Analytical Methods - HH-RA.org

Bibliography Tag: analytical methods

Meuling et al., 2005

Meuling, W. J., Ravensberg, L. C., Roza, L., & van Hemmen, J. J.; “Dermal absorption of chlorpyrifos in human volunteers;” International Archives of Occupational and Environmental Health, 2005, 78(1), 44-50; DOI: 10.1007/s00420-004-0558-6.

ABSTRACT:

OBJECTIVE: The methods and results are described of a study on the dermal absorption of chlorpyrifos (CPF) in humans established via urinary excretion of the metabolite 3,5,6-trichloro-2-pyridinol (TCP).

METHODS: Two dermal, single, doses of CPF were applied in two study groups (A and B) each comprising three apparently healthy male volunteers who gave their written informed consent. The clinical part of the study was conducted in compliance with the ICH Guideline and the EC principles of good clinical practice (GCP). An approximately 0.5 ml dilution of CPF in ethanol was applied to an area of approximately 100 cm(2) of the volar aspect of the forearm, resulting in doses of either 5 mg (A) or 15 mg (B) of CPF per study subject. Duration of dermal exposure was 4 h, after which the non-absorbed fraction was washed off. The following samples were collected at pre-determined intervals for the determination of either CPF or its metabolite TCP: dosing solutions, wash-off fractions and urine samples collected up to 120 h after dosing.

RESULTS: A relatively large fraction of CPF (42%-67% of the applied dose) was washed off from the exposed skin area. Application of either 5 mg (A) or 15 mg CPF (B) resulted in the total urinary excretion of 131.8 microg (A) or 115.6 microg (B) of TCP 120 h after dosing. This indicated that 4.3% of the applied dose has been absorbed (A), while in group (B) no significant increase in urinary TCP (115.6 microg) was established. The latter indicates that an increase in the dermal dose at a fixed area does not increase absorption, which suggests that the percutaneous penetration rate was constant. Further, it was observed that the clearance of CPF by the body was not completed within 120 h, suggesting that CPF or TCP was retained by the skin and/or accumulated in the body. A mean elimination half-life of 41 h was established.

CONCLUSION: The results show that daily occupational exposure to CPF may result in accumulation of CPF and/or its metabolites, possibly resulting in adverse effects. FULL TEXT

O’Leary et al., 1970

O’Leary, James A., Davies, John E., Edmundson, Walter F., & Reich, George A.; “Transplacental passage of pesticides;” American Journal of Obstetrics and Gynecology, 1970, 107(1), 65-68; DOI: 10.1016/s0002-9378(16)33891-1.

ABSTRACT:

The levels of chlorinated hydrocarbon pesticides in blood and tissues of pregnant women have not been adequately studied, although it has been stated that DDT or its metabolites may be detected in most infants born in America today. The occurrence of these chemicals in neonates has been documented by Denes. For the most part, the biological effects of acute exposure to many pesticides are well known, although this is not true regarding chronic and subacute exposure. In addition, the chlorinated hydrocarbons have been shown to be powerful stimulators of the hepatic microsomal enzyme system:; and these effects remain to be determined. For this reason increased emphasis in this research area is advisable.

The application of gas chromatography and development of the electron capture detector have made possible the determination of levels of many pesticides in every tissue, thus opening new avenues of investigation. The data in this report are presented as an effort toward the clearer understanding of the possible effects of concentrations of pesticides in blood and other tissues during pregnancy, and represent conclusive evidence of the quantitative transfer of DDT and its metabolites to the fetus. The variables of maternal race and fetal maturity are considered. FULL TEXT

Macfarlane et al., 2013

Macfarlane, E., Carey, R., Keegel, T., El-Zaemay, S., & Fritschi, L.; “Dermal exposure associated with occupational end use of pesticides and the role of protective measures;” Safety and Health at Work, 2013, 4(3), 136-141; DOI: 10.1016/j.shaw.2013.07.004.

ABSTRACT:

BACKGROUND: Occupational end users of pesticides may experience bodily absorption of the pesticide products they use, risking possible health effects. The purpose of this paper is to provide a guide for researchers, practitioners, and policy makers working in the field of agricultural health or other areas where occupational end use of pesticides and exposure issues are of interest.

