Reconstruction of human exposure to heavy metals using synchrotron radiation microbeams in prehistoric and modern humans

Objective Teeth can serve as records of environmental exposure to heavy metals during their formation. We applied a new technology — synchrotron radiation microbeams (SRXRF) — for analysis of heavy metals in human permanent teeth in modern and historical samples. Methods Each tooth was cut in half. A longitudinal section 200 μm in thickness was subjected to the determination of the heavy metal content by SRXRF or conventional analytical methods (ICP-MS analysis or reduction–aeration atomic absorption spectrometry). The relative concentrations of Pb, Hg, Cu and Zn measured by SRXRF were translated in concentrations (in g of heavy metal/g of enamel) using calibration curves by the two analytical methods. Results Concentrations in teeth in the modern females (n = 5) were 1.2 ± 0.5 μg/g (n = 5) for Pb; 1.7 ± 0.2 ng/g for Hg; 0.9 ± 1.1 μg/g for Cu; 150 ± 24.6 μg/g for Zn. The levels of Pb were highest in the teeth samples obtained from the humans of the Edo era (1603–1868 ad) (0.5–4.0 μg/g, n = 4). No trend was observed in this study in the Hg content in teeth during 3, 000 years. The concentrations of Cu were highest in teeth of two medieval craftsmen (57.0 and 220 μg/g). The levels of Zn were higher in modern subjects (P < 0.05) than those in the Jomon (~1000 bc) to Edo periods [113.2 ± 27.4 (μg/g, n = 11)]. Reconstruction of developmental exposure history to lead in a famous court painter of the Edo period (18th century) revealed high levels of Pb (7.1–22.0 μg/g) in his childhood. Conclusions SRXRF is useful a method for reconstructing human exposures in very long trends

Assessment of Surface Water Quality Using Heavy Metal Pollution Index in Subarnarekha River, India

Surface water samples were collected from 21 sampling sites throughout the Subarnarekha River during pre-monsoon, monsoon and post-monsoon seasons. The concentrations of Al, As, Ba, Cr, Co, Cu, Fe, Mn, Ni, Se, V and Zn were determined using inductively coupled plasma-mass spectrometry for seasonal fluctuation, source apportionment and heavy metal pollution indexing. The results demonstrated that concentrations of the metals showed significant seasonality and most variables exhibited higher levels in the pre-monsoon season. Principal component analysis outcome of four factors together explained 73.13 % of the variance with >>1 initial Eigenvalue indicating both innate and anthropogenic activities as contributing factors of metal profusion in the river. To assess the composite influence of all the considered metals on the overall quality of the water, heavy metal pollution indices were calculated. The HPI for surface water of the river considering all the seasons and locations was 32.27. The HPI of the river calculated for the individual locations showed great variations ranging from 3.55 to 388.9. All the locations fall under low to medium classes of HPI except few locations which are under the influence of industries, mining or near the estuary. The enhanced concentrations of certain metals in the Subarnarekha River near industrial and mining establishments may be attributed to anthropogenic contribution from the industrial and mining activities of the area

Source apportionment of particulate matter in a large city of southeastern Po Valley (Bologna, Italy)

This study reports the results of an experimental research project carried out in Bologna, a midsize town in central Po valley, with the aim at characterizing local aerosol chemistry and tracking the main source emissions of airborne particulate matter. Chemical speciation based upon ions, trace elements, and carbonaceous matter is discussed on the basis of seasonal variation and enrichment factors. For the first time, source apportionment was achieved at this location using two widely used receptor models (principal component analysis/multi-linear regression analysis (PCA/MLRA) and positive matrix factorization (PMF)). Four main aerosol sources were identified by PCA/MLRA and interpreted as: resuspended particulate and a pseudo-marine factor (winter street management), both related to the coarse fraction, plus mixed combustions and secondary aerosol largely associated to traffic and long-lived species typical of the fine fraction. The PMF model resolved six main aerosol sources, interpreted as: mineral dust, road dust, traffic, secondary aerosol, biomass burning and again a pseudo-marine factor. Source apportionment results from both models are in good agreement providing a 30 and a 33 % by weight respectively for PCA-MLRA and PMF for the coarse fraction and 70 % (PCA-MLRA) and 67 % (PMF) for the fine fraction. The episodic influence of Saharan dust transport on PM10 exceedances in Bologna was identified and discussed in term of meteorological framework, composition, and quantitative contribution