Table 1. Chemical toxicity categories in aquatic organisms.

Toxicity category	Aquatic organism acute concentration (PPM)	Binary classification	Ternary classification
Very highly toxic	<0.1	1	2
Highly toxic	0.1–1	1	2
Moderately toxic	1–10	1	1
Slightly toxic	10–100	0	0
Nontoxic	>100	0	0