Chemical Time Bomb Concept (CTB) refers to �events resulting in the delayed occurrence of harmful effects due to the mobilization of chemicals stored in soils and sediments�1, and upon oversaturation, metal(loid) release is often suggested as the cause of contamination. However, field observations reveal some ecosystems accept contaminants with little to no impact. If soils/sediments are sinks for metal(loid) contaminants, it is due to a favorable hydrogeochemical environment.  Here, we propose a new approach to the CTB concept.  In estimating the point at which retention capacity will be reached; it is not oversaturation, but the ability of soils/sediments sinks to resist physio-chemical changes that is important. Soils/sediments retain metal(loid) pollutants as long as the controlling parameters, i.e., mostly pH and Eh, are stable.  pH or Eh buffer capacity of the solid is therefore the controlling parameter in metal(loid) contaminant release. Examples of natural and contaminated systems will be presented.1) STIGLIANI, W. M. et al., 1991

Chemical time bomb concept revisited: The ability of ecosystems to resist biogeochemical aggressions

244th National Meeting (2012)

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