1. Agrawal, M., Singh, S. K., Singh., J. and Rao, D. N.: 1991, ‘Biomonitoring of air pollution around industrial sites’, J. Environ. Biol. 211–222.
2. Alfani, A., Batroli, G., Rutigliano, F. A., Maisto, G. and VirzoDeSanto, A.: 1996, ‘Trance metal biomonitoring in the soil and the leaves of Quercus Ilex in the urban area of Naples’, Biol. Trace Element Res. 51(1), 117–131.
3. A. P. H. A.: 1998, ‘Standard methods for the examination of water and waste water’, 20th ed., American Public Health Association, Washington.
4. Arnon, D. I.: 1949, ‘Copper enzyme in isolated chloroplasts. Polyphenol oxidase in Beta vulgaris’, Plant Physiol. 130, 267–272.
5. Bache, C. A., Gutenmann, W. H., Rutzke, M., Chu, G., Elfving, DC. and Lisk, D. J.: 1991, ‘Concentrations of metals in grasses in the vicinity of a municipal refuse incinerator’, Arc. Environ. Contam. Toxicol. 20(4), 538–542.