What is a soil contaminant?

A soil contaminant is any substance that exceeds naturally occurring-levels and poses human health risks. The most risks occur in urban and former industrial areas. Common contaminants are heavy metals such as lead, pesticides, petroleum, and other substances from former human activity.

increasing soil lead concentration ranges

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Regional Educator ResourcesOther Educator ResourcesTechnical Resources
Title Source Resource type and Date Short Summary / Preview
Soil Contaminants
Soil Science Society of America Peer-reviewed webpage

Not Dated

A general website about soil contaminants from the Soil Science Society of America.
Assessing the Educational Needs of Urban Gardeners and Farmers on the Subject of Soil Contamination
Journal of Extension Peer-reviewed Publication

Feb 2013

This is about a survey done with urban farmers in the Kansas City area to ask what kinds of information they wanted. The conclusion is that they needed and wanted information on growing food crops on mildly contaminated soils.
Gardening on Lead-Contaminated soils Kansas State University Extension Publication

Jun 2017

An extension publication with details on the reasons why urban soils might have elevated lead levels, how to find if your soils contain lead, and information on what kinds of crops can and can’t be grown in soils with elevated lead content.
Urban Soil Testing Kansas State University How-to Video

Oct 2011

Ashley Harms, a research associate in the Department of Agronomy and Kansas State University, demonstrates how easy it is to collect some soil for testing.

Other Nutrients SARE Book Excerpt


Although farmers understandably focus on nitrogen and phosphorus—because of the large quantities used and the potential for environmental problems—additional nutrient and soil chemical issues remain important.
Zinc* Illinois Department of Public Health Governmental Webpage

Not Dated

Zinc is a metal that is normally found in small amounts in nature. It is used in many commercial industries and can be released into the environment during mining and smelting (metal processing) activities.

*indicates a focus on human health, not plant health.

Title Source Resource type and date Short Summary
Healthy Soils, Healthy Communities Metals in Urban Garden Soils Cornell University Extension/Government Fact sheet

Not Dated

Some metals, such as copper and zinc, are taken up by plants and can be toxic to plants (phytotoxic) at levels below guidance values protective of public health.
Home Gardens and Lead University of California University Fact Sheet

Sep 2010

Lead (Pb) is a heavy metal that occurs in low levels in all soils. Natural concentrations of lead in most soils range from 10 to 30 parts per million (ppm).
Lead in Garden Soils* University of Maryland Extension Fact Sheet


We don’t usually think of our gardens as dangerous or toxic, but unfortunately, some garden soils do contain moderate to very high levels of lead. Garden soils contaminated with lead pose a serious health risk.
Lead in Residential Soils: Sources, Testing, and Reducing Exposure Penn State Extension Extension Webpage

Sep 2010

Lead occurs naturally in soils, typically at concentrations that range from 10 to 50 mg/kg.
Soil Lead Fact Sheet University of Massachusetts Amherst University Fact Sheet

Dec 2019

Lead is naturally present in all soils. It generally occurs in the range of 15 to 40 parts lead per million parts of soil (ppm), or 15 to 40 milligrams lead per kilogram of soil (mg/kg). Pollution can increase soil lead levels to several thousand ppm. The major cause of soil lead contamination in populated areas is the weathering, chipping, scraping, sanding, and sand-blasting of structures bearing lead-based paint.

*indicates a focus on human health, not plant health.

Title Source Resource type and Date Short Summary
Zinc in Soil Environment for Plant Health and Management Strategy Universal Journal of Agricultural Research Peer-reviewed Publication


Under severe zinc deficiency, the shoot apices die (‘die-back’) as is widely distributed. Zinc toxicity leads to chlorosis in young leaves.

*indicates a focus on human health, not plant health.

Technical review: March 18, 2020