NITRATE AND NITRITE IN FRESH VEGETABLES FROM QUEENSLAND

Vegetables were collected near peak harvest from the main production r egions in Queensland and were analysed for residues of nitrate and nit rite. A small sample of hydroponic produce was also included in the su rvey. Nitrite-N from 1 to 4 mg kg(-1) was found only in dwarf beans an d in lettuces. Levels of nitrate in potatoes, cabbages and beets were higher than those reported in other surveys and exceeded threshold lim its set in one other country. The median nitrate-N concentration measu red in hydroponic lettuce (465 mg kg(-1) nitrate-N) was more than twic e the median concentration for field-grown lettuce. Poor correlation b etween total N and nitrate in vegetables raises doubts about the use o f total N alone as an indicator of N status.