Extractive waste management: A risk analysis approach.

Abandoned mine sites continue to present serious environmental hazards because the heavy metals associated with extractive waste are continuously released into the environment, where they threaten human life and the environment. Remediating and securing extractive waste are complex, lengthy and costly processes. Thus, in most European countries, a site is considered for intervention when it poses a risk to human health and the surrounding environment. As a consequence, risk analysis presents a viable decisional approach towards the management of extractive waste. To evaluate the effects posed by extractive waste to human health and groundwater, a risk analysis approach was used for an abandoned nickel extraction site in Campello Monti in North Italy. This site is located in the Southern Italian Alps. The area consists of large and voluminous mafic rocks intruded by mantle peridotite. The mining activities in this area have generated extractive waste. A risk analysis of the site was performed using Risk Based Corrective Action (RBCA) guidelines, considering the properties of extractive waste and water for the properties of environmental matrices. The results showed the presence of carcinogenic risk due to arsenic and risks to groundwater due to nickel. The results of the risk analysis form a basic understanding of the current situation at the site, which is affected by extractive waste.

Bioaccessibility and size distribution of metals in road dust and roadside soils along a peri-urban transect.

Road dust (RD), together with surface soils, is recognized as one of the main sinks of pollutants in urban environments. Over the last years, many studies have focused on total and bioaccessible concentrations while few have assessed the bioaccessibility of size-fractionated elements in RD. Therefore, the distribution and bioaccessibility of Fe, Mn, Cd, Cr, Cu, Ni, Pb, Sb and Zn in size fractions of RD and roadside soils (<2.5µm, 2.5-10µm and 10-200µm) have been studied using aqua regia extraction and the Simple Bioaccessibility Extraction Test. Concentrations of metals in soils are higher than legislative limits for Cu, Cr, Ni, Pb and Zn. Fine fractions appear enriched in Fe, Mn, Cu, Pb, Sb and Zn, and 2.5-10µm particles are the most enriched. In RD, Cu, Pb, Sb and Zn derive primarily from non-exhaust sources, while Zn is found in greater concentrations in the <2.5µm fraction, where it most likely has an industrial origin. Elemental distribution across soils is dependent on land use, with Zn, Ni, Cu and Pb being present in higher concentrations at traffic sites. In addition, Fe, Ni and Cr feature greater bioaccessibility in the two finer fractions, while anthropic metals (Cu, Pb, Sb and Zn) do not. In RD, only Zn has significantly higher bioaccessibility at traffic sites compared to background, and the finest particles are always the most bioaccessible; >90% of Pb, Zn and Cu is bioaccessible in the <2.5µm fraction, while for Mn, Ni, Sb, Fe and Cr, values vary from 76% to 5%. In the 2.5-10µm fraction, the values were 89% for Pb, 67% for Zn and 60% for Cu. These results make the evaluation of the bioaccessibility of size-fractionated particles appear to be a necessity for correct estimation of risk in urban areas.

Expression of specific genes involved in Cd uptake, translocation, vacuolar compartmentalisation and recycling in Populus alba Villafranca clone.

Cadmium (Cd) is a heavy metal toxic to humans and its occurrence in soils represents a significant environmental problem. Poplar trees may provide one possible option to help remove Cd contamination from soil. However, before this is practicable, the ability of poplar to accumulate Cd needs to be enhanced. A better understanding of the genes involved in Cd accumulation in poplar would help to achieve this goal. Here, we monitored the expression of genes known to be involved in Cd uptake, accumulation and translocation from other species, in order to provide information on their potential role in Cd accumulation in poplar. Cd concentration in poplar was significantly higher in roots than in stem and leaves in Cd treated plants. Expression of the poplar homologues of IRT1, NRAMP and OPT3 was initially increased after exposure to Cd but reduced after longer term Cd exposure. Exposure to Cd also influenced the accumulation of Fe, Ca, Cu, Mg and Mn in poplar. In particular, Cd treated plants had a higher concentration of Fe, Ca, Cu, and Mg in leaves and stem compared to control plants after one day and one week of experiment; while in roots after one month Cd treated plants had a lower concentration of Mn, Fe, Cu, Co, and Mg.