is Key

Diversifying your diet with a variety of grains, fruits, vegetables, and other foods can reduce your exposure to heavy metals from a single source. A balanced diet also ensures that you receive a wide range of essential nutrients, which can support the body's natural detoxification processes.

Conclusion

While studies confirm that barley can accumulate heavy metals from contaminated soil and irrigation water, the extent of contamination is not inherent to the crop itself but rather depends heavily on its growing environment and agricultural practices. In general, barley accumulates lower levels of potentially toxic metals like cadmium and arsenic in its grain compared to some other common cereals like wheat and rice. Choosing barley from responsible sources, utilizing proper washing techniques, and maintaining a balanced diet are effective strategies for minimizing potential exposure and ensuring the safety of your food. The safety of consuming barley is determined more by the conditions under which it was grown rather than by an inherent property of the grain.

Frequently Asked Questions

No, not all barley contains high levels of heavy metals. A barley plant's heavy metal content is largely determined by its growing environment, specifically the quality of the soil and water used for irrigation.

The most concerning heavy metals found in contaminated barley are cadmium and lead, as these are the most common environmental contaminants that plants absorb. However, other metals like arsenic, copper, and zinc can also accumulate to unsafe levels in polluted environments.

Studies suggest that barley grain may accumulate lower levels of certain heavy metals, such as cadmium and arsenic, compared to other cereals like wheat and rice, under similar growing conditions. However, the safety of any grain depends on its specific source and growing environment.

While washing barley thoroughly can help remove some surface-level contaminants, it cannot eliminate heavy metals that have been absorbed into the grain from the soil. However, some processing techniques, like malting, have shown to reduce levels of surface contamination.

Farming practices significantly affect heavy metal levels. The use of contaminated irrigation water, application of certain chemical fertilizers and pesticides, and managing soil pH are all factors that influence how much heavy metal is available for the plant to absorb.

Soil pH is a critical factor. Heavy metals are more soluble and bioavailable to plants in acidic soils (low pH). Liming, or increasing soil pH, is a common practice to reduce the uptake of heavy metals by crops.

Yes, regulatory bodies like the World Health Organization (WHO) and regional food safety authorities, such as the European Food Safety Authority (EFSA), set maximum permissible limits for various heavy metals in food products to ensure consumer safety. It is important for food producers to regularly monitor and adhere to these standards.