; and (II) perfluorooctane sulfonic acid (commonly referred to as PFOS ). (ii) Alternative procedures (I) In general Not later than 1 year after the validation by the Administrator of an equally effective quality control and testing procedure to ensure compliance with that national primary drinking water regulation to measure the levels described in subclause (II) or other methods to detect and monitor perfluoroalkyl and polyfluoroalkyl substances in drinking water, the Administrator shall add the procedure or method as an alternative to the quality control and testing procedure described in that national primary drinking water regulation by publishing the procedure or method in the Federal Register. (II) Levels described The levels referred to in subclause (I) are— (aa) the level of a perfluoroalkyl or polyfluoroalkyl substance; (bb) the total levels of perfluoroalkyl and polyfluoroalkyl substances; and (cc) the total levels of organic fluorine. (iii) Inclusions The Administrator may include a perfluoroalkyl or polyfluoroalkyl substance or class of perfluoroalkyl or polyfluoroalkyl substances on— (I) the list of contaminants for consideration of regulation under paragraph (1)(B)(i)