Pakistan Journal of Biological Sciences1028-88801812-5735Asian Network for Scientific Information10.3923/pjbs.2003.1108.1117RamadanAdel A.122003613In this study, the pollution levels and the toxicity status were estimated regarding four
heavy metals (Zn, Pb, Cd and Hg) thought to be among the major contaminants in the
environment of Lake Manzala. Our target was to define and utilize certain plant species,
from the lake`s vegetation, as biomonitors, in comparison with the sediments as abiotic
monitor for heavy metal pollution. The native wild plants (passive biomonitors) were
represented by eight species (Atriplex portulacoides, Zygophyllum album, Typha
domingensis Juncus rigidus, Cyperus laevigatus, Arthrocnemum macrostachyum, Salsola
sp. and Phragmites australis). The introduced plants (active biomonitors) were
represented by two crop-species (Trifolium alexandrinum and Raphanus sativa) grown
and irrigated by polluted water at some islands in the southern sector of LM. Based on
the concentration and toxicity status, induced in the lake`s vegetation and sediments, the
four metals are arranged in the following decreasing order: Hg > Zn > Pb > Cd.
Compared with the standard normal and critical toxicity ranges in plants and soils, the
detected values of Zn, Pb and Cd were within the critical ranges. However, Hg showed
the highest values and alarming toxicity levels and it is considered as one of the most
hazardous pollutants in Lake Manzala. The overall evaluation of the tested metals
showed that their ratios were as much as 2.5 – 5 times higher in active monitors than in
passive ones and 2 times than in sediments. They were also 2 times higher in sediments
than in passive monitors. The monitoring materials are arranged in a decreasing order,
based on their efficiency for accumulating heavy metals as follows: Introduced (active)
monitors > Sediments > Native (passive) monitors. Certain species are also proposed as
biomonitors (and/or biofilters) for the studied heavy metal pollutants. The results showed
that there is a significant difference between the accumulation rate of some metals in
different plant organs (e.g. Zn, Hg) since they showed more tendency for accumulation
in root more than shoot systems. Also, there is a high positive correlation between
combinations of different metal pairs in either plant`s root or shoot system. It is evident
that while the degree of metal pollution in the lake increased southwards, the values of
water-quality parameters (e.g. dissolved oxygen %, salinity and pH-value) increased
northwards.]]>Abdel-Moati, A.R.,19851985Abdel-Moati, A.R. and N.M. Dowidar,198814183202Angold, P.G.,199734409417Anonymous,19821982Anonymous,19941994Atkins, D.P., I.C. Trueman, C.B. Clarke and A.D. Bradshaw,1982Festuca rubra on a motorway verge.]]>27233241Biernacki, M., J.L. Doust and L.L. Doust,1996Vallisneria americana as a biomonitor of aquatic ecosystems: Leaf-to-root surface area ratios and organic contamination in the Huron-Erie Corridor.]]>22289303Biernacki, M., J.L. Doust and L.L. Doust,1997Vallisneria americana.]]>2397107Bishai, M.H. and S.F. Yossef,197773151Boulos, L.,1995Bowen, H.J.M.,1979Chaphekar, S.B.,199112163168Crowder, A.,199171171203Engler, R.M. and W.H. Jr. Patrick,1975119217221Farag-Alla, K.A.K.,20012001Gambrell, R.P., P.A. Khalid and W.H. Jr. Patrick,19761976pp: 418-434pp: 418-434Halem, Y. and S.K. Guerguess,19784435438Hem, J.D.,19728661679Holmes, C.M., E.A. Slade and C.J. McLerran,19748255259Ishak, I.F. and E.F. El- Halawany,19893295107Jackson, M.L.,1974Kabata-Pendias, A. and H. Pendias,19922nd Edn.,Pages: 365Pages: 365Khalil, M.T.,19856162171Khalil, M.T.,1990196193199Korhola, A., J. Weckstrom and M. Nyman,19993610211034Kovacs, M. and J. Podani,1986371929Lambou, V.W. and L.R. Williams,19801980pp: 1118Doust, L.L., J.L. Doust and M. Biernacki,1994Vallisneria Americana, as a biomonitor of organic contaminants in aquatic ecosystems.]]>20333354Doust, J.L., M. Schmidt and L.L. Doust,199469147186Madden, K.E. and B.J. Fox,19973412391256Maltby, L. and P. Calow,1989188-1896576Mekki, L.,1996Allium cepa, Allium sativum, Vicia faba and Zea mays.]]>2267274Mengel, K. and E.A. Kirkby,19823rd Edn.,pp: 655pp: 655Montasir, A.H.,193712150Moriarty, F.,19902nd Edn.,Outridge, P.M. and B.N. Noller,1991121163Phillips, D.J.H.,197826167229Piper, C.S.,1947 1st Ed.Ramadan, A.A.,20025819824Ramadan, A.A. and L. Mekki,19961996Salib, E.A. and M.T. Khalil,19861291100Shaheen, A.H. and S.F. Yossef,197848339367Siegel, F.R., M.I. Slaboda and D.J. Stanely,1994238998Smith, B.M.,19911991pp: 41-59pp: 41-59Spurgeon, D.J. and S.P. Hopkin,199936173183Tackholm, V.,19741st Edn.,Pages: 888Pages: 888Youssif, W.M.E.,19921992Zahran, M.A., M.E. Abu Ziada, M.A. El-Demerdash and A.A. Khedr,198915607643Zahran, M.A., M.A. El-Demerdash and I.A. Mashaly,19901305310Zaki, M.M.M.,19941994Soliman, F.A. and A.A. Ramadan,19931993