METHODS: This paper characterizes the health effects of pesticide exposure, jobs associated with pesticide use, pesticide-related tasks, absorption of pesticides through the skin, and the use of personal protective equipment (PPE) for reducing exposure.

CONCLUSIONS: Although international and national efforts to reduce pesticide exposure through regulatory means should continue, it is difficult in the agricultural sector to implement engineering or system controls. It is clear that use of PPE does reduce dermal pesticide exposure but compliance among the majority of occupationally exposed pesticide end users appears to be poor. More research is needed on higher-order controls to reduce pesticide exposure and to understand the reasons for poor compliance with PPE and identify effective training methods.

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Baldi et al., 2006

Baldi, I., Lebailly, P., Jean, S., Rougetet, L., Dulaurent, S., & Marquet, P.; “Pesticide contamination of workers in vineyards in France;” Journal of Exposure Science and Environmental Epidemiology, 2006, 16(2), 115-124; DOI: 10.1038/sj.jea.7500443.

ABSTRACT:

In order to build tools to quantify exposure to pesticides of farmers included into epidemiological studies, we performed a field study in Bordeaux vineyards during the 2001 and 2002 treatment seasons to identify parameters related to external contamination of workers. In total, 37 treatment days were observed in tractor operators corresponding to 65 mixing operations, 71 spraying operations and 26 equipment cleaning. In all, four operators with backpack sprayers and seven re-entry workers were also monitored. We performed both detailed observations of treatment characteristics on the whole day and pesticide measurements of external contamination (dermal and inhalation) for each operation. The median dermal contamination was 40.5 mg of active ingredient per day for tractor operators, 68.8 mg for backpack sprayers and 1.3 mg for vineyard workers. Most of the contamination was observed on the hands (49% and 56.2% for mixing and spraying, respectively). The median contribution of respiratory route in the total contamination was 1.1%. A cleaning operation resulted in a 4.20 mg dermal contamination intermediate between a mixing (2.85 mg) and a spraying operation (6.13 mg). Farm owners experienced higher levels than workers and lower contaminations were observed in larger farms. The contamination increased with the number of spraying phases and when equipment cleaning was performed. Types of equipment influenced significantly the daily contamination, whereas personal protective equipment only resulted in a limited decrease of contamination. FULL TEXT

Lebailly et al., 2009

Lebailly, P., Bouchart, V., Baldi, I., Lecluse, Y., Heutte, N., Gislard, A., & Malas, J. P.; “Exposure to pesticides in open-field farming in France;” Annals of Occupational Hygeine, 2009, 53(1), 69-81; DOI: 10.1093/annhyg/men072.

ABSTRACT:

OBJECTIVES: Identification of parameters associated with measured pesticide exposure of farmers in open-field farming in France.

METHODS: Open-field volunteer farmers were monitored during 1 day use of the herbicide isoproturon on wheat and/or barley during the winters 2001 (n = 9) or 2002 (n = 38) under usual conditions of work. The whole-body method was used to assess potential dermal exposure using coveralls and cotton gloves. Mixing-loading and application tasks were assessed separately with 12 different body areas (hands, arms, forearms, legs, chest, back and thighs) measured for each task (mixing-loading and application separately).

RESULTS: Daily potential dermal exposure to isoproturon ranged from 2.0 to 567.8 mg (median = 57.8 mg) in 47 farmers. Exposure during mixing-loading tasks accounted for 13.9-98.1% of the total exposure (median = 74.8%). For mixing-loading, hands and forearms were the most contaminated body areas accounting for an average of 64 and 14%, respectively. For application, hands were also the most contaminated part of the body, accounting for an average of 57%, and thighs, forearms and chest or back were in the same range as one another, 3-10%. No correlations were observed between potential dermal exposure and area sprayed, duration of spraying or size of the farm. However, a significant relationship was observed between exposure and the type of spraying equipment, with a rear-mounted sprayer leading to a higher exposure level than trailer sprayers. Technical problems, particularly the unplugging of nozzles, and the numbers mixing-loading or application tasks performed were also significantly related with higher levels of exposure.

