Introduction
Chemicals or substances in one way or another have been part of human life, maintaining many of the daily activities, controlling and preventing illnesses and improving the production in the agricultural field. However, if the utilization of these substances is not proper, they may have detrimental effects in our health and pollute the environment. All chemicals are harmful but the difference is in the degree harm that depends on the dosage. In simplicity, the level of harm that any chemical can cause on a person or an organism depends on the quantity of the chemical or the level of exposure. The effects or harm caused by the chemicals range from minor effects like irritation to effects that are more serious like kidney or liver damage to even more severe and lasting disability like liver cancer or liver cirrhosis. Toxicology refers to the study of the undesirable effects of substances on human beings or any other living organism. Individuals may be at risk due to exposure to different chemicals in their places of work or in the environment. The main aim of toxicology is to know the properties of chemicals that are lethal so that one can prevent and control the detrimental effects by the formation of suitable exposure or management guidelines (Schrager, n.d, par.1).
Main body
This paper criticizes an article that deals with toxicological applications, which are relevant to the occupational health and safety. As toxicology has developed into the current world of science, however, it has advanced to capture all types of detrimental health effects, which chemicals might produce that are extremely harmful and have fatal effects. Environmental and occupational diseases or illnesses are detrimental health effects, the incidence and severity is mostly associated with the period of exposure to the risk factors at the work place, or an environment that is not work related. Examples of occupational illness include memory loss, lung scarring, anemia, headache, abdominal pain, hearing loss and hepatitis B among others (Williams, James & Roberts, 2000, p.499).
Some of the substances that may have adverse effects both to the living things and the environment include; Dichlorodiphenyltrichloroethane (DDT), polychlorinated biphenyls (PCBs), some fungicides, herbicides and pesticides among others. The most devastating thing is that, though some of these substances have been prohibited by the developed countries because of the dangerous effects, some countries, organizations and agencies continues to advice people to use them. For instance, the United States prohibits the use of DDT because of its adverse effects on the environment and human health. However, the World Health Organization (WHO) supports the utilization of DDT for vector control for indoor residual spraying in malaria endemic countries like Africa (World Health organization, n.d, p.5). The various types of data that could assist one to re-assess the WHO policy based on the toxicology include; quantity of the DDT applied, individual exposure period to the chemical, effectiveness of the DDT, routes in which DDT may get into the body of the individuals and the time DDT may persist in the environment.
There are four phases of the disposition of toxic substances which include; absorption of the chemical into the system through the membranes, distribution into the system, metabolism within the system and excretion of the substance from the body system (Timbrell, 2000, p.35). DDT gets its way into the body through the following routes, eyes, dermal, inhalation, mouth and parenteral. The process of DDT absorption from the gastrointestinal tract is very slow. Research on the toxicity point out that the absorption of dissolved DDT found in vegetable or animal fats is approximately 1.5 than undissolved DDT. Distribution of DDT is in all tissues of the body some of which include, kidney, liver, blood, heart and the brain among others. However, higher DDT disposition is mostly in the adipose tissues. After DDT is absorbed into the tissues, de-hydro-chlorination changes it into toxic dichlorodiphenyldichloroethylene (DDE). However, DDE does not undergo further conversion but it persists in the adipose tissues. Excretion process of DDT from the body is very slow and it is about 1% of the DDT stored in the body in a day. Elimination of DDT from the body is through urine and human milk. DDT is not the real chemical that contributes to adverse effects but the DDE (International Programme on Chemical Safety, n.d, par.6).
Exposure to DDT can be either acute or chronic. Acute exposure is associated with the lesser semen limit in males, showing that there are undesirable effects on the testicular role and the reproductive hormones regulation. Chronic exposure to DDT either at work place or at general environment has led to infertility in men (Androl, 2006, par.1). Ingestion of DDT accidentally causes excitation of the central nervous system, including convulsions and tremors. Other responses include nausea, headache, vomiting, dizziness, memory loss, malaise, fatigue, skin lesion and tumors. In acute and chronic exposure, liver is the main target in man and animals and it leads to liver cancer or liver cirrhosis. Chronic exposures are also associated with human carcinogens (Duah, 2002, p.105).
Conclusion
Though the use of DDT is effective in control of malaria parasite, it has adverse effects to the environment and human beings. These effects are fatal in that they eventually lead to death and some like cancer are terminal. Accumulation of DDT in the environment for a long time also affects the agricultural productivity since DDT also kills the microorganisms that aerate and decompose materials in the soil. Therefore, WHO should not continue to approve the use of DDT to combat malaria but instead should look for alternatives like the use of long lasting insecticide treated nets (L. L. I. Ns) since they are easy to use and maintain.
Reference list
Androl, J. (2006). Reduced seminal parameters associated with environmental DDT exposure and p, p’-DDE concentrations in men in Chiapas, Mexico: a cross- sectional study. National Centre for Biotechnology Information, 27 (1): 16- 27.
Duah, A. (2002). Exposure Assessment: Analysis of Human intake of chemicals. Public health risk assessment for human exposure to chemicals.
International Programme on Chemical Safety, n.d. DDT.
Schrager, F. What is Toxicology? Toxicology Source. Web.
Timbrell, A. (2000). Factors affecting Toxic Responses: Disposition. Principles of Biochemical Toxicology.
Williams, L., James, C. & Roberts, M. (2000). Occupational and environmental health. Principles of toxicology: environmental and industrial applications.
World Health Organization, n.d. The use of DDT in malaria vector control: WHO position statement. Web.