Robert H. Hill

Profiles of Great Lakes critical pollutants: a sentinel analysis of human blood and urine.

To determine the contaminants that should be studied further in the subsequent population-based study, a profile of Great Lakes (GL) sport fish contaminant residues were studied in human blood and urine specimens from 32 sport fish consumers from three Great Lakes: Lake Michigan (n =10), Lake Huron (n = 11), and Lake Erie (n = 11). Serum was analyzed for 8 polychlorinated dioxin congeners, 10 polychlorinated furan congeners, 4 coplanar and 32 other polychlorinated biphenyl (PCB) congeners, and 11 persistent chlorinated pesticides. Whole blood was analyzed for mercury and lead. Urine samples were analyzed for 10 nonpersistent pesticides (or their metabolites) and 5 metals. One individual was excluded from statistical analysis because of an unusual exposure to selected analytes.

Pentachlorophenol measurements in body fluids of people in log homes and workplaces.

Human exposure to pentachlorophenol (PCP) was evaluated in the normal population (controls), residents of PCP-treated log homes, and persons exposed primarily in the workplace. Blood and urine samples were analyzed by gas chromatography after extraction and acetylation. For 34 controls, serum PCP values ranged from 15–75 ppb with a mean of 40 ppb. For 123 residents of log homes, serum levels ranged from 69–1,340 ppb with a mean of 420 ppb. In such homes, serum levels for children were significantly higher than those for parents, averaging 1.8 times greater. Serum and urine values for workers varied widely, depending on the workplace, with serum levels ranging from 26 to 84,900 ppb of PCP. Urinary concentrations when corrected for creatinine values correlated well (r=0.92) with serum concentrations. Coating PCP-treated logs of home interiors with a sealant reduced serum PCP levels in the residents.

Residues of chlorinated phenols and phenoxy acid herbicides in the urine of Arkansas children.

Urine samples from 197 Arkansas children were analyzed for eight chlorinated phenols and four chlorinated phenoxy herbicides by using a new procedure that combined gas chromatography with tandem mass spectrometry. With the detection limit of 1 part per billion (ppb), six of these pesticides were detected in more than 10% of the samples. 2,5-Dichlorophenol (a metabolite ofp-dichlorobenzene), and pentachlorophenol were detected in 96% and 100%, respectively, of the childrens urine at median concentrations of 9 ppb and 14 ppb, respectively. 2,4,5-Trichlorophenol was detected in 54% of the childrens urine at a median concentration of 1 ppb. One trichlorophenol and three other dichlorophenols were found in 3% to 27% of the samples. The herbicide 2,4-dichlorophenoxyacetic acid was observed in 20% of all samples. The concentrations of all analytes are reported as background or reference levels for use in future studies. The finding of 2,5-dichlorophenol as a ubiquitous contaminant merits further study.

Contaminants in L-Tryptophan associated with eosinophilia myalgia syndrome

In late 1989, an epidemic of eosinophilia-myalgia syndrome (EMS) that resulted in several thousand cases of the syndrome and 36 deaths was recognized in the United States. Physicians in New Mexico linked the epidemic to the ingestion of L-tryptophan (LT). Results of studies indicated that one or more trace contaminants in LT were likely causes of the EMS epidemic. Investigators traced the LT that was taken by most patients with EMS to a single manufacturer, Showa Denko K.K. of Japan.We now report results of high performance liquid chromatographic analysis of LT samples from this manufacturer. Three sets of blind-coded samples were analyzed: the priority case lot set, which included 54 case-associated LT lots and 50 noncase-associated LT lots that were taken by case and control subjects who used only one brand of LT; the single lot case set, which included 73 case-associated LT lots and 25 noncase associated LT lots taken by case and control subjects who used only a single lot of LT; and the South Carolina tablet set, which included LT tablets taken by case subjects (n=26) and by control subjects (n=52). We statistically compared the concentration of each contaminant in case-associated, noncase-associated, and control samples of each sample set. The analyses showed that there were more than 60 minor contaminants in the LT from Showa Denko K.K., and that six of these contaminants were associated with EMS. The structures of three contaminants are known, but the identities of the other three contaminants are currently unknown. In this paper, we discuss each sample set and results of the analysis of each, the combined results of all sets, the identity of the six contaminants, and implications for future research into the etiology of EMS.

Bioassay screening for toxicants in oil samples from the toxic-oil syndrome outbreak in Spain

A bioassay screening procedure was developed using an agar-plate inhibition assay and applied to a set of 32 oil samples obtained during investigations of the toxic-oil syndrome in Spain. After blind-decoding, it was noted that the assay had singled out the case-associated sample as the most toxic oil from the 32-sample set. Five other oil samples were also selected by the assay. Further evaluation showed that these case-associated, suspect case-associated, and miscellaneous oils had significantly more peroxidation than the controls, as indicated by the thiobarbituric acid assay. Products reactive with dinitrophenylhydrazine were present in greater amounts in the assay-selected oils, also indicating larger amounts of aldehydic and ketonic peroxidation products. A volatile peroxidation product, 4-hydroxy-2,3-nonenal (4-hydroxynonenal), was identified and was very toxic to the bioassay screen. The assay-selected oils had significantly greater amounts of this compound. Heating the toxic oils either removed or destroyed the toxic components as revealed by bioassay testing. The 4-hydroxynonenal and other unidentified toxic products were present in the assay-selected oils before heating and absent after heating. Toxic peroxidation products apparently caused the observed response in the assay-selected oils. These findings may indicate that peroxidation, or some type of free radical process, was associated with the toxicity of these oils to humans. The bioassay procedure should be applied to a larger set of epidemiologically documented oils to determine if this screening process can contribute to a better understanding of the toxic-oil syndrome.

Reference Range Data for Assessing Exposure To Selected Environmental Toxicants

We analyzed blood and urine specimens from 32 charter boat captains, anglers, and spouses from both groups, who reportedly ate fish from Lakes Michigan, Huron, or Erie, for selected environmental toxicants. The toxicants measured in serum were polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), coplanar polychlorinated biphenyls, other polychlorinated biphenyls (PCBs), and persistent pesticides. Nonpersistent pesticides and elements were measured in urine; and elements were measured in blood. Internal dose levels of these toxicants will be compared to reference range data that we have compiled. These reference range data will be used to ascertain the exposure status of individuals or groups within this study.

Structure elucidation of some minor components of the polybromobiphenyl mixture, Firemaster

The polybrominated biphenyl known as “Firemaster” is a flame retardant that accidentally became mixed with cattle feed in Michigan in 1973. The resulting toxicosis to animals and humans prompted extensive study to determine Firemasters toxic components. Although 4 of 12 major Chromatographic peaks of Firemaster produce mixed enzyme induction, they do not account for the total toxicity. By capillary gas chromatography, it was observed that Firemaster FF-1, lot FH 7042, consisted of at least 60 compounds. We have isolated or otherwise determined the structure for 10 minor components of Firemaster: 3,3′,4,4′-tetra-,2,2′,3,5′, 6-penta-,2,2′,4,4′,5-penta-,3,3′, 4,4′,5-penta-,2,3,3′, 4,4′, 5-hexa-,2,3,3′,4,4′,5′-hexa-, 3,3′,4,4′,5,5′-hexa-, 2,2′, 3,3′,4,5,5′- hepta-,2,3,3′,4,4′,5,5′- hepta-and 2,2′,3,3′,4,5,6′- hepta-bromobiphenyl. All of these polybromobiphenyl congeners except 2,2′,4,4′,5-pentabromobiphenyl are in the latest eluting (most polar) fraction by normal-phase high-performance liquid chromatography of Firemaster. This fraction exhibits biological activity. Hyperkeratosis induction tests were carried out on rabbit ears with 3,3′,4,4′-tetra-,2,2′,3,5′, 6-penta-, 2,3,3′,4,4′,5-hexa-, 3,3′,4,4′,5,5′-hexa-, and 2,2′,3,3′,4,5,6′-heptabromobiphenyl, but only 3,3′,4,4′-tetra- and 3,3′,4,4′,5,5′-hexabromobiphenyl gave positive responses. Apparently, these two compounds and 3,3′,4,4′,5-pentabromobiphenyl are significant contributors to the hyperkeratotic activity of Firemaster.

Electron-capture, capillary column gas chromatographic determination of low-molecular-weight diols in serum

Research on alcoholism has revealed that concentrations of 1,2-propanediol, d,1-2,3-butanediol and meso-2,3-butanediol may be greater in the serum of chronic alcoholics than in the serum of social drinkers and nondrinkers. In connection with one of these studies, we developed methodology to determine these diols at the micromolar levels in 500 serum samples. The procedure consisted primarily of extraction of the serum with acetonitrile containing internal standard. The extract was then concentrated to dryness and reacted with p-bromophenylboric acid. The reaction mixture was injected into a gas chromatograph fitted with a capillary column and an electron-capture detector. The total coefficients of variation were best for 1,2-propanediol, 6.82 and 10.00%, and worst for d,1-2,3-butanediol, 13.64 and 19.22%. The observed means for the analytes were all within 10% of the spiked level.

Premature thelarche in Puerto Rico: A search for environmental estrogenic contamination

As part of an investigation into the cause of premature thelarche in Puerto Rico, the Centers for Disease Control (CDC) conducted various laboratory analyses to screen for estrogenic sources. Samples were obtained from case and control households, children, parents, and environmental sources. Serum samples were analyzed from parents and children and household water samples for chlorinated hydrocarbons and no results were found above normal. Using gas chromatography/ mass spectroscopy (GC/MS) procedures, serum was analyzed for zearalanol and its derivatives. Fifteen case samples especially collected from recently diagnosed cases and six controls were analyzed by a contract laboratory and 21 residual case samples previously collected for hormone determinations were analyzed by the CDC laboratory. Four case samples from the residual sample set were reported presumptively positive for zearalanol. Sufficient sera were not available for confirmation. All other serum samples were negative at the 10–20 ppb1 detection level for both laboratories. Analyses of 96 case samples for estradiol, follicle-stimulating hormone (FSH) and luteinizing hormone (LH) yielded values within the normal reference range. The rat uterine cytosol-receptor assay was used as nonspecific screen for estrogenic activity. Two different contract laboratories used this assay to analyze milk, meat, poultry, and water samples collected from the households and local markets. The reliability of this assay was dependent upon the type of sample matrix. No significant difference between case and control samples were found with this screening assay.

Epidemiology of the Toxic Oil Syndrome

During the early 1980’s importation of rapeseed oil into Spain for human consumption was illegal, except for the Canary Islands, although denatured rapeseed oil could be legally imported for industrial use. Denaturation of imported food oils with castor oil, methylene blue, or aniline was required by Spanish law and indicated that the oil was intended for industrial use due to undesirable properties of the denaturants.