Industrial sites mean any type of industry from big manufacturer plants to small enterprises which produce, use, and/or store chemicals. At such sites, the polluting chemicals may be released into the environment during normal operation as well as through accidental spills and leaks. Once released, the chemicals travel in the vicinity areas by various means (including air, dust, and/or water) and may cause pollution issues.
The most common chemicals handled at most industrial sites are a group of chemicals generically called chlorinated solvents. These are organic chemicals that do not form naturally. They consist of carbon, hydrogen, and Cl (usually from 1 to 4 chlorine atoms).
There are several chlorinated solvents with most common use including:
Chlorinated solvents are volatile compounds, which means that they volatilize (partially changes to a gaseous form and gets released into the air) under normal temperature and pressure conditions. Additionally, they may bind to the organic matter from soil particles (the higher the organic matter, the higher the amount of chlorinated solvents bound to it). In water, these chemicals have enough solubility to dissolve in excess of their risk-free values (recommended by various regulatory agencies). These compounds are also heavier (denser) than water and thus tend to migrate vertically to deeper depths than other pollutants (such as petroleum hydrocarbons for example) and may create pools entrapped in subsurface – which act as a continuous release source. An important characteristic of chlorinated solvents is their ability to resist biodegradation / degradation. All these characteristics, make chlorinated solvents very problematic to the environment, since they may be transported in various ways and persist for decades.
Some of the types of enterprises that may be factors of pollution are foundries, chemical plants, landfills, airports and harbors, mines, manufacturing plants, foundries and even convenience stores.