On a recent balmy afternoon, Joseph Alexiou clambered down a ladder on the side of the Union Street Bridge. At the bottom was a small platform, coated in layers of raw sewage, industrial pollutants and rusted blue-green paint. Clouds of fecal matter and rainbow-patterned oil slicks floated slowly by, drawing the eye upstream to their source. The view was hemmed in by graffiti covered warehouses and a decrepit fuel depot, but the churning, noxious headwaters of the Gowanus Canal could be seen nearby. It was a vista with its own unique appeal, enjoyed that day by only a few other Brooklyn visitors. "Can you go swimming in it?" asked one, a local high school student who had taken up a position on the opposite footing. "You could probably go swimming once and be fine," replied Alexiou. "But I wouldn't do it myself, having learned the history of it. I would go to an emergency room, and I would make sure to get antibiotics."