MAMMALS and birds sometimes seek shelter or nesting sites in the ground. Many of them scarcely affect the soil as a medium for plant growth. A notable exception is the soil-dwelling rodents. Although their acreweight is usually only about a few pounds even in the uncultivated land, their soil transporting activities sometimes are considerable. In building their tunnels and nests, they transport...

A ll transition metals are highly toxic to life at low levels, but at the same time some, such as manganese, iron, cobalt, nickel, copper, zinc and molybdenum, are essential micronutrients needed to catalyse key enzymatic reactions. To survive, living organisms have had to evolve mechanisms that either remove such metals from their bodies or detoxify and make use of them metabolically. Many of ...

background: in addition to gas pollutants, many chemicals and air pollutants are in the form of particulate matter. particulate matter consists of a complex mixture of variable sized particles and physicochemical composition. these particles mainly contain minerals including fe, al, ca, k, cu, ti, mn, ni, v and their size, chemical composition and concentration are important to assess the exten...

background: tea is the most popular nonalcoholic beverage worldwide. in recent years, some iranian studies have shown the occurrence of toxic elements in fresh or dried tealeaves as well as in brewed tea. the present study aimed to ascertain the health risks associated with exposure to toxic and essential element through black tea consumption in iran by systematically reviewing the accredited a...