Atrazine aquatic plants

These high levels were sporadic and transitory. However, some of them were high enough to have caused phytotoxicity, and more work needs to be done to establish whether herbicides are having adverse effects upon populations of aquatic plants in areas highlighted in this study. It should also be borne in mind that there may have been additive or synergistic effects caused by the combinations of herbicides found in these samples. For example, urea herbicides such as diuron and chlortoluron act upon photosynthesis by a common mechanism, so it seems likely that any effects upon aquatic plants will be additive. Similarly, simazine and atrazine share a common mechanism of action. 

Atrazine effects on selected species of aquatic plants... 

Table 11.4 (continued) Atrazine Effects on Selected Species of Aquatic Plants... 

Forney, D.R. 1980. Effects of Atrazine on Chesapeake Bay Aquatic Plants. M.S. Thesis. Auburn University, Auburn, AL. 76 pp. 

Jones, T.W. and PS. Estes. 1984. Uptake and phytotoxicity of soil-sorbed atrazine for the submerged aquatic plant, Potamogeton perfoliatus L. Arch. Environ. Contam. Toxicol. 13 237-241. 

FIGURE 4.5 Risk curves based on exposure distribution for annual maximum atrazine concentrations in Tennessee ponds and chronic species sensitivity distributions for aquatic plants and animals. 

Aquatic animals were less sensitive to the triazines than were aquatic plants. Toxicity to fish and arthropods varied, with fish or crustaceans sharing the position of most sensitive aquatic animal, depending on the herbicide. In the case of atrazine, arthropods were generally more sensitive than fish. Ratios of the 10th centiles between animals and plants were varied. The animal/plant ratio for atrazine (arthropods) was 24, while hexazinone was 202800. The hexazinone data were from a small data set, and the atrazine data were for arthropods and could not be compared to data for the other triazines. However, the ratios for the other triazines also varied over an order of magnitude, from 176 for prometon to 1688 for prometryn. Since the molecular weights of the triazines are similar, one would expect their... 

Some authorities, however, suggest that the effects of atrazine on aquatic plants may be substantial. For example, atrazine concentrations between 1.0 and 5.0 xg/L adversely affect phytoplankton growth and succession this, in turn, can adversely affect higher levels of the food chain, beginning with the zooplankton. Also, exposure to environmentally realistic concentrations of 3.2-12.0 tLg atrazine/L for about 7 weeks was demonstrably harmful to wild celery... 

II. 0 xg/L for salt marsh algae, based on the least effect level of 110.0 Jig/L, and an uncertainty factor of 10. Atrazine concentrations >11.0 xg/L sometimes occur during periods of runoff and non-flushing, but rarely persist at levels necessary to markedly inhibit photosynthesis in aquatic plants, i.e., 60.0-70.0 xg/L. At 80.0 xg/L, rainbow trout show kidney necrosis of endothelial cells after exposure for 28 days, and this suggests that atrazine criteria that protect sensitive plants will also protect aquatic vertebrates. 

Skipper HD, Gilmour CM, Furtick WR (1967) Microbial versus chemical degradation of atrazine in soils. Soil Sci Soc Am Proc 31 653-656 Sliwinski MK, Goodman RM (2004) Comparison of cienarchaeal consortia inhabiting the rhizosphere of diverse terrestrial plants with those in bulk soil in native environments. Appl Environ Microbiol 70 1821-1826 Stumm W, Morgan JJ (1996). Aquatic chemistry - chemical equlibrium and rates in Natural Waters (3rd edn). Wiley, New York Vega D, Bastide J (2003) Dimethylphthalate hydrolysis by specific microbial esterase. Chemosphere 51 663-668... 

Atmospheric transport of atrazine-contaminated aerosol particulates, dusts, and soils may contribute significantly to atrazine burdens of terrestrial and aquatic ecosystems. The annual atmospheric input of atrazine in rainfall to the Rhode River, Maryland, as one example, was estimated at 1016 mg/surface ha in 1977, and 97 mg/ha in 1978 (Wu 1981). A similar situation exists with fog water. When fog forms, exposed plant surfaces become saturated with liquid for the duration of the fog (Glotfelty et al. 1987). 

Correll, D.L. and T.L. Wu. 1982. Atrazine toxicity to submersed vascular plants in simulated estuarine microcosms. Aquat. Bot. 14 151-158. 

In the United States, about 80% of the 23 million kg of technical PCP produced annually — or about 46% of worldwide production — is used mainly for wood preservation, especially utility poles (Pignatello etal. 1983 Kinzell etal. 1985 Zischke etal. 1985 Choudhury etal. 1986 Mikesell and Boyd 1986 USPHS 1994). It is the third most heavily used pesticide, preceded only by the herbicides atrazine and alachlor (Kinzell et al. 1981). Pentachlorophenol is a restricted-use pesticide and is no longer available for home use (USPHS 1994). Before it became a restricted-use pesticide, annual environmental releases of PCP from production and use were 0.6 million kg to the atmosphere from wood preservation plants and cooling towers, 0.9 million kg to land from wood preservation use, and 17,000 kg to aquatic ecosystems in runoff waters of wood treatment plants (USPHS 1994). There are about 470 wood preservative facilities in the United States, scattered among 45 states. They are concentrated in the South, Southeast, and Northwest — presumably due to the availability of preferred timber species in those regions (Cirelli 1978). Livestock facilities are often constructed of wood treated with technical PCP about 50% of all dairy farms in Michigan used PCP-treated wood in the construction of various components of livestock facilities (Kinzell et al. 1985). The chemical is usually applied to wood products after dilution to 5% with solvents such as mineral spirits, No. 2 fuel oil, or kerosene. More than 98% of all wood processed is treated with preservative under pressure about 0.23 kg of PCP is needed to preserve 1 cubic foot of wood (Cirelli 1978). Lumber treated with PCP retains its natural appearance, has little or no odor, and can be painted as readily as natural wood (Wood et al. 1983). 

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