CONCLUSIONS: The main results obtained in this study on a large number of observation days are as follows: (i) the mixing-loading step was the most contaminated task in open field accounting for two-thirds of the total daily exposure, (ii) no positive correlation was noted with classically used pesticide-related parameters: farm area, area sprayed and duration of application and (iii) relevant parameters were the type of spraying equipment, the type and number of tasks and technical problems or cases of overflowing. FULL TEXT

Calafat, 2012

Calafat, A. M.; “The U.S. National Health and Nutrition Examination Survey and human exposure to environmental chemicals;” International Journal of Hygiene and Environmental Health, 2012, 215(2), 99-101; DOI: 10.1016/j.ijheh.2011.08.014.

ABSTRACT:

Researchers are increasingly interested in using human biomonitoring – the measurement of chemicals, their metabolites or specific reaction products in biological specimens/body fluids – for investigating exposure to environmental chemicals. General population human biomonitoring programs are useful for investigating human exposure to environmental chemicals and an important tool for integrating environment and health. One of these programs, the National Health and Nutrition Examination Survey (NHANES), conducted in the United States is designed to collect data on the health and nutritional status of the noninstitutionalized, civilian U.S. population. NHANES includes a physical examination, collecting a detailed medical history, and collecting biological specimens (i.e., blood and urine). These biological specimens can be used to assess exposure to environmental chemicals. NHANES human biomonitoring data can be used to establish reference ranges for selected chemicals, provide exposure data for risk assessment, and monitor exposure trends. FULL TEXT

Linhart et al., 2021

Linhart, Caroline, Panzacchi, Simona, Belpoggi, Fiorella, Clausing, Peter, Zaller, Johann G., & Hertoge, Koen; “Year-round pesticide contamination of public sites near intensively managed agricultural areas in South Tyrol;” Environmental Sciences Europe, 2021, 33(1); DOI: 10.1186/s12302-020-00446-y.

ABSTRACT:

BACKGROUND: In a previous study, we found that 45% of public playgrounds near intensively managed agricultural areas were contaminated with mainly endocrine active pesticide residues in spring. Here, we investigated potential contamination over the course of a year.

METHODS: Residue data were analyzed from 96 grass samples collected in spring, summer, autumn, and winter by the South Tyrolean Medical Service in 19 public playgrounds, four schoolyards, and one marketplace located within intensively managed agricultural landscapes. Samples were analyzed for 281 substances using gas-chromatography and mass-spectrometry.

RESULTS: A total of 32 pesticide residues and one preservative agent were found. Almost all of the sites (96%) were contaminated with at least one residue during the year; in 79% of the sites, more than one residue was found. Among the detected residues, 76% are classified as endocrine active substances, with the highest concentrations of the insecticide chlorpyrifos-methyl (0.71 mg kg−1), the herbicide oxadiazon (0.64 mg kg−1), and the fungicides captan (0.46 mg kg−1) and fluazinam (0.23 mg kg−1). The number of residues, their concentrations, and the proportion of contaminated sites varied across seasons (p < 0.001). Twenty-five residues were found in 83% of the sites in spring (median concentration 0.240 mg kg−1), nine in 79% of the sites in summer (0.092 mg kg−1), three in 50% of the sites in autumn (0.076 mg kg−1), and four in 17% of the sites in winter (0.155 mg kg−1). Playgrounds already examined in 2017 in the previous study, were more often contaminated with multiple pesticide residues in 2018 (p = 0.045).

CONCLUSION: This study confirms previous findings of widespread pesticide contamination of public sites within intensively managed agricultural areas. Moreover, pesticide residues were also found in periods with little or no pesticide application in the field (autumn and winter). It is worrisome that many of the detected residues are endocrine active substances and that some of them (thiacloprid, bupirimate, captan, folpet) are “suspected human carcinogens”, according to EU authorities. Thus, we call for more effective controls of pesticide applications to minimize pesticide drift into public places. FULL TEXT

Zhang et al., 2019b

Zhang, J., Huang, Y., Reddy, K. N., & Wang, B.; “Assessing crop damage from dicamba on non-dicamba-tolerant soybean by hyperspectral imaging through machine learning;” Pest Management Science, 2019, 75(12), 3260-3272; DOI: 10.1002/ps.5448.

ABSTRACT:

BACKGROUND: Dicamba effectively controls several broadleaf weeds. The off-target drift of dicamba spray or vapor drift can cause severe injury to susceptible crops, including non-dicamba-tolerant crops. In a field experiment, advanced hyperspectral imaging (HSI) was used to study the spectral response of soybean plants to different dicamba rates, and appropriate spectral features and models for assessing the crop damage from dicamba were developed.

RESULTS: In an experiment with six different dicamba rates, an ordinal spectral variation pattern was observed at both 1 week after treatment (WAT) and 3 WAT. The soybean receiving a dicamba rate >/=0.2X exhibited unrecoverable damage. Two recoverability spectral indices (HDRI and HDNI) were developed based on three optimal wavebands. Based on the Jeffries-Matusita distance metric, Spearman correlation analysis and independent t-test for sensitivity to dicamba spray rates, a number of wavebands and classic spectral features were extracted. The models for quantifying dicamba spray levels were established using the machine learning algorithms of naive Bayes, random forest and support vector machine.

CONCLUSIONS: The spectral response of soybean injury caused by dicamba sprays can be clearly captured by HSI. The recoverability spectral indices developed were able to accurately differentiate the recoverable and unrecoverable damage, with an overall accuracy (OA) higher than 90%. The optimal spectral feature sets were identified for characterizing dicamba spray rates under recoverable and unrecoverable situations. The spectral features plus plant height can yield relatively high accuracy under the recoverable situation (OA = 94%). These results can be of practical importance in weed management. (c) 2019 Society of Chemical Industry.

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Baker et al., 2019

Baker, S. E., Serafim, A. B., Morales-Agudelo, P., Vidal, M., Calafat, A. M., & Ospina, M.; “Quantification of DEET and neonicotinoid pesticide biomarkers in human urine by online solid-phase extraction high-performance liquid chromatography-tandem mass spectrometry;” Analytical and Bioanalytical Chemistry, 2019, 411(3), 669-678; DOI: 10.1007/s00216-018-1481-0.

ABSTRACT:

Neonicotinoid insecticides are widely used replacements for organophosphate and carbamate insecticides, but the extent of human exposure is largely unknown. On the other hand, based on urinary concentrations of DEET metabolites, human exposure to N,N-diethyl-m-toluamide (DEET) appears to be widespread. We developed a fast online solid-phase extraction high-performance liquid chromatography-isotope dilution tandem mass spectrometry (HPLC-MS/MS) method to measure in 200 muL of human urine the concentrations of six neonicotinoid biomarkers (acetamiprid, N-desmethyl-acetamiprid, clothianidin, imidacloprid, 5-hydroxy-imidacloprid, thiacloprid), and two DEET biomarkers (3-diethyl-carbamoyl benzoic acid, 3-ethyl-carbamoyl benzoic acid). Limits of detection ranged from 0.01 to 0.1 mug/L, depending on the biomarker. Accuracy ranged from 91 to 116% and precision ranged from 3.7 to 10 %RSD. The presented method can be used to increase our understanding of exposure to neonicotinoid insecticides and DEET, and to evaluate the potential health effects from such exposures. FULL TEXT

Sheppard et al., 2020

Sheppard, L., McGrew, S., & Fenske, R. A.; “Flawed analysis of an intentional human dosing study and its impact on chlorpyrifos risk assessments;” Environment International, 2020, 143, 105905; DOI: 10.1016/j.envint.2020.105905.

ABSTRACT:

In March 1972, Frederick Coulston and colleagues at the Albany Medical College reported results of an intentional chlorpyrifos dosing study to the study’s sponsor, Dow Chemical Company. Their report concluded that 0.03 mg/kg-day was the chronic no-observed-adverse-effect-level (NOAEL) for chlorpyrifos in humans. We demonstrate here that a proper analysis by the original statistical method should have found a lower NOAEL (0.014 mg/kg-day), and that use of statistical methods first available in 1982 would have shown that even the lowest dose in the study had a significant treatment effect. The original analysis, conducted by Dow-employed statisticians, did not undergo formal peer review; nevertheless, EPA cited the Coulston study as credible research and kept its reported NOAEL as a point of departure for risk assessments throughout much of the 1980’s and 1990’s. During that period, EPA allowed chlorpyrifos to be registered for multiple residential uses that were later cancelled to reduce potential health impacts to children and infants. Had appropriate analyses been employed in the evaluation of this study, it is likely that many of those registered uses of chlorpyrifos would not have been authorized by EPA. This work demonstrates that reliance by pesticide regulators on research results that have not been properly peer-reviewed may needlessly endanger the public. FULL TEXT

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