Jon A. Lebo

Use of semipermeable membrane devices for in situ monitoring of polycyclic aromatic hydrocarbons in aquatic environments

Abstract A method is given for the recovery, cleanup, and analysis of polycyclic aromatic hydrocarbons (PAHs) that have been sequestered in SPMDs (semipermeable membrane devices). SPMDs are polymeric membranes enclosing lipids, and mimic the bioconcentration process of aquatic animals. SPMDs are used as passive, in situ monitors of contamination by organic pollutants of aquatic environments. The method reported here includes dialytic recovery of the PAHs, cleanup of the dialysates using size exclusion, adsorption, and argentation chromatographic modules in tandem, then analysis by gas chromatography with photoionization or mass spectrometric detection. The method is demonstrated to overcome the presence of a variety of environmental co-contaminants and other potential interferents in the dialysates. A field application is also demonstrated in which SPMDs are used to monitor PAH contamination in an urban creek. Approaches to the use of SPMD data to calculate aqueous concentrations of PAHs are discussed. The use of SPMDs in combination with the complementary, PAH-specific cleanup procedure provides a unique approach to the analysis of PAH residues in the aquatic environment.

Use of the Semipermeable Membrane Device as an in Situ Sampler of Waterborne Bioavailable PCDD and PCDF Residues at Sub-Parts-per-Quadrillion Concentrations

Semipermeable membrane devices (SPMDs) were used to passively sample aqueous polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) in Bayou Meto, AR. The two sites were upstream and downstream from the confluence with a tributary that delivers PCDDs and PCDFs to the Bayou. Following dialysis, cleanup, and fractionation, four replicate 17-g SPMD samples from each site were analyzed by GC/MS, and four were evaluated by H411E bioassay. Traces of only OCDD and HpCDDs were detected in samples from the upstream site. The four samples from below the tributary contained averages of 1550 ± 80 pg of 2,3,7,8-TCDD, 1640 ± 80 pg of 2,3,7,8-TCDF, and lesser quantities of other congeners. The TCDD equivalents obtained by bioassay of replicate SPMD samples agreed well with results obtained by GC/MS. The quantities of 2,3,7,8-TCDD and 2,3,7,8-TCDF sequestered by SPMDs at the downstream site were used to estimate the aqueous concentrations for both compounds as 2 pg/L.

Contaminated sediments from tributaries of the Great Lakes: chemical characterization and carcinogenic effects in medaka (Oryzias latipes).

Sediments from four inshore industrial sites and a reference site in the Great Lakes were extracted with organic solvents to produce a crude extract, which was separated on alumina into two fractions: predominantly polycyclic aromatic hydrocarbons; and predominantly nitrogencontaining polycyclic aromatic compounds. Crude extracts were redissolved in acetone and analyzed by gas chromatography and gas chromatography-mass spectrometry. The acetone-redissolved crude extracts from the four industrialized sites contained 5.6–313.3 μg total polycyclic aromatic compounds/g sediment and 3.0–36.4 μg other compounds/g sediment. In addition to the typical EPA priority pollutants, a substantial amount (228.7 μg/g sediment) of alkyl-polycyclic-aromatic compounds was detected in sediments from one of the industrialized sites. Extracts from the reference site contained 1.55 μg total polycyclic aromatic compounds/ g sediment. Medaka (Oryzias latipes) were exposed to multiple pulse doses of acetone-redissolved extracts and fractions. Medaka were also exposed to a known carcinogen, methylazoxymethanol acetate, to verify that chemicals produced tumors in the test fish. Acetone-redissolved extracts and fractions from contaminated sediments were toxic to medaka. Fin erosion and non-neoplastic liver abnormalities were more prevalent in medaka after exposure to acetoneredissolved extracts and fractions from contaminated sediments. Neoplasms previously associated with chemical exposure in wild fishes were induced in medaka exposed to acetone-redissolved extracts and fractions from two of the contaminated sites, but not from the reference site or controls. These findings further support the hypothesis that chemical contaminants in sediments are involved in epizootics of neoplasms in wild fishes at contaminated sites.

Determination of waterborne bioavailable organochlorine pesticide residues in the Lower Missouri River

The semipermeable membrane device (SPMD) technology, was used to determine the presence of bioavailable organochlorine (OC) pesticides in the water of the main stem Missouri River. SPMDs were deployed for 28 days at five main stem sites - Sioux City, IA; Nebraska City,NE; Kansas City, MO; Glasgow, MO; and Hermann, MO. In general, OCs were present at all sites. Of all targeted analytes, the chlordane components, heptachlor expoxide, toaxaphene, and dieldrin were generally present at the highest concentrations. Replicate (n = 4) SPMD samplers sequestered similar quantities (typical CV = 10-35% ) of each OC pesticide. The sequestered residues represent an estimation of bioavailable (by respiration process) or dissolved OCs present in the main stem of the Missouri River.

Toxicological and chemical screening of Antarctica sediments: Use of whole sediment toxicity tests, microtox, mutatox and semipermeable membrane devices (SPMDs)

Abstract Eight whole sediment samples from Antarctica (four from Winter Quarters Bay and four from McMurdo Sound) were toxicologically and chemically evaluated. Also, the influence of ultraviolet radiation on the toxicity and bioavailability of contaminants associated with the sediment samples was assessed. The evaluations were accomplished by use of a 10-day whole sediment test with Leptocheirus plumulosus, Microtox®, Mutatox® and semipermeable membrane devices (SPMDs). Winter Quarters Bay sediments contained about 250 ng g−1 (dry weight) total PCBs and 20 μg g−1 total PAHs. These sediments elicited toxicity in the Microtox test and avoidance and inhibited burrowing in the L. plumulosus test. The McMurdo Sound sediment samples contained only trace amounts of PCBs and no PAHs, and were less toxic in both the L. plumulosus and Microtox tests compared to the Winter Quarters Bay sediments. The sediments from McMurdo Sound apparently contained some unidentified substance which was photolytically modified to a more toxic form. The photolytic modification of sediment-associated contaminants, coupled with the polar ozone hole and increased incidence of ultraviolet radiation could significantly increase hazards to Antarctic marine life.

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