Table 1

Enzyme test	Normal exposure students			Mild to high Exposure students
Enzyme test	Mean ± s (n)	p	%	Mean ± s(n)	p	%	r
AChE activity *10^-15 Mol/min	4.23 ± 1.27(35)	0	45.7	5.02 ± 1.27(60)	0.001**	54.2
Time of exposure	14.2 min ± 1.22(35)			3.1hr ±1.3(60)			0.25*

p*: significant, p** : very significant

Table 1: Results of RBC-AChE activity tests in different groups of students.