Ion

Sea salt fraction (%)

Terrestrial fraction

Crust fraction (%)

Anthropogenic source fraction (%)

K⁺

29.1

70.9

-

Ca²⁺

0.80

99.2

-

Mg²⁺

5.0

95.0

-

${\text{NO}}_3^{-}$

-

0.77

99.23

Cl⁻

54.20

0.42

45.38

${\text{SO}}_4^{2-}$

7.31

1.83

90.86