Behavior and toxic effects of PCBs and PCDFs in Yusho patients for 35 years

From the follow-up data of three Yu-cheng patients and five Yusho patients, fat-based concentrations of TEQ and PCBs in the Yusho patients were estimated to have decreased from 40 ppb and 75 ppm, respectively, in 1969, to 0.6 ppb and 2.3 ppm, respectively, in 1999. Estimated median half-lives of three PCDFs and six PCBs were 3.0 and 4.6 years, respectively, in the first 15 years after the incident, and 5.4 and 14.6 years, respectively, in the following 15 years. Patients have recovered gradually from the typical Yusho symptoms of acneform eruptions, dermal pigmentation and increased eye discharge. However, enzyme- and/or hormone-mediated signs of high serum triglyceride, high serum thyroxine, immunoglobulin disorder, etc. remain persistent for more than 30 years.