Laura Sperni

Correlation between inorganic (heavy metals) and organic (PCBs and PAHs) micropollutant concentrations during sewage sludge composting processes

The nature and congener composition of PCBs and PAHs present in sewage sludge composting processes was investigated. These studies included analysis of the most significant process parameters (such as pH, temperature, weight percentage variation) and in addition heavy metals whose typical composting speciation and behaviour were also considered in order to better understand organic compound time profiles. The significant correlation found between Pb, Cd, Cu and PCBs and between PAHs and Hg implies that quite a strong adsorption of PCBs onto organic matter takes place and also provides evidence for the volatilisation of PAHs. Chemical characteristics of inorganic species and organic compounds are summarised to account for the observed correlation and time trend profiles. Moreover, single congener concentrations demonstrate that the number of Cl substituents for PCBs and condensed benzene rings for PAHs determine to what extent they can be broken down for biodegradation and removed through volatilisation respectively.

Clam Transplantation and Stress-Related Biomarkers as Useful Tools for Assessing Water Quality in Coastal Environments

In this study, the Active BioMonitoring (ABM) approach has been investigated using species of indigenous (from a pristine site) and transplanted (to a polluted area) hard clam Mercenaria mercenaria as an indicator organism of water/sediment pollution in Tampa Bay, Florida, a highly urbanized and industrialized subtropical estuary. A range of possible induced stress indices was selected and used on the basis of potential pollutant toxicity mechanisms including specific enzymatic responses (MFO as BPH and NADPH cytochrome c reductase, antioxidant enzymes as SOD and caltalase, PDH) and general cellular damage (lysosomal latency, histopathological lesions). The organic sediment contamination compared to the animal body burden revealed bioaccumulation activity in transplanted clams. The marked increases of BPH and catalase activities, together with the significant reduction of lysosomal membrane stability in transplanted animals, suggested their potential for application as biomarkers in subtropical coastal pollution monitoring.

Biochemical and histochemical responses to environmental contaminants in clam, Tapes philippinarum, transplanted to different polluted areas of Venice Lagoon, Italy.

In this study the clam, Tapes philippinarum, a filter-feeding bivalve living in soft bottoms, was used to investigate the water/sediment pollution in Venice Lagoon (Venice, Italy), a heavily urbanised and industrialised area. To this end, clams collected from indigenous populations in a clean farming area (Val Dogà) were transplanted into a relatively low contaminated site (Palude della Rosa) and in a heavily polluted area (Porto Marghera), for 5 weeks. A range of possible induced stress indices were measured, on the basis of potential toxicity mechanisms, including specific enzymatic activities [Bap hydroxylase and NADPH cytochrome c reductase, superoxide dismutase, catalase, glutathione peroxidase and propionaldehyde dehydrogenase (PDH)] and general cellular responses (lysosomal latency). Moreover, chemical analyses (polychlorinated biphenyls, polycyclic aromatic hydrocarbon, DDTs) were carried out on sediments and animal tissues at the beginning and end of the transplantation experiments. The chemical results show an active bio-accumulation activity from sediment in clams translocated to the most polluted area. Correspondingly, biological data indicate marked effects on PDH activity and latency in T. philippinarum from the same site. In contrast, no similar pattern has been observed in the other considered indices, possibly due to antagonistic effects of the complex contaminant mixture present in the environment.

Gas chromatographic determination of organic micropollutants in samples of sewage sludge and compost: Behaviour of PCB and PAH during composting

Abstract A simple method for a simultaneous gas chromatographic determination of polyclorobiphenyls and polycyclic aromatic hydrocarbons in samples of sewage sludge and compost is described. Certified materials were used for the evaluation of the method. Organic micropollutants were extracted from freeze-dried samples through a mixture of organic solvents - n-hexane/dichloromethane, 4:1 v:v-in a sonification bath. A multilayer clean-up/ separation column was used to remove interfering organic compounds and to divide PCBs and PAHs into two distinct fractions; and additional purification with metallic mercury was necessary to eliminate sulphur. Fractions are quantifiable with GC-ECD and GC-MS-SIM. The method was applied to determine the concentrations of both PCBs and PAHs during the composting process; a characteristic time profile was traced.

