That's completely false. It's been proven that, even though they aren't always entirely pesticide free because of pesticide remaining in soil / water / nearby fields that have been spread, their levels are much lower
It's common knowledge. Do more than 5 minutes of research into what it takes to earn a USDA sticker as well as the ingredients and administration practices of conventional pesticides.
There are studies in France that showed it. It's been widely discussed here because of the opposition of the population to the pro-pesticide agro-industrial lobbies.
You can't just say this without a link.