Table 6.

Test statistics for equal effect of each factor on heavy metal accumulation.

Group	Test	Statistics	Significance
Season	Mann-Whitney test	5522.00	0.823∗∗
Site	Kruskal-Wallis test	2.7	0.952∗∗
	Jonckheere-Terpstra test	12053.500	0.152
Crop	Mann-Whitney test	5522	0.823∗∗
HMG	Kruskal-Wallis test	3.225	0.521∗∗
	Jonckheere-Terpstra test	10216.500	0.868∗∗
Metal	Kruskal-Wallis test	164.050	0.000∗
	Jonckheere-Terpstra test	4539.00	0.000∗

^∗Significant at 5%.

^∗∗Significant at 1%.