Heavy metals impact at plants using photoacoustic spectroscopy technology with tunable CO 2 laser in the quantification of gaseous molecules

Heavy metals (HM) are common pollutants and received considerable attention since they may also have impacts on human via the food chain, drinking water, air inhalation or may be absorbed through the skin when they enter into contact with humans in agriculture and in manufacturing, pharmaceutical, industrial or residential settings. In this research, the effects of some HM: Hg, Pb, Cd, Cu and Zn on common wheat seeds (Triticum aestivum), Spelt wheat (Triticum spelta), common corn (Zea mays), alfalfa (Medicago sativa) and green peas (Pisum sativum) were investigated using photoacoustics as a non-invasive analysis method, in the detection of two gaseous molecules: ethene (ethylene) and ammonia. From the point of view of toxicology and oxidation states, the determinations demonstrates that seeds/grains germinated with HM, determine a greater increase of ammonia vapors in the respiration of plants and a greater decrease of ethylene vapors in the respiration of vegetation. In the same time, the investigations presented in this paper showed that the photoacoustic technology with tunable CO2 laser, in the quantification of gaseous molecules, was able also to distinguish between seeds/grains germinated with HM and seeds/grains germinated with distilled water and can play an important role in testing the contaminated biological samples.