Consideration of risk management practices in regulatory risk assessments: evaluation of field trials with micro-dams to reduce pesticide transport via surface runoff and soil erosion

Environmental Sciences Europe

Table 3 Results from lowering the standard values of the runoff curve number (CN; intermediate antecedent moisture conditions, AMC II) by 10%: maximum predicted environmental concentrations for surface water (PECsw,max) (µg/l), calculated using FOCUS PRZM and TOXSWA and the standard scenarios for potatoes; The recalculated PECsw,max are based on runoff mass fluxes from FOCUS PRZM, considering a dilution from the upper catchment in the stream scenarios

	Aclonifen (immobile) (1200 g ha⁻¹) [10]			Fluazinam (mod. mobile) (750 g ha⁻¹) [11]			Metribuzin [9] (highly mobile) (350 g ha⁻¹)
	Regular CN	CN − 10%	PECsw,max red. (%)	Regular CN	CN − 10%	PECsw,max red. (%)	Regular CN	CN − 10%	PECsw,max red. (%)
R1 stream^a	1.43	0.35	76	0.85	0.20	76	0.61	6.7E−03	99
R2 stream^b	0.50	0.20	60	0.21	0.08	60	1.21	0.42	66
R3 stream^c	1.83	0.50	73	1.32	0.33	75	21.1	0.22	99

The substances under investigation are aclonifen, fluazinam and metribuzin, applied once ± 14 days relative to emergence
^aACL and FLZ: event causing PECsw,max occurs on May 20th and on May 30th 1984 without and with the application of micro-dams, respectively; MTB: on May 7th and on May 20th 1984, respectively
^bAll three substances: both with and without the application of micro-dams, PECsw,max causing event occurs on March 11th 1977
^cAll three substances: event causing PECsw,max occurs on April 2nd and on April 20th 1980 without and with the application of micro-dams