Table 1.
Definition of symbols and ratings for each toxicity category.
| Variables | Symbol | Score 1 | Score 3 | Score 5 |
|---|---|---|---|---|
| (1) Long-term health effects (chronic) | C | Little–none | Possible | Definite |
| (2) Dermal toxicity (rat LD50) | DT | >2000 mg/kg | 200–2000 mg/kg | 0–200 mg/kg |
| (3) Bird toxicity (8-day LC50) | D | >1000 ppm | 100–1000 ppm | 1–100 ppm |
| (4) Bee toxicity | Z | Nontoxic | Moderately toxic | Highly toxic |
| (5) Beneficial arthropod toxicity | B | Low impact | Moderate | Severe impact |
| (6) Fish toxicity (96 h LC50) | F | >10 ppm | 1–10 ppm | <1 ppm |
| (7) Plant surface half-life | S | 1-2 weeks | 2–4 weeks | >4 weeks |
| (8) Soil residue half-life (TI/2) | P | <30 days | 30–100 days | >100 days |
| (9) Mode of action | SY | Nonsystem | Systemic | |
| (10) Leaching potential | L | Small | Medium | Large |
| (11) Surface runoff potential | R | Small | Medium | Large |