(a) Water treatment residuals shall not be land applied if the concentration of any metal in the water treatment residuals exceeds the ceiling concentration for the metals in Table 1 of §312.43(b)(1) of this title (relating to Metal Limits).(b) The applicant shall determine the soil concentration of cadmium in accordance with §312.12(a)(1)(I) of this title (relating to Registrations) and demonstrate to the satisfaction of the executive director that the proposed cumulative cadmium loading will not result in a toxic condition or increase the toxicity of the existing soil.