Risk Assessment

2.     Assignment: Risk Assessment

You are a member of the Genericville City Council. A proposal has been brought forth to use the insecticide spray, Malathion. Currently, the council is split on its decision, and your vote will determine whether Malathion can be used in the city.

·         Read Risk Assessment of Malathion in Appendix B.

·         Create an outline of the risk of using Malathion according to the four steps of risk assessment presented in Ch. 4 Figure 4.1 of Visualizing Environmental Science.

·         Hazard identification

·         Dose-response

·         Exposure

·         Risk characterization

Decide your vote for the city council based on your outline.

·         Write a 700- to 1,050-word paper that presents your evaluation of the risk of Malathion based on your outline. Explain the reasoning for your vote based on the four steps of risk assessment. Consider any relevant political, social, and economic aspects involved.

·         Format your paper according to APA guidelines.

Malathion is a pesticide that is widely used in agriculture, residential landscaping, public recreation areas, and in public health pest control programs such as mosquito eradication. In the US, it is the most commonly used organophosphate insecticide. Malathion is classified by US EPA as having “suggestive evidence of carcinogenicity.” Carcinogenicity is defined as any substance or agent that tends to produce a cancer. They based this classification on examining liver tumors that develop in mice and rats at excessive doses. The Agency has also determined there is potential for inhalation exposure to adults and children if using ultra low volume (ULV) aerial applications such as we would for mosquito control.

Malathion is of low toxicity but absorption or ingestion results in its metabolism to Malaoxon. Malaoxon is the oxygen analog of Malathion and is even more lethal when exposed to a human body. There is a potential risk of drinking water contamination through ground or surface water. According to EPA model predictions and monitoring studies, Malathion and its degradate Malaoxon will most certainly reach drinking water sources which will then be ingested by the local residents. Chlorination phase of water treatment will turn any Malathion present in the water to Malaoxon. Acute exposure to extremely high levels of Malathion over a prolonged period of time can cause body-wide symptoms that could include skin and eye irritations, cramps, nausea, diarrhea, excessive sweating, seizures and even death.

There is also an exposure risk to mammals, birds and insects that eat grass for sustenance. The data indicated Malathion may be highly toxic to bees and other agricultural insects. Bees are already endangered and have been proven as a ecological need in order to pollinate our crops which are already overtaxed by our population growth. There is also a risk to some aquatic organisms such as the fish in the river near where we will be spraying the insecticide. The exposure risk to both Malathion and Malaoxon increases in toddlers if aerial spray is carried to any hard surfaces such as playgrounds.

The biggest factor to consider is the potential illness and fatality assessment. Currently, without using any methods of removal of the mosquito population, we can expect up to fifty cases of illnesses with around two fatalities from West Nile infected mosquitoes. According to a Florida Study using the same pesticide (Agency for Toxic Substances and Disease Registry, 2005, Section 3), if we use the Malathion pesticide, we can expect as many as ninety cases of Malathion-related illnesses with up to four fatalities. That is an eighty percent increase in illness cases and one hundred percent increase in fatalities by using Malathion pesticide versus exposure to West Nile carrying mosquitoes. While mosquitoes can carry other harmful diseases West Nile is among the most lethal diseases known to be carried and transmitted by mosquitoes.

There is also the mosquitoes themselves to consider. The mosquitos, for the most part, are nectar feeders. The females generally only feed on human blood while developing eggs. While they may seem at the present time to be pests, we are always discovering new information about the world around us. Once upon a time bees where considered a pest, a pest that stung and can cause death in individuals with an allergy. Now we know they are an essential part of our ecological system without which we would all most certainly suffer extreme food hardships if eradicated.

After careful consideration from both sides of the issue, while the risk is undoubtedly low as to the exposure or untimely illness or death by Malathion or even Malaoxon exposure, my vote will have to be against using Malathion to control the mosquito population. I feel there are other ways to protect the citizens of Genericville and its tourists against any potential disease carrying mosquitoes without the necessity of eradicating the mosquito population which may upset a delicate balance in our ecosystem that we are yet unaware of.

Dictionary.com (2009) http://dictionary.reference.com/browse/Carcinogenicity Retrieved Nov 2009.

EPA (July 2006) http://www.epa.gov/pesticides/reregistration/REDs/malathion_red.pdf Retrieved Nov 2009

Regulations.gov (Sept, 2005) “Overview of Malathion Risk Assessment” Docket ID: EPA-HQ-OPP-2004-0348 http://www.regulations.gov Retrieved Nov 2009.

Wikipedia.com (Oct 2009) “Malathion” http://en.wikipedia.org/wiki/Malathion#cite_note-12 Retrieved Nov 2009

Wikipedia.com (Oct 2009) “Mosquito” http://en.wikipedia.org/wiki/Mosquitoes Retrieved Nov 2009