Four variables mean brood size, day of first reproduction, longevity and per capita rate of increase ( r ) -were compared in four 70-d chronic toxicity tests in which Daphnia pulex were exposed to cadmium or copper in continuous and pulsed exposures. With these data we asked the question: Is the population-level variable ( r ) more sensitive than the three organism-level variables (mean brood s...

silver nanoparticles (ag nps) have been widely used as new potent antimicrobial agents in cosmetic and hygienic products. present study compares the tissue levels of ag nps in different organs of guiana pigs quantitatively after dermal application and analysis the morphological changes and pathological abnormalities on the basis of the ag nps tissue levels. before toxicological assessments,the ...

This strongly alkaline chemical is widely used in industry as a feed stock for nitrogen-based chemicals such as fertilizers, plastics and explosives (ATSDR, 1990). Ammonia is also used as a refrigerant. The general public is exposed by off-gasing from cleaning solutions containing aqueous ammonia. Household ammonia solutions contain 5-10% ammonia in water while industrial strength can be up to ...

Toluene occurs naturally as a component of crude oil and is produced in petroleum refining and coke oven operations; toluene is a major aromatic constituent of gasoline (HSDB, 1999). It is used in household aerosols, nail polish, paints and paint thinners, lacquers, rust inhibitor, adhesives and solvent based cleaning agents. Toluene is also utilized in printing operations, leather tanning and ...

Sediment toxicity tests are valuable tools for assessing the potential effects of contaminated sediments in dredged material evaluations because they inherently address complexity (e.g., unknown contaminants, mixtures, bioavailability). Although there is a need to understand the chronic and sublethal impacts of contaminants, it is common to conduct only short-term lethality tests in evaluations...