Publications

Vertebrate embryos are particularly sensitive to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Identification of tissues that are susceptible to the adverse effects of TCDD is requisite for understanding the embryo toxic effects of TCDD. The objective of the present study was to quantitate the temporal appearance of and dose dependence of apoptosis in TCDD-exposed medaka embryos (Oryzias...

We evaluated the toxic-units model developed by Wildhaber and Schmitt (1996) as a predictor of indices of mean tolerance to pollution (i.e., Lenat, 1993; Hilsenhoff, 1987) and other benthic community indices from Great Lakes sediments containing complex mixtures of environmental contaminants (e.g., polychlorinated biphenyls – PCBs, polycyclic aromatic hydrocarbons – PAHs, pesticides...

This study determined the relative sensitivity of five species of aquatic macrophytes and six species of algae to four commonly used herbicides (atrazine, metribuzin, alachlor, and metolachlor). Toxicity tests consisted of 96-h (duckweed and algae) or 14-d (submerged macrophytes) static exposures. The triazine herbicides (atrazine and metribuzin) were significantly more toxic to aquatic...

On 14 May 1994, tadpoles were collected from Lateral Pond and Municipal Lake in Bryan, Texas. These waters are immediately downstream from Finfeather Lake which was directly contaminated during 53 years of industrial production of arsenic (As)-based cotton defoliants. The tadpoles contained elevated levels of arsenic, chromium (Cr) and zinc (Zn). As far as it is known, the mean...

Benthic invertebrate samples were collected from 23 pools in the Upper Mississippi River (UMR) and from one station in the Saint Croix River (SCR) as part of a study to assess the effects of the extensive flooding of 1993 on sediment contamination in the UMR system. Sediment contaminants of concern included both organic and inorganic compounds. Oligochaetes and chironomids constituted...

Microtox® and Mutatox® were used to evaluate the acute toxicity and genotoxicity, respectively, of organic sediment extracts from Pensacola Bay and St. Andrew Bay, two estuaries that cover about 273 and 127 km2, respectively, along the Gulf coast of Florida, USA. The sensitivity and selectivity of these two bioluminescent toxicity assays were demonstrated in validation studies with over...

The CETAC ADX-500 autodiluter system was tested with ELAN?? v 2.1 software and the ELAN 6000 ICP-MS instrument to determine on-line automated dilution performance during analysis of standard solutions containing nine analytes representative of the mass spectral range (mass 9 to mass 238). Two or more dilution schemes were tested for each of 5 test tube designs. Dilution performance was...

Methanol extracts of dorsal skin layers, eyes, gills, and livers from ultraviolet-B (UVB) radiation-sensitive and UVB-tolerant species of freshwater fish were examined for a substance that appears to be photoprotective. Significantly larger amounts of this substance were found in extracts of outer dorsal skin layers from both UVB-sensitive and UVB-tolerant fish when compared with...

A standard methodology for assessing the impacts of simulated solar ultraviolet-B radiation (UV-B) on aquatic invertebrates was established. A solar simulator was used to expose a variety of aquatic invertebrates to different levels of UV-B. The simulator was calibrated as close as possible to match local ambient solar radiation measured in and out of water with a scanning...

An acute (96 h) pore-water toxicity test protocol using germination and growth of Ulva fasciatazoospores as endpoints was developed to test the toxicity of marine and estuarine sediment pore-water samples. Tests with an organic toxicant (sodium dodecyl sulfate; SDS), three metals (Cd, Cu, and Zn), and ammonia (NH3) were conducted to determine zoospore sensitivity. Zoospore germination...

An in-depth review of the recent contribution to this journal by Gustafson and Dickhut [1] prompts us to share our concerns regarding some of their conclusions. The paper presents data comparing three techniques for determining aqueous concentrations of freely dissolved polycyclic aromatic hydrocarbons (PAHs) gas sparging, lipid-containing semipermeable membrane devices (SPMDs) of the U...

The role of riparian vegetation is assessed quantitatively by using a five-decade record of valley bottom vegetation and channel dynamics developed from historical aerial photography. A 12-kilometer reach of a typical Ozarks stream was mapped using aerial photographs from 1938, 1948, 1955, 1965, 1976, and 1989; maps were then analyzed in a digital geographic information system. Analysis...