In 2016, a chemical-safety bill in Congress put an old problem back in the news: polychlorinated biphenyls, better known as PCBs. These industrial chemicals were banned decades ago, yet they're still with us. They're a useful reminder of why it pays to think about where our food comes from, and what organic farming can and can't do about it.
What are PCBs?
PCBs are a group of man-made organic chemicals. Because they don't burn easily, are chemically stable and insulate electricity well, they were used in hundreds of industrial and commercial products, from transformers and capacitors to oils and plastics. According to the EPA, PCBs were manufactured in the US from 1929 until their manufacture and import were banned in 1979, based on mounting evidence that they were toxic to people and the environment. Monsanto, now part of Bayer, was the best-known US producer and has faced extensive litigation over them.
Why do PCBs still matter if they were banned in 1979?
Because they don't break down easily. The EPA notes that PCBs cycle between air, water and soil, have been found far from where they were released, and can accumulate in plants, food crops and animals. People are exposed mainly through food, especially fish from contaminated waters, where PCBs build up in fatty tissue.
They are a real health concern. The International Agency for Research on Cancer classifies PCBs as carcinogenic to humans, and the EPA reports a range of adverse health effects in animals and people.
Does eating organic reduce your exposure to chemicals?
Organic farming can't remove legacy pollutants like PCBs from the environment. Where it helps is with the pesticides used on food today. A meta-analysis of 343 studies found a lower incidence of pesticide residues in organically grown crops, and when four US families switched to an organic diet, researchers saw significant drops in urinary levels of several pesticides.
It's worth being honest about the limits, too. A large systematic review concluded that the published evidence doesn't show organic foods are significantly more nutritious than conventional ones, although eating organic may reduce exposure to pesticide residues. For more on the trade-offs, read what you need to know about eating organic.
What can you do?
- Buy organic where you can, especially for foods you eat often.
- Eat plenty of whole, minimally processed foods and fewer heavily processed ones.
- Check local fish advisories before eating fish caught in lakes and rivers, since PCBs accumulate in fish.
- Buy local and seasonal to support nearby organic and sustainable farms. Our seasonal produce guide is a good place to start.
Above all, be aware of what your money says when it does the talking. Choosing brands that use organic, non-GMO ingredients and are open about their sourcing sends a message about the food system you want.
