The Nantucket Land Council is advising islanders to avoid any contact with Capaum Pond, after detecting harmful levels of neurotoxins in a blue-green algae bloom on the surface of the water last week. "Ingestion is the most dangerous type of exposure, but physical exposure may be harmful as well," Land Council executive director Emily Molden said. "Please exercise caution and do not expose yourself or your pets to pond water when an algae bloom is present. If you are unsure, stay away from the water. As temperatures cool, the blooms will dissipate." The Nantucket Conservation Foundation, which owns property along the pond, on the island's north shore, started placing signs around the pond earlier this month, warning people not to go in, or let their pets loose, along the shore. The bacteria in the pond can spread through the introduction of nutrients from septic systems and fertilizers, like phosphorus and nitrogen, Molden said.Their spores can release a potentially-harmful neurotoxin that can easily be consumed by people, pets or animals in or drinking the pond water. Consumption can lead to tissue damage, and skin irritation, she said.