Comparative Toxicity of Heavy Metals Cd, Pb, and Zn to Three Acrocarpous Moss Species using Chlorophyll Contents

Mosses have often been used for biomonitoring because of their diversity of habitats, structural simplicity, and rapid multiplication rate. This research aimed to study the tolerance of heavy metal in 3 species of terricolous mosses i.e., Barbula consanguinea, Hyophila apiculata, and H. involuta. The gametophores of mosses were immersed at 4 concentrations of each of the heavy metals Cd, Pb, and Zn as well as in controls with no heavy metal. After 10, 20, and 30 days of exposure, mosses were extracted for chlorophyll-a in ethanol. The extracted chlorophyll-a was analyzed by spectrophotometer at 664 nm. The results revealed that the amount of chlorophyll-a in all species decreased with increasing concentrations of Cd, Pb, and Zn. The degree of metal toxicity for all species was Cd > Pb > Zn. By comparing the ratio of extracted chlorophyll-a in heavy metal-treated mosses to chlorophyll-a extracted in control mosses, the tolerance against 3 heavy metals in 3 mosses was H. involuta > B. consanguinea > H. apiculata. Possibly, H. involuta can be used for biomonitoring of heavy metals in contaminated environments in the future.