Bricks as historical record of heavy metals fallout: Study on copper accumulation in Agra soils since 1910.

Peat, ice deposits and aquatic sediments, which have been used as a geochemical monitor of atmospheric heavy metal pollution until now, are open and dynamic systems and can be easily affected by climatic variations. In contrast, bricks, which are more compact, can act as a better geochemical monitor. Analysis of Cu, Cr, Ni, Pb and Zn in scores of soil and brick (baked/unbaked) samples, collected from a large area in and around a rapidly growing Indian city, Agra, reveals approximately similar concentrations in soils and bricks, thereby showing insignificant fractionation of these metals during brick making. Further, metals concentration in the core of bricks remains unaffected by any significant amount of acidic and alkaline rain. Thus, the feasibility of a novel role of bricks as a geochemical monitor of atmospheric heavy metal pollution has been tested. Utilizing this concept, an attempt has also been made to trace the history of atmospheric copper depositions in the soils of Agra during the last 100 years.