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ACS Omega Jun 2021Halogen-halogen nonbonded interactions were studied for methyl halides and phenyl halides using both B3LYP and MP2 along with 6-311+G* and aug-cc-pVTZ. With the methyl...
Halogen-halogen nonbonded interactions were studied for methyl halides and phenyl halides using both B3LYP and MP2 along with 6-311+G* and aug-cc-pVTZ. With the methyl halides, the linear approach was found to lead to little stabilization, whereas the "90°" approach gave 1-2 kcal/mol. This modest stabilization was due to long-range electron correlation effects. The lowest-energy arrangement had the molecules side-by-side, with the major stabilization being derived from halogen-hydrogen interactions. The results for methyl bromide were quite similar. Chlorobenzene dimer with the 90° orientation gave a small stabilization energy, but the best arrangement had the two benzene rings oriented over each other. The meta orientation of the chlorines had a lower energy than ortho or para. The dimerization energy was larger than that for two benzene rings sitting directly above each other, suggesting that whereas Cl···Cl interaction is not very important, the effect of the halogen on the electron distribution does have an effect. This suggests that much of the crystallographic results for these compounds may not be due to halogen-halogen interactions but rather the interaction between the substituted benzene rings along with crystal forces.
PubMed: 34151099
DOI: 10.1021/acsomega.1c01356 -
BMJ (Clinical Research Ed.) Mar 2019To examine associations between early developmental exposure to ambient pesticides and autism spectrum disorder.
OBJECTIVE
To examine associations between early developmental exposure to ambient pesticides and autism spectrum disorder.
DESIGN
Population based case-control study.
SETTING
California's main agricultural region, Central Valley, using 1998-2010 birth data from the Office of Vital Statistics.
POPULATION
2961 individuals with a diagnosis of autism spectrum disorder based on the , fourth edition, revised (up to 31 December 2013), including 445 with intellectual disability comorbidity, were identified through records maintained at the California Department of Developmental Services and linked to their birth records. Controls derived from birth records were matched to cases 10:1 by sex and birth year.
EXPOSURE
Data from California state mandated Pesticide Use Reporting were integrated into a geographic information system tool to estimate prenatal and infant exposures to pesticides (measured as pounds of pesticides applied per acre/month within 2000 m from the maternal residence). 11 high use pesticides were selected for examination a priori according to previous evidence of neurodevelopmental toxicity in vivo or in vitro (exposure defined as ever never for each pesticide during specific developmental periods).
MAIN OUTCOME MEASURE
Odds ratios and 95% confidence intervals using multivariable logistic regression were used to assess associations between pesticide exposure and autism spectrum disorder (with or without intellectual disabilities) in offspring, adjusting for confounders.
RESULTS
Risk of autism spectrum disorder was associated with prenatal exposure to glyphosate (odds ratio 1.16, 95% confidence interval 1.06 to 1.27), chlorpyrifos (1.13, 1.05 to 1.23), diazinon (1.11, 1.01 to 1.21), malathion (1.11, 1.01 to 1.22), avermectin (1.12, 1.04 to 1.22), and permethrin (1.10, 1.01 to 1.20). For autism spectrum disorder with intellectual disability, estimated odds ratios were higher (by about 30%) for prenatal exposure to glyphosate (1.33, 1.05 to 1.69), chlorpyrifos (1.27, 1.04 to 1.56), diazinon (1.41, 1.15 to 1.73), permethrin (1.46, 1.20 to 1.78), methyl bromide (1.33, 1.07 to 1.64), and myclobutanil (1.32, 1.09 to 1.60); exposure in the first year of life increased the odds for the disorder with comorbid intellectual disability by up to 50% for some pesticide substances.
CONCLUSION
Findings suggest that an offspring's risk of autism spectrum disorder increases following prenatal exposure to ambient pesticides within 2000 m of their mother's residence during pregnancy, compared with offspring of women from the same agricultural region without such exposure. Infant exposure could further increase risks for autism spectrum disorder with comorbid intellectual disability.
Topics: Adolescent; Adult; Agriculture; Autism Spectrum Disorder; California; Case-Control Studies; Environmental Exposure; Female; Humans; Infant; Infant, Newborn; Intellectual Disability; Male; Maternal Exposure; Pesticides; Pregnancy; Prenatal Exposure Delayed Effects; Risk Factors; Sex Distribution; Young Adult
PubMed: 30894343
DOI: 10.1136/bmj.l962 -
Acta Crystallographica. Section E,... Jun 2013There are two independent mol-ecules (A and B) in the asymmetric unit of the title compound C11H10BrClO2, which represents the Z isomer. The methyl-acrylate moieties are...
There are two independent mol-ecules (A and B) in the asymmetric unit of the title compound C11H10BrClO2, which represents the Z isomer. The methyl-acrylate moieties are essentially planar, within 0.084 (2) and 0.027 (5) Å in mol-ecules A and B, respectively. The benzene ring makes dihedral angles of 13.17 (7) and 27.89 (9)° with the methyl-acrylate moiety in mol-ecules A and B, respectively. The methyl-bromide moiety is almost orthogonal to the benzene ring, making dihedral angles of 81.46 (16)° in mol-ecule A and 79.61 (16)° in mol-ecule B. The methyl-acrylate moiety exhibits an extended trans conformation in both mol-ecules. In the crystal, pairs of C-H⋯O hydrogen bonds result in the formation of quasi-centrosymmetric R 2 (2)(14) AB dimers.
PubMed: 23795037
DOI: 10.1107/S1600536813012117 -
Insects Jan 2023Invasive snails and flies are major pests of imported orchids, controlled by methyl bromide (MB) fumigation in Korea. We compared the efficacy and phytotoxicity of ethyl...
Invasive snails and flies are major pests of imported orchids, controlled by methyl bromide (MB) fumigation in Korea. We compared the efficacy and phytotoxicity of ethyl formate (EF) and MB on four species of imported orchids using juvenile stages of Achatina fulica and third and fourth instars of Lycoriella mali. EF was as effective as MB. The LCt99 values of EF were 68.1 and 73.1 g h/m3 at 15 °C; and those of MB were 95.9 and 78.4 g h/m3 at 15 °C for A. fulica and L. mali, respectively. In the scale-up trials, EF treatment at 35 g/m3 for 4 h at 15 °C resulted in complete control of both pests. MB treatment based on the current treatment guidelines for imported orchids (48 g/m3, 2 h, at >15 °C) resulted in complete control of L. mali but not of A. fulica. Chlorophyll content and hue values of treated orchids were not affected by EF treatment but significantly changed by MB (p-value < 0.05). All four treated species of orchids died within 30 d of MB treatment, while only one species died from EF treatment. Our results suggest that EF is a potential alternative to MB in phytosanitary treatment of imported orchids.
PubMed: 36661994
DOI: 10.3390/insects14010066 -
Cancer Causes & Control : CCC Jun 2012Methyl bromide is a genotoxic soil fumigant with high acute toxicity, but unknown human carcinogenicity. Although many countries have reduced methyl bromide use because...
PURPOSE
Methyl bromide is a genotoxic soil fumigant with high acute toxicity, but unknown human carcinogenicity. Although many countries have reduced methyl bromide use because of its ozone depleting properties, some uses remain in the United States and other countries, warranting further investigation of human health effects.
METHODS
We used Poisson regression to calculate rate ratios (RR) and 95 % confidence intervals (CI) for associations between methyl bromide use and all cancers combined, as well as 12 specific sites, among 53,588 Agricultural Health Study pesticide applicators with follow-up from 1993 to 2007. We also evaluated interactions with a family history for four common cancers (prostate, lung, colon, and lymphohematopoietic). We categorized methyl bromide exposure based on lifetime days applied weighted by an intensity score.
RESULTS
A total of 7,814 applicators (14.6 %) used methyl bromide, predominantly before enrollment. Based on 15 exposed cases, stomach cancer risk increased monotonically with increasing methyl bromide use (RR = 1.42; 95 % CI, 0.51-3.95 and RR = 3.13; 95 % CI, 1.25-7.80 for low and high use compared with no use; p (trend) = 0.02). No other sites displayed a significant monotonic pattern. Although we previously observed an association with prostate cancer (follow-up through 1999), the association did not persist with longer follow-up. We observed a nonsignificant elevated risk of prostate cancer with methyl bromide use among those with a family history of prostate cancer, but the interaction with a family history did not achieve statistical significance.
CONCLUSIONS
Our results provide little evidence of methyl bromide associations with cancer risk for most sites examined; however, we observed a significant exposure-dependent increase in stomach cancer risk. Small numbers of exposed cases and declining methyl bromide use might have influenced our findings. Further study is needed in more recently exposed populations to expand on these results.
Topics: Agricultural Workers' Diseases; Agriculture; Cohort Studies; Confidence Intervals; Female; Follow-Up Studies; Herbicides; Humans; Hydrocarbons, Brominated; Iowa; Male; Middle Aged; North Carolina; Occupational Exposure; Poisson Distribution; Risk Factors; Stomach Neoplasms; Surveys and Questionnaires
PubMed: 22527160
DOI: 10.1007/s10552-012-9949-2 -
Journal of Occupational Medicine and... Oct 2022Fumigants are gaseous pesticides or biocides which eradicate pests by suffocation or poisoning. Worker exposure to fumigants is mainly via inhalation, followed by dermal... (Review)
Review
Fumigants are gaseous pesticides or biocides which eradicate pests by suffocation or poisoning. Worker exposure to fumigants is mainly via inhalation, followed by dermal contact and ingestion, leading to various acute and chronic health effects. Implementation of appropriate workplace controls such as adequate ventilation, training and personal protective equipment ensure that exposure to fumigants are kept to the lowest level as practically possible. In addition, routine medical examinations also allow for doctors to identify and manage possible exposure to fumigants and ascertain workers' fitness to work.While management guidelines after an acute exposure to such fumigants is clear and consistent, the guidelines on routine medical examination for fumigators is sparse. Components of the medical examinations vary according to the fumigant, workers are exposed to and its chronic health effects. Hence, this paper highlights the health hazards of commonly utilised fumigants; Methyl Bromide, Hydrogen Cyanide, Hydrogen Phosphide and Sulfuryl Fluoride; and outlines the guidance for routine medical examinations for exposed fumigators.
PubMed: 36307823
DOI: 10.1186/s12995-022-00361-3 -
Environmental Health : a Global Access... Jan 2012Although ozone-depleting methyl bromide was destined for phase-out by 2005, it is still widely applied as a consequence of various critical-use-exemptions and mandatory... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Although ozone-depleting methyl bromide was destined for phase-out by 2005, it is still widely applied as a consequence of various critical-use-exemptions and mandatory international regulations aiming to restrict the spread of pests and alien species (e.g. in globalized transport and storage). The withdrawal of methyl bromide because of its environmental risk could fortuitously help in the containment of its human toxicity.
METHODS
We performed a systematic review of the literature, including in vitro toxicological and epidemiological studies of occupational and community exposure to the halogenated hydrocarbon pesticide methyl bromide. We focused on toxic (especially chronic) or carcinogenic effects from the use of methyl bromide, on biomonitoring data and reference values. Eligible epidemiological studies were subjected to meta-analysis.
RESULTS
Out of the 542 peer reviewed publications between 1990-2011, we found only 91 referring to toxicity of methyl bromide and 29 using the term "carcinogenic", "neoplastic" or "mutagenic". Several studies provide new additional data pertaining to the mechanistic aspects of methyl bromide toxicity. Few studies have performed a detailed exposure assessment including biomonitoring. Three evaluated epidemiological studies assessed a possible association between cancer and methyl bromide. Overall, exposure to methyl bromide is associated with an increased risk of prostate cancer OR, 1.21; 95% CI (0,98-1.49), P = 0.076. Two epidemiological studies have analyzed environmental, non-occupational exposure to methyl bromide providing evidence for its health risk to the general public. None of the epidemiological studies addressed its use as a fumigant in freight containers, although recent field and case reports do refer to its toxic effects associated with its use in shipping and storage.
CONCLUSIONS
Both the epidemiological evidence and toxicological data suggest a possible link between methyl bromide exposure and serious health problems, including prostate cancer risk from occupational and community exposure. The environmental risks of methyl bromide are not in doubt, but also its health risks, especially for genetically predisposed subjects, should not be underestimated.
Topics: Conservation of Natural Resources; Environmental Exposure; Humans; Hydrocarbons, Brominated; Male; Occupational Exposure; Pesticides; Prostatic Neoplasms; Risk Assessment
PubMed: 22284215
DOI: 10.1186/1476-069X-11-5 -
The Journal of International Medical... Oct 2022Methyl bromide is a pre-plant soil fumigant that is widely used to control nematodes, insects, and fungi in farmlands. Methyl bromide enters the human body through...
Methyl bromide is a pre-plant soil fumigant that is widely used to control nematodes, insects, and fungi in farmlands. Methyl bromide enters the human body through dermal absorption or inhalation and can damage the respiratory, nervous, circulatory, urinary, and other systems. A 62-year-old man who had inhaled a large amount of methyl bromide was admitted to our department. He presented with respiratory failure and pink foamy sputum. He was started on dexamethasone, alanyl glutamine, sulbactam, furosemide, vitamin B, mouse nerve growth factor, and other treatments, and mechanical ventilation and continuous venovenous hemodiafiltration (CVVHF) were performed daily. He subsequently developed coagulopathy because of the CVVHF, for which protamine, recombinant human brain natriuretic peptide, and albumin were administered intravenously. Notably, the patient developed sustained anuria and eventually died owing to multiple organ failure; specifically, failure of the brain, heart, lungs, and kidneys. This report presents the diagnosis, clinical course, management, and prognosis of a patient who was treated at our hospital for severe methyl bromide poisoning.
Topics: Acute Kidney Injury; Albumins; Animals; Anuria; Dexamethasone; Furosemide; Glutamine; Humans; Hydrocarbons, Brominated; Male; Mice; Middle Aged; Natriuretic Peptide, Brain; Nerve Growth Factors; Protamines; Soil; Sulbactam; Vitamins
PubMed: 36250482
DOI: 10.1177/03000605221122619