Toxicant Responses and Culturing Characteristics of Long-Term Laboratory-Reared and Field Populations of Ceriodaphnia dubia.

Ceriodaphnia dubia is a standardized test organism for regulatory toxicity testing of surface waters and commercial chemicals because of its simplicity to culture and responsiveness to toxicants. For testing convenience, C. dubia is often cultured for extended periods in the laboratory with little knowledge of the impact on subsequent generations.

Aquatic toxicity of hydroquinone and catechol following metal oxide treatment to Ceriodaphnia dubia and Pimephales promelas.

Metal oxides comprise a large group of chemicals used in water treatment to adsorb organic pollutants. The ability of titanium dioxide (TiO) and iron (III) oxide (FeO) to reduce the chronic toxicity of (phenolic) CH(OH) isomers, namely hydroquinone (HQ) and catechol (CAT) to Ceriodaphnia dubia and Pimephales promelas (less than 24 h-old) were investigated. The toxic endpoints following metal oxide treatment were compared to endpoints of untreated CAT and HQ.

Comparison of Measured to Predicted Estimations of Nonpoint Source Contaminants Using Conservation Practices in an Agriculturally-Dominated Watershed in Northeast Arkansas, USA.

In efforts to reduce nonpoint source runoff and improve water quality, Best Management Practices (BMPs) were implemented in the Outlet Larkin Creek Watershed. Farmers need to make scientifically informed decisions concerning BMPs addressing contaminants from agricultural fields. The BMP Tool was developed from previous studies to estimate BMP effectiveness at reducing nonpoint source contaminants.

Cadmium Accumulation in Periphyton from an Abandoned Mining District in the Buffalo National River, Arkansas.

The Rush Mining District along the Buffalo River in Arkansas has a significant history of zinc and lead mining operations. The tails and spoils of these operations deposit heavy amounts of raw ore into streams. One element commonly found in the earth's crust that becomes a minor constituent of the deposition is cadmium.

Turbidity and Total Suspended Solids on the Lower Cache River Watershed, AR.

The Cache River Watershed (CRW) in Arkansas is part of one of the largest remaining bottomland hardwood forests in the US. Although wetlands are known to improve water quality, the Cache River is listed as impaired due to sedimentation and turbidity. This study measured turbidity and total suspended solids (TSS) in seven sites of the lower CRW; six sites were located on the Bayou DeView tributary of the Cache River.

Metals, Parasites, and Environmental Conditions Affecting Breeding Populations of Spotted Salamanders (Ambystoma maculatum) in Northern Arkansas, USA.

The spotted salamander (Ambystoma maculatum) is indigenous to northern Arkansas, and several breeding sites are known to exist in the region. Spotted salamanders (n = 17) were collected and examined for parasites and only three females harbored nematodes (Physaloptera spp.).

Earthworm Preference Bioassays to Evaluate Land Management Practices.

Earthworm preference tests, especially in soil-dosed exposures, can be an informative tool for assessing land management practices. Agricultural management intended to increase crop yield and improve soil sustainability includes physical manipulation of topsoil through conventional tillage, reduced or no-tillage, and/or winter cover crops. Soil amendments include the addition of inorganic nitrogen or organic nitrogen derived from soil amendments including biosolids from sewage treatment plants, poultry litter, or locally available industrial effluent.

Detection of Lead (Pb) in Three Environmental Matrices of the Cache River Watershed, Arkansas.

Water bodies contaminated with lead (Pb) represent a considerable threat to both human and environmental health. The Cache River, located in northeastern Arkansas has been listed as impaired on the 303(d) list due to Pb contamination. However, historical data for the watershed is limited in both sampled waterways and analyses performed.

Concentrations in human blood of petroleum hydrocarbons associated with the BP/Deepwater Horizon oil spill, Gulf of Mexico.

During/after the BP/Deepwater Horizon oil spill, cleanup workers, fisherpersons, SCUBA divers, and coastal residents were exposed to crude oil and dispersants. These people experienced acute physiological and behavioral symptoms and consulted a physician. They were diagnosed with petroleum hydrocarbon poisoning and had blood analyses analyzed for volatile organic compounds; samples were drawn 5-19 months after the spill had been capped.

Current and emerging technologies for rapid detection and characterization of Salmonella in poultry and poultry products.

Salmonella is the leading cause of foodborne illnesses in the United States, and one of the main contributors to salmonellosis is the consumption of contaminated poultry and poultry products. Since deleterious effects of Salmonella on public health and the economy continue to occur, there is an ongoing need to develop more advanced detection methods that can identify Salmonella accurately and rapidly in foods before they reach consumers. Rapid detection and identification methods for Salmonella are considered to be an important component of strategies designed to prevent poultry and poultry product-associated illnesses.

Distribution and concentrations of petroleum hydrocarbons associated with the BP/Deepwater Horizon Oil Spill, Gulf of Mexico.

We examined the geographic extent of petroleum hydrocarbon contamination in sediment, seawater, biota, and seafood during/after the BP/Deepwater Horizon Oil Spill (April 20-July 15, 2010; 28.736667°N, -88.386944°W).

Measurement of accumulation of semiconductor nanocrystal quantum dots by pimephales promelas.

As the production and use of nanomaterials increases, it is important to understand their environmental and biological fate. Because their unmatched chemical, physical, and optical properties make them useful in a wide variety of applications including biomedical imaging, photo-voltaics, and light emitting diodes, the use of semiconductor nanocrystals such as quantum dots (QDs) is increasing rapidly. Although QDs hold great potential in a wide variety of industrial and consumer applications, the environmental implications of these particles is largely unexplored.

Fractionating nanosilver: importance for determining toxicity to aquatic test organisms.

This investigation applied novel techniques for characterizing and fractionating nanosilver particles and aggregates and relating these measurements to toxicological endpoints. The acute toxicity of eight nanosilver suspensions of varying primary particle sizes (10-80 nm) and coatings (citrate, polyvinylpyrrolidone, EDTA, proprietary) was assessed using three aquatic test organisms (Daphnia magna, Pimephales promelas, Pseudokirchneriella subcapitata). When 48-h lethal median concentrations (LC50) were expressed as total silver, both D.

Aqueous toxicity and food chain transfer of Quantum DOTs in freshwater algae and Ceriodaphnia dubia.

Innovative research and diagnostic techniques for biological testing have advanced during recent years because of the development of semiconductor nanocrystals. Although these commercially available, fluorescent nanocrystals have a protective organic coating, the inner core contains cadmium and selenium. Because these metals have the potential for detrimental environmental effects, concerns have been raised over our lack of understanding about the environmental fate of these products.