'Organic' isn't clean or toxin free

If environmentalists really care about the environment, they might not want to promote organic food (Bloomberg):

Like all farms, those that grow organic products rely on fertilizer. Often, organic farmers use animal manure rather than chemicals derived from petroleum or minerals.

In one study of greenhouses in Israel, the use of manure led to much more nitrogen leaching into groundwater compared with use of conventional fertilization. Nitrogen contamination, the study noted, is one of the main reasons for closing drinking-water wells. And by the way, nitrogen from all sorts of farming is one of the main pollutants behind algae blooms, fish kills and dead zones in bodies of water from local farm ponds to the northern Gulf of Mexico.

A broader study of 12 different farm products in California found that in seven cases, those using conventional methods had lower greenhouse-gas emissions. A big reason for the difference? Conventional farming tends to be more efficient than organic farming, meaning fewer inputs are needed to generate the same amount of food.

That hits on a critical issue for organic farming, as noted in a 2012 analysis of more than 100 studies of farming methods across Europe: Getting the same unit production from organic farming tended to lead to "higher ammonia emissions, nitrogen leaching and nitrous oxide emissions." And while organic farming tends to use less energy, it also leads to "higher land use, eutrophication potential" -- that's the dead zones mentioned above -- "and acidification potential per product unit."