A recent study comparing the presence of chemical contaminants in conventionally and hydroponically grown produce found pesticide residues in a larger number of conventional samples than in hydroponic samples, as well as significantly higher levels of lead and cadmium in conventionally grown produce. Phthalate levels were consistent between conventional and hydroponic samples.
The study tested 177 samples across four vegetable commodity groups—lettuce, celery, tomatoes, and cucumbers—taken from conventional and hydroponic farming operations. The samples were assessed for 120 pesticides, 18 phthalates, and two toxic heavy metals (lead and cadmium).
Of the total 177 samples, 53 percent contained at least one pesticide residue, and, while 84 percent of conventionally grown vegetables contained pesticides, residues were detected in only 30 percent of the hydroponic samples. Additionally, 51 percent of the conventionally grown samples contained two or more pesticide residues, compared to 7 percent in the hydroponic samples. The frequency of detection of insecticides was significantly higher for conventional samples (57 percent) than that of hydroponic samples (12 percent), as well as for fungicides (40 percent of conventional versus 5 percent of hydroponic samples). The researchers explain that this is due to decreased need for pesticides, insecticides, and fungicides in hydroponic operations, as the absence of soil in the cultivation of hydroponic crops means there are no soilborne hazards to control.
Read more at food-safety.com