Micellar Promoted Multi-Component Synthesis of 1,2,3-Triazoles in Water at Room Temperature

Micellar media in water provide a simple and efficient environment favoring the multi-component synthesis of 1,2,3-triazoles from organic bromides, sodium azide and terminal alkynes in the presence of [Cu(IMes)Cl] 1 catalyst at room temperature within a few hours. The micellar medium favors both the in situ formation of the organic azide and its metal promoted cycloaddition with the alkyne.

Supramolecular Encapsulation of Neutral Diazoacetate Esters and Catalyzed 1,3-Dipolar Cycloaddition Reaction by a Self-Assembled Hexameric Capsule

Diazoacetate esters proved to be suitable neutral guests for the self‐assembled resorcin[4]arene hexameric capsule. The hydrogen‐bonded supramolecular host catalyzed the 1,3‐dipolar cycloaddition reaction between diazoacetate esters and electron‐poor alkenes such as acrolein, acrylonitrile, predominantly trans‐crotonaldehyde, trans‐2‐hexenal, methyl, and butyl acrylate, which led to the corresponding 4,5‐dihydro‐1H‐pyrazole derivatives. The cycloaddition reaction occurred within the cavity of the capsule. In fact, substantial inhibition of the catalytic activity was observed by employing tetraethylammonium tetrafluoroborate characterized by greater affinity for the hexameric capsule as a competitive guest; its presence inhibited access of the substrates. The 1,3‐dipolar cycloaddition reaction between diazoacetate esters and acrylate esters of different lengths showed a significant degree of substrate selectivity owing to the encapsulation of the reagents before the cycloaddition reaction.

Hydration of aromatic alkynes catalyzed by a self-assembled hexameric organic capsule

The combination of a Bronsted acid catalyst and a supramolecular organic capsule formed by the self-assembly of six resorcin[4]arene units efficiently promotes the mild hydration of aromatic alkynes to their corresponding ketones. The capsule provides a suitable nanoenvironment that favors protonation of the substrate and addition of water.

CONTAMINATION IN MYTILUS GALLOPROVINCIALIS BY CHLORINATED HYDROCARBONS (PCBS AND PESTICIDES), PAHS AND HEAVY METALS IN THE LAGOON OF VENICE

Polychlorobiphenyls, chlorinated pesticides, polycyclic aromatic hydrocarbons and heavy metals (Cd, Pb, Cr, Ni, Hg, Cu, Fe, Zn) were measured in the entire tissue of the mussel Mytilus galloprovincialis, collected at five sites in the Lagoon of Venice and one reference site outside the Lagoon, in the Adriatic Sea. Total concentrations ranged from 57.5 ± 0.2 to 779 ± 11 ng g−1 d.w. for PAHs, from 52 ± 4 to 286 ± 1 ng g−1 d.w. for PCBs, and from 2.6 ± 0.8 to 37 ± 4 ng g−1 d.w. for pesticides, indicating significantly higher contamination in the central part of the Lagoon with respect to the northern and southern ones. As regards heavy metals, only Cd presented a pattern similar to that of organic compounds. The other metals showed peculiar distribution in the six sites of the Lagoon in relation to their sources. The risk to human health as a result of eating these mussels was evaluated by comparison of daily dietary intake with toxicological threshold limits. In mussels from Porto Marghera, Cd, hexachlorobenzene and pyrene had concentrations potentially harmful to human health.

Efficient epoxide isomerization within a self-assembled hexameric organic capsule

The isomerization of epoxides to the corresponding carbonyl compounds is efficiently catalyzed by the supramolecular organic nano-capsule formed by the self-assembly of six resorcin[4]arene units. The capsule provides a combination of weak Bronsted acidity and a suitable nano-environment that favors the metal-free isomerization reaction.

Copper‐mediated 1,4‐Conjugate Addition of Boronic Acids and Indoles to Vinylidenebisphosphonate leading to gem‐Bisphosphonates as Potential Antiresorption Bone Drugs

A wide range of gem‐bisphosphonate tetraethyl esters as precursors for bisphosphonic acids, which are potent inhibitors of bone resorption, bearing alkyl, aryl, and indole substituents in the β position were prepared through the CuII‐catalyzed 1,4‐conjugate addition of boronic acids and indoles to vinylidenebisphosphonate tetraethyl ester.