Biomonitoring of lake sediments using benthic macroinvertebrates

The Water Framework Directive (2000/60/EC) is an innovative piece of legislation aimed at protecting the quality of all continental and coastal waters in Europe through an ecological evaluation of the ecosystems. Since it is widely acknowledged that the greater the ecological realism the greater the difficulty of its definition, we describe the different uses of benthic organisms as a tool for assessing the quality of sediment in lakes. We review the responses from single species to the community. We focus on studies in the laboratory and in the field, and we also critically consider the use of predictive models for these evaluations. Our discussion of the information collected underlines the importance of the relation between sensitivity of single species and contaminants. Moreover, the recent approach in developing mechanistic models to predict the response of natural communities seems to be particularly powerful for community ecology, and we strongly recommend more effort along these lines

Selection of the optimal extraction protocol to investigate the interaction between trace elements and environmental plastic

The interaction between environmental plastic and trace elements is an issue of concern. Understanding their interaction mechanisms is key to evaluate the potential threats for the environment. To this regard, consolidating confidence in extraction protocols can help in understanding the amount of different species present on plastic surface, as well as the potential mobility of trace elements present inside the plastic matrix (e.g., additives). Here we tested the efficacy of different reagents to mimic the elemental phases bonded to meso- and microplastic in the environment, in relation to the grade of ageing and the polymer composition. Results showed that a relatively high portion of trace elements is bonded in a weak phase and that other phases abundant in other matrices (e.g., oxides and bonded to organic matter) are only present to a limited degree in the plastic samples. The comparison of different sample types highlighted the important role of plastic ageing in governing interactions with trace elements, while the polymer composition has a limited influence on this process. Finally, the future steps toward a tailored extraction scheme for environmental plastic are proposed

Levels, sources and chemical fate of persistent organic pollutants in the atmosphere and snow along the western Antarctic Peninsula

The Antarctic continent is among the most pristine regions; yet various organic contaminants have been measured there routinely. Air and snow samples were collected during the austral spring (October November, 2010) along the western Antarctic Peninsula and analyzed for organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) to assess the relative importance of long-range transport versus local primary or secondary emissions. Highest concentrations of PCBs, PBDEs and DDTs were observed in the glacier\u27s snow sample, highlighting the importance of melting glaciers as a possible secondary source of legacy pollutants to the Antarctic. In the atmosphere, contaminants were mainly found in the vapor phase (\u3e65%). Hexachlorobenzene (33.6 pg/m(3)), PCBs (11.6 pg/m(3)), heptachlor (5.64 pg/m(3)), PBDEs (4.22 pg/m(3)) and cis-chlordane (2.43 pg/m(3)) were the most abundant contaminants. In contrast to other compounds, PBDEs seem to have originated from local sources, possibly the research station itself. Gas-particle partitioning for analytes were better predicted using the adsorption partitioning model than an octanol-based absorption approach. Diffusive flux calculations indicated that net deposition is the dominant pathway for PBDEs and chlordanes, whereas re-volatilization from snow (during melting or metamorphosis) was observed for PCBs and some OCPs. (C) 2016 Elsevier Ltd. All rights reserved

Relationships between structural and thermal properties of anhydrous and solvated crystalline forms of brodimoprim

The isolation and physicochemical characterization of four crystalline modifications of brodimoprim (5-[(4-bromo-3,5-dimethoxyphenyl)methyl]-2,4-pyrimidinediamine, hereinafter BMP), a structural analog of trimethoprim (TMP), are reported. These phases include an unsolvated form of BMP, a hemihydrate (BMP0.5H2O), a 1:1 solvate containing isopropanol (BMPC3H7OH(iso)), and a hemichloroformate (BMP0.5CHCl3). Unsolvated BMP was isolated both by recrystallization from a range of common solvents as well as by thermal decomposition of the above solvates and no evidence for polymorphism was found. PXRD data indicated that the three solvates crystallize in different arrangements. Data from thermal analysis (thermogravimetry (TGA), hot stage microscopy (HSM), differential scanning calorimetry (DSC)) of the solvates containing water and iso-propanol were interpreted on the basis of their singlecrystal X-ray structures which revealed that the modes of solvent inclusion in BMP0.5H2O and BMPC3H7OH(iso) may be described as ‘isolated site’ and ‘lattice channel’ type inclusions, respectively

Relazioni tra carico organico, nutrienti e microinquinanti: depurare aumenta il rischio chimico?

Poich\ue9 la problematica dei microinquinanti \ue8 molto complessa sia per il numero elevato di potenziali agenti tossici sia per le interazioni tra le diverse specie chimiche presenti nell\u2019acqua, risulta indispensabile affiancare alle metodiche analitiche l\u2019uso di metodi biologici che rispondono in modo integrato all\u2019insieme dei potenziali inquinanti. Tali metodologie sono state ampiamente applicate al fiume Po, soprattutto in un punto critico rappresentato dalla confluenza del fiume Lambro. La recente entrata in funzione dei depuratori di Milano, che dovrebbe drasticamente diminuire il carico organico e dei nutrienti potrebbe aumentare la biodisponibilit\ue0 di metalli e altre sostanze potenzialmente pericolose. Questa ipotesi \ue8 corroborata da uno studio in cui si dimostra che la tossicit\ue0 del nichel presente nelle acque del Lambro su Ceriodaphnia dubia \ue8 attenuata dal carbonio organico disciolto (DOC). D\u2019altra parte la riduzione dell\u2019eutrofizzazione culturale dei laghi potrebbe aumentare la biodisponibilit\ue0 di inquinanti organici persistenti (POP), favorendo il bioaccumulo negli organismi acquatici, come si dimostra in uno studio in cui si confrontano tre grandi laghi italiani interessati da recenti fenomeni di inquinamento da DDT