Phyto-indicators in detection of lindane residues in water

Abstract

Intensive use of pesticides, especially insecticides, in agriculture during the past several decades has already led to contamination of surface and underground waters and sediments in some regions, thus presents a serious problem for the environment. Lindane was one of frequently applied insecticides for soil treatment. In Serbia, it has been in use since 1944, but in the period 2001-2007 its use was restricted only to timber treatments. In 2009 an international ban on the use of lindane in agriculture was implemented under the Stockholm Convention on Persistent Organic Pollutants. However, due to a long-term use and persistence, its residues can be present in underground water and sediment, thus present a potential risk for incorporation in food chains. According to Directive 2008/105/EC it is listed as one of the priority water pollutants, whose presence is mainly detected by chemical methods. However, biological tests are gaining in importance in the last few years and since some plant species are highly sensitive to certain pollutants. This work aimed to assess potential of white mustard (Sinapis alba L.), cucumber (Cucumis sativus L.) and barley (Hordeum vulgare L.) as phyto-indicators of water contamination with lindane. The effect of lindane (rates 0.1 μg a.i./L--maximal allowable concentration (MAC) in water; 0.2; 0.5; 1 and 2 μg a.i./L) was assessed on physiological (germination energy and germination- %) and morphological parameters (root and shoot lengths, fresh and dry weights) of tested species. Assay was carried out using slightly modified filter paper method recommended by ISTA Regulations book (2011). The experiment was set in four replicates. Data were processed using Duncan's multiple range test for determining the differences between treatments for confidence interval 95%. Results of bioassay indicate that germination energy (70.75%) and germination (79.00%) of white mustard were significantly inhibited by lindane applied at MAC rate compared to the control (79.75, 82.00%, respectively). Physiological parameters of other test species were not affected by this insecticide. Lindane inhibited root elongation of barley seedlings at 2 μg a.i./L (20-fold MAC) and of cucumber at 0.5 μg a.i./L (5-fold MAC). Only fresh root weight of barley was inhibited by lindane at MAC quantities. Based on presented results, valid and reliable indicators of lindane presence in water can be considered germination energy and germination of white mustard and fresh root weight of barley seedlings.