Treat this study with a grain of salt. The Environmental Working Group is essentially a lobbying group for the organic food industry. They tend to stigmatize "conventional" farming in pseudo-scientific ways to make organic food seem better or healthier, when the differences are typically just marketing.

More details:

https://www.agdaily.com/insights/dirty-deception-ewg-dirty-d...

https://skeptoid.com/episodes/4623/