Table 4.
Outcome of the aquatic risk assessment for the representative uses of S‐metolachlor at FOCUS Step 3
| Use | Fish | Aquatic invertebrates | Algae (a) | Aquatic macrophytes (b) | Sediment‐dwelling | |||
|---|---|---|---|---|---|---|---|---|
| Acute | Chronic | Acute | Chronic | |||||
| Maize |
1 × 1,440 g a.s./ha (BBCH 00–10 pre‐emergence) |
Low |
High (2/8 scenarios: R3/ and R4/ stream) |
Low |
High (3/8 scenarios: R1/,R3/ and R4/stream) |
High (8/8 scenarios: D3/ and D6/ditch; D4/, D5/, R1/, R2/, R3/ and R4/stream) |
High (8/8 scenarios: D3/ and D6/ditch; D4/, D5/, R1/, R2/, R3/ and R4/stream) |
Low |
|
1 × 1,250 g a.s./ha (BBCH 00–10 pre‐emergence) |
Low |
High (2/8 scenarios: R3/ and R4/ stream) |
Low |
High (3/8 scenarios: R1/, R3/ and R4/stream) |
High (7/8 scenarios: D3/ and D6/ditch; D5/, R1/, R2/, R3/ and R4/stream) |
High (6/8 scenarios: D3/ and D6/ditch; R1/, R2/, R3/ and R4/stream) |
Low | |
|
1 × 1,440 g a.s./ha (BBCH 11–18 post‐emergence) |
Low |
High (3/8 scenarios: R1/, R3/ and R4/stream) |
Low |
High (4/8 scenarios: R1/, R2/, R3/ and R4/stream) |
High (8/8 scenarios: D3/ and D6/ditch; D4/, D5/, R1/, R2/, R3/ and R4/stream) |
High (8/8 scenarios: D3/ and D6/ditch; D4/, D5/, R1/, R2/, R3/ and R4/stream) |
Low | |
|
1 × 1,250 g a.s./ha (BBCH 11–18 post‐emergence) |
Low |
High (2/8 scenarios: R3/ and R4/ stream) |
Low |
High (3/8 scenarios: R1/, R3/ and R4/stream) |
High (8/8 scenarios: D3/ and D6/ditch; D4/, D5/, R1/, R2/, R3/ and R4/stream) |
High (6/8 scenarios: D3/ and D6/ditch; R1/, R2/, R3/ and R4/stream) |
Low | |
| Sunflower |
1 × 1,440 g a.s./ha (BBCH 00–09 pre‐emergence) |
Low |
High (2/4 scenarios: R3/ and R4/stream) |
Low |
High (3/4 scenarios: R1/, R3/ and R4/stream) |
High (4/4 scenarios: D5/, R1/ R3/ and R4/stream) |
High (4/4 scenarios: D5/, R1/ R3/ and R4/stream) |
Low |
|
1 × 1,250 g a.s./ha (BBCH 00–09 pre‐emergence) |
Low |
High (2/4 scenarios: R3/ and R4/stream) |
Low |
High (2/4 scenarios: R3/ and R4/stream) |
High (4/4 scenarios: D5/, R1/ R3/ and R4/stream) |
High (3/4 scenarios: R1/ R3/ and R4/stream) |
Low | |
Most sensitive group among those for which a reliable endpoint was available. By applying risk mitigation measures, low risk was indicated for all the representative FOCUS surface water scenarios except for R1/, R2/, R3/ and R4/stream (10 m buffer, resulting in 60% run off reduction) and for R3/ and R4/stream (20 m vegetative buffer, resulting in 80% solute run‐off reduction) for the pre‐ and post‐emergence uses in maize and for R1/, R3/ and R4/stream (10 m buffer, resulting in 60% run off reduction) and for R3/ and R4/stream (20 m vegetative buffer, resulting in 80% solute run‐off reduction) for the uses in sunflower.
The risk assessment for aquatic macrophytes could not be finalised in the absence of a study covering the full life‐cycle of the sensitive species Elodea canadensis.