ENVIRONMENTAL POLLUTION

Environmental pollution

ENVIRONMENTAL POLLUTION

Environmental pollution is defined as the undesirable change in physical, chemical and biological characteristic of our air, land and water. (Arias et al., 2008) As a result of over population, rapid industrializations, and other human activities like agriculture and deforestation etc, the earth has become loaded with diverse pollutants. According to the US EPA   (1995), pollutants are generally grouped into two classes.

(a) Biodegradable pollutants: These are the pollutants that can be broken down by the activity of micro-organisms and which subsequently enter into the biogeochemical cycles. Examples of such pollutants are domestic waste products, urine and feacal matter, sewage, agricultural residue, paper, wood, cloth e.t.c.

(b) Non-biodegradable pollutants: Non-biodegradable pollutants generally have stronger chemical bonds and do not break down into simpler and harmless product. These include various  pesticides and compounds containing different heavy metals such as Pb, Hg and As,  other non-biodegradable are plastics, radioactive waste etc. (Hallenbeck, et al., 1985).

PROBLEMS OF PERSISTENT PESTICIDE POLLUTION 

Persistent organic pesticides are a set of toxic chemicals that do not break down easily in the environment and as such are able to last for several years before breaking down.
Persistent organic pesticides circulate globally and chemicals released in one part of the world can be deposited at far distance from their original source through a repeated process of evaporation and deposition. (Arias, et al., 2008)

This makes it very hard to trace the original source of the chemical. Persistent organic pesticides are philippic, which means that they accumulate in the fatty tissue of living animals and human beings,in these tissues, the concentration can become magnified by up to 70,000 times higher than the background levels. (Bradbury, et al., 1989).

As you move up the food chain, concentrations of persistent organic pesticides tend to increase so that animals at the top of the food chain such as fish, predatory birds, mammals and humans tend to have the greatest concentration of these  chemicals, in their bodies and therefore are also at the highest risk from acute and chronic toxic effects. (UNEP, 2003)

EFFECTS OF PERSISTENT ORGANIC PESTICIDES

Persistent organic pesticides are highly toxic and exposure can take place through diet, environmental exposure, or accidents. They negatively affect humans, plants and animal species and natural ecosystems both in close proximity and at significant distances away from the original source of discharge. (Dupont et al., 1989)

Exposure to persistent organic pesticides in humans can cause several negative health effects including death, cancers, allergies, hypersensitivity and developmental changes (U.S EPA 2008). Other problems associated with the exposure to these group of chemicals are; damage to the central and peripheral nervous systems, Disruption of the endocrine, reproductive and immune systems. (UNEP, 2003)

A study published in 2006 suggests that an increased level of persistent organic pesticide in human blood serum can be linked to Diabetes (Lee et al., 2006).
According to the U.S Environmental Protection Agency (EPA) there are links between persistent organic pesticide’s exposure and the increased frequency of diseases and / or abnormalities in wildlife species, including certain kinds of fish, birds and mammals. (U.S EPA, 1988).

The negative effects of pesticides in the marine and coastal environments include changes in reef community structure, such as decreases in live coral cover and increases in algae and sponges and damage to seagrass beds and other aquatic vegetation from herbicides. (Lee et al.,2006) Persistent organic pesticides are chemicals that were developed to kill insect or weed pests that threaten agricultural or forest crops. Some pesticides, when thedy are exposed to sunlight and rain, quickly break down into less toxic materials. ‘’Persistent” pesticides however are those that do not break down in the environment, but remain toxic to fish, animals and humans for many years. (Bradbury, et al., 1989).