Table 1. Acute 96-h toxicity of chlorpyrifos in adult shrimp (Litopenaeus vannamei).

Concentration (μg/L)	Percentage of mortality ± SE	LC50 (μg/L)	95% confidence level		Regression equation	Chi square
			LCL	UCL		df
Control	0 ± 0
23	100
23	100
5.4	83.3 ± 2.3
2.1	50 ± 1.4	2.1	2.04	2.16	Y = 2.14x + 2.97	6.10
1.4	33.3 ± 1.3
0.6	16.7± 1.1

Values of mortality percentages are presented as the overall mean of three replicates ± SE (Standard error). p < 0.05