Ted R. Schwartz

Determination and occurrence of AHH-active polychlorinated biphenyls, 2,3,7,8-tetrachloro-p-dioxin and 2,3,7,8-tetrachlorodibenzofuran in Lake Michigan sediment and biota. The question of their relative toxicological significance

Abstract An analytical procedure has been developed for the determination of the 18 PCB congeners which are inducers of methylcholanthrene-like mixed function oxidase activity in animals and include the most toxic PCBs. Determinations of the toxic PCB congeners in samples of eggs of predatory fish and piscivorous birds of the Great Lakes and in Aroclor mixtures demonstrate that the apparent toxic potency of PCB residues in these samples is dominated by two congeners, 3,3′,4,4′,5- and 2,3,3′,4,4′-pentachlorobiphenyl. Furthermore, the analyses demonstrate that the potential toxicity of PCB residues can increase 5 to 10 fold as they reach upper levels of aquatic food chains and most often exceed the potential toxicity of chlorinated dibenzodioxins and furans in higher animals even in environments highly contaminated by the latter compounds.

Uptake of planar polychlorinated biphenyls and 2,3,7,8-substituted polychlorinated dibenzofurans and dibenzo-p-dioxins by birds nesting in the lower fox river and Green Bay, Wisconsin, USA

The uptake of persistent polychlorinated hydrocarbons (PCHs) by four avian species was investigated at upper trophic levels of two aquatic food chains of the lower Fox River and Green Bay, Wisconsin. Accumulation of total and specific planar polychlorinated biphenyls (PCBs), polychlorinated dibenzofurans (PCDFs), polychlorinated dibenzo-p-dioxin (PCDDs), and H411E rat hepatoma cell bioassay-derived 2,37,8-tetrachlorodibenzop-dioxin equivalents (TCDD-EQ) was evaluated in Forsters tern (Sterna forsteri) and common tern (Sterna hirundo) chicks, and in tree swallow (Tachycineta bicolor) and red-winged blackbird (Agelaius phoeniceus) nestlings from colonies nesting in several locations within the watershed. Concentrations of the PCHs were greatest in eggs and chicks of the two tern species, less in the tree swallows and least in the red-winged blackbirds. Young of all four species accumulated total PCBs, PCB congeners 77, 105, 126, and 169, and TCDD-EQ. The young birds also accumulated small concentrations of several 2,3,7,8-sbustituted PCDF and PCDD congeners. Uptake rates for certain of the PCHs for the Forsters tern chicks were: 15 μg/day for total PCBs, 70, 200, 6.5, and 0.14 ng/day for PCB congeners 77, 105, 126, and 169, respectively, and 270 μg/day for TCDD-EQ. Principal components analysis revealed that the patterns of PCH concentrations in the samples were influenced by species of bird, their age (or length of exposure) and nesting location. Collectively, our findings demonstrate that exposure of avian species to contaminants derived from aquatic food chains can be characterized and quantified for the purposes of ecological risk assessment.

Chemometric comparison of polychlorinated biphenyl residues and toxicologically active polychlorinated biphenyl congeners in the eggs of Forster's Terns (Sterna fosteri)

The separation and characterization of complex mixtures of polychlorinated biphenyls (PCBs) is approached from the perspective of a problem in chemometrics. A technique for quantitative determination of PCB congeners is described as well as an enrichment technique designed to isolate only those congener residues which induce mixed aryl hydrocarbon hydroxylase enzyme activity. A congener-specific procedure is utilized for the determination of PCBs in whichn-alkyl trichloroacetates are used as retention index marker compounds. Retention indices are reproducible in the range of ±0.05 to ±0.7 depending on the specific congener. A laboratory data base system developed to aid in the editing and quantitation of data generated from capillary gas chromatography was employed to quantitate chromatographic data. Data base management was provided by computer programs written in VAX-DSM (Digital Standard MUMPS) for the VAX-DEC (Digital Equipment Corp.) family of computers.In the chemometric evaluation of these complex chromatographic profiles, data are viewed from a single analysis as a point in multi-dimensional space. Principal Components Analysis was used to obtain a representation of the data in a lower dimensional space. Two-and three-dimensional proections based on sample scores from the principal components models were used to visualize the behavior of Aroclor® mixtures. These models can be used to determine if new sample profiles may be represented by Aroclor profiles. Concentrations of individual congeners of a given chlorine substitution may be summed to form homologue concentration. However, the use of homologue concentrations in classification studies with environmental samples can lead to erroneous conclusions about sample similarity. Chemometric applications are discussed for evaluation of Aroclor mixture analysis and compositional description of environmental residues of PCBs in eggs of Forsters terns (Sterna fosteri) collected from colonies near Lake Poygan and Green Bay, Wisconsin. The application of chemometrics is extended to the comparison of: a) Aroclors and PCB-containing environmental samples; to b) fractions of Aroclors and of environmental samples that have been enriched in congeners which induce mixed aryl hydrocarbon hydroxylase enzyme activity.

Determination, fate, and potential significance of PCBs in fish and sediment samples with emphasis on selected AHH-inducing congeners

Abstract Total PCB residues, non- o , o ′-Cl PCBs, and the most AHH-active mono- o , o′ -Cl PCB congener were determined in Great Lakes fish and sediment samples. Toxic 3,3′,4,4′-tetrachlorobiphenyl and 2,3,3′,4,4′-pentachlorobiphenyl were detected in both fish and sediments. There appeared to be some reduction in the percentage content of the selected AHH-active congeners in fish and sediment PCB residues when compared to their percentage content in the Aroclor mixtures suspected as sources of contamination. The TCDD equivalents (AHH induction potency normalized to TCDD, times residue concentration in pg/g) were as high as 666 pg/g in fish; PCB residues in one sediment sample appeared to have undergone reductive dechlorination by anaerobic microorganisms.

Determination of mono- and non-o,o′-chlorine substituted polychlorinated biphenyls in Aroclors and environmental samples

Abstract High resolution capillary gas chromatography (GC) is the best known technique for the separation of complex mixtures; however, no single GC column has yet separated all 209 congeners of polychlorinated biphenyls (PCBs). A number of coeluting PCB congener pairs exist, and even under favorable separation conditions such as with multidimensional GC, assignment of peak identities to known PCB structures is tedious, subject to errors from other contaminants, and requires enrichment to achieve the necessary detection limits for the most toxic PCB congeners. Routine analysis of PCBs is also complicated by coelution with other halogenated hydrocarbons such as naphthalenes, terphenyls, dibenzofurans, and pesticides. Therefore, techniques for class separations of PCBs prior to gas chromatography must be developed. These techniques should separate PCB congeners along lines that have environmental or toxicological significance. The unique ability of activated carbon to separate halogenated aromatics on the basis of molecular planarity and degree of halogenation has been demonstrated. We present a method that uses dispersed carbon on glass fibers and commercially available instrumentation to fractionate and determine mono- and non- o , o ′-chlorine substituted PCB congeners in Aroclors and environmental samples.

Investigations into the effects of PCB congeners on reproduction in lake trout from the Great Lakes

Abstract Eggs of feral lake trout collected in Lake Michigan were reared under laboratory conditions and monitored for egg hatchability, physical abnormalities, and survival of fry. Subsamples of eggs were also analyzed for PCB congeners. A negative correlation was found between egg hatchability and total PCBs but expressing PCB dose as dioxin equivalents did not produce as strong a correlation. No other measure of reproductive success correlated significantly with PCB concentration in the egg.

Polychlorinated biphenyl congeners in emergent mayflies from the upper Mississippi River

We determined polychlorinated biphenyls (PCBs) in emergent mayflies (Hexagenia bilineata) from a 1250-km reach of the upper Mississippi River (UMR). Total PCB concentrations (sum of 125 congeners) ranged from 0.21 to 4.1 μg/g of dry weight (1.2-29 μg/g of lipid weight). Concentrations were highest in pools near the Twin Cities and the Quad Cities metropolitan areas. Longitudinal movement of PCBs was extensive downstream from the Twin Cities (175-320 K) but was not apparent downstream from the Quad Cities. The PCB composition of mayflies was relatively homogeneous throughout most of the river. However, the congener composition in mayflies from two distant locations differed markedly from the other samples and contained a greater abundance of lower molecular weight congeners

Organochlorine contaminants in double-crested cormorants from Green Bay, WI: I. Large-scale extraction and isolation from eggs using semi-permeable membrane dialysis

A 41.3-kg sample of double-crested cormorant (Phalacrocorax auritus) egg contents was extracted, yielding over 2 L of egg lipid. The double-crested cormorant (DCC) egg extract, after clean-up and concentration, was intended for use in egg injection studies to determine the embryotoxicity of the organic contaminants found within the eggs. Large-scale dialysis was used as a preliminary treatment to separate the extracted contaminants from the co-extracted sample lipids. The lipid was dialyzed in 80×5 cm semi-permeable membrane devices (SPMDs) in 50-ml aliquants. After the removal of 87 g of cholesterol by freeze-fractionation, the remaining lipid carryover (56 g) was removed by 100 routine gel permeation chromatography (GPC) operations. A 41,293-g sample was thus extracted and purified to the extent that it could easily be placed at a volume of 5 ml, the volume calculated to be necessary for the egg injection study. Analyses were performed comparing contaminant concentrations in the final purified extract to those present in the original egg material, in the extract after dialysis and cholesterol removal, and in the excluded materials. Recoveries of organochlorine pesticides through dialysis and cholesterol ranged from 96% to 135%. Total polychlorinated biphenyls in the final extract were 96% of those measured in the original egg material. Analysis of excluded lipid and cholesterol indicated that 92% of the polychlorinated dibenzo-dioxins and-furans were separated into the final extract.