Community Gardens

The Community Gardens project offers resources for garden managers, Extension agents, and Master Gardeners to identify, understand, and manage risks associated with soil contaminants that may be present in garden soils.

Soil Contamination Basics

What are soil contaminants?
Soil contaminants are naturally occurring or human-made chemicals in soil that can have a negative impact on human and/or environmental health. Exposure is typically low, but gardeners can be exposed to soil contaminants through direct skin contact with the soil, inhaling or ingesting soil particles, and by eating contaminated produce. Exposure to high enough levels of soil contaminants over a long period of time can impact health, especially for children.

Where do soil contaminants come from?
Soil contaminants can occur naturally in soils or be introduced by past or current human activities. Industrial land use, lead paint use, traffic pollution, runoff, and several other sources can introduce contaminants into nearby soils. Some pollutants can persist in soils for years or even decades after they are introduced.

Do I need to test for soil contaminants?
Maybe. Typical soil nutrient testing (like the testing services offered by NCSU Cooperative Extension) do not include any tests for possible soil contaminants. This Quiz can help garden managers identify nearby sources of contaminants and whether additional testing for soil contaminants may be necessary.

How can I limit or reduce my exposure to garden soil contaminants?
Unless your soil is heavily contaminated and requires clean-up, there are easy steps that can be taken to minimize exposure to lower levels of soil contaminants. Healthy Garden Habits are especially important for children, pregnant women, or those with preexisting health conditions who are spending time in your garden as they may be more susceptible to the health impacts of contaminants.


Some contaminants like lead, arsenic, and human-made chemicals can be introduced into soils from nearby sources of pollution and may remain in the soil for long periods of time. There is a higher chance of soil contamination in gardens located on land that was previously used for another purpose or located near older buildings, and some soils maybe high in arsenic or other metals due to the natural geology of the area.


Unfortunately, soil nutrient testing (like the services offered by Agricultural Extension) do not test for soil contaminants, and so gardeners are often unaware of the presence of soil contaminants. The Community Gardens project offers resources for garden managers to identify, understand, and manage risks from soil contaminants that may be present in garden soils.

Gardeners can come into contact with these contaminants by eating, touching, or breathing soil particles or contaminated produce, but this exposure is typically low compared to other sources of exposure. However, long-term contact with low levels of some contaminants can lead to illness. Some contaminants, like lead and mercury, also have the potential to affect the way children learn and develop.

Gardening is a fun and rewarding activity for all ages, and in most cases the risks from soil contaminants can be greatly reduced by adopting Healthy Garden Habits and smart garden management practices to limit exposure to soil contaminants.