Study of canal sediments contaminated with heavy metals: fungal versus bacterial bioleaching techniques.

Filamentous fungi and lithotrophic bacteria were used to leach heavy metals from dredged sediments in semi-pilot scale air-lift bioreactors. A preliminary physico-chemical characterization of the sediments comprising a sequential extraction study revealed their high metallic contamination and a predominant association of the metals with sulphides and organic matter. The mobility of heavy metals from sediments was ranked by decreasing order as follows: Mn > Zn > Cd > Cu > Pb.

Toxicity of 58 substituted anilines and phenols to algae Pseudokirchneriella subcapitata and bacteria Vibrio fischeri: comparison with published data and QSARs.

A congeneric set of 58 substituted anilines and phenols was tested using the 72-h algal growth inhibition assay with Pseudokirchneriella subcapitata and 15-min Vibrio fischeri luminescence inhibition assay. The set contained molecules substituted with one, two or three groups chosen from -chloro, -methyl or -ethyl. For 48 compounds there was no REACH-compatible algal toxicity data available before.

Particle-size effect of CuO and ZnO on biogas and methane production during anaerobic digestion.

The effects of bulk- and nano-sized CuO and ZnO particles on biogas and methane production during anaerobic digestion of cattle manure were studied for a period of 14 days at 36 °C using the ISO 13641-2 guidelines. Biogas production was severely affected at concentrations of bulk and nanoparticles over 120 and 15 mg/L for CuO and 240 and 120 mg/L for ZnO, respectively. EC50 concentrations for methane inhibition were estimated to be 129 mg Cu/L for bulk CuO, 10.

Changes in the Daphnia magna midgut upon ingestion of copper oxide nanoparticles: a transmission electron microscopy study.

This work is a follow-up of our previous paper (Heinlaan et al., 2008. Chemosphere 71, 1308-1316) where we showed about 50-fold higher acute toxicity of CuO nanoparticles (NPs) compared to bulk CuO to water flea Daphnia magna.

E-SovTox: An online database of the main publicly-available sources of toxicity data concerning REACH-relevant chemicals published in the Russian language.

A new open-access online database, E-SovTox, is presented. E-SovTox provides toxicological data for substances relevant to the EU Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH) system, from publicly-available Russian language data sources. The database contains information selected mainly from scientific journals published during the Soviet Union era.

From ecotoxicology to nanoecotoxicology.

For hazard assessment of NPs quantitative nanoecotoxicological data are required. The objective of this review was to evaluate the currently existing literature data on toxicity (L(E)C50 values) of synthetic NPs in environmentally relevant species in order to: (i) identify tentatively most harmful NPs and most sensitive organism groups, and (ii) to provide relevant ecotoxicological information for further risk assessment. The focus was set on selected synthetic NPs (nano TiO(2), nano ZnO, nano CuO, nano Ag, SWCNTs, MWCNs and C60-fullerenes) and organism groups representing main food-chain levels (bacteria, algae, crustaceans, ciliates, fish, yeasts and nematodes).

Toxicity of nanoparticles of ZnO, CuO and TiO2 to yeast Saccharomyces cerevisiae.

The aim of this study was to evaluate the toxic effect of nanosized ZnO, CuO and TiO(2) to Saccharomyces cerevisiae - a widely used unicellular eukaryotic model organisms in molecular and cell biology. The effect of metal oxide nanoparticles, their bulk forms and respective ionic forms were compared. The bioavailable Zn(2+) and Cu(2+) ions in the growth medium were quantified by recombinant microbial sensors.

Toxicological information on chemicals published in the Russian language: Contribution to REACH and 3Rs.

This review is reporting on the current situation of publicly available toxicological and ecotoxicological information on chemicals published in Russian language in various libraries, databases as well as in the Internet. This information can be beneficial for the new EU chemical policy REACH and for the development of intelligent testing strategies (involving also QSAR and QAAR) that enable a significant increase in the use of non-testing information for regulatory decision making, thus minimizing the need for animal testing according to the 3R's strategy. Currently, the access to this information is limited due to the language barrier and low level of digitalization of respective journals and books.

Toxicity of nanoparticles of CuO, ZnO and TiO2 to microalgae Pseudokirchneriella subcapitata.

Toxicities of ZnO, TiO2 and CuO nanoparticles to Pseudokirchneriella subcapitata were determined using OECD 201 algal growth inhibition test taking in account potential shading of light. The results showed that the shading effect by nanoparticles was negligible. ZnO nanoparticles were most toxic followed by nano CuO and nano TiO2.

Biotests and Biosensors for Ecotoxicology of Metal Oxide Nanoparticles: A Minireview.

Nanotechnologies have become a significant priority worldwide. Several manufactured nanoparticles - particles with one dimension less than 100 nm - are increasingly used in consumer products. At nanosize range, the properties of materials differ substantially from bulk materials of the same composition, mostly due to the increased specific surface area and reactivity, which may lead to increased bioavailability and toxicity.

Toxicity of nanosized and bulk ZnO, CuO and TiO2 to bacteria Vibrio fischeri and crustaceans Daphnia magna and Thamnocephalus platyurus.

As the production of nanoparticles of ZnO, TiO2 and CuO is increasing, their (eco)toxicity to bacteria Vibrio fischeri and crustaceans Daphnia magna and Thamnocephalus platyurus was studied with a special emphasis on product formulations (nano or bulk oxides) and solubilization of particles. Our innovative approach based on the combination of traditional ecotoxicology methods and metal-specific recombinant biosensors allowed to clearly differentiate the toxic effects of metal oxides per se and solubilized metal ions. Suspensions of nano and bulk TiO2 were not toxic even at 20 g l(-1).

Rapid screening for soil ecotoxicity with a battery of luminescent bacteria tests.

A bacterial test battery, involving i) Microtox, an aquatic test, ii) the Flash assay, a soil-suspension test (with Vibrio fischeri as the test organism), and iii) the Metal Detector assay, a semi-specific aquatic test for heavy metals (with recombinant luminescent Escherichia coli), was used in a combined toxicological and chemical hazard assessment of Estonian soils sampled from a former Soviet military airfield (13 samples) and from traffic-influenced roadsides (5 samples). The soils showed slightly elevated levels of total petroleum hydrocarbons (TPH), but not of heavy metals. In most of the samples, the levels of TPH did not exceed the Estonian permitted limit values set for residential areas.

Biotests and biosensors in ecotoxicological risk assessment of field soils polluted with zinc, lead, and cadmium.

The combined chemical and ecotoxicological hazard evaluation study was conducted on 60 smelter-influenced soils containing 1 to 13, 50 to 653, and 100 to 1,198 mg/kg of Cd, Pb, and Zn, respectively. For these soils (liquid-to-soil ratio = 10), water extractability of Zn, Cd, and Pb was less than 0.19% (median values).

Toxicity testing of heavy-metal-polluted soils with algae Selenastrum capricornutum: a soil suspension assay.

A small-scale Selenastrum capricornutum (Rhapidocelis subcapitata) growth inhibition assay was applied to the toxicity testing of suspensions of heavy-metal-polluted soils. The OECD 201 standard test procedure was followed, and algal biomass was measured by the fluorescence of extracted chlorophyll. The soils, which contained up to (per kilogram) 1390 mg of Zn, 20 mg of Cd, and 1050 mg of Pb were sampled around lead and zinc smelters in northern France.

Recombinant luminescent bacterial sensors for the measurement of bioavailability of cadmium and lead in soils polluted by metal smelters.

Environmental hazard of heavy metals in soils depends to a large extent on their bioavailability. The approach used in this study enables the determination of bioavailable metals in solid-phase samples. Two recombinant bacterial sensors, one responding specifically to cadmium and the other to lead and cadmium by increase of luminescence (firefly luciferase was used as a reporter) were used to determine the bioavailability of these metals in soil-water suspensions (a contact assay) and respective particle-free extracts.