Fortified to meet the requirements of NELAC Fields of Testing, RCRA Solid. The Reference Values were determined by USEPA SW846 (3rd edition) method 8081A.Certified valuesAldrin. 126 μg/Kg Endosulfan sulfate 319 μg/Kg4,4'-DDD . 397 μg/Kg Endrin336 μg/Kg4,4