Related Experiment Video
Updated: May 26, 2026
05:20
Determination of 45 Pesticides in Avocado Varieties by the QuEChERS Method and Gas Chromatography-Tandem Mass Spectrometry
Published on: December 8, 2023
Exceptional use: examining methyl bromide applications in California 2016-2022
Yoshira Ornelas Van Horne1, Jill E Johnston2
1Department of Environmental Health Sciences, Fielding School of Public Health, University of California Los Angeles, Los Angeles, CA 90095, United States of America.
Environmental Research Communications
|May 25, 2026
Summary
Methyl bromide (MeBr) fumigation persists in California despite its toxicity and ozone-depleting nature. Data from 2016-2022 reveals continued use in 36 counties, with Los Angeles being the highest application area.
Area of Science:
- Environmental Science
- Toxicology
- Public Health
Background:
- Methyl bromide (MeBr) is a fumigant with known toxic effects on development, neurology, and respiration.
- MeBr is an ozone-depleting substance regulated under the Montreal Protocol, with phase-out targets and critical use exemptions.
- Despite phase-out efforts, MeBr continues to be used for quarantine and preshipment fumigation.
Purpose of the Study:
- To analyze the spatial and temporal patterns of MeBr use in California from 2016 to 2022.
- To assess non-agricultural MeBr applications and associated public exposure risks.
- To evaluate ambient MeBr concentrations in high-use areas and compare them to established standards.
Main Methods:
- Utilized publicly available pesticide application data for MeBr in California (2016-2022).
- Quantified MeBr quantities applied for non-agricultural fumigation across different counties.
- Monitored ambient MeBr concentrations in specific communities, including West Long Beach.
Main Results:
- MeBr applications were recorded in 36 out of 58 California counties.
- Over 582,000 kg of MeBr were applied for non-agricultural fumigation across 25 counties between 2016-2022.
- Los Angeles County accounted for 46% of total non-agricultural MeBr use, with ambient concentrations exceeding state standards in West Long Beach.
Conclusions:
- Continued MeBr use, particularly in populated areas like Los Angeles, poses ongoing public health risks.
- The study highlights the need for re-evaluation of chemical phase-out policies and enhanced monitoring and enforcement.
- Improved regulatory oversight is crucial to ensure public health protection from toxic fumigants like MeBr.
Related Concept Videos
01:27Chemical Agents for Microbial Control
Chemicals play important roles in controlling microbial growth by targeting microbial structures and functions as sanitizers, antiseptics, disinfectants, and sterilants.Alcohols are commonly used sanitizers, effectively disrupting lipid membranes, which compromises cell integrity. They are also used as antiseptics and disinfectants due to their rapid action and versatility.Phenols and their derivatives phenolics , known for denaturing proteins and disrupting cell membranes, are particularly...
01:27Radical Substitution: Halogenation of Alkanes and Alkyl Substituents
In the presence of heat or light, alkanes react with molecular halogens to form alkyl halides by a substitution reaction called radical halogenation. This reaction has three steps: initiation, propagation, and termination, as seen in the radical chlorination of methane to produce methyl chloride.
In the initiation step of the reaction, the chlorine molecule undergoes homolytic cleavage in the presence of light or heat, forming two highly reactive chlorine radicals. Propagation occurs in two...
In the initiation step of the reaction, the chlorine molecule undergoes homolytic cleavage in the presence of light or heat, forming two highly reactive chlorine radicals. Propagation occurs in two...
02:46Halogenation of Alkenes
Halogenation is the addition of chlorine or bromine across the double bond in an alkene to yield a vicinal dihalide. The reaction occurs in the presence of inert and non-nucleophilic solvents, such as methylene chloride, chloroform, or carbon tetrachloride.
Consider the bromination of cyclopentene. Molecular bromine is polarized in the proximity of the π electrons of cyclopentene. An electrophilic bromine atom adds across the double bond, forming a cyclic bromonium ion intermediate.
Consider the bromination of cyclopentene. Molecular bromine is polarized in the proximity of the π electrons of cyclopentene. An electrophilic bromine atom adds across the double bond, forming a cyclic bromonium ion intermediate.
01:28Microbial Bioremediation of Pesticides
Pesticides often feature structurally complex chemical architectures, incorporating halogen groups and multiple aromatic rings. These characteristics confer high chemical stability, rendering many pesticides resistant to natural degradation processes. This resistance poses significant environmental concerns, as persistent pesticide residues can accumulate in ecosystems and affect non-target organisms.Despite the inherent stability of many pesticides, certain microorganisms possess the metabolic...
01:33Carboxylic Acids to Methylesters: Alkylation using Diazomethane
Carboxylic acids react with diazomethane in an ether solvent via alkylation at the carboxylate oxygen atom to give methyl esters of the corresponding acid with excellent yields.