I didn't refer to them specifically. The environmental estrogens can be byproducts of things like PCBs, but they also come in through personal care products. They've been documented to have influences at the site where sewage treatment plants may release their materials, but there's so much dilution by the water itself that those effects have not been seen at larger scales.
Things like polyaromatic hydrocarbons and other hydrophobic chemicals that don't mix with the water and tend to stay in the sediments are legacy industrial byproducts that have been around for many years. They're still there in the sediments, and when the sediments are dredged to clean them, or perhaps washed away by water levels and so on, that's when they can become reintroduced into the water system and can have their effects there.