Combined effects of the fungicide propiconazole and agricultural runoff sediments on the aquatic bryophyte Vesicularia dubyana

Abstract

Pesticides, firmly attached to the topsoil, might enter nearby watercourses at periods with high erosive loss of sediments. Therefore, exposure of aquatic organisms to these low mobility pesticides, in many cases, will coincide with a high sediment concentration. In this study, both individual and combined effects of propiconazole and runoff sediment on the aquatic model bryophyte Vesicularia dubyana are studied. Individual exposure to propiconazole induced responses in V. dubyana at rather low concentration levels (approximately 1 microg/L), showing that harmful effects of propiconazole potentially may occur in watercourses draining propiconazole-treated fields. Individual exposure to the sediment size fractions S1 (0.16-2 microm) and S2 (0.03-0.16 microm) caused plant stress at a concentration of 100 mg/L. The coarser fraction S1 showed strong inhibition effects on photosynthesis, probably due to light attenuation. Compared to S1, the suspension with the finer fraction S2 showed lower turbidity, higher nutrient content, and a higher proportion of sediment-bound propiconazole. The combined effects of propiconazole and suspended sediment are dependent on concentrations of sediment and propiconazole. At low sediment concentration (e.g., 100 mg/L), neither S1 nor S2 reduce the toxicity of propiconazole, as only 2% of propiconazole are bound to particles. An increase in sediment concentration decreases the bioavailable concentration of propiconazole; however, at the same time, this increases the turbidity, thereby inhibiting plant photosynthesis.

Determination of acid dissociation constants of triazole fungicides by pressure assisted capillary electrophoresis

“…Usage of these corrections results in 0.14-0.5 pH unit decrease of pK a values as compared to pK a values calculated from the non-corrected effective mobilities. For comparison, the values of the acid dissociation constants of the triazole fungicides and the 1,2,4-triazole itself calculated by SPARC online calculator [39] and pK a s found in the literature [8,14,40,41] are also listed in this Table. The pK a s determined by pCE in this work are slightly higher than the values calculated by SPARC online calculator [39]. The highest difference between the calculated and the experimentally determined pK a was observed for flusilazole, which contains silicon atom in its structure.…”

Investigating Potential Water Quality Impacts of Fungicides Used to Combat Soybean Rust in Indiana

“…Potter et al (2001) showed that the fungicide chlorothalonil presented a risk to aquatic life as a result of runoff from treated fields in southeastern states. Wu et al (2005) observed that propiconazole was toxic to aquatic bryophytes at low concentrations.…”

Micropollutants in three tributaries of Lake Constance, Argen, Schussen and Seefelder Aach: a literature review

“…20000 Widenfalk et al [137] Mikroorganismen (Sediment) Bakterielle Aktivität 0,09 Johansson et al [135] Rana temporaria Larvalentwicklung 416000 Continued overleaf [139] Daphnia magna Entwicklung 250 Hurst & Sheahan [124] Saccharomyces cerevisiae Hefezell-Östrogentest 12500 (Routledge & Sumpter 1996) Wu et al [140] Vesicularia dubyana (Javamoos) Photosyntheserate 1 Bringolf et al [141] Lampsilis siliquoidea Glochidien-Tox. 19210 (48 h) Juvenil-Tox.…”