A water quality conference was held Thursday in Oakdale to discuss threats to Long Island's drinking water supply.

Environmental experts say nitrogen is the biggest threat to Long Island's drinking water supply. Long Island gets all of its drinking water from underground aquifers, and environmental experts say nitrogen from septic tanks and lawn chemicals is slowly poisoning underground water supplies.

While Long Island has made efforts to clean up its waterways, some say more work needs to be done. State Assemblyman Robert Sweeney (D-Lindenhurst) says new legislation will be introduced to increase water quality standards and fund septic system improvements.

Sweeney hopes Albany will vote on his bill before the end of the session in about a month.