To confuse matters even more, some products list the amounts of vitamins and minerals by milligrams or micrograms, while others use international units (a microgram equals 3.33 international units).
Under the previously allowed four pound per acre rate of chlorpyrifos, the ADI was right at the one microgram per kilogram a day limit.
The trouble was that a mere microgram (millionth of a gram) can kill, if lodged in the lungs.
The device can detect even tiny concentrations of less than one microgram (one millionth of a gram) per liter.
What this means is that the maximum safe dose for ingested mercury is 0.1 microgram per kilogram of weight of the person ingesting the mercury per day.
The rats received either 60 or 300 micrograms per kilogram of body weight.
One strain survived less than a day when exposed to a concentration of at least 2 micrograms per milliliter.
The concentrations of manganese in two samples of surface soil taken from area A were 748 and 629 micrograms per gram, dry weight.
In Nairobi's Central Business District the lead levels were 5,000 micrograms per kilogram.
The results are expressed in micrograms per milligram protein.