A dark, toxic leachate has been observed around woodpiles of trembling aspen (Populus tremuloides Michx.) cut in winter for pulp or structural lumber. We measured production of leachate from 18 m3 of harvestable aspen logs stacked in an open field near Dawson Creek, British Columbia, Canada. The logpile began producing leachate during the first winter thaw and continued to do so for the duratio...

A 1-compartment toxicokinetic model is used to characterize the chemical exposure toxicity space (CETS), providing a novel graphic tool that can aid in the design of aquatic toxicity tests for fish and for interpreting their results. The graph depicts the solution to the differential equation describing the uptake kinetics of a chemical by a modeled fish under conventional bioassay conditions. ...

Recently, much has been written about the extreme urgency of elaborating the regulations for engineered nanomaterials. Such regulations are needed both from lawmakers, to protect people from potentially adverse effects, and from industry representatives, to prove that nanoproducts are produced carefully and with caution to avoid possible lawsuits. However, developing regulations has proven to b...

INTRODUCTION Cholestasis leads to liver cell death, fibrosis, cirrhosis, and eventually liver failure. Bile duct ligated rats constitute an interesting model to study the mechanism of cholestasis, and its action on several organs and tissues, including the brain. AIM To analyze brain bile acids individually in ligated rats to evaluate if its profile is altered towards a more toxic condition i...

Copper is an essential element involved in fundamental processes like respiration and photosynthesis. However, it becomes toxic at high concentration, which has forced organisms to control its cellular concentration. We have recently described a copper resistance system in the cyanobacterium Synechocystis sp. PCC 6803, which is mediated by the two-component system, CopRS, a RND metal transport ...

In man, therapeutic doses of imipramine suppress ventricular arrhythmias, and toxic doses can cause severe intraventricular conduction disturbances and cardiac arrest. To determine the cellular mechanisms responsible for these actions, we studied the effects of imipramine hydrochloride at concentrations from 3 x 1<T to 3 x 10~ g/ml on the transmembrane potentials of sheep and calf Purkinje and ...

The Ekati Diamond Mine, located approximately 300 km northeast of Yellowknife in Canada's Northwest Territories, uses mechanical crushing and washing processes to extract diamonds from kimberlite ore. The processing plant's effluent contains kimberlite ore particles (< or =0.5 mm), wastewater, and two wastewater treatment polymers, a cationic polydiallydimethylammonium chloride (DADMAC) polymer...

The concept of plant defense using toxic mineral elements originated as an explanation for extremely elevated concentrations of some elements (termed hyperaccumulation) in some plant tissues. The Defensive Enhancement Hypothesis suggests that hyperaccumulation evolved because, after an initial defensive benefit accrued from a relatively low initial concentration, increased concentration of an e...

Iron is essential to virtually all organisms but it can be toxic in excess. High concentration of iron and other trace elements could restricted bacterial growth and modify their metabolic pattern as well. However, this study aimed to find out the influence of iron, chromium, cadmium and synergism or antagonism between these elements on growth of a gram negative bacterium. In the series of expe...

BACKGROUND When planning radioactive iodine therapy, it frequently happens, both in Poland and world-wide, that inadequate attention is paid to such easily measurable parameter sas: 1) the serum concentration of thyrotropin (TSH) before administering radioiodine, which is a key factor for extranodular(non-autonomous) iodine uptake of the thyroid gland, 2) thyroid gland iodine uptake, and 3) the...