Drift, dissipation and risk to wildlife following targeted herbicide applications on boreal transmission rights-of-way
| Autor: | Chelsea L. Voinorosky, Katherine J. Stewart |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
Willow
Environmental Engineering 0208 environmental biotechnology Triclopyr Salix bebbiana 02 engineering and technology 010501 environmental sciences Management Monitoring Policy and Law Biology 01 natural sciences chemistry.chemical_compound Soil Temperate climate Ecosystem Waste Management and Disposal 0105 earth and related environmental sciences Herbivore Herbicides Salix General Medicine biology.organism_classification 020801 environmental engineering Agronomy Boreal chemistry visual_art visual_art.visual_art_medium Bark |
| Zdroj: | Journal of environmental management. 280 |
| ISSN: | 1095-8630 |
| Popis: | Herbicide use on boreal transmission line rights-of-way has been relatively limited compared to more temperate regions and therefore challenges exist in estimating and communicating the associated risks. Herbicides directly enter the ecosystem through deposition on vegetation and soils and can be a vector of contamination to browsing herbivores. Triclopyr drift and foliage concentrations were quantified following basal bark (Garlon RTU) and low-volume foliar (Garlon XRT) field treatments to aspen (Populus tremuloides) saplings and willow (Salix bebbiana) shrubs, respectively. Greater drift concentrations localized at the stem base were observed following basal bark treatments. Conversely, concentrations in foliage following the low-volume foliar treatment (DT50 = 5.7 days and DT90 = 34.6 days) were much higher than following basal bark treatment, which also required two days to translocate into the leaves. However, dissipation was rapid from both application methods and triclopyr in foliage was less than 20 μg g−1 a year following application. A risk assessment revealed an acceptable level of risk for acute toxicity to wildlife browsing on contaminated leaves from the residues detected in this study; however, an unacceptable level of risk for chronic toxicity to long-term browsing moose. Site-specific data regarding browsing behaviour on herbicide treated rights-of-ways and species-specific reference values are needed to improve confidence in the tier-two risk assessment. Basal bark application is ideal when stem density is lower and toxic effects for herbivores is of concern and low-volume foliar applications are best suited in areas with higher stem density when off-target herbicide deposition is less acceptable. |
| Databáze: | OpenAIRE |
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