Nonpoint source contamination of the Mississippi River and its tributaries by herbicides

Pereira, Wilfred E.; Hostettler, Frances D.

doi:10.1021/es00045a008

Cited by 183 publications

(118 citation statements)

References 18 publications

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“…Furthermore, bicarbonate is the major anion in streams and rivers and is linked to many other element cycles, so large scale changes in bicarbonate demand compensating changes in other important ions, such as calcium and silica 28 . Finally, any element (for example, nitrogen or phosphorus) 22,29 or pollutant 22,29 that has elevated fluxes due to agricultural practices is undoubtedly also being affected by the increase in discharge from agricultural watersheds, potentially on a similar scale to those reported here for bicarbonate.…”

mentioning

confidence: 59%

Anthropogenically enhanced fluxes of water and carbon from the Mississippi River

Raymond

Turner

et al. 2008

Nature

528

384

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The water and dissolved inorganic carbon exported by rivers are important net fluxes that connect terrestrial and oceanic water and carbon reservoirs 1 . For most rivers, the majority of dissolved inorganic carbon is in the form of bicarbonate. The riverine bicarbonate flux originates mainly from the dissolution of rock minerals by soil water carbon dioxide, a process called chemical weathering, which controls the buffering capacity and mineral content of receiving streams and rivers 2 . Here we introduce an unprecedented high-temporal-resolution, 100-year data set from the Mississippi River and couple it with sub-watershed and precipitation data to reveal that the large increase in bicarbonate flux that has occurred over the past 50 years (ref.3) is clearly anthropogenically driven. We show that the increase in bicarbonate and water fluxes is caused mainly by an increase in discharge from agricultural watersheds that has not been balanced by a rise in precipitation, which is also relevant to nutrient and pesticide fluxes to the Gulf of Mexico. These findings demonstrate that alterations in chemical weathering are relevant to improving contemporary biogeochemical budgets. Furthermore, land use change and management were arguably more important than changes in climate and plant CO 2 fertilization to increases in riverine water and carbon export from this large region over the past 50 years.The riverine bicarbonate flux is a sink for atmospheric CO 2 and a small but important net flux in terrestrial systems. In the preindustrial era, chemical weathering of silicate versus carbonate minerals sequestered CO 2 for disparate timescales owing to carbonate deposition in the oceans, with silicate weathering sequestering atmospheric CO 2 for millions of years and carbonate weathering for only tens to hundreds of thousands of years 4 . Oceanic acidification 5 , however, has changed the solubility of CaCO 3 , and considerably lengthened the timescale for CO 2 sequestration by carbonate weathering. Although the positive feedbacks between global change and chemical weathering are used in geochemical models of atmospheric CO 2 (ref. 6), these feedbacks are believed to operate on long timescales and are therefore generally left out of the current discussion on human alterations of the carbon budget. Current global carbon budgets, for example, assume that pre-and post-anthropogenic riverine carbon fluxes are equal 1 .

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mentioning

confidence: 59%

Anthropogenically enhanced fluxes of water and carbon from the Mississippi River

Raymond

Turner

et al. 2008

Nature

528

384

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“…However, toxic effects such as ultrastructural change in testes of gobiid fish, reduction in larval production in sand fiddler crabs, chronic toxicity in hens, acute toxicity in birds, reptiles, and fish, and decreases in muscarinic receptor function in rat retina have been reported (Mullie et al 1999;Schoor et al 2000;Tandon et al 1994;Tuler and Bowen 1999;Zutshi and Murthy 2001). Furthermore, it has been reported that fenthion and its oxidation products, fenthion sulfoxide and fenthion oxon, contaminate olives, mosquitos, fish, and the environment (Cavanna and Molinari 1998;Fukushima 1991;Kitamura et al 2000;Lacorte et al 1997;Meyer et al 1998;Peiris and Hemingway 1996;Pereira and Hostettler 1993;Prasad et al 1997;Tsuda et al 1996). The relationship between the toxicity and metabolism of fenthion has been examined in human neuroblastoma cell lines, birds, and fish, and either an increase or a decrease in toxicity as a result of metabolism was found (Cova et al 1995;Kitamura et al 2000;Roux et al 1995).…”

Section: Fenthion [Oo-dimethyl-o-(4-methylmercapto)-3-methylphenylthmentioning

confidence: 99%

Antiandrogenic activity and metabolism of the organophosphorus pesticide fenthion and related compounds.

Kawa

Suzuki

Ohta

et al. 2003

Environ Health Perspect

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We investigated the endocrine-disrupting actions of the organophosphorus pesticide fenthion and related compounds and the influence of metabolic transformation on the activities of these compounds. Fenthion acted as an antagonist of the androgenic activity of dihydrotestosterone (10(-7)M) in the concentration range of 10(-6)-10(-4)M in an androgen-responsive element-luciferase reporter-responsive assay using NIH3T3 cells. The antiandrogenic activity of fenthion was similar in magnitude to that of flutamide. Fenthion also tested positive in the Hershberger assay using castrated male rats. Marked estrogenic and antiestrogenic activities of fenthion and related compounds were not observed in MCF-7 cells. When fenthion was incubated with rat liver microsomes in the presence of NADPH, the antiandrogenic activity markedly decreased, and fenthion sulfoxide was detected as a major metabolite. The oxidase activity toward fenthion was exhibited by cytochrome P450 and flavin-containing monooxygenase. Fenthion sulfoxide was negative in the screening test for antiandrogens, as was fenthion sulfone. However, when fenthion sulfoxide was incubated with liver cytosol in the presence of 2-hydroxypyrimidine, an electron donor of aldehyde oxidase, the extract of the incubation mixture exhibited antiandrogenic activity. In this case, fenthion was detected as a major metabolite of the sulfoxide. Metabolic interconversion between fenthion and fenthion sulfoxide in the body seems to maintain the antiandrogenic activity.

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“…The rapid reduction of the concentration of propanil from 3600 to 0.1 µg L -1 is due to its fast hydrolysis (Barceló et al, 1998). However, propanil and its metabolite 3,4-dichloroaniline (3,4-DCA) can constitute a risk for surface waters and for human health (Pereira & Hostettler, 1992;Pastorelli et al 1998). Monitoring studies of surface water carried out in the USA showed that 3% of the 1560 analyzed samples contained propanil in a concentration of up to 2 µg L -1 and 3,4-DCA was detected in 50% of the samples with concentration of up to 8,9 µg L -1 (EPA, 2006).…”

Section: Wwwintechopencommentioning

confidence: 99%

Herbicides Persistence in Rice Paddy Water in Southern Brazil

Zanella¹,

Adaime²,

Peixoto³

et al. 2011

Herbicides - Mechanisms and Mode of Action

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Nonpoint source contamination of the Mississippi River and its tributaries by herbicides

Cited by 183 publications

References 18 publications

Anthropogenically enhanced fluxes of water and carbon from the Mississippi River

Anthropogenically enhanced fluxes of water and carbon from the Mississippi River

Antiandrogenic activity and metabolism of the organophosphorus pesticide fenthion and related compounds.

Herbicides Persistence in Rice Paddy Water in Southern Brazil

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