What is a ‘safe’ level of roundup?

Call me naive, but changing the amount of Roundup allowed in food based on how much Roundup a farmer puts on his crop seems a little back the front to me…

How come the ‘safe level’ of Roundup varies from food to food? How come more roundup is allowed in wheat and canola than in rice and figs? (see chart here)

Is roundup any less toxic when it is in wheat than in rice?

Or could it be that the levels of roundup allowed in food are actually based on the amount of roundup that a farmer want’s to use, rather than on how toxic it is to humans…

Where they spray roundup on a crop just before they harvest it (e.g. canola and, in the usa, wheat) more roundup is ‘safe’. Where roundup is only used pre-emergent herbicide, less is allowed. Coincidence?

Allowable levels of Roundup in water (if there was a glyphosate spillage) are 1 mg/L, that’s 1 part per million.

(“If present in drinking water as a result of a spillage or through misuse, glyphosate would not be a health concern unless the concentration exceeded 1 mg/L.”)

source

How come we are allowed 20 times that level in our canola, sunflower seed and wheat bran?

Call me naive, but changing the amount of Roundup allowed in a food based on how much Roundup a farmer puts on his crop seems a little back the front to me…