title: Effects of toxicants on populations: a qualitative approach II. First order kinetics.
abstract: System level effects exhibited by a population subjected to a chronic or an acute dose of toxicant are the emphasis of this study. A three dimensional model of a toxicant and a population, with state variables (the population biomass, the concentration of toxicant in an organism, and the concentration of toxicant in the environment) coupled by a linear dose-response function, is analyzed analytically. One of the main results presents sufficient conditions, in terms of a system level parameter, for the persistence, and for the extinction, of a population exposed to a chronic dose of toxicant. When depuration and degradation are negligible processes, the effects of toxicant accumulation associated with an acute exposure of a population are analyzed in some detail. Both persistence and extinction are shown to be viable behavior modes of a population in this biochemical setting.
mesh_terms: D004785:Environmental Pollutants / Q000633:toxicity*; D007700:Kinetics; D008433:Mathematics; D008954:Models, Biological; D011157:Population Dynamics
chemical_list: D004785:Environmental Pollutants