Aquae Calidae, Bulgaria well as from Kabyle, Mesambria (now Nessebar), Odessos, Histria, Tomis, Byzantium, Abdera, Maroneia and the islands of the Aegean, the oldest from Apollonia Pontica from the 5th century BC. The first baths at the Sanctuary of the Three Nymphs originated when the Roman Empire under Lucullus conquered the region, during the Third Mithridatic War in 72 BC. Under Trajan (98-117) nearby Anchialos became the administrative centre of the region and the baths were expanded and extended with two more swimming pools. During this time the Via Pontica was built connecting Constantinople via Deultum, Anchialos, Aquae Calidae with Dorostorum and Sexaginta
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