Flood-induced transport of PAHs from streambed coal tar deposits.

We assessed whether coal tar present in contaminated streambed sediments can be mobilized by flood events and be re-deposited in an adjacent floodplain. The study was conducted within a contaminated urban stream where coal tar wastes were released into a 4-km reach from a coke plant in Chattanooga, Tennessee, USA. Sediments containing visible amounts of coal tar were dredged from the streambed in 1997-98 and 2007 as part of a cleanup effort.

Standardized application of yeast bioluminescent reporters as endocrine disruptor screen for comparative analysis of wastewater effluents from membrane bioreactor and traditional activated sludge.

A standardized protocol is demonstrated for bioluminescent strains Saccharomyces cerevisiae BLYES, BLYAS and BLYR as high-throughput screening tools to monitor the estrogenic, androgenic and toxic potencies in wastewater. The sensitivity and reproducibility of the assay in wastewater monitoring was evaluated for 7 day semi-continuous batch reactor using activated sludge with hormones spiked raw sewage. Yeast bioluminescent assay successfully captured the rapid removal of estrogenic and androgenic activities in the bioreactors, and demonstrated rapid response (≤4 h) with good reproducibility.

Extraction of 3,4,4'-Trichlorocarbanilide from Rat Fecal Samples for Determination by High Pressure Liquid Chromatography-Tandem Mass Spectrometry.

Triclocarban (3,4,4'-Trichlorocarbanilide; TCC) in the environment has been well documented. Methods have been developed to monitor TCC levels from various matrices including water, sediment, biosolids, plants, blood and urine; however, no method has been developed to document the concentration of TCC in fecal content after oral exposure in animal studies. In the present study, we developed and validated a method that uses liquid extraction coupled with HPLC-MS/MS determination to measure TCC in feces.

Early life triclocarban exposure during lactation affects neonate rat survival.

Triclocarban (3,4,4'-trichlorocarbanilide; TCC), an antimicrobial used in bar soaps, affects endocrine function in vitro and in vivo. This study investigates whether TCC exposure during early life affects the trajectory of fetal and/or neonatal development. Sprague Dawley rats were provided control, 0.

A computational approach predicting CYP450 metabolism and estrogenic activity of an endocrine disrupting compound (PCB-30).

Endocrine disrupting chemicals influence growth and development through interactions with the hormone system, often through binding to hormone receptors such as the estrogen receptor. Computational methods can predict endocrine disrupting chemical activity of unmodified compounds, but approaches predicting activity following metabolism are lacking. The present study uses a well-known environmental contaminant, PCB-30 (2,4,6-trichlorobiphenyl), as a prototype endocrine disrupting chemical and integrates predictive (computational) and experimental methods to determine its metabolic transformation by cytochrome P450 3A4 (CYP3A4) and cytochrome P450 2D6 (CYP2D6) into estrogenic byproducts.

C60 reduces the bioavailability of mercury in aqueous solutions.

The effects of C60 on mercury bioavailability and sorption were investigated at different C60 dosages, reaction times, and pH ranges using the merR::luxCDABE bioluminescent bioreporter Escherichia coli ARL1. The results demonstrated that the bioavailability of mercury (Hg(2+)) decreased with increasing C60 dosage. Approximately 30% of aqueous mercury became biologically unavailable 2h after interaction with C60 at a mass ratio of C60 to mercury as low as 0.

Lack of androgenicity and estrogenicity of the three monomers used in Eastman's Tritan™ copolyesters.

Eastman Tritan™ copolyester, a novel plastic from Eastman is manufactured utilizing three monomers, di-methylterephthalate (DMT), 1,4-cyclohexanedimethanol (CHDM), and 2,2,4,4-tetramethyl-1,3-cyclobutanediol (TMCD) in various ratios. As with most any polymer, the monomers along with the high molecular weight oligomers, whose toxicity is most commonly represented by the monomers, make up the predominate amount of free chemicals available for leaching into the environment and/or foods. In light of the high level of public concern about the presence of endocrine (primarily estrogenic) activity ascribed to certain plastics and chemicals in the environment, Tritan's™ monomers were evaluated using QSAR for binding to the androgen receptor and estrogen receptors (alpha and beta) as well as a battery of in vitro and in vivo techniques to determine their potential androgenicity or estrogenicity.

Detection of dichloromethane with a bioluminescent (lux) bacterial bioreporter.

The focus of this research effort was to develop an autonomous, inducible, lux-based bioluminescent bioreporter for the real-time detection of dichloromethane. Dichloromethane (DCM), also known as methylene chloride, is a volatile organic compound and one of the most commonly used halogenated solvents in the U.S.

The association between nC60 and 17α-ethinylestradiol (EE2) decreases EE2 bioavailability in zebrafish and alters nanoaggregate characteristics.

Manufactured nanoparticles (NPs) released into surface waters will associate with other substances and these interactions may affect environmental fate and bioavailability of NPs and the associated substances. We investigated the association between aqueous aggregates of C(60) (nC(60)) and synthetic estrogen, 17α-ethinylestradiol (EE2), and considered nC(60) physicochemistry and EE2 bioavailability (by measuring vitellogenin (vtg1A/B) gene expression) in zebrafish. Bioavailability of EE2 was reduced with increasing concentration of nC(60) (P < 0.

No bioavailability of 17α-ethinylestradiol when associated with nC60 aggregates during dietary exposure in adult male zebrafish (Danio rerio).

The C(60) fullerene is a manufactured carbon nanoparticle (CNP) that could pose a risk to humans and other organisms after release into the environment. In surface waters, C(60) is likely to be present as aggregates of nC(60) and these aggregates can associate with other substances that are toxic. Our goal was to evaluate the association of a model contaminant [17α-ethinylestradiol (EE2)] with nC(60) and determine bioavailability of EE2 after accumulation by a filter feeding organism [Brine shrimp (BS) Artemia sp.

Phosphatidylserine synthase and phosphatidylserine decarboxylase are essential for cell wall integrity and virulence in Candida albicans.

Phospholipid biosynthetic pathways play crucial roles in the virulence of several pathogens; however, little is known about how phospholipid synthesis affects pathogenesis in fungi such as Candida albicans. A C. albicans phosphatidylserine (PS) synthase mutant, cho1 Delta/Delta, lacks PS, has decreased phosphatidylethanolamine (PE), and is avirulent in a mouse model of systemic candidiasis.

Attributing effects of aqueous C60 nano-aggregates to tetrahydrofuran decomposition products in larval zebrafish by assessment of gene expression.

Background: C(60) is a highly insoluble nanoparticle that can form colloidal suspended aggregates in water, which may lead to environmental exposure in aquatic organisms. Previous research has indicated toxicity from C(60) aggregate; however, effects could be because of tetrahydrofuran (THF) vehicle used to prepare aggregates.

Objective: Our goal was to investigate changes in survival and gene expression in larval zebrafish Danio rerio after exposure to aggregates of C(60) prepared by two methods: a) stirring and sonication of C(60) in water (C(60)-water); and b) suspension of C(60) in THF followed by rotovaping, resuspension in water, and sparging with nitrogen gas (THF-C(60)).

Distribution and transport of coal tar-derived PAHs in fine-grained residuum.

We investigated the distribution and transport of coal tar-derived polycyclic aromatic hydrocarbons (PAHs) in fine-grained residuum and alluvial floodplain deposits that underlie a former manufactured gas plant. All 16 USEPA priority pollutant PAHs are present at this site and have penetrated the entire 4-5m thickness of clayey sediments, which unconformably overly limestone bedrock. Concentrations of less hydrophobic PAHs (e.

Abundance of dioxygenase genes similar to Ralstonia sp. strain U2 nagAc is correlated with naphthalene concentrations in coal tar-contaminated freshwater sediments.

We designed a real-time PCR assay able to recognize dioxygenase large-subunit gene sequences with more than 90% similarity to the Ralstonia sp. strain U2 nagAc gene (nagAc-like gene sequences) in order to study the importance of organisms carrying these genes in the biodegradation of naphthalene. Sequencing of PCR products indicated that this real-time PCR assay was specific and able to detect a variety of nagAc-like gene sequences.