Exposure to sulfosulfuron in agricultural drainage ditches: field monitoring and scenario-based modelling.
Field monitoring and scenario-based modelling were used to assess exposure of small ditches in the UK to the herbicide sulfosulfuron following transport via field drains. A site in central England on a high pH, clay soil was treated with sulfosulfuron, and concentrations were monitored in the single drain outfall and in the receiving ditch 1 km downstream. Drainflow in the nine months following application totalled 283 mm. Pesticide lost in the first 12.5 mm of flow was 99% of the total loading to drains (0.5% of applied). Significant dilution was observed in the receiving ditch and quantifiable residues were only detected in one sample (0.06 microg litre(-1)). The MACRO model was evaluated against the field data with minimal calibration. The parameterisation over-estimated the importance of macropore flow at the site. As a consequence, the maximum concentration in drainflow (2.3 microg litre(-1)) and the total loading to drains (0.76 g) were over-estimated by factors of 2.4 and 5, respectively. MACRO was then used to simulate long-term fate of the herbicide for each of 20 environmental scenarios. Resulting estimates for concentrations of sulfosulfuron in a receiving ditch were weighted according to the prevalence of each scenario to produce a probability distribution of daily exposure.
Cranfield Centre for EcoChemistry, Cranfield University, Silsoe, Bedfordshire, UK. c.brown@cranfield.ac.uk
Colin D
CD
Brown
Igor G
IG
Dubus
Paul
P
Fogg
Marie
M
Spirlet
Christophe
C
Gustin
D000383:Agriculture / Q000295:instrumentation / Q000379:methods; D004781:Environmental Exposure / Q000032:analysis*; D008954:Models, Biological; D010573:Pesticide Residues / Q000032:analysis*; D011743:Pyrimidines / Q000032:analysis*; D012987:Soil / Q000032:analysis; D013449:Sulfonamides / Q000032:analysis*; D014874:Water Pollutants, Chemical / Q000032:analysis; D014877:Water Pollution, Chemical / Q000032:analysis*
D010573:Pesticide Residues; D011743:Pyrimidines; D012987:Soil; D013449:Sulfonamides; D014874:Water Pollutants, Chemical; C439268:sulfosulfuron