Portskewett The village lost its railway station (on the Newport to Gloucester line) when it was closed under the Beeching Axe in 1964. Black Rock, on the Severn estuary immediately south east of the village, has been an important crossing point of the River Severn for many centuries. Numerous coins found in the mud show that it was in constant use throughout the Roman period, on the route between Aquae Sulis (Bath) and Venta Silurum (Caerwent). By the 18th century, a regular ferry service crossed the Severn estuary from Black Rock to New Passage on the Bristol side, carrying passengers, cattle
Aphanizomenon flos-aquae toxic chemicals released when cells die. Once released (lysed), and ingested, these toxins can damage liver and nerve tissues in mammals. In areas where water quality is not closely monitored, the World Health Organization has assessed toxic algae as a health risk, citing the production of anatoxin-a, saxitoxins, and cylindrospermopsin. Dogs have been reported to have become ill or have fatal reactions after swimming in rivers and lakes containing toxic "A. flos-aquae". Microcystin toxin has been found in all 16 samples of "A. flos-aquae" products sold as food supplements in Germany and Switzerland, originating from Lake Klamath: 10 of 16