Butterflies as bioindicators of metal contamination.

Anthropogenic trace metal contamination has significantly increased and has caused many hazardous consequences for the ecosystems and human health. The Terni basin valley (Central Italy) shows a heavy load of pollutants from industrial activities, while the characteristic orography structure of the valley favours air stagnation, thus limiting air pollution dispersal. The present study conducted in 2014 aimed to determine the concentration of ten metals in five species of butterflies at nine sites in the Terni valley along a 21-km-long transect, including both relatively pristine and industrial areas. At sites where soil contamination was high for a given metal, such as for chromium as in the case of site 4 (the closest to the steel plant) and for lead as in the case of site 2 (contaminated by a firing range), higher levels of contamination were observed in the tissues of butterflies. We found a correlation between soil contamination and the concentration of Cr, Al and Sr in the tissues of some species of butterflies. The sensitivity to contamination differed among the five species; in particular, Coenonympha pamphilus was generally the species that revealed the highest concentrations of all the ten trace metals at the sites closer to the industrial area. It is known that C. pamphilus is a sedentary species and that its host plants are the Poaceae, capable of accumulating high quantities of metals in their rhizosphere region, thus providing the link with soil contamination. Therefore, monitoring the metal concentration levels in butterflies might be a good indicator and a control tool of environmental quality, specifically in areas affected by high anthropogenic pollution loads linked to a specific source.

Sex and seasonal differences in metal accumulation of selected tissues in red swamp crayfish from Lake Trasimeno (Umbria, Italy).

Concentrations of essential metals (Cu, Co, Cr, Fe, Ni, Mn, and Zn) and non-essential and toxic metals (Ag, Cd, Hg, and Pb) were quantified in hepatopancreas and abdominal muscle for 73 specimens (37 males and 36 females) of Procambarus clarkii from Lake Trasimeno (Italy) in a year's campaign (July 2018 to June 2019). Elemental concentrations determined in crayfish differed in tissues, seasons, and gender. Both sexes showed lower concentrations in abdominal muscle than in hepatopancreas. Essential metals accumulated in higher concentrations in both tissues than non-essential elements, while associations between essential metals were stronger, especially for females; however, a strong correlation was also observed between Cu and Ag in both sexes. No significant differences in concentrations were recorded between sexes for all seasons; contrarily, significant differences among the total seasonal concentrations (males plus females) were observed only for essential metals and for Ag. Seasonal Toxic Contamination Index (TCI) for Cr, Ni, Cu, Zn, Cd, Pb, and Hg were calculated to assess the toxicity level of metals in the sediments. TCI higher than 1 was detected for Ni only in summer, confirming the close connection between the fluctuating hydrological levels of the shallow Lake Trasimeno, strongly dependent on precipitation, and the metal contamination levels of sediments.

Sources and trends of trace elements and polycyclic aromatic hydrocarbons in a shallow lake in the Mediterranean area from sediment archives of the Anthropocene.

In this study, the anthropogenic contamination in Trasimeno lake (Central Italy) was investigated using three sediment cores spanning over the last 150 years (Anthropocene) to identify the primary sources of pollution and quantify the level of contaminant enrichment in the basin. First, based on the relative cumulative frequency and linear regression methods, we obtained a geochemical baseline for the lake using the deeper parts of the sediment cores. The geochemical baseline allowed us to determine the values of trace elements enrichment factors. On this knowledge, as a second result, we were able to reconstruct the natural sources and the anthropogenic impact on the lake with a biennial resolution. This goal has been obtained by combining different inorganic and organic chemical proxies such as trace elements, polycyclic aromatic hydrocarbons, and lead isotope ratios and exploiting both principal component and factor analysis to associate chemical proxies to human-driven contamination processes. Five different groups of elements have been identified, one of which is of natural origin and four of anthropogenic origin. In particular, it was possible to identify the times and impacts of the industrial activities during the Second World War, which dispersed heavy metals in sediments. Moreover, we found evidence of the recent human activities that have characterized the surroundings of the basin, such as Pb inputs related to the use of gasoline and the enrichment of certain elements generally used in agricultural activities (such as P, Cu, and Mn) due to the development of this sector in the last 40 years.