Biomonitoring the superficial heavy metals settling on five selected herbal plants and their corresponding habitat

Abstract

Unsustainable anthropogenic activities place under threat herbaceous floras which generally provide benefits to humankind unless they are poisonous or intoxicated by nature. In the Maltese Islands, herbal plants are not being over exploited but anthropogenic pollution derived from industrial activates and vehicular emissions are causing strains. Non-essential heavy metals aerosols are one of the major environmental pollutants of great concern. For this study five herbal plants including Lantana camara, Hibiscus rosa-sinensis, Diplotaxis tenufolia, Ecballium elaterium and Malva sylvestris, and their corresponding soils (0-10cm), were collected from Rabat, Birkirkara and Marsaxlokk. The samples were weighed, washed with de-ionized water, filtered and then diluted up to 50ml with de-ionized water. The diluted samples have been quantitatively analysed by Agilent 4100 microwave plasma-atomic emission spectrometry to trace any superficial settlings of heavy metals of Zinc (Zn), Iron (Fe), Lead (Pb) and Potassium (K). In addition, the Folin-Ciocalteu test was conducted to determine the plant polyphenolic content of the plant extracts which was analysed with Gen 5 software. Ultimately, the electromagnetic radiation absorbance values and types were identified with the UV-Visible spectrophotometry. The following four parameters including tonality ratio, colour intensity, flavonoid ratio and anthocyanin content were calculated.