Top Worst Forms of Pollution For everything we take from the Earth, there is a byproduct or consequence. Perhaps pollution is a symptom of nature's imbalance. Some people reap from the Earth, but countless others become sick, displaced or harmed due to the resulting pollution — affecting wildlife and more. On the off chance that a guilty conscience is an unknown symptom of overexploitation, here's a list of the 10 worst forms of pollution and their effects on humans. Oil spills In the wake of the Gulf oil spill, the harmful effects of marine oil spills are obvious. Birds, fish and other marine life can be devastated from a spill, and the ecosystems often take decades to recover. The oil is ingested by some animals, allowing pollutants to enter the food chain, harming fisheries and other industries in the region. Many people don't realize that most oil pollution actually comes from land-based activity. One way or another, oil has seeped into nearly all of Earth's ecosyst