Environmental Pollutants

What are Toxicants and Toxins?

Compounds that produce adverse health effects fall under two classifications: toxicants and toxins. Both cause biochemical harm in different ways.


Toxicants (toxic chemicals) are natural or artificial products introduced into the environment through human activity (anthropogenic) or natural events. Examples are industrial waste products, pesticides, carcinogens (e.g., asbestos), and volatile organic compounds (VOCs). At PCS, we mainly handle environmental pollutants that are toxicants. 


Toxins are poisons produced from living cells or organisms, such as plants, animals, and bacteria. Examples of a toxin are poisonous mushrooms or venom transferred from a snake’s bite. Toxins can damage different bodily functions (e.g., hemotoxins in snakes can destroy red blood cells and necrotoxins produced in bacteria can destroy cells in tissues). 


Are children more susceptible to pollutants compared to adults?

Children generally eat more food, drink more water, and breathe more per pound than adults. This means that children have the potential for greater pollutant intake compared to adults. The metabolism and defense systems of children are also not fully developed, which increases their susceptibility to chemical exposures. In addition, children's bodies are growing and developing more rapidly; therefore, chemicals that harm developmental functions can be extremely damaging at this critical time. 

Since children are exposed to toxicants as early as conception, in-utero development may be affected by compounds that enter the mother's body via inhalation, ingestion, and/or dermal contact. Parents of infants and toddlers are challenged by children constantly putting their hands and other objects into their mouths. This creates a concern of ingesting pollutants, such as pesticides, heavy metals, allergens, and dust particulates. The small stature of children also exposes them to volatiles that are low lying or emitted from carpet or other flooring, as well as those condensed in dust. 

Where do the pollutants come from?

There are a variety of chemical contaminants from a variety of sources. These could be of natural origin or resulting from human activities. The primary source of human-made compounds is the chemical industry (e.g., industrial solvents, paints, adhesives, oil and petrochemical industries, household products, pesticides and fertilizers, fabric materials & furnishings). Regarding chemicals of natural origin, a good example are heavy metals that are present in the environment (e.g., arsenic, mercury, lead) apart from being the product of human processes. 

PCS Chemical Fact Sheets:

PCS Chemical Fact Sheets provide a summary of the properties on select chemicals. They cover basic information that is accessible to everyone. Currently, the fact sheets include chemical identity, where the chemical comes from, how we might be exposed to that chemical, potential health effects (signs and symptoms associated with exposures), and how we can reduce the exposure to that chemical. This basic information allows communities to be aware of the consequences of exposure to these chemicals. The list of environmental pollutants that produce adverse health effects is long. However, the following list contains chemicals that are common environmental pollutants, as well as pollutants that have the potential to be involved in emergency situations within Harris County: 

In the case of occupational exposure, fact sheets have more detailed information. They are very useful to comply with the "right to know principle," providing workers with information and training that ensures their awareness of the chemical hazards used in their work area.