New research into sargassum used as fertilizer has found that vegetables grown in soil that was enriched with sargassum had elevated levels of potentially toxic heavy metals. The findings have prompted scientists to warn farmers that they should stop using sargassum to enhance animal feeds or as a fertilizer for food crops until more studies ca be done. A joint project between WWF-Mexico and STINAPA Bonaire resulted in an experiment in which one planter box was filled with a 50-50 mix of potting soil and dried sargassum, while the other contained potting soil only. Researchers wanted to test whether the sargassum-enriched soil would result in faster seed development, and whether the vegetables subsequently produced would have detectable levels of heavy metals post-harvest. What they found was that while there were generally no significant…