Environmental Contaminants

Contaminants are common in many environments, even in soils and dusts, and are generally safe. However, certain metals and other elements are dangerous when they accumulate, especially where we live, eat, or play.

The table below indicates the accepted levels of soil contamination from several authoritative bodies. Click on the column headers for each published source. Look below the table for descriptions of the sources and effects of each metal and metalloid in the table.

Element (mg/kg)	Australia NEPC (2013) Residential A	Australia NEPC (2013) Residential B	Australia NEPC (2013) Recreational C	California CEPA (2005)	Canada CCME (2013)	Norway NPCA (2009)	United States EPA (2019)
Lead	300	1200	600	80	140	90	400
Barium	-	-	-	5200	500	-	15000
Copper	6000	30000	17000	3000	63	150	3100
Manganese	3800	14000	19000	-	-	-	1800
Chromium VI	100	500	300	17	0,4	75	0,3
Cadmium	20	150	90	1,7	10	12,2	71
Nickel	400	1200	1200	1600	50	90	1500
Zinc	7400	60000	30000	23000	200	300	23000
Arsenic	100	500	300	0,07	12	12	0,68

Except for barium, this table was compiled by Professor Mark Taylor and Marek Rouillon at Maquarie University. Click here for the original table.

Residential A- with garden/accessible soil (home-grown produce <10% fruit and vegetable intake (no poultry), also includes childcare centers, preschools, and primary schools.
Residential B - with minimal opportunities for soil access; includes dwellings with fully and permanently paved yard space such as high-rise buildings and apartments.
Residential C - Public open space such as parks, playgrounds, playing fields (e.g. ovals), secondary schools and footpaths

Metals

Lead

Lead (Pb) occurs naturally in the environment in small amounts, but leaded gasoline, lead-based paint, and industrial pollution have all artificially increased lead levels in soil, especially in urban centers.

Lead is toxic when it is inhaled or ingested. It accumulates in bones and is distributed throughout the blood and most organ systems, including the brain. Especially in the still-developing brains of young children, lead is mistaken for calcium, but it is a poor substitute and impairs communication between neurons.

Even low levels of lead exposure in childhood can result in reduced IQ, attention span, and impulse control and increased antisocial behavior. People who experience childhood lead poisoning make less money over their lifetime and are more likely to be incarcerated than their peers.

https://www.atsdr.cdc.gov/substances/toxsubstance.asp?toxid=22

Barium

Barium (Ba) is found in small amounts in the natural environment. It is also used in several compounds used by a variety of industries.

Symptoms of acute barium poisoning include abdominal cramps, vomiting, diarrhea, and abnormal blood pressure and heart rhythm. Typically, only people who work in industries making or using barium compounds are at a significant risk of acute barium poisoning. Research has yet to determine if there are any health effects of chronic exposure to low levels of barium.

https://www.atsdr.cdc.gov/substances/toxsubstance.asp?toxid=57

Copper

Copper (Cu) is a naturally-occurring element and an essential nutrient for humans in trace amounts. It is artificially amplified in the environment in a number of ways, including through bake dust from the wearing of the brake pads of cars.

Chronic exposure to high levels of copper can result in liver damage or failure, but this is rare.

https://www.atsdr.cdc.gov/substances/toxsubstance.asp?toxid=37

Manganese

Chromium

Like many other heavy metals, concentrations of naturally-occurring chromium (Cr) are artificially increased by industry. Chromium exists in several different forms, including relatively nontoxic Cr(III) and toxic Cr(VI), also called hexavalent chromium. In the United States, roughly a third of atmospheric chromium emissions are of this toxic hexavalent form.

People who work in industries that use chromium face the greatest exposure, but for the majority of the population that isn't occupationally exposed, the greatest source of intake is from foods that contain chromium. Dietary sources include produce grown in chromium-contaminated soils and fish and meat that have accumulated chromium from their diet.

Chromium exposure is known to cause cancer, and it can also cause damage to the eyes, skin, and respiratory system.

https://www.atsdr.cdc.gov/substances/toxsubstance.asp?toxid=17

Cadmium

Cadmium (Cd) naturally occurs in minerals in conjuncture with elements such as oxygen, sulfur, and chlorine. Cadmium exposure can be the result of breathing cigarette smoke, consumption of contaminated food, and misuse of nickel-cadmium batteries. Food is the most significant source of Cd exposure in non-smokers.

Cadmium exposure through ingestion will cause vomiting and diarrhea. Breathing high levels of cadmium at once is lethal. Long-term exposure to cadmium through breathing cigarette smoke or repeated ingestion of contaminated food will cause kidney damage, bone damage leading to fractures, and some types of cancer.

https://www.atsdr.cdc.gov/substances/toxsubstance.asp?toxid=15

Nickel

Nickel (Ni) is a very abundant, naturally occurring element found in water and soil, but excessive soil contamination can be caused by proximity to industrial exhaust.

Nickel exposure can occur when consuming food grown in contaminated soil, drinking water with high levels of nickel, and breathing cigarette smoke containing nickel, and working in an industry that regularly handles nickel.

Approximately 10-20% of people are allergic to nickel and will develop a skin rash upon contact. Some allergic reactions will also have asthma attacks or develop reactions when eating, drinking, or breathing nickel. People who regularly work with and are exposed to high levels of nickel can develop kidney and blood damage from eating or drinking nickel and chronic bronchitis, decreased lung function, and some types of cancer from breathing nickel.

https://www.atsdr.cdc.gov/substances/toxsubstance.asp?toxid=44

Zinc

Zinc (Zn) is naturally very common in the Earth's crust, and as a result is also commonly found in food, water, air, and soil. It is also commonly used to create rust-resistant coatings, dry-cell batteries, and pennies (US currency).

Excessive exposure to zinc mainly occurs in humans due to the consumption of contaminated vegetables, which in turn incorporated zinc due to contaminated soil or waste-water irrigation. Excessive exposure can also occur in people who regularly work with it in industrial work.

High zinc exposure can cause damage to people's gastrointestinal system, blood, and respiratory system.

https://www.atsdr.cdc.gov/substances/toxsubstance.asp?toxid=54

Metalloids

Arsenic

Arsenic (As) can occur naturally in organic and inorganic forms in soil, sediments, and groundwater. It can also occur artificially as a result of mining, ore refining, and the waste of industrial arsenic use.

Inorganic arsenic is mainly incorporated into the body through food and water intake. Some groundwater has naturally higher levels of arsenic.

High doses of inorganic arsenic can cause various gastrointestinal issues and shock. Long-term arsenic exposure can be responsible for skin lesions, increased risk of diabetes, high blood pressure, and some cancers.

https://www.atsdr.cdc.gov/substances/toxsubstance.asp?toxid=3