Concentration and Transport of Chlordane and Nonachlor Associated with Suspended Sediment in the Mississippi River, May 1988 to June 1990

Ce, Rostad

doi:10.1007/s002449900266

Cited by 8 publications

(4 citation statements)

References 33 publications

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“…In the past, researchers investigating contaminant transport along the Mississippi River have used measurements from sites in Southern Louisiana to estimate the pesticide load discharged into the Gulf of Mexico ( − ). From the data presented here, we can provide an estimate of the annual amount of toxaphene discharged into the Gulf of Mexico by the Mississippi River.…”

Section: Resultsmentioning

confidence: 99%

Transport of Suspended-Sediment-Bound Toxaphene in the Mississippi River

Raff

Hites

2004

Environ. Sci. Technol.

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Suspended sediment samples from ∼30 locations along the Mississippi River and six of its major tributaries were collected during July and August 2002 and March 2003 to investigate the distribution and transport of toxaphene in the Mississippi River. The concentration of toxaphene was measured, and the load of toxaphene carried by the river at each site was calculated using water discharge and suspended sediment concentrations. Results indicate that toxaphene is widespread throughout the Mississippi River Basin with the highest concentrations and loads observed for samples collected in the Lower Mississippi River. Among the tributaries, the Yazoo River carried the largest load, amounting to ∼21% of the estimated load carried by the Mississippi River just below Vicksburg, MS. The majority of the contamination is most likely from nonpoint source runoff from agricultural lands. We also found evidence of a localized toxaphene source in the vicinity of Memphis, perhaps coming from the Wolf River. From our data we estimate that between 200 and 1000 kg of toxaphene were released into the Gulf of Mexico in 2002 from the main stem of the Mississippi River.

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Section: Resultsmentioning

confidence: 99%

Transport of Suspended-Sediment-Bound Toxaphene in the Mississippi River

Raff

Hites

2004

Environ. Sci. Technol.

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“…It was reported that the ratio of cis-chlordane to trans-chlordane in technical chlordane is 0.79 (Dearth and Hites 1991;Rostad 1997). The cis-chlordane to trans-chlordane ratios were around 0.79 dominantly in waters, sediments, and soils both in the underground river and in the surface systems, which indicate that the sources were derived from commercial chlordane in waters, sediments, and soils (Fig.…”

Section: Seasonal Variations Of Ocps In Different Samplesmentioning

confidence: 82%

“…The ratio of heptachlor to trans-chlordane corresponds to 3.5 in commercial grade heptachlor, while it is 0.5 in commercial grade chlordane (Rostad 1997;Tomlin 1999). Sci (2014Sci ( ) 71:1977Sci ( -1987Sci ( 1981 The ratios of heptachlor to trans-chlordane in groundwaters and surface waters were around 0.5.…”

Section: Seasonal Variations Of Ocps In Different Samplesmentioning

confidence: 99%

Sources and transports of organochlorine pesticides in the Nanshan underground river, China

et al. 2013

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Karst areas have much higher ecological vulnerability and are prone to be contaminated. Organochlorine pesticides (OCPs) were detected in waters and sediment from the two sites of the karst Nanshan underground river system, China, to understand the sources and transport of OCPs in the underground river systems. Obviously, seasonal variations were found both in the waters and the sediments. Detected OCPs ranged from 61 to 936 ng L -1 in the groundwaters and 51-3,842.0 ng g -1 in the underground sediments, respectively. OCPs in groundwaters were mixture of younger and older residues from commercial sources. The maximum OCPs in the sediments of the underground river were historically older residues from commercial sources. The sources of OCPs in the waters and sediments of the underground river indicated that the surface systems play an important role in OCPs transport and pollution in the underground river. Karst features were liable for the transport behavior.

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“…P ollution of aquatic systems through runoff from agricultural fields is a major environmental problem worldwide. Pesticides both in suspension and incorporated into depositional sediments are considered potential pollutant sources (Rostad, 1997; Gilliom et al, 1999; Schulz and Liess, 2001). Propiconazole (Fig.…”

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confidence: 99%

Size Distribution of Organic Matter and Associated Propiconazole in Agricultural Runoff Material

Riise

Kretzschmar

2003

J of Env Quality

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Sorption and desorption characteristics of propiconazole (1-[[2-(2,4-dichlorophenyl)-4-propyl-1,3-dioxolan-2-yl]methyl]-1H-1,2,4-triazole) to different particle/aggregate-size fractions of agricultural runoff material were investigated. Emphasis was put on clay and colloidal size fractions to evaluate their role as potential sorbents and carriers for this pesticide. The runoff material was separated into size fractions ranging from 2 mm to ca. 15 nm by wet sieving, sedimentation, centrifugation, and membrane ultrafiltration. Each fraction was characterized by its organic C content and C/N ratio. Distinctive sorption properties of clay-sized particles and colloids were investigated. The obtained size fractions differed significantly in their organic C concentration, C/N ratio, and sorption properties to propiconazole. Organic matter was mainly associated in aggregates >2 microm. Binding of propiconazole to this coarse fraction made up 80% of the sorbed propiconazole. The distribution coefficient between solid and aqueous phases increased with decreasing particle size. The colloidal fraction (<0.16 microm) exhibited the highest sorbtivity, with a distribution coefficient of 113 L kg(-1), which was more than four times higher than that in the bulk sample (27 L kg(-1)). The fraction <2 microm represented 8% of the total sample weight, but contributed to 20% of the sorbed propiconazole. Strong hysteresis was observed for the sorption-desorption of propiconazole on the runoff material. Under dilution very little sorbed propiconazole will be released into the water phase. Due to its high sorbtivity and mobility and the strong sorption-desorption hysteresis, particles in the fraction <2 microm can be important carriers of propiconazole in runoff suspensions with high sediment load.

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Concentration and Transport of Chlordane and Nonachlor Associated with Suspended Sediment in the Mississippi River, May 1988 to June 1990

Cited by 8 publications

References 33 publications

Transport of Suspended-Sediment-Bound Toxaphene in the Mississippi River

Transport of Suspended-Sediment-Bound Toxaphene in the Mississippi River

Sources and transports of organochlorine pesticides in the Nanshan underground river, China

Size Distribution of Organic Matter and Associated Propiconazole in Agricultural Runoff Material

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