Determinants of Polybrominated Biphenyl Serum Decay among Women in the Michigan PBB Cohort

Abstract

Accidental contamination of the food chain in Michigan in 1973 with polybrominated biphenyls (PBBs) led to the establishment of a registry of exposed individuals in 1976. Serum was collected and analyzed for PBB at the time of enrollment and for targeted studies in the following years. We used the archived PBB data to study the elimination of PBB and to identify factors associated with elimination. A total of 380 women ≥ 16 years of age who had an initial PBB level of 2 ppb and at least two serum samples drawn when they were not pregnant were included in the analysis. The mean initial PBB level was 20.9 ppb (median 4) and mean time between the first and last measurement was 4.2 years (range 0.5-11.1). PBB was assumed to reach equilibrium in the body before substantial amounts were eliminated and before the first serum measurements were taken; therefore, the entire body was modeled as a single compartment for PBB with exponential decay. Subject-specific decay rate estimates were regressed on predictor variables including initial age, body mass index (BMI), smoking history, breast-feeding duration, and parity. In women with an initial PBB level < 10 ppb, the median half-life was 12.9 years; in those with > 10 ppb, the median half-life was 28.7 years. Decay was significantly slower among women with an initial BMI at or above the median (BMI ≥ 23). The calculated half-life values are estimates of decay and can be used to estimate body burden of PBB at various points in time other than at the time of serum collection.Address correspondence to M. Marcus, 1518 Clifton Road NE, Room 460, Department of Epidemiology, Rollins School of Public Health, Emory University, Atlanta, GA 30322 USA. Telephone: (404) . mmarcus@sph.emory.edu. PBBs were used as fire retardants for molded plastic parts, such as the cases of televisions, typewriters, and business machines. In 1973, an industrial accident resulted in the inadvertent substitution of FireMaster for NutriMaster (feed-grade magnesium oxide), a nutritional supplement, into livestock feed. In the following months, many Michigan residents unknowingly ate animal and dairy products that had been contaminated with PBBs. Once the PBB contamination was discovered, public concern prompted assessment of possible adverse health consequences in exposed individuals. A pilot study was conducted in 1974 and a registry of exposed individuals was established in 1976. Details of the incident and the cohort have been described previously (1-5). HHS Public AccessThere is renewed interest in the possible human health effects of PBBs because of their potential role as endocrine disruptors. Endocrine-disrupting chemicals include a family of structurally similar halogenated organics that have the ability to mimic or block normal hormonal activity. They are widespread in occurrence, resistant to degradation, and accumulate in fatty tissue. These chemicals include DDT and its degradation product DDE; 2, 3, 7, 8-tetrachlorodibenzo-P-dioxin (TCDD); polychlorinated biphenyls (PCBs); and PBBs. ...

Children's health and the environment: public health issues and challenges for risk assessment.

“…Early exposures to these compounds have the potential to alter anatomic structures and may influence the subsequent course of endocrine functioning (Longnecker et al 2002;Peterson et al 1993), neurological development (Jacobson and Jacobson 1996), and sexual development over the life span (Birnbaum 1994;Blanck et al 2000aBlanck et al , 2000bColborn et al 1996;Euling and Kimmel 2001;Gray et al 2000;Guillette et al 1994;Longnecker and Daniels 2001;Selevan et al 2000;Wu et al 2003).…”

Breast-feeding among women exposed to polybrominated biphenyls in Michigan.

“…For each woman, the first singleton live birth after the initial PBB serum measurement was the pregnancy used in the analysis. We estimated serum PBB levels at delivery of the infant using a decay rate model previously described (18). Exposure was evaluated both for initial serum PBB levels and for estimated PBB levels at birth.…”

Retardantes de chama bromados: uma revisão

“…15,33,34,[39][40][41][42] Muitos trabalhos referem-se especialmente ao acidente ocorrido em Michigan ou a região de descarga de efluentes da Michigan Chemical Corporation. 25,31,36,37,43 Entre eles, alguns reportaram valores elevados em amostras de sangue humano (933 a 1744 µg L -1 ) e em amostras de água (0,01 e 0,07 µg L -1 ) e sedimento (100 e 77000 ng g -1 ). 25,31 A absorção dos PBBs pelos organismos ocorre de forma rápida e inversamente proporcional ao número de bromos na molécula.…”

“…48,49 Em humanos, pode variar de 8 a 30 anos. 43 Esses tempos vão depender da idade, massa corpórea, gestação, histórico de vida, etc. Em sedimentos e solos a meia-vida é maior que 6 meses, devido à resistência de misturas de PBB à degradação microbiana.…”