DiBartolomeis et al., 2019
DiBartolomeis, M., Kegley, S., Mineau, P., Radford, R., & Klein, K.; “An assessment of acute insecticide toxicity loading (AITL) of chemical pesticides used on agricultural land in the United States;” Plos One, 2019, 14(8), e0220029; DOI: 10.1371/journal.pone.0220029.
ABSTRACT:
We present a method for calculating the Acute Insecticide Toxicity Loading (AITL) on US agricultural lands and surrounding areas and an assessment of the changes in AITL from 1992 through 2014. The AITL method accounts for the total mass of insecticides used in the US, acute toxicity to insects using honey bee contact and oral LD50 as reference values for arthropod toxicity, and the environmental persistence of the pesticides. This screening analysis shows that the types of synthetic insecticides applied to agricultural lands have fundamentally shifted over the last two decades from predominantly organophosphorus and N-methyl carbamate pesticides to a mix dominated by neonicotinoids and pyrethroids. The neonicotinoids are generally applied to US agricultural land at lower application rates per acre; however, they are considerably more toxic to insects and generally persist longer in the environment. We found a 48- and 4-fold increase in AITL from 1992 to 2014 for oral and contact toxicity, respectively. Neonicotinoids are primarily responsible for this increase, representing between 61 to nearly 99 percent of the total toxicity loading in 2014. The crops most responsible for the increase in AITL are corn and soybeans, with particularly large increases in relative soybean contributions to AITL between 2010 and 2014. Oral exposures are of potentially greater concern because of the relatively higher toxicity (low LD50s) and greater likelihood of exposure from residues in pollen, nectar, guttation water, and other environmental media. Using AITL to assess oral toxicity by class of pesticide, the neonicotinoids accounted for nearly 92 percent of total AITL from 1992 to 2014. Chlorpyrifos, the fifth most widely used insecticide during this time contributed just 1.4 percent of total AITL based on oral LD50s. Although we use some simplifying assumptions, our screening analysis demonstrates an increase in pesticide toxicity loading over the past 26 years, which potentially threatens the health of honey bees and other pollinators and may contribute to declines in beneficial insect populations as well as insectivorous birds and other insect consumers. FULL TEXT
Kasiotis and Machera, 2015
Kasiotis, K. M., & Machera, K.; “Neonicotinoids and their Metabolites in Human Biomonitoring: A Review;” Hellenic Plant Protection Journal, 2015, 8(2), 33-45; DOI: 10.1515/hppj-2015-0006.
ABSTRACT:
Neonicotinoids (NNDs) constitute a major class of insecticides with a broad and versatile spectrum of applications in agriculture. Hence, their residues are found in several environmental compartments and can be transferred via several pathways to numerous organisms. Despite their profound impact on honeybees and wild bees (impairment of memory, impact on immune system), their presence in humans is far less reported, possibly due to the low to moderate toxicological eff ects that they elicit. The aim of the present review is to emphasize on developments in the biomonitoring of NNDs. It focuses mainly on chromatographic analysis of NNDs and their metabolites in human biological fl uids, discussing key features, such as sample preparation and analytical method validation. Nonetheless, case reports regarding intoxication incidents are presented, highlighting the signifi cance of such cases especially in the developing world. FULL TEXT
Han et al., 2018
Han, Wenchao, Tian, Ying, & Shen, Xiaoming; “Human exposure to neonicotinoid insecticides and the evaluation of their potential toxicity: An overview;” Chemosphere, 2018, 192, 59-65; DOI: 10.1016/j.chemosphere.2017.10.149.
ABSTRACT:
Neonicotinoid insecticides have become the fastest growing class of insecticides over the past few decades. The insecticidal activity of neonicotinoids is attributed to their agonist action on nicotinic acetylcholine receptors (nAChRs). Because of the special selective action on nAChRs in central nervous system of insects, and versatility in application methods, neonicotinoids are used to protect crops and pets from insect attacks globally. Although neonicotinoids are considered low toxicity to mammals and humans in comparison with traditional insecticides, more and more studies show exposure to neonicotinoids pose potential risk to mammals and even humans. In recent years, neonicotinoids and their metabolites have been successfully detected in various human biological samples. Meanwhile, many studies have focused on the health effects of neonicotinoids on humans. Our aims here are to review studies on human neonicotinoid exposure levels, health effect, evaluation of potential toxicity and to suggest possible directions for future research.
Thomas et al., 2010
Thomas, K. W., Dosemeci, M., Hoppin, J. A., Sheldon, L. S., Croghan, C. W., Gordon, S. M., Jones, M. L., Reynolds, S. J., Raymer, J. H., Akland, G. G., Lynch, C. F., Knott, C. E., Sandler, D. P., Blair, A. E., & Alavanja, M. C.; “Urinary biomarker, dermal, and air measurement results for 2,4-D and chlorpyrifos farm applicators in the Agricultural Health Study;” Journal of Exposure Science and Environmental Epidemiology, 2010, 20(2), 119-134; DOI: 10.1038/jes.2009.6.
ABSTRACT:
A subset of private pesticide applicators in the Agricultural Health Study (AHS) epidemiological cohort was monitored around the time of their agricultural use of 2,4-dichlorophenoxyacetic acid (2,4-D) and O,O-diethyl-O-3,5,6-trichloro-2-pyridyl phosphorothioate (chlorpyrifos) to assess exposure levels and potential determinants of exposure. Measurements included pre- and post-application urine samples, and patch, hand wipe, and personal air samples. Boom spray or hand spray application methods were used by applicators for 2,4-D products. Chlorpyrifos products were applied using spray applications and in-furrow application of granular products. Geometric mean (GM) values for 69 2,4-D applicators were 7.8 and 25 microg/l in pre- and post-application urine, respectively (P<0.05 for difference); 0.39 mg for estimated hand loading; 2.9 mg for estimated body loading; and 0.37 microg/m(3) for concentration in personal air. Significant correlations were found between all media for 2,4-D. GM values for 17 chlorpyrifos applicators were 11 microg/l in both pre- and post-application urine for the 3,5,6-trichloro-2-pyridinol metabolite, 0.28 mg for body loading, and 0.49 microg/m(3) for air concentration. Only 53% of the chlorpyrifos applicators had measurable hand loading results; their median hand loading being 0.02 mg. Factors associated with differences in 2,4-D measurements included application method and glove use, and, for hand spray applicators, use of adjuvants, equipment repair, duration of use, and contact with treated vegetation. Spray applications of liquid chlorpyrifos products were associated with higher measurements than in-furrow granular product applications. This study provides information on exposures and possible exposure determinants for several application methods commonly used by farmers in the cohort and will provide information to assess and refine exposure classification in the AHS. Results may also be of use in pesticide safety education for reducing exposures to pesticide applicators. FULL TEXT
Barr et al., 2005
Barr, D. B., Allen, R., Olsson, A. O., Bravo, R., Caltabiano, L. M., Montesano, A., Nguyen, J., Udunka, S., Walden, D., Walker, R. D., Weerasekera, G., Whitehead, R. D., Jr., Schober, S. E., & Needham, L. L.; “Concentrations of selective metabolites of organophosphorus pesticides in the United States population;” Environmental Research, 2005, 99(3), 314-326; DOI: 10.1016/j.envres.2005.03.012.
ABSTRACT:
We report population-based concentrations (stratified by age, sex, and composite race/ethnicity variables) of selective metabolites of chlorpyrifos (3,5,6-trichloro-2-pyridinol; TCPY), chlorpyrifos methyl (TCPY), malathion (malathion dicarboxylic acid; MDA), diazinon (2-isopropyl-4-methyl-6-hydroxypyrimidine; IMPY), methyl parathion (para-nitrophenol; PNP), and parathion (PNP). We measured the concentrations of TCPY, MDA, IMPY, and PNP in 1997 urine samples from participants, aged 6-59 years, of the National Health and Nutrition Examination Survey, 1999-2000. We detected TCPY in more than 96% of the samples tested. Other organophosphorus pesticide metabolites were detected less frequently: MDA, 52%; IMPY, 29%; and PNP, 22%. The geometric means for TCPY were 1.77 microg/L and 1.58 microg/g creatinine. The 95th percentiles for TCPY were 9.9 microg/L and 8.42 microg/g creatinine. The 95th percentiles for MDA were 1.6 microg/L and 1.8 microg/g creatinine. The 95th percentiles for IMPY and PNP were 3.7 microg/L (3.4 microg/g creatinine) and 5.0 microg/L (4.2 microg/g creatinine), respectively. Multivariate analyses showed that children aged 6-11 years had significantly higher concentrations of TCPY than adults and adolescents. Similarly, adolescents had significantly higher TCPY concentrations than adults. Although the concentrations between sexes and among composite racial/ethnic groups varied, no significant differences were observed. FULL TEXT
Castorina et al., 2010
Castorina, R., Bradman, A., Fenster, L., Barr, D. B., Bravo, R., Vedar, M. G., Harnly, M. E., McKone, T. E., Eisen, E. A., & Eskenazi, B.; “Comparison of current-use pesticide and other toxicant urinary metabolite levels among pregnant women in the CHAMACOS cohort and NHANES;” Environmental Health Perspectives, 2010, 118(6), 856-863; DOI: 10.1289/ehp.0901568.
ABSTRACT:
BACKGROUND:
We measured 34 metabolites of current-use pesticides and other precursor compounds in urine samples collected twice during pregnancy from 538 women living in the Salinas Valley of California, a highly agricultural area (1999-2001). Precursors of these metabolites included fungicides, carbamate, organochlorine, organophosphorus (OP), and pyrethroid insecticides, and triazine and chloroacetanilide herbicides. We also measured ethylenethiourea, a metabolite of the ethylene-bisdithiocarbamate fungicides. Repeat measurements of the compounds presented here have not been reported in pregnant women previously. To understand the impact of the women’s regional environment on these findings, we compared metabolite concentrations from the CHAMACOS (Center for the Health Assessment of Mothers and Children of Salinas) cohort with U.S. national reference data for 342 pregnant women sampled by the National Health and Nutrition Examination Survey (1999-2002).
RESULTS:
The eight metabolites detected in > 50% of samples [2,4-dichlorophenol (2,4-DCP); 2,5-dichlorophenol (2,5-DCP); 1- and 2-naphthol; ortho-phenylphenol (ORTH); para-nitrophenol (PNP); 2,4,6-trichlorophenol (2,4,6-TCP); and 3,4,6-trichloro-2-pyridinol (TCPy)] may be related to home or agricultural pesticide use in the Salinas Valley, household products, and other sources of chlorinated phenols. More than 78% of women in this study had detectable levels of at least one of the OP pesticide-specific metabolites that we measured, and > 30% had two or more. The 95th percentile values of six of the most commonly detected (> 50%) compounds were significantly higher among the CHAMACOS women after controlling for age, race, socioeconomic status, and smoking [(2,4-DCP; 2,5-DCP; ORTH; PNP; 2,4,6-TCP; and TCPy); quantile regression p < 0.05].
CONCLUSIONS:
Findings suggest that the CHAMACOS cohort has an additional burden of precursor pesticide exposure compared with the national sample, possibly from living and/or working in an agricultural area. FULL TEXT
Alexander et al., 2006
Alexander, B. H., Burns, C. J., Bartels, M. J., Acquavella, J. F., Mandel, J. S., Gustin, C., & Baker, B. A.; “Chlorpyrifos exposure in farm families: results from the farm family exposure study;” Journal of Exposure Science and Environmental Epidemiology, 2006, 16(5), 447-456; DOI: 10.1038/sj.jes.7500475.
ABSTRACT:
We used urinary biological monitoring to characterize chlorpyrifos (O,O-diethyl-O-(3,5,6-trichloro-2-pyridinyl) phosphororthioate) exposure to farm family members from Minnesota and South Carolina who participated in the Farm Family Exposure Study. Five consecutive 24-h urine samples were obtained from 34 families of licensed pesticide applicators 1 day before through 3 days after a chlorpyrifos application. Daily 3,5,6-trichloro-2-pyridinol (TCP) urinary concentrations characterized exposure profiles of the applicator, the spouse, and children aged 4-17 years. Self-reported and observed determinants of exposure were compared to the maximum postapplication TCP concentration. All participants had detectable (> or = 1 microg/l) urinary TCP concentrations at baseline. Applicators’ peak TCP levels occurred the day after the application (geometric mean (GM) = 19.0 microg/l). Postapplication TCP change from baseline in the spouses and children was negligible, and the only reliable predictor of exposure was assisting with the application for children aged 12 years and older. The applicators’ exposure was primarily influenced by the chemical formulation (GM = 11.3 microg/l for granular and 30.9 microg/l for liquid), and the number of loads applied. Repairing equipment, observed skin contact, and eating during the application were moderately associated TCP levels for those who applied liquid formulations. Estimated absorbed doses (microg chlorpyrifos/kg bodyweight) were calculated based on TCP excretion summed over the 4 postapplication days and corrected for pharmacokinetic recovery. The GM doses were 2.1, 0.7, and 1.0 microg/kg bodyweight for applicators, spouses, and children, respectively. Chlorpyrifos exposure to farm family members from the observed application was largely determined by the extent of contact with the mixing, loading, and application process. FULL TEXT
Arnold et al., 2015
Arnold, S. M., Morriss, A., Velovitch, J., Juberg, D., Burns, C. J., Bartels, M., Aggarwal, M., Poet, T., Hays, S., & Price, P.; “Derivation of human Biomonitoring Guidance Values for chlorpyrifos using a physiologically based pharmacokinetic and pharmacodynamic model of cholinesterase inhibition;” Regulatory Toxicology and Pharmacology, 2015, 71(2), 235-243; DOI: 10.1016/j.yrtph.2014.12.013.
ABSTRACT:
A number of biomonitoring surveys have been performed for chlorpyrifos (CPF) and its metabolite (3,5,6-trichloro-2-pyridinol, TCPy); however, there is no available guidance on how to interpret these data in a health risk assessment context. To address this gap, Biomonitoring Guidance Values (BGVs) are developed using a physiologically based pharmacokinetic and pharmacodynamic (PBPK/PD) model. The PBPK/PD model is used to predict the impact of age and human variability on the relationship between an early marker of cholinesterase (ChE) inhibition in the peripheral and central nervous systems [10% red blood cell (RBC) ChE inhibition] and levels of systemic biomarkers. Since the PBPK/PD model characterizes variation of sensitivity to CPF in humans, interspecies and intraspecies uncertainty factors are not needed. Derived BGVs represent the concentration of blood CPF and urinary TCPy associated with 95% of the population having less than or equal to 10% RBC ChE inhibition. Blood BGV values for CPF in adults and infants are 6100 ng/L and 4200 ng/L, respectively. Urinary TCPy BGVs for adults and infants are 2100 mug/L and 520 mug/L, respectively. The reported biomonitoring data are more than 150-fold lower than the BGVs suggesting that current US population exposures to CPF are well below levels associated with any adverse health effect. FULL TEXT
Cai et al., 2020
Cai, Wenyan, Zhang, Feng, Zhong, Lixin, Chen, Dongya, Guo, Haoran, Zhang, Hengdong, Zhu, Baoli, & Liu, Xin; “Correlation between CYP1A1 polymorphisms and susceptibility to glyphosate-induced reduction of serum cholinesterase: A case-control study of a Chinese population;” Pesticide Biochemistry and Physiology, 2020, 162, 23-28; DOI: 10.1016/j.pestbp.2019.07.006.
ABSTRACT:
Glyphosate (GLP) is one of the most common herbicides worldwide. The serum cholinesterase (ChE) may be affected when exposed to glyphosate. Reduction of serum ChE by herbicides is probably related to cytochrome P450 (CYP450) family polymorphisms. We suspect that the abnormal ChE caused by GLP could be correlated with the CYP family members. To determine whether CYP1B1 (rs1056827 and rs1056836) and CYP1A1 (rs1048943) gene polymorphisms and individual susceptibility to GLP-induced ChE abnormalities were interrelated in the Chinese Han population, we performed this genetic association study on a total of 230 workers previously exposed to GLP, including 115 cases with reduced serum ChE and 115 controls with normal serum ChE. Two even groups of cases and controls were enrolled. The CYP1A1 and CYP1B1 polymorphisms in both groups were genotyped using TaqMan. Subjects with the CYP1A1 rs619586 genotypes showed an increased risk of GLP-induced reduction of serum ChE, which was more evident in the following subgroups: female,>35 years old, history of GLP exposure time<10 years and>10 years, nonsmoker and nondrinker. The results show that CYP1A1 rs619586 was significantly associated with the GLP-induced reduction in serum ChE and could be a biomarker of susceptibility for Chinese GLP exposed workers. Because of a large number of people exposed to glyphosate, this study has a significance in protecting their health. FULL TEXT
Perro, 2019
Perro, Michelle, “Childhood Leukemia, the Microbiome, and Glyphosate: A Doctor’s Perspective,” GMOScience.org, January 15, 2019.
SUMMARY:
- Childhood leukemia is on the rise
- Exposure to pesticides is known to increase the risk of childhood leukemia, as well as other types of cancer
- New research links an impoverished gut microbiome (bacterial community) and chronic inflammation with increased risk of childhood leukemia
- Diet-related ways are being sought to improve the microbiome and prevent the inflammation that triggers childhood leukemia
- Glyphosate herbicides are used on around 90% of GM crops; glyphosate has been classified as a probable carcinogen by the World Health Organization’s cancer agency IARC
- Exposure to glyphosate-based and other pesticides has been shown to disrupt the gut microbiome in laboratory animals
- People who eat organic food have been found to have a 25% reduced risk of cancer
- Clinical experience shows that switching to an organic and non-GMO diet improves people’s health
- Controlled studies are needed to verify how switching to an organic and non-GMO diet affects the microbiome and certain disease conditions.