PBBs in humans

Polybrominated Biphenyls. No studies were located regarding absorption of PBBs in humans after inhalation exposure. However, absorption of PBBs by inhalation (and by dermal contact) in humans can be inferred by the relatively high levels of PBB residues detected in adipose tissue and serum of workers involved in PBB manufacturing (Brown et al. 1981 Landrigan et al. 1979 Stross et al. 1981). 

Polybrominated Biphenyls. No studies were located regarding distribution of PBBs in humans after inhalation exposure. 

No estimate on PBB intake by the general population from air, water, and food was located in the literature. However, current intake of PBBs for the neral population is expected to be zero or very small. However, populations near the contaminated farms in lower Michigan may still have low exposures from air, water, and food. The level of PBBs in human tissue and body fluids in the exposed population of Michigan has been extensively studied (Brilliant et al. 1978 Cordle et al. 1978 Eyster et al. 1983 Humphrey and Hayner 1975 Lambert et al. 1990 Landrigan et al. 1979 Wolff et al. 1979a,... 

A cross-section of the population of Michigan was studied in 1978, 5 years following the agriculture episode involving FireMaster BP-6, to deteimine the levels of PBBs in human tissues. Levels of PBBs were highest in the part of state in which the episode occurred (median adipose tissue, 500 g/kg serum, 1.7 g/L) and were lowest in the upper peninsula (median adipose tissue, 15 g/kg serum,... 

The concentrations of PBBs in the breast milk of females from the lowo peninsula of Michigan (exposed area) were generally higher than in breast milk of females from the upper peninsula (farthest from the sources) (Brilliant et al. 1978). PBB levels in breast milk of five females from the exposed farms were 0.21 92.7 mg/kg (Cordleet al. 1978 Humphrey and Hayner 1976). In a cohort of Michigan residents, the ratio of PBBs in breast milk to maternal serum was 107 122 to 1 and in adipose tissue to breast milk was 1.1 1.5 to 1 (Eyster et al. 1983 Landri n et al. 1979). The concentrations of PBBs found in human tissues and body fluids are given in Table 6-4. Recent levels of PBBs in human breast milk (i.e., 1990 to present) were not located (WHO 1994b). 

Miceli JN, Nolan DC, Marks B, et al. 1985. Persistence of polybrominated biphenyls (PBB) in human post-mortem tissue. Environ Health Perspect 60 399-403. 

Extraction of blood and serum follows pretreatment of the serum with methanol, and extraction is performed with a hexane/ether mixture. This method described by Burse et al. [30] is a standard extraction method for blood and serum, and has been used in most studies. Florisil columns are used in the sample-clean up. An analytical method was developed to quantitate PCBs and PBBs in human serum. This method includes a hexane-ethyl ether extraction of methanol-denatured serum, and an adsorption chromatography with deactivated silica gel [31]. 

A recent method of detection is electron capture negative ionisation (ECNI) as ionization technique in combination with GC-MS analysis. This method is advantageous because it offers a high sensitivity for compounds with four or more bromine atoms [36]. The sensitivity of ECNI for these compounds is approximately 10 times higher than with the use of an electron capture detector (ECD) [5]. In the analytical method which was developed to quantitate PCBs and PBBs in human serum, GC/ECD was used [30]. Because the response, and therefore the sensitivity, of the ECD depends on the position of the halogen on the biphenyl nucleus as well as the number of halogen atoms, it is necessary to run a standard for each compound to be determined [2], The use of narrow bore (0.15 mmi.d.) capillary columns is advised to obtain the required resolution [5]. 

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