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

Background:

Yusho polychlorinated biphenyl (PCB) poisoning occurred in northern Kyushu in 1968, and the patients have been suffering from various symptoms for 35 years. From the epidemiological survey of 141 Yusho patients in Fukuoka, the total amounts of PCBs, polychlorinated dibenzofurans (PCDFs) and the toxic equivalent quantity (TEQ) ingested by each patient were calculated to be 633, 3.4 and 0.62 mg, respectively.

Objectives:

The purpose of this paper is to review the behavior and toxic effects of these polychlorinated congeners in Yusho patients.

Results and conclusions:

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.