engleski

Biomonitoring Of Surface Waters Using Duckweed (Lemna Minor L.)

Water pollution by toxic micropollutants, which is predominantly the consequence of human activities (industry, agriculture and urbanisation) is one of the most critical problems concerning drinking water resources and environmental protection of water bodies. Usage of plant test species has proven essential in investigation, detection and quantification of toxic activity in the natural environment. Toxic effects were investigated in several surface waters (Sava River basin, Croatia) collected monthly over a 3 month-monitoring period. Duckweed (Lemna minor L.) is often used as a plant model because it is a widely spread monocot which multiplies rapidly. Heavy metals were determinated by atomic absorption spectrometry, while nutrients determination was conducted using spectrometry and ionic chromatography. The fitotoxic indicators (relative frond number, relative fresh weight, chlorophyll and carotenoid contents) were monitored after seven days of exposure. All samples of tested waters caused growth inhibition and decrease of chlorophyll and carotenoid contents. The biological effects of water samples appeared related to the physicochemical characteristics. Therefore, bioassays should be included, along with conventional chemical analysis, in water quality monitoring programs. The results also suggest that duckweed should be used in the biomonitoring of water quality because of its simplicity, sensitivity and cost-effectiveness.

aquatic plant; growth; chlorophyll; toxicity

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