El medio ambiente en la minería

117 :(': .' PEA G. BROMAN historieal deposits. Since it derives its nourishment from· ..the air. the metal content. of the moss reflects the deposit relationship durinJ the past two to three years. Figure 5 provides an example of a study ofIQ.oss, jnwhich comparisoos of the metal content ofmoss are made at an approximate i Ó year intervalo The figure illustrates that the heavy inerease that could be ascertained teos of kilometers from the plants in 1979 had been radically improved during the period up to 1990. 1979 1990 Figure 5: Lead in moss, 1979 and 1990.