Yusho incident

CDD/CDF body burdens, elimination half-lives corrected for alterations in body weight ranged from 3.5 years for 1,2,3,4,6,7,8-HpCDF to 7.9 years for 2,3,7,8-TCDD and 15 years for 1,2,3,4,7,8-HxCDD (Rohde et al. 1997). In the same study, half-lives for elimination due only to fecal excretion ranged from 10 years for OCDD to 22 years for 2,3,7,8-TCDD and 27 years for 1,2,3,7,8-PeCDD. The half-lives for 2,3,4,7,8-PeCDF in humans exposed to contaminated rice oil in the Yusho incident range from 2 to 30 years, and were inversely dependent on adipose tissue concentrations above approximately 10 ng/kg body weight (i.e., the higher the body burden, the faster the elimination) (Ryan et al. 1993a). 

J Recent reports of MeS02-PCBs exist for Swedish harbour porpoise [125],harbour, hood, harp and ringed seal, and several porpoise and whale species from Atlantic Ocean [145], and grey seals from the Isle of May, Scotland [147], c The Yusho incident has been extensively reviewed [143],... 

Inclusion of Additional Studies. When reviewing the public comments on endocrine effects, the panelists listed several studies that ATSDR should consider incorporating in the toxicological profile. One panelist thought the profile should include more data from human studies, specifically the Yusho incident and the Dutch studies (Koopman-Esseboom et al. 1994 ... 

Yusho incident exhibited retarded growth, abnormal tooth development and... 

The severe health effects observed in the Japanese Yusho incident of 1968 were attributed to the ingestion of polychlorinated biphenyls (PCBs). At that time, the forefront of analytical chemistry was represented by the determination of trace components at the parts per million (ppm) concentration level. It was not until about ten years later that analytical methodology was able to detect polychlorinated dibenzofurans (PCDFs) and polychlorinated dibenzodioxins (PCDDs) at concentrations of 10 parts per billion (ppb) or less in the presence of PCBs. The significance of the determinations lies in the assessment of risk to human populations exposed to undegraded PCBs and to mixtures of chemically similar compounds of concern derived from uncontrolled reactions such as might occur when a PCB filled transformer undergoes eventful failure. 

A poisoning very similar to the Japanese Yusho incident occurred in Taiwan in 1978-1979 and is known as the Yu-Cheng incident. In this... 

The Toxic Substances Control Act stemmed from the Yusho incident. Section 6(e) of TSCA requires proper disposal of PCBs, and prohibits the manufacture, processing, distribution in commerce, and use of PCBs. 

Polychlorinated dibenzofurans, which occur as impurities in many PCB grades, were identified in the rice oil involved in the Yusho incident, and in the livers of the individuals poisoned by the oil they have recently been reported at the trace level in the fat of seal and turtle [110]. 

Human fatal poisoning incidents have been recorded, particularly for PCB (the Yusho incident, [59]), PCN [81] and hexachlorobenzene [80, 134]. The effects of poisoning are chloracne, hepatic porphyria, liver damage, blood disorders and, at lower concentrations, disorders of the nervous system. 

No studies were located regarding dermal effects in humans exposed specifically to CDDs by the oral route. Evidence from human case reports in the Yusho/Yu-Cheng incidents (which involved exposure to CDFs, PCBs, and CDDs) and from animal studies, however, indicates that dermal effects could occur after exposure by the oral route (ATSDR 1994). 

Ocular Effects. The incidence of eye irritation correlated with the intensity of chloracne in a study of workers employed in a 2,4,5-T factory (Poland et al. 1971), but the role of 2,3,7,8-TCDD, if any, cannot be established. No studies were located regarding ocular effects in humans exposed specifically to CDDs by the oral route. Evidence from the human case reports in the Yusho/Yu-Chcng incidents (which involved exposure to CDFs, PCBs, and less so CDDs) and from animal studies, however, indicates that ocular effects could occur after exposure by the oral route (ATSDR 1994). Ocular effects observed in... 

Ryan JJ, Gasiewicz TA, Brown Jr JR. 1990. Human body burden of polychlorinated dibenzofiirans associated with toxicity based on the Yusho and Yucheng incidents. Fund Appl Toxicol 15 722-731. 

Yoshimura T, Kaneko S, Hayabuchi H (2001) Sex ratio in offspring of those affected by dioxin and dioxin like compounds The Yusho, Seveso, and Yucheng incidents. Occup Environ Med, 58 540-541. 

The carcinogenic effects of PCDDs and PCDFs have been extensively investigated in several highly exposed groups, including industrial workers, herbicide applicators, individuals poisoned in the Yusho and Yu-Cheng incidents in Japan... 

The potential toxicity of PCBs to humans first came into the public arena in 1968, when over 1,500 people around Fukuoka in south-west Japan were poisoned by eating food cooked in rice oil contaminated with PCBs. This was not a single (acute) poisoning incident as the victims used the contaminated rice oil for cooking for some three months. The oil had become contaminated with PCBs as a result of a leak in the machinery in the plant producing the rice oil. People started to suffer from various diseases, and the illness became known as Yusho disease (meaning rice oil disease). Most prominent was chloracne, a severe effect on the skin which is also caused by dioxins. Babies born to women who were exposed also showed symptoms of the disease. Eventually some 2,000 cases of Yusho disease were recorded. 

PCDFs are very similar to dioxins and, like them, are very toxic, especially 2,4,7,8-tetrachlorodibenzofuran, although this is not quite as toxic as TCDD. They have been found to be contaminants of PCBs and in the Yusho and Yu-Cheng poisoning incidents were more abundant in the PCBs than was usual. As with dioxins and PCBs, there are many different isomers and congeners. 

In humans, clinical studies of PCB workers reported associations between increased serum levels of liver-related enzymes, lipids, and cholesterol and serum PCBs. Studies of people exposed to PCBs by ingestion of contaminated fish in Triana, Alabama or contaminated rice oil in the Yusho or Yu-Cheng incidents have reported increases in serum levels of some liver enzymes characteristic of microsomal enzyme induction or liver damage, but these effects cannot be attributed solely to PCBs due to the mixed chemical nature of the contaminated fish and heated rice oil exposures. Serum cholesterol, but not triglycerides, was increased in consumers of contaminated fish, whereas increased serum triglycerides, but not cholesterol, were associated with Yusho and Yu-Cheng exposure. 

Increased urinary excretion of porphyrins appears to be associated with occupational exposure to PCBs (Colombi et al. 1982 Maroni et al. 1984 Smith et al. 1982). Hepatic porphyria was commonly observed in people exposed during the Yu-Cheng PCB incident, although it was not a usual finding in Yusho cases (Chang et al. 1980 Gladen et al. 1988 Hsu et al. 1994 Lu et al. 1980 Masuda et al. 1994). 

Evaluation of Human Studies. Limited information on immunological effects of PCBs in humans is available from studies of people exposed in the workplace, by consumption of contaminated fish and other marine foods, by consumption of contaminated rice oil in the Yusho and Yu-Cheng poisoning incidents, and via general enviromnental exposures. A comparison of PCB levels in blood and breast milk in some of these studies is included in Appendix A. 

Menstrual irregularities (i.e., altered intervals, duration, and flow) were observed in women exposed during the Yusho poisoning incident (Kusuda 1971). Heating of the PCB-contaminated rice oil also resulted in the formation of other contaminants of concern (i.e., dibenzofurans and ter-, and... 

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