Managing the Nutrition of Plants and People

Table 3

Statutory maximum annual metal loading rates (kg ha⁻¹ y⁻¹) over a ten-year period for agricultural soils in the United Kingdom [190] and the European Communities [191], statutory maximum cumulative metal loading rates (kg ha⁻¹) for agricultural soils in the United States of America [192], and critical soil concentrations (kg ha⁻¹) considered to be phytotoxic calculated assuming a soil bulk density of 1200 kg m⁻³ and a depth of 0.10 m [193].

Element	UK (kg ha^−1 y^−1)	EC (kg ha^−1 y^−1)	USA (kg ha^−1)	Critical (kg ha^−1)
Cd	0.15	0.15	39	6.0
Hg	0.1	0.1	17	3.7
Ni	3	3	420	120
Cu	7.5	12	1500	120
Cr	15	3	—	113
Pb	15	15	300	150
Zn	15	30	2800	390
Mo	0.2	—	—	8.1
Se	0.15	—	100	11
As	0.7	—	41	38