¶ … Pesticde Assessment Methods Community Health Board of Directors

FROM: John E. Brown, Commissioner on Agriculture

The Assessment of the Use of Pesticides on the Human Population

Food safety is multidimensional especially as it pertains to the use of industrial chemicals in food production. There are a variety of chemicals used directly in food production including fertilizers being added to soil to promote growth of food and flavorings used to enhance food appeal. Stabilizers are added to give processed foods structure. The focus of this Memo is pesticides. Pesticides are a large number of industrial chemicals used in combating such pests as weeps, fungus, insects, and rodents having been developed to assist agriculture in the production of a stable supply of food. Human exposure to pesticides occurs through residues in food and are transmitted by air, water, and soil-borne exposures for those living near field where foods are grown and pesticides used. The policy controversy addressed in this Memo involves the current governing law on pesticide safety, the Food Quality Protection ACT (FQPA) of 1996, which provides the United States Environmental Protection Agency the authority to conduct comprehensive analysis of the risk of pesticide consumption. EPA has the task of determination of safe levels of exposure to pesticide. This Memorandum will inform the reader of the risks associated with pesticide use, the potential methods of exposure, and the measures and assessment used to mitigate any possible harm to members of the community, agricultural workers and all stakeholders that might be exposed directly or inadvertently to pesticides.

I. Introduction

According to the Environmental Protection Agency website, the Food Quality Protection ACT (FQPA) of 1996, makes a requirement of "an explicit determination that tolerances are safe for children…[and] includes an additional safety factor of up to tenfold, if necessary to account for uncertainty in data relative to children…" [and} require consideration of children's special sensitivity and exposure to pesticide chemicals." (EPA.gov, 2013, p.1) The revised agreement contains the following elements: (1) dates are established for conducting cumulative risk assessment for organophosphate pesticides; (2) dates are established to issue Reregistration Eligibility Decisions (REDs) or revised risk assessment for 11 specific pesticides; (3) the new rules establishes dates for certain regulatory decisions (if necessary) for three pesticides; (4) dates are established to determine if certain classes of pesticides share a mechanism of toxicity that is common; and (5) efforts are continued for the establishment of screening that is both scientific and validated and (6) efforts are continued to establish a scientifically validated screening and testing program for potential endocrine-disrupting chemicals. (EPA.gov, 2013, p.1)

II. Health Risk Assessments

The assessment of health risks from exposure to pesticide is inclusive of four specific steps including the following stated steps:

(1) Step One- This is hazard identification;

(2) Step 2: Dose Response Assessment

(3) Step 3 -- Exposure Assessment; and (4) Step 4 -- Risk characterization. (EPA.gov, 2013, p.1)

The step of hazard identification involves identifying all the possible effects to health that might occur due to being exposed to various types of pesticide. The full range of the potential health problems of a pesticide are considered. The Dose Response Assessment involves giving consideration to the levels of the dose and which adverse effects were observed ion testing of animals and then calculating a dose that is equal in humans. The third step, or that of exposure assessment makes the following assumptions in regards to the three ways that the individual can become exposed to the pesticide: (1) inhalation of pesticides; (2) Absorption of pesticides through the skin; and (3) Getting pesticides in the mount or digestive tract; (EPA.gov, 2013, p.1 EPA.gov, 2013, p.1) The typical sources of exposure to pesticide is stated to be inclusive of: (1) food; (2) home and personal use; (3) pesticides in drinking water; and (4) worker exposure to pesticides. (EPA.gov, 2013, p.1) The fourth step is that of 'Risk Characterization' which is the last step in conducting assessment of humans for health risks due to exposure to pesticides. This process combined the hazard, dose-response and exposure assessment in describing the combined risk from a pesticide. In addition, it provides an explanation of the assumptions made in the assessment of exposure and the lack of certainty that are inherent in the dose-response assessment. The strength of the database as a whole is given consideration and conclusions that are broad in nature made.

III. EPA Formula For Determination of Risk Associated With Exposure To Pesticide

The formula used by the EPA in the evaluation of toxicity and exposure and in determining the risk associated with pesticide use is stated as follows:

RISK = TOXICITY x EXPOSURE. (EPA.gov, 2013, p.1)

What this means is that the human health risk due to exposure to...

This means that the risk to human health from pesticide exposure depends on both the toxicity of the pesticide and the likelihood of people coming into contact with it. The Environmental Protection Agency states as follows:
"At least some exposure and some toxicity are required to result in a risk. For example, if the pesticide is very poisonous, but no people are exposed, there is no risk. Likewise, if there is ample exposure but the chemical is non-toxic, there is no risk. However, usually when pesticides are used, there is some toxicity and exposure, which results in a potential risk." (EPA.gov, 2013, p.1)

The variations between animals and different species is noted by the EPA which when attempting to account for the variability, uncertainty factors are intentionally built in to the risk assessment. The uncertainty factors serve to create "an additional margin of safety for protecting people who may be exposed to the pesticides." (EPA.gov, 2013, p.1) The FQPA makes a requirement that a 10-fold safety factor is utilized by the EPA in the protection of small children and infants from the effects of pesticides.

V. EPA Methods For Testing Effects of Pesticides

There are various types of testing for specific types of effects including those stated as follows:

(1) Acute Testing: Short-term exposure; a single exposure (dose).

Oral, dermal (skin), and inhalation exposure

Eye irritation

Skin irritation

Skin sensitization

Neurotoxicity (EPA.gov. 2013, p.1)

(2) Sub-chronic Testing: Intermediate exposure; repeated exposure over a longer period of time (i.e., 30-90 days).

Oral, dermal (skin), and inhalation

Neurotoxicity (nerve system damage) (EPA.gov. 2013, p.1)

(3) Chronic Toxicity Testing: Long-term exposure; repeated exposure lasting for most of the test animal's life span. Intended to determine the effects of a pesticide after prolonged and repeated exposures.

Chronic effects (non-cancer)

Carcinogenicity (cancer) (EPA.gov. 2013, p.1)

Included are "Developmental and Reproductive Testing" used in identifying effects in the unborn child when the mother is exposed to pesticide and Mutagenicity Testing, which involves an assessment of the potential of the pesticide to affect the genetic components of the cell. Finally Hormone Disruption Testing is conducted to measure the potential for pesticides to disrupt the endocrine system.

VI. Risk Management Methods and Procedures

Following the completion of the risk assessment process for pesticides the EPA utilizes the information gained to make a determination if "there is a reasonable certainty that the pesticide will not harm a person's health." (EPA.gov. 2013, p.1) The conclusion of the risk assessment is used by the EPA in making a decision that is well-informed in relation to the approval of the use of a pesticide as proposed or if there will need to be protective measures added to the use of the pesticides so that occupational and non-occupational exposures are kept at a minimum. The EPA may prohibit the use of certain pesticides on crops if it is believed that consumption of the food will result in consumers being exposed to an unacceptable risk level. The EPA is required to evaluate the 'cumulative risk' of exposure to pesticides as compared to similar toxic effects of other pesticides in terms of their "common mechanism of toxicity." (EPA.gov. 2013, p.1) As well, the EPA is required to made a determination whether children and infants are at an increased risk when exposed to pesticides as compared to adults requiring the use of a 10-fold safety risk facto assessment.

VII. Assessment Methods

The cumulative risk assessment of pesticides includes risk assessment for five pesticide groups including the following:

Organophosphates (OPs)

N-methyl carbamates

Triazines

Chloroacetanilides

Pyrethrins/Pyrethroids (EPA.gov. 2013, p.1 )

VIII. Pesticide Toxicity and Cumulative Data Assessment Models

There are three assessment models used by the EPA Office of Pesticide Programs including:

(1) The DEEM (Dietary Exposure Evaluation Model)/Calendex,

(2) Lifeline, and (3) CARES (Cumulative and Aggregate Risk Evaluation System). (EPA.gov. 2013, p.1)

These models utilize food and drinking water data provided by the USDA Continuing Survey of Food Intake by Individuals ( (CSFII 1994-96, 1998) along with "user-entered residue data to estimate dietary exposure using probabilistic techniques. Each of these three models also has the capability of performing residential exposure assessments and appropriately aggregating exposures across multiple pathways and routes." (EPA.gov. 2013, p.1) It is reported that the goal of the Lifeline Software and Auxiliary Software is to make the provision of a chance for users to conduct examination of potential exposure within a specific population and the impacts that might be expected on the…