Table 1.

Occurrence of the first 10 elements in article keywords with “heavy metal” or “potentially toxic element” in the subject of the articles published in International Journal of Environmental Research and Public Health (sourced from Scopus, data accessed on 10 October 2019).

Rank	“Heavy Metal” (n = 996)			Rank	“Potentially Toxic Element” (n = 131)
	Element	n	%		Element	n	%
1	Pb	321	32	1	Pb	72	55
2	Cd	298	30	2	Cd	70	54
3	Zn	228	23	3	Zn	58	44
4	Cu	225	23	4	Cu	57	44
5	As	208	21	5	As	47	36
6	Cr	193	19	6	Cr	44	34
7	Ni	158	16	7	Ni	38	29
8	Hg	141	14	8	Hg	29	22
9	Mn	107	11	9	Mn	23	18
10	Fe	85	9	10	Co	20	15