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Tannic acid capped gold nanoparticles with a mean diameter of 20nm were efficiently prepared by the green synthetic route. The size and morphology of gold nanoparticles were investigated by transmission electron microscopy and atomic force microscopy. The gold nanoparticles were effectively applied for the development of a sensing system that can detect and extract Hg2+ions as well as Pefloxacine in a single step due to the strong interaction of gold nanoparticles with Hg2+ions and pefloxacin. The sensing ability of gold nanoparticles was deliberated for the selective removal of Hg2+ions and pefloxacin using UV visible absorption. The UV visible absorption of tannic acid capped gold nanoparticles was satisfied by different metal salts and drugs. The synthesized nanoparticles showed stability within a pH range of 3-12 and to heating at 100 ºC for 5 minutes. Quenching of the peak and precipitation is observed with various concentrations of brine solutions. Job’s plot analysis shows the binding stoichiometry to be a 1:1 ratio. This newly designed sensor offers a simple low-cost alternative tool for recognition and extraction of Hg2+and pefloxacin. &nbsp

Mercury (Hg) contamination of environment is a major threat to human health in developing countries like Pakistan. Human populations, particularly children, are continuously exposed to Hg contamination via dust particles due to the arid and semi-arid climate. However, a country wide Hg contamination data for dust particles is lacking for Pakistan and hence, human populations potentially at risk is largely unknown. We provide the first baseline data for total mercury (THg) contamination into dust particles and its bioaccumulation trends, using scalp human hair samples as biomarker, at 22 sites across five altitudinal zones of Pakistan. The human health risk of THg exposure via dust particles as well as the proportion of human population that are potentially at risk from Hg contamination were calculated. Our results indicated higher concentration of THg in dust particles and its bioaccumulation in the lower Indus-plain agricultural and industrial areas than the other areas of Pakistan. The highest THg contamination of dust particles (3000ppb) and its bioaccumulation (2480ppb) were observed for the Lahore district, while the highest proportion (>40%) of human population was identified to be potentially at risk from Hg contamination from these areas. In general, children were at higher risk of Hg exposure via dust particles than adults. Regression analysis identified the anthropogenic activities, such as industrial and hospital discharges, as the major source of Hg contamination of dust particles. Our results inform environmental management for Hg control and remediation as well as the disease mitigation on potential hotspots.