This article describes methods for determining the degree of concentration of chemical substances in the body of fish and shellfish, especially fish. Although the details described here are sufficient to conduct the test, the test design may be changed in consideration of the unique circumstances of each test facility, and the content may be modified depending on the characteristics of the test substance. good. A continuous water flow type is recommended for the test system, but a semi-static type may be used if the test effectiveness criteria are met.