Worker exposure to paraquat and diquat

Wojeck, G. A.; Price, James F.; Nigg, H. N.; Stamper, J. H.

doi:10.1007/bf01055003

Cited by 40 publications

(20 citation statements)

References 15 publications

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“…Some of those studies are listed in Table 7 because estimates of dosage from biomonitoring based on half the LOQ would substantially exceed the estimated PD dosage; therefore actual metabolite presence in urine was questionable. Examples include Wojeck et al, 1983;Chester et al, 1991;Cowell et al, 1991;Lavy et al, 1992;Krieger et al, 1996;Findlay and Wiseman, 2000. Some published studies on occupational paraquat exposure involving concurrent PD and biomonitoring were excluded primarily because the urinary concentrations of paraquat were less than the LOQ (e.g., Wojeck et al, 1983;Chester et al, 1993). The point of these observations is that the analytical sensitivity determines whether the absorbed dose estimated via PD is less than, greater than, or equivalent to the biomonitoring dose estimated by use of half the LOQ and urine volumes.…”

Section: Exclusion Of Proprietary and Published Pd-biomonitoring Studmentioning

confidence: 99%

Comparative evaluation of absorbed dose estimates derived from passive dosimetry measurements to those derived from biological monitoring: Validation of exposure monitoring methodologies

Ross

Chester²,

Driver³

et al. 2007

J Expo Sci Environ Epidemiol

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Passive dosimetry (PD) methods for measuring and estimating exposure to agricultural workers (i.e., persons handling agricultural chemicals and working in treated crops) have been in use since the 1950s. A large number of studies were conducted in the 1950s through 1970s to characterize exposure. Since the 1980s quantitative dermal PD methods are used in conjunction with inhalation PD methods to measure whole-body exposure. These exposure or absorbed dose estimates are then compared to ''no effect'' exposure levels for hazards identified in toxicology studies, and have become the standard for risk assessment for regulatory agencies. The PD methods used have never been validated. Validation in the context of human exposure monitoring methods means that a method has been shown to measure accurately a delivered dose in humans. The most practical alternative to isolating parts of the body for validating recovery methods is to utilize field exposure studies in which concurrent or consecutive measurements of exposure and absorbed dose have been made with PD and biomonitoring in the same cohorts of individuals. This ensures that a direct comparison can be made between the two estimates of absorbed dose, one derived from PD and the other from biomonitoring. There are several studies available (published and proprietary) employing both of these approaches. Reports involving 14 concurrent or consecutive PD-biomonitoring studies were quantitatively evaluated with 18 different methods of application or reentry scenarios for eight different active ingredients for which measured human kinetics and dermal absorption data existed. This evaluation demonstrated that the total absorbed dose estimated using PD for important handler and reentry scenarios is generally similar to the measurements for those same scenarios made using human urinary biomonitoring methods. The statistical analysis of individual worker PD:biomonitoring ratios showed them to be significantly correlated in these studies. The PD techniques currently employed yield a reproducible, standard methodology that is valid and reliably quantifies exposure.

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Section: Exclusion Of Proprietary and Published Pd-biomonitoring Studmentioning

confidence: 99%

Comparative evaluation of absorbed dose estimates derived from passive dosimetry measurements to those derived from biological monitoring: Validation of exposure monitoring methodologies

Ross

Chester²,

Driver³

et al. 2007

J Expo Sci Environ Epidemiol

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“…The human clinical toxicology of diquat is discussed in Section 5.17. Since there are no diquat epidemiology investigations or worker exposure studies (Wojeck, 1983), the potential human exposure to diquat-treated water has been derived from the chemical use-rates and results of the diquat aquatic analytical studies. Risk assessments were calculated based on various types and routes of diquat aquatic exposure and findings from animal laboratory toxicology studies.…”

Section: Diquat Toxicology Information and Assessmentmentioning

confidence: 99%

“…The absence of systemic poisoning associated with diquat dermal exposure either in occupational or contact through aquatic herbicidal use, is due to the poor skin penetration of the chemical and low product label use-rates (Clark and Hurst, 1970;Feldman and Maibach, 1974;MacGregor, 1979;Wojeck, 1983;Scott, 1985Scott, , 1988. Fingernails or toenails exposed to diquat concentrate will crack and shed, followed by normal regrowth.…”

Section: Human Case Reports and Studiesmentioning

confidence: 99%

“…Once a person wears protective breathing equipment or is removed from the exposure situation, the signs and symptoms of diquat inhalation overexposure remit. Spray particle sizes necessary to reach the lung alveoli or air spaces must be in the respirable range of <10 microns (Swan, 1969;Wojeck, 1983). Diquat surface water spray applications for aquatic weed control use even larger droplets than used in terrestrial agricultural situations in order to ensure direct application to the target vegetation and prevent drift to nontarget areas.…”

Section: Human Case Reports and Studiesmentioning

confidence: 99%

“…Based on the weight of the evidence from the diquat toxicology investigations, occupational use and clinical findings, the chemical is not considered to be a neurotoxin. No neurological effects have been reported from incidental ingesting of spray dilution or swallowing of diquat treated water while swimming or in situations where the treated water was used as a drinking water source (Swan, 1969;Schonborn, 1971;Crabtree, 1977;Vanholder, 1981;Van Den Heede, 1982;Wojeck, 1983;Hantson, 2000;Schmidt, 2000).…”

Section: Human Neurological Case Reportsmentioning

confidence: 99%

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Worker exposure to paraquat and diquat

Cited by 40 publications

References 15 publications

Comparative evaluation of absorbed dose estimates derived from passive dosimetry measurements to those derived from biological monitoring: Validation of exposure monitoring methodologies

Comparative evaluation of absorbed dose estimates derived from passive dosimetry measurements to those derived from biological monitoring: Validation of exposure monitoring methodologies

Effects of Aquatic Herbicides and Housing Density on Abundance of Pond-Breeding Frogs

Alkylpyridines and Miscellaneous Organic Nitrogen Compounds

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