Multidimensional approach to invasive species prevention.

Nonindigenous species (NIS) cause global biotic homogenization and extinctions, with commercial shipping being a leading vector for spread of aquatic NIS. To reduce transport of NIS by ships, regulations requiring ballast water exchange (BWE) have been implemented by numerous countries. BWE appears to effectively reduce risk for freshwater ports, but provides only moderate protection of marine ports.

Comparative toxicity and bioconcentration of nonylphenol in freshwater organisms.

Degradation of alkylphenol ethoxylates to more persistent alkylphenols such as nonylphenol occurs in wastewater treatment plants where nonylphenol is released to aquatic systems. In this study, acute and chronic tests were conducted to determine the toxicity and bioconcentration of nonylphenol to freshwater organisms for use in deriving national water quality criteria. Acute median effect concentrations (EC50s) based on loss of equilibrium, immobility, and lethality for species representing several taxonomic groups ranged from 21 to 596 microg/L.

Toxicity of nonylphenol, nonylphenol monoethoxylate, and nonylphenol diethoxylate and mixtures of these compounds to Pimephales promelas (fathead minnow) and Ceriodaphnia dubia.

Three phenolic compounds were evaluated for their toxicity to the freshwater species Pimephales promelas (fathead minnow) and Ceriodaphnia dubia. Acute toxicity tests using nonylphenol (NP), nonylphenol monoethoxylate (NP1EO), and nonylphenol diethoxylate (NP2EO) were conducted using the single chemicals and as binary and tertiary mixtures. These compounds frequently coexist in surface waters as the result of discharges from wastewater treatment plants that are inefficient at removing nonylphenolic compounds.

Toxicity of silver in water and sediment to the freshwater amphipod Hyalella azteca.

Hyalella azteca was exposed to Ag as AgNO3 over a 10-d period in water and two lake sediments that were selected on the basis of their differences in metal-binding properties. The median lethal concentrations (LC50s) for waterborne exposures were 5.4 and 4.

An assessment of the toxicity of phthalate esters to freshwater benthos. 2. Sediment exposures.

Seven phthalate esters were evaluated for their 10-d toxicity to the freshwater invertebrates Hyalella azteca and Chironomus tentans in sediment. The esters were diethyl phthalate (DEP), di-n-butyl phthalate (DBP), di-n-hexyl phthalate (DHP), di-(2-ethylhexyl) phthalate (DEHP), diisononyl phthalate (DINP), diisodecyl phthalate (DIDP), and a commercial mixture of C7, C9, and C11 isophthalate esters (711P). All seven esters were tested in a sediment containing 4.

An assessment of the toxicity of phthalate esters to freshwater benthos. 1. Aqueous exposures.

Tests were performed with the freshwater invertebrates Hyalella azteca, Chironomus tentans, and Lumbriculus variegatus to determine the acute toxicity of six phthalate esters, including dimethyl phthalate (DMP), diethyl phthalate (DEP), di-n-butyl phthalate (DBP), butylbenzyl phthalate (BBP), di-n-hexyl phthalate (DHP), and di-2-ethylhexyl phthalate (DEHP). It was possible to derive 10-d LC50 (lethal concentration for 50% of the population) values only for the four lower molecular weight esters (DMP, DEP, DBP, and BBP), for which toxicity increased with increasing octanol-water partition coefficient (Kow) and decreasing water solubility. The LC50 values for DMP, DEP, DBP, and BBP were 28.

Differential genetic influence for components of memory in aging adult twins.

Objective: To investigate the relative proportion of genetic and environmental contributions to verbal memory in community-dwelling World War II veteran twins.

Design: The California Verbal Learning Test (CVLT) was administered to 94 monozygotic (MZ) and 89 dizygotic (DZ) elderly male twin pair participants in the fourth examination of the National Heart, Lung, and Blood Institute Twin Study.

Setting: Subjects voluntarily participated on an outpatient basis at a research or medical center facility in 1 of 4 sites in the United States.

Callosal transfer of finger localization information in phonologically dyslexic adults.

Dyslexia, particularly phonological dyslexia, has been hypothesized to be associated with deficits in interhemispheric interactions mediated by the corpus callosum. Twenty-one dyslexic subjects were compared to 21 controls on the Finger Localization Test in order to observe patterns of tactile-motor integration and interhemispheric collaboration. When compared to control subjects, dyslexics showed consistent deficits in finger localization, particularly when more complex trials had to be completed.

Bimanual coordination in dyslexic adults.

Various types of dyslexia have been associated with tactile-motor coordination deficits and inefficient transfer of information between the two cerebral hemispheres. Twenty-one dyslexic adults were compared to 21 controls on the Bimanual Coordination Task, a test of tactile-motor coordination and interhemispheric collaboration. When compared to control subjects, dyslexics showed a consistent pattern of deficits in bimanual motor coordination, both with and without visual feedback.