New incident report
Incident Report Number: 2024-0077
Registrant Reference Number: M-782675-01-1
Registrant Name (Full Legal Name no abbreviations): BAYER CROPSCIENCE INC.
Address: 160 QUARRY PARK BOULEVARD SE SUITE 130
City: CALGARY
Prov / State: AB
Country: CANADA
Postal Code: T2C 3G3
Scientific Study
PMRA Registration No. 19204 PMRA Submission No. EPA Registration No.
Product Name: PHENMEDIPHAM TECHNICAL HERBICIDE
Unknown
Unknown
Title Lemna gibba G3 - Growth inhibition test with Phenmedipham TC under semi-static conditions
Date 08-DEC-21
No
Increased health or environmental risk
The active substance, phenmedipham, was tested on Duckweed (Lemna gibba) for 7 days in a semi-static exposure system to nominal concentrations of: 0 (control) and solvent control (dimethylformamide at 0.1 AuL/mL), 0.200, 0.633, 2.00, 6.33, 20.0, 63.3 and 200 Aug a.s./L (corresponding to geometric mean-measured concentrations of 0.131, 0.388, 0.963, 3.10, 11.6, 44.6 and 163 Aug a.s./L). Treatment endpoint inhibition levels were compared to the pooled controls. Test conditions met all guideline validity criteria. The 7-day ErC50=33 Aug a.s/L (95% C.L. = 31.1 to 35.9 Aug a.s./L), was based on mean growth rate of frond numbers, and the 7-day ErC50=69.3 Aug a.s/L (95% C.L. = 62.2 to 77.5 Aug a.s./L), was based on mean growth rate of plant dry weight. These values were lower than the current Lemna minor EC50 value of 160 I 1/4g a.i./L that is considered in the risk assessment and thus would meet the criteria for adverse effects reporting. [Scheerbaum, D.; (1998) Phenmedipham: Substance Technical: 98.5% w/w: Code: AE B038584 00 1D98 00: Lemna minor: Semi-Static Phytotoxicity Test..; MRID 49682516].
Yes
Phenmedipham is moderately toxic to freshwater aquatic organisms on an acute exposure basis. The vascular aquatic plant study with phenmedipham active substance met reportability criteria for Canada due to lower endpoints as compared to the duckweed study with Lemna minor. The lower endpoints do not affect the risk assessment for phenmedipham as the level of concern was low for adverse effects to vascular aquatic plants.