widespread use of pharmaceuticals has resulted in mixture concentrations ranging from mg/l in effluent to µg/l concentrations in surface water. in a 2008 study, 13 pharmaceuticals, ranging in amounts from 0.0028 to 0.1757 µg/l, were identified in the tennessee river, usa and its tributaries. in order to address the need for risk assessment of environmentally relevant pharmaceutical mixtures, da...

Trichloroethylene (TCE) was found as a contaminant in the well supplying water to an aquatic testing laboratory. The groundwater was routinely screened by a commercial laboratory for volatile and semivolatile compounds, metals, herbicides, pesticides, and polychlorinated biphenyls using U.S. Environmental Protection Agency methods. Although TCE was the only reportable peak on the gas chromatogr...

2,4-dichlorophenoxyacetic acid and monosodium methanearsonate are often sold in commercial herbicide mixtures. Toxicity studies have been performed for each herbicide individually, but there is a dearth of information concerning the toxicity of these herbicides in a mixture. The following study examined the toxicity of a mixture of these two herbicides in the red swamp crawfish, Procambarus cla...

Evidence suggests that there are separate binding domains for type I and II pyrethroid insecticides on the voltage gated sodium channel of the nerve cell axon, but there are no studies that have examined the mixture toxicity of nonester pyrethroids and type I and II pyrethroids. Therefore, we examined the effect of nonester pyrethroid (etofenprox), type I (permethrin), and type II (cypermethrin...

A new mixture toxicity model was developed to predict the time-dependent toxicity of a mixture with toxicokinetic interactions directed specifically toward addressing biotransformation. The Damage Assessment Model (DAM), a toxicokinetic-toxicodynamic model that describes and predicts the time-dependent toxicity of a single compound, was extended to a multicomponent model for mixture toxicity. T...

The high propensity for simultaneous exposure to multiple environmental chemicals necessitates the development and use of models that provide insight into the toxicity of chemical mixtures. In this study, we developed a mathematical model that combines concepts of concentration addition, response addition, and toxicokinetic chemical interaction to assess toxicity of chemical mixtures. A ternary...

Background: Methotrexate (MTX) is an anti-metabolite drug used in the treatment of many cancers and autoimmune diseases. Methods: This study investigated the protective effect of flaxseed oil, sesame seed oil, and their mixture on the MTX-induced hepatorenal toxicity. Thirty rats divided into five groups of: normal control, MTX control, and flaxseed oil, sesame seed oil, and the mixture groups...