Hi,

Generally, the limits depend of the legislation of each country. For exemple, Europe is less permissive than the U.S.A. To get the right numbers, you have to determine the country you're interested in.

Hope it helps,

Sincerely.

FAO/WHO Codex Alimentarius is Main regulation source for finding updated regulations on this topic:

Regarding of Copper - is quite big differences according of cauntris - please check local regulations.

About Cadmium:

PROPOSED DRAFT MAXIMUM LEVELS FOR CADMIUM IN FOOD

MAXIMUM LEVEL (mg/kg)

Fruit - 0.05

Vegetable, including potatoes (edible part) - 0.05

Leafy Vegetable - 0.2

Cereals, Pulses and Legumes - 0.1

Source: http://www.fao.org/docrep/meeting/005/x7137e/x7137e20.htm

in EUROPE

the proposed maximum levels for Cadmium is according mentioned in Annex XIII of ALINORM 01/12 - with the following exceptions: (1) Vegetables: the level of 0.05 mg/kg should exclude leafy vegetables, fresh herbs, fungi, stem vegetables, root vegetables and potatoes.

- maximum level of 0.1 mg/kg should be provided for stem vegetables, root vegetables and potatoes (to apply to the peeled potatoes)

- The limit of 0.2 mg/kg for leafy vegetables should be extended to also include herbs, celeriac and all fungi.

Source: http://www.fao.org/tempref/codex/Meetings/CCFAC/CCFAC33/fa01_28e.pdf

they are heavy metals, Heavy metals are natural components of the earth’s crust and cannot be destroyed. there is no recommend upper level for them. but the lower level is always positive,

These elements have no known bio-importance in human biochemistry and physiology, and consumption, even at very low concentrations, can cause toxic effects, because they tend to accumulate in the human body over time.