It has been discovered that the prickly pear cactus sucks up selenium, regarded as a pollutant in the West San Joaquin Valley, slowly enough to not be toxic but enough to be of benefit to selenium-deficient diets. In small quantities, it seems, selenium is actually an essential nutrient for human beings. Now, if we can get the people of Europe, Asia, and Australia to develop a taste for nopales, we have achieved both a natural way to help the environment and a new exportable agricultural product.
Related: “Cactus may offer cure for poisoned Valley cropland” by Mark Grossi at SacBee.com