Proposed rule revisions include amendments to surface water quality criteria for Arsenic, Halomethanes, Cadmium, Iron, and Total Coliforms. In addition, clarifying language is proposed in the introductory paragraph to Rule 62-302.530, F.A.C., to take into account natural and statistical variability when evaluating ambient waters for the purposes of determining impairment. Finally, a number of non-substantive, editorial changes are made to update cross-references and correct typographical errors.