Evaluation of a new battery of toxicity tests for boreal forest soils: assessment of the impact of hydrocarbons and salts.

The ability to assess the toxic potential of soil contamination within boreal regions is currently limited to test species representative of arable lands. This study evaluated the use of six boreal plant species (Pinus banksiana, Picea glauca, Picea mariana, Populus tremuloides, Calamagrostis Canadensis, and Solidago canadensis) and four invertebrate species (Dendrodrilus rubidus, Folsomia nivalis, Proisotoma minuta, and Oppia nitens) and compared their performance to a suite of standard agronomic soil test species using site soils impacted by petroleum hydrocarbon (PHC) and salt contamination. To maintain horizon-specific differences, individual soil horizons were collected from impacted sites and relayered within the test vessels.

Phytotoxkit: a critical look at a rapid assessment tool.

Terrestrial plant toxicity testing contributes critical information to many site risk assessments, but standardized tests can be labor-intensive, use large amounts of soil, and employ long test durations. The Phytotoxkit (MicroBioTests, Environmental Bio-Detection Products) minimizes the time and cost associated with terrestrial plant testing with a unique test setup, a shorter test duration, and less soil. However, the sensitivity of the test remains an open question.

Handling nonnormality and variance heterogeneity for quantitative sublethal toxicity tests.

The advantages of using regression-based techniques to derive endpoints from environmental toxicity data are clear, and slowly, this superior analytical technique is gaining acceptance. As use of regression-based analysis becomes more widespread, some of the associated nuances and potential problems come into sharper focus. Looking at data sets that cover a broad spectrum of standard test species, we noticed that some model fits to data failed to meet two key assumptions-variance homogeneity and normality-that are necessary for correct statistical analysis via regression-based techniques.

Cd accumulation in roots and shoots of durum wheat: the roles of transpiration rate and apoplastic bypass.

Cadmium is readily taken up from soils by plants, depending on soil chemistry, and variably among species and cultivars; altered transpiration and xylem transport and/or translocation in the phloem could cause this variation in Cd accumulation, some degree of which is heritable. Using Triticum turgidum var. durum cvs Kyle and Arcola (high and low grain Cd accumulating, respectively), the objectives of this study were to determine if low-concentration Cd exposure alters transpiration, to relate transpiration to accumulation of Cd in roots and shoots at several life stages, and to evaluate the role of apoplastic bypass in the accumulation of Cd in shoots.