Bromacil is a chemical compound that functions as a herbicide. It was first registered as a pesticide in the U.S. in 1961. Its primary purpose is to control unwanted plant growth, acting as a broad-spectrum herbicide to manage various annual and perennial weeds and brush.
How Bromacil Works
Bromacil functions as a photosystem II inhibitor, a classification of herbicides that disrupt the process of photosynthesis in plants. Absorbed by a plant, primarily through its root system, bromacil moves upward through the xylem vessels to the leaves. It travels throughout the plant tissues, targeting the entire plant, including the roots.
Once in the leaves, bromacil interferes with the light-harvesting complexes by blocking the photosystem II reaction, which prevents the conversion of light energy into chemical energy. This inhibits the plant’s ability to produce sugars and amino acids, substances essential for its growth and survival. The plant gradually weakens and eventually dies. Visible effects of bromacil on weeds may take several weeks to become apparent, as it is a slow-acting herbicide.
Common Applications
Bromacil is widely applied for broad-spectrum weed control, particularly in non-crop areas where complete vegetation removal is desired. These areas include industrial sites, along railroads, around electrical switching stations, and near fences. It serves as a bare-ground herbicide, aiming to prevent all plant growth in the treated area.
Bromacil is also used for selective weed control in specific agricultural contexts, such as citrus groves and pineapple fields. In these applications, it controls a range of annual and perennial weeds while allowing cultivated crops to thrive. It is known for its effectiveness against perennial grasses. The herbicide is available in various formulations, including granular, liquid, and wettable powder forms, and can be applied using sprayers or spreaders.
Environmental Impact
Bromacil’s environmental impact is a concern due to its persistence in soil and potential to move into groundwater. Its half-life in soils can range from 60 days to 8 months. Moderate solubility in water and light adsorption to soil particles allow it to leach readily through the soil profile, potentially contaminating groundwater.
The herbicide can also affect non-target vegetation if not applied carefully, as it inhibits photosynthesis in any plant it contacts. This includes harming shade trees or other desirable plants near the application site. Bromacil shows low to moderate toxicity to most fauna, but concerns exist regarding its potential effects on aquatic ecosystems. It does not tend to accumulate significantly in fish tissue. Proper application is important to minimize environmental spread and reduce risks to non-target organisms.
Safety and Regulatory Oversight
Handling bromacil requires specific safety precautions to minimize exposure risks. Individuals mixing, loading, or applying bromacil products should wear personal protective equipment (PPE), including long-sleeved shirts, long pants, chemical-resistant gloves, and shoes plus socks. For wettable powder formulations, a dust mask is also recommended.
Proper storage and disposal are important to prevent accidental exposure or environmental contamination. Bromacil should be stored in its original container in a cool, dry place, separate from fertilizers, food, and feed. Empty containers should be completely emptied into application equipment and then disposed of in a sanitary landfill, by incineration, or through other methods approved by local authorities. Preventing contamination of surface or groundwater during equipment cleaning or waste disposal is also emphasized on product labels.
Governmental bodies, such as the U.S. Environmental Protection Agency (EPA), regulate bromacil to ensure its safe use and minimize risks. The EPA requires all pesticides sold in the U.S. to be registered based on scientific studies demonstrating they can be used without posing unreasonable risks to people or the environment. Regulations like 40 Code of Federal Regulations (CFR) Part 180 govern allowable residues of bromacil in food crops like citrus and pineapple, where tolerances have been established at 0.1 parts per million (ppm). The EPA has also mandated mitigation measures, such as reducing application rates, to address potential environmental and worker risks.