Polychlorinated biphenyls (PCBs) are an example of toxic substances, as they are made up of chlorine, carbon and hydrogen and exude harmful properties such as endocrine disruption, carcinogenic effects and bioaccumulation in living organisms and the environment/ ecosystem. Toxins are chemicals produced naturally by living organisms that can pose a potential danger to the ecosystem, especially its living populations. An example of a toxin is the venom produced by snakes and spiders. It is important to note that toxins and chemicals are not the same thing. All chemicals are NOT toxins, but all toxins are chemicals. Toxic substances are chemicals that enter the environment through anthropogenic activities. Toxic substances are often characterized as “man-made.” Herbicides are a good example of a toxic substance, as they are harmful chemicals used to eliminate the presence of unwanted plant growth and are introduced into the environment by humans, usually farmers and agricultural workers. Poisons are chemicals that can cause harmful effects in the biological system of its host, following exposure. Again, possible hosts include the environment, humans, plants, animals, and other biotic factors in the ecosystem. All chemicals could potentially be classified as poisons, as the term goes