Biosorption of aquatic copper (II) by mushroom biomass Pleurotus eryngii: kinetic and isotherm studies.

Biosorption is an effective method for removing heavy metals from effluent. This work mainly aimed to evaluate the adsorption performance of the widely cultivated novel mushroom, Pleurotus eryngii, for the removal of Cu(II) from single aqueous solutions. Kinetics and equilibria were obtained using a batch technique. The sorption kinetics follows the pseudo-second-order model, whereas the adsorption equilibria are best described by the Langmuir model. The adsorption process is exothermic because both the Langmuir-estimated biosorption capacity and the heat of adsorption estimated from the Temkin model decreased with increasing tested temperature. Based on the adsorption intensity estimated by the Freundlich model and the mean adsorption free energy estimated by the Dubinin-Radushkevich model, the type of adsorption is defined as physical adsorption. The biomass of the macro-fungus P. eryngii has the potential to remove Cu(II) from a large-scale wastewater contaminated by heavy metals, because of its favorable adsorption, short biosorption equilibrium time of 20 min and remarkable biosorption capacity (15.19 mg g⁻¹ as calculated by the Langmuir model). The adsorbed metal-enriched mushroom is a high-quality bio-ore by the virtue of its high metal content of industrial mining grade and easy metal extractability.

Certain antioxidant enzymes and lipid peroxidation of radish (Raphanus sativus L.) as early warning biomarkers of soil copper exposure.

Copper (Cu) is a major heavy metal contaminant with various anthropogenic and natural sources. Recently, using biomarkers to monitor the effects of pollutants has attracted increased interest. Pot culture experiments using radish (Raphanus sativus L.) was performed to investigate Cu phytotoxic effects on antioxidant enzymes and other early warning biomarkers of soil Cu exposure. Under low dose Cu stress (lower than the EC10, Cu concentration reducing root length by 10%), activity and isozyme expression of superoxide dismutase (SOD), catalase (CAT), and peroxidases (POD) increased significantly; no significant variations in chlorophyll, carotenoid, and malondialdehyde (MDA) content in leaves and toxic symptoms were observed. Under a slightly higher Cu stress (close to the EC10), activity and isozyme expression of SOD and MDA content were enhanced significantly; those of CAT and POD decreased due to an inverted U-shape dose response. Chlorophyll content remained unchanged. Thus, antioxidant enzymes and MDA content are more sensitive to Cu stress, showing significant variations ahead of chlorophyll and toxic symptoms under Cu stress (lower than about 200 mg kg(-1) soil). Thus, the joint monitoring of antioxidant enzymes and MDA content of R. sativus can be used as biomarkers of soil Cu contamination.

Retracted: Long-term copper toxicity in apple trees (Malus pumila Mill) and bioaccumulation in fruits.

The following article from Environmental Toxicology, 'Long