Examples of soil pollutants are toxic chemicals, pesticides, lead, sewage and metals. Others include acid, solvents and herbicides. Leftover ash can get in the ground through coal production and disposal.
Pesticides are used to eradicate insects that damage crops, but the leftover chemicals can stay in the soil for decades. These chemicals remain in the ground because the elements contained within fail to break down. For instance, the pesticide DDT has been found in the soil 40 years after its application. Traces of these chemicals can be found in plants, and residue can get onto pets and into homes.
Industrial pollutants in the form of lead and solvents are also not biodegradable. These are leftover byproducts from manufacturing centers. One example is dioxin, a common industrial hazard that is a leftover remnant when waste products are incinerated. These toxins also escape into the air and end up in the soil when rain water lands on the ground.
Acid rain is a prime example of a hazardous chemical that seeps into the ground. Acid rain is caused by natural occurrences, such as volcanic activity, but certain industries can also cause this phenomenon. For example, the fossil fuel industry can create acid rain. Acid rain contains high amounts of sulfur and nitrate, which are acids that destroy nutrients and minerals in the ground that plants and trees need to survive.