The heavy metal bioaccumulation levels of 13 species of mushrooms were studied. 13 different species of wild mushrooms growing in China were analyzed for Cu, Zn, Pb, Cd, and As. Contents of Cu, Zn, Cd and Pb in mushroom and Cu, Zn in soil were tested by atomic absorption spectrometer (AAS), and As in samples by atomic fluorescent light (AFL). Contents of Cd and Pb in soil were analyzed by graphite furnace AAS. The results showed that contents of Cu, Pb, Cd, and As in Termitomyces microcarpus were the highest in the tested mushroom samples, which were 135.00, 13.28, 65.30, and 1.60 mg kg 1 (dry biomass) respectively, and the corresponding bioconcentration factor (BCF) for Cu and Cd was 57 and 1 674 separately, which was the highest data in 13 mushroom species. The capability of Boletus griseus for Cd accumulation was very strong with BCF of 300. when people consume the wild edible mushrooms, contents of Cd and Pb should be greatly considered.

ab s t r ac tThe biosorption of Cd 2+ and Pb 2+ by fruiting body wastes of macrofungi Flammulina velutipes was studied. The factors affecting absorbtion including pH, initial metal concentration, biosorbent dosages and mutual competitive biosorption of both metal ions were focused. The sorption of Cd 2+ and Pb 2+ was increased with pH value from 2 to 6 and maximum biosorption was at pH 6. The quantity of Cd 2+ and Pb 2+ adsorbed increased with the initial concentration of metal ions and both metals removal gradually increased with the biosorbent dosage. There existed mutual competitive biosorption between Cd 2+ and Pb 2+ when they were in the same solution. The Langmuir isotherm model fitted both metal ions sorption data well in the experiment and the calculated maximum sorption capacity of Cd 2+ and Pb 2+ by F. velutipes was 8.4317 mg/g dry biomass with R 2 of 0.9228 and 18.3486 mg/g dry biomass with R 2 of 0.9280, respectively. Pseudo-first order equation fitted for adsorption data of Cd 2+ with R 2 of 0.9504, while pseudo-second order equation more fitted for adsorption data of Pb 2+ with R 2 of 0.9917.

No abstract

The mechanism of Cu-Sn-Pb bronze (18.2 wt-% Sn) in a simulated soil solution was examined using optical microscopy, scanning electron microscopy, scanning Kelvin probe, X-ray photoelectron spectroscopy, X-ray diffraction and electrochemical techniques. The findings demonstrated that the α-phase possessed a more negative corrosion potential, and the central annular position was more active owing to the difference in the solid-solution tin content during casting. Cl − was not directly involved in the production of corrosive products in the early stage of corrosion, but it damaged the copper oxide layer and promoted the loss of copper ions. Subsequently, the tin oxide was gradually produced on the surface, and the selective copper dissolution led to abundant tin compounds on the surface.

For searching biological material for heavy metal removal of waste-water, using macrofungus Auricularia polytricha as biosorbent for Cu 2+ and Pb 2+ removal was investigated. After shaking and biosorbing Cu 2+ and Pb 2+ in solution by biosorbents, the filtrates were tested by AAS and the adsorbed quantity of Cu 2+ and Pb 2+ was calculated . The biosorbents were effective in removal of Cu 2+ and Pb 2+ on the biosorbents that showed a highest value around pH 5-6. The biosorption rate of Cu 2+ and Pb 2+ on A. polytricha biomass decreased with increasing the initial concentration of Cu 2+ and Pb 2+ in the medium. The biosorption of Cu 2+ and Pb 2+ on the biomasses follows pseudo-second order kinetics. The determined maximum biosorption capacities presented by the fungus biomass were 3.34 and 13.03 mg·g -1 dry weight for Cu 2+ and Pb 2+ , respectively by the biosorption equilibrium with Langmuir adsorption isotherm. According to the whole data analysis in each experiment of studying Cu 2+ and Pb 2+ biosorption including condition factors and adsorption isotherm, the adsorbed capacity of Pb 2+ by A. polytricha biomass was bigger than Cu 2+ . The biosorption by A. polytricha was most effective when pH 5-6. The biosorbents are suitable for low Cu 2+ and Pb 2+ concentration waste-water, especially for Pb 2+ removal. Environment pollution issues, in particular water pollution by toxic heavy metal contamination, is the result of several activities and its control over the last decades has been a challenge. Conventional methods of treating solutions, which contain heavy metals in concentration of 1-100 mg·L -1 , include: precipitation, coagulation, reduction process, ionic exchange, membrane technologies and adsorption in activated coal. These method associated with either a high cost or a low efficiency, not guaranteeing the limits of metal concentration demanded by legal standards [1] . Biosorption processe appears as a new technology, capable of removing traces of heavy metals from dilute aqueous solutions. Biosorbents such as algae, fungi and bacteria are examples of biomass tested for biosorption of several metals species with very encouraging results [2] . In recent years, some researchers have reported a few of cultivated mushroom to occupy the strong ability in bio-accumulating metal ion [3] . The research results of Galli et al [4] indicated mushroom mycelium could accumulate high concentration of copper and he utilized Auricularia polytricha mycelium as biosorbent in copper removal in solution and studied several physical effecting factors on absorption. Veit et al [5] reported the biosorption onto copper by Pleurotus pulmonarius and Schizophyllum commune and mastered optimum sorption condition. Also, the experimental data fitted Langmuir isotherm.