Chemical Auditing and Monitoring

• Auditing and monitoring ensure the safe handling of chemicals throughout their lifecycle, from discovery to disposal
• Clear standards must be established for auditing and monitoring to be effective
• GIFAP's checklist is an ideal starting point for pesticide packaging guidelines
• Toxicological data and properties are key to evaluating risks during auditing and monitoring
• Auditing and monitoring should begin at discovery and continue through disposal
• Focus is often on characterizing and managing product-related risks to health, safety, and the environment

Auditing

• Audits use checklists to assess the life cycle of a product for potential risks
• The sincerity of workers affects audit quality
• Audit frequency depends on factors like toxicity, flammability, chemical volume, time spent processing, knowledge of personnel, plant design, equipment, and instrumentation
• Sites producing highly toxic compounds require more frequent audits
• Plants handling flammable compounds need regular electrical and spark source audits
• Plant design aims to minimize risks associated with the compounds being produced
• Knowledge and skills of personnel that run the plant are important for safety and risk reduction

Monitoring

• Pesticide monitoring helps registrants design field studies to measure pesticide exposure
• Prevent unreasonable risk to humans and the environment
• Studies estimate exposure through passive dosimetry and biological monitoring
• Passive dosimetry measures chemicals on skin or available for inhalation
• Biological monitoring estimates internal dose through body fluid measurements or from pesticide metabolites

Routes of Pesticide Exposure

• Four routes of entry apply
• Dermal exposure accounts for about 97% of pesticide exposures and is also preventable
• It occurs through careless handling during mixing, loading, applying, or disposing of pesticides and their containers
• Common causes are splashes, spills, or drift
• Inhalation occurs when pesticides are breathed into the lungs
• Oral exposure often affects children due to pesticides being put into unmarked containers
• Eyes can absorb enough pesticide to be hazardous, usually through contaminated hands

Passive Dosimetry

• Passive dosimetry differentiates exposure levels during work activities
• It does this by discovering the relative contribution of dermal and respiratory exposure
• Critical for evaluating and planning exposure reduction practices using PPE
• Data identifying high exposure periods lead to actions like requiring chemical resistant gloves and face shields
• Dermal monitoring covers all body areas, including penetration of clothing
• Exposure monitoring should not subject participants to unnecessary added risks
• Methods should not allow subjects to wear respirators that afford less protection than the label specifies
• Human safety must not be compromised in methods chosen

Dermal Exposure Monitoring

• Absorption through the skin is estimated by trapping or removing material before absorption
• Pads and clothing trap residues by swabbing or rinsing
• Pads must be absorbent, able to retain liquid, porous, and strong enough for field conditions
• Alpha-cellulose and multi-layered gauze pads are recommended for monitoring dermal exposure to pesticides
• These pads of pads are easy to construct, easy to use, and extraction of residues is easy

Water Sensitive Paper

• Water-sensitive paper demonstrates contamination; it doesn't require extraction
• Water sensitive paper is rigid with a coated yellow surface that turns dark blue on contact with aqueous droplets
• CropLife Philippines has used this paper to demonstrate pesticide contamination on mango spray workers
• Droplet number is used to rate the level of contamination

Number and Location of Dermal Pads

• Several questions need answering for a successful experiment i.e. How many dermal pads do I use? How long is the exposure time? etc.
• Durham and Wolfe's method is standard for dermal pad placement
• The EPA requires at least ten pads in specific locations around the body
• Extras can be placed under clothing to estimate residue penetration
• Workers should avoid touching exposure pads

Monitoring Hand Exposure

• Previous methods used lightweight absorbent gloves or sections from back and palm of such gloves
• Issues can arise in cases where residues are absorbed into the skin
• Absorbent gloves may overestimate hand exposure
• Bag washing is recommended to measure a worker's exposure to a substance

Dermal Exposure Calculation

• Worker exposure is estimated after the amount of exposure to pads is defined
• The amount of pesticide is extrapolated to the area it covers on the pad
• Pads represent certain regions of the body, therefore it is assumed that the surfaces on the pads represent that area of the body

Respiratory Exposure Monitoring

• Respiratory exposure can be associated with a small part of handling pesticides
• Exposure can easily be inhalation of dust, fumes, and spray in a contained environment
• In this case, a trapping medium must be used to efficiently assess these conditions and their dangers
• Various methods for respiratory exposure monitoring are available
• Choice of method depends on the chemical and physical nature of the material
• Potential exposure is estimated by personal monitors, from gauze pads in respirators to air samplers
• The gauze pad procedure is convenient, using pads similar to dermal pads
• Airflow during breathing traps material, ensuring a well-fitted respirator worn during the exposure period
• Solid absorbents are gaining popularity, though they require ventilation rate estimation
• Another issue can be airflow restriction by particles
• Contamination should be prevented during all activities of the test
• A written protocol is needed for sampling, selection, and instrumentation analysis

Bilogical Monitoring

• Biological monitoring means that biological factors are part of exposure measurement
• Information from studies varies from health effects to absorbed dose of a chemical
• Blood analysis i.e. cholinesterase levels, can be used to see the health effects chemicals have on workers
• A regular testing program is recommended for workers who use organophosphorus pesticides
• A number of methods have been established to determine cholinesterase levels in blood by measuring activity in the blood, and comparing values compared to past ones

Advantages and Disadvantages of Estimating Methods

• Advantages include routes and areas of exposure that are well defined

• Disadvantages include required knowledge of absorption, and also that not all exposures are measurable

• Cholinesterase activity varies among individuals and even day to day which can be a concern

• Normal Cholinesterase ranges vary from site to site, so each lab must establish its ranges

• Baseline values should be established before work seasons to compare test during the work week to off time after a month

• Blood testing at least once every two weeks is recommended, followed be at least once a month

• Cholinesterase reduction determines if employee should be removed

• Follow testing should be evaluated and employees must prevent further exposure

• The degree and nature of exposure affect the rate of recovery regarding organophoshorus pesticide

• Large exposure amounts takes body longer to recover

• Biological monitoring involves blood extraction before and after the study

• A common problem for monitoring is participants will not show up

• To solve this problem, a "token incentive" can be promised

• Participants should sign a waiver for the extraction of blood to avoid legal ramifications

Dermal Exposure Estimation

• Determine the amount of ug on each path via chemical analysis

• Divide the ug found on the patch by the area the total area of its surface

• Then multiply by the area of the body area the patch covers

• Sum all the product from each body area interested in the data

• Then divide by the total amount of substance given for each pound

• In cases for a covered worker that are wearing protective gloves, exposed areas are the face, the v of the neck, and hands

• Once the experiment is finished you can divide each by the 100 in the surface area

• You should recognize the area of representation, and treated by means

• One body exposure estimation can be normalized to each pesticide amount.