Investigation on the potential use of aquatic plants for biomonitoring of the important aquatic ecosystems of the country-The first phase: Anzali Wetland

Abstract

This research project was conducted during 2007-2008 in Anzali wetland, aiming feasibility study on aquatic plants different species (emerged, sub emerged and floating leaved plants) as essential and non essential elements concentration Biological indicators utilization including Ni, B, Cd, Pb, Cu, Mo, Se, Si, Cl, Zn, Mn, Fe, Na, Mg and Ca. and their tolerance and capabilities assessment toward exposing different elements and study on water and sediments rational role in elements absorption and important environmental factors (DO, pH, etc…) effects on absorbed quantities. Azolla filiculoides, Hydrocotyle vulgaris, Ceratophyllum demersum,Trapa natans were the gathered aquatic plants field samples. Water and sediment samples were also collected from Shijan, Abkenar and Siahkeshim sampling sites respecting 1, 2 and 3 and were digested according to the standard methods. Element concentrations were determined using ICP-AES and AAS. Lab samples were Hydrocotyle , Lemna , Ceratophyllum and exposed to Ni, Zn, Cd, Pb, Cu and Ca in Swedish standard, (SIS), Lemna growth Medium 648, Hogland's E+Medium (22,23) implementation. The results shows a significant variation (p≤ 0/0001) among the plants, sampling sites and the elements which is compatible with previous similar projects results at national and international scales, rationally. Totally pattern of the elements occurrence in the plants would be: Cd < Mo, Pb <Co < Si, Ni < Cu < Cl < B < Zn < Fe < Mn, Ca < Na. On concentrated metals in the plant tissues and their amounts in the waters There is no any clear proportion for Azolla and Ceratophyllum however there is for concentrated Ni, Cl and Zn in Hydrocotyle and the water samples and also Co, Cl, Cu, Mn for Trapa and the sampling site 3. There is positive harmony between existed elements in Hydrocotyle and 3 stations sediments and this is obvious for Fe, Na, Mg, Ca in Trapa and stations 1 and 3 stations. This trend in Azolla and the sediments is current for Ni, Mg and just Co in Ceratophyllum. Water temperature, Do and pH variation trends are the same and could be arrange in stations as 2>1>3 and this is 1>2>3 for hazy and no trend for TOM variations. The lab samples test results on metal concentration illustrates Hydrocotyle and Ceratophyllum similar trends for maximum Zn and minimum Pb absorbing. However, for Lemna the highest and least absorption rates belong to Ni and Cd. Density factor sequence in heavy metals exposed lab samples would be: Lemna > Hydrocotyle > Ceratophyllum.