Sorption, mineralization and mobility of N-(phosphonomethyl)glycine (glyphosate) in five different types of gravel

TY - JOUR

T1 - Sorption, mineralization and mobility of N-(phosphonomethyl)glycine (glyphosate) in five different types of gravel

AU - Strange-Hansen, R

AU - Holm, PE

AU - Jacobsen, OS

AU - Jacobsen, Carsten Suhr

PY - 2004/6

Y1 - 2004/6

N2 - Sorption, mineralization and mobility of glyphosate were studied in six substrates: the five types of gravel most frequently used as surfacing in Denmark and a sandy agricultural soil from Simmelkaer that served as a reference soil. Cumulative mineralization of [methyl-C-14]glyphosate in batch studies was highest in coarse gravel, amounting to 14% after 4 days at 30degreesC and 32% after 31 days. Mineralization was slowest in the sandy reference soil, amounting to only 2% after 31 days. The adsorption coefficient (K-d) of glyphosate in gravel ranged from 62 to 164 litre kg(-1) while that in the sandy reference soil was 410 litre kg(-1). The results indicate that the relatively low K-d in gravel allows a relatively high rate of glyphosate mineralization by the biomass. When K-d is high, in contrast, mineralization is slow. Lowering the temperature to 10 degreesC decreased mineralization by 50% in one of two gravels. The leaching of glyphosate was screened in simple columns of gravel or soil in which precipitation events (20 mm over a 2-h period) were simulated on three occasions, starting either immediately after or 2 days after application of glyphosate. [C-14]Glyphosate was applied as a tracer mixed with the commercial product Roundup((R)) Garden at the recommended rate of 2.4 kg glyphosate ha(-1), equivalent to 1 mug g(-1) soil. The highest concentration of [C-14] compounds (expressed in terms of glyphosate concentration) in leachate from the columns exceeded 1300 mug litre(-1), and was detected in rounded gravel after the first rain event. No glyphosate was detected in leachate from the sandy reference soil. (C) 2004 Society of Chemical Industry.

AB - Sorption, mineralization and mobility of glyphosate were studied in six substrates: the five types of gravel most frequently used as surfacing in Denmark and a sandy agricultural soil from Simmelkaer that served as a reference soil. Cumulative mineralization of [methyl-C-14]glyphosate in batch studies was highest in coarse gravel, amounting to 14% after 4 days at 30degreesC and 32% after 31 days. Mineralization was slowest in the sandy reference soil, amounting to only 2% after 31 days. The adsorption coefficient (K-d) of glyphosate in gravel ranged from 62 to 164 litre kg(-1) while that in the sandy reference soil was 410 litre kg(-1). The results indicate that the relatively low K-d in gravel allows a relatively high rate of glyphosate mineralization by the biomass. When K-d is high, in contrast, mineralization is slow. Lowering the temperature to 10 degreesC decreased mineralization by 50% in one of two gravels. The leaching of glyphosate was screened in simple columns of gravel or soil in which precipitation events (20 mm over a 2-h period) were simulated on three occasions, starting either immediately after or 2 days after application of glyphosate. [C-14]Glyphosate was applied as a tracer mixed with the commercial product Roundup((R)) Garden at the recommended rate of 2.4 kg glyphosate ha(-1), equivalent to 1 mug g(-1) soil. The highest concentration of [C-14] compounds (expressed in terms of glyphosate concentration) in leachate from the columns exceeded 1300 mug litre(-1), and was detected in rounded gravel after the first rain event. No glyphosate was detected in leachate from the sandy reference soil. (C) 2004 Society of Chemical Industry.

KW - N-(phosphonomethyl)glycine

KW - glyphosate

KW - mineralization

KW - sorption

KW - mobility

KW - gravel

KW - PHOSPHONATE HERBICIDE GLYPHOSATE

KW - CLAY-MINERALS

KW - MICROBIAL-DEGRADATION

KW - ADSORPTION

KW - SOILS

KW - DESORPTION

KW - PHOSPHATE

KW - WATER

KW - ACID

U2 - 10.1002/ps.842

DO - 10.1002/ps.842

M3 - Journal article

C2 - 15198330

SN - 1526-498X

VL - 60

SP - 570

EP - 578

JO - Pest Management Science

JF - Pest Management Science

IS - 6

T2 - International Symposium on Non-agricultural Use of Pesticides

Y2 - 7 May 2003 through 9 May 2003

ER -