Incorporating Science, Economics, and Sociology in Developing Sanitary and Phytosanitary Standards in International Trade Proceedings of a Conference (2000) / Chapter Skim
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3 An Overview of Risk Assessment
3 An Overview of Risk Assessment
Pages 51-64
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From page 51... ...
What are the risks associated with the introduction of an exotic species to a country or new geographical region that does not already have this species? How does the introduction of exotic species impact humans, crops, domesticated animals, and the habitats that we wish to protect?
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From page 52... ...
Some examples are various insect pests that are introduced in produce such as the Mediterranean fruit fly, species that are introduced in something other than a commodity such as the Asian longhorn beetle, infectious agents such as prions that cause mad cow disease, and weed pests like purple loose strife.
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From page 53... ...
Dose can be thought of as chemical concentration or the number of individuals of an exotic species that are introduced to a geographic area over time. The most commonly used measure of toxic effect is the LDso The LD50 is a statistically derived measure of the dose-response relationship and is an estimate of the lethal dose that causes 50 percent mortality of a group of organisms being studied.
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From page 54... ...
(ma chemical/kg body weight) <0.001 mg/kg 9 mg/kg 1 80 mg/kg 338 mg/kg 350 mg/kg 1,500 mg/kg 2,800 mg/kg 3,750 mg/kg 1 0,600 mg/kg aLDso is the lethal dose that kills 50 percent of a population.
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From page 55... ...
Mortality is the endpoint of interest for many acute studies whereas life span, reproduction, weight gain, cancer, and birth defects are of interest in chronic studies. To establish the amount of pesticide that can be ingested over a lifetime without causing illness, the lowest no observable effect level (lowest value for the endpoints studied—cancer, offspring, life span, etc.)
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Is there a Problem? Risk characterization integrates the toxicity data and exposure assessment to arrive at probabilities of effects occurring.
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The above data are run through a computer program (Monte Carlo simulation is an example of such probabilistic approaches) and the following exposures are generated: · 78 percent of the population is not exposed to the pesticide, · 1 percent is exposed to the highest exposure level (50 ~g/kg body · 5 percent is exposed to 40 ~g/kg body weight, · 7 percent is exposed to 30 ~Lg/kg body weight, and · 9 percent is exposed to 10 )
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As mentioned above, the reference dose is the amount of pesticide residue that can be ingested daily (daily allowable intake) by an average adult without an appreciable risk to human health.
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Plants, Domestic Animals, and Wildlife When we think of plant protection, crops obviously come to mind, but we must also think of the risk posed to plant species that are not crops. Arthropod species and disease organisms that attack plants and weed species that compete with native species and other plants that we wish to protect are the major risk concerns.
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From page 60... ...
Exotic species do not always enter a country directly on or in an agricultural commodity. An example of two species that have invaded the United States not through produce but related to commerce are the Asian longhorn beetle that entered the United States through shipping pallets originating in China, and the zebra mussel that entered the Great Lakes through the discharge
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coli-related foodborne illnesses in the United States to realize that food safety is a major concern worldwide. The recent outbreak of mad cow disease in the United Kingdom resulted in trade barriers being erected in other European Union nations.
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CONCLUSIONS Risk assessment is a valuable tool that combines science and expert judgment. Increasingly more sophisticated means of risk assessment have been developed, particularly in the areas of human health and the environment.
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1994. Assessment of variability and uncertainty distributions for practical risk analysis.
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From page 64... ...
1994. Dramatic decline of native unionid bivalves in offshore waters of western Lake Erie after infestation by the zebra mussel, Dreissena polymorpha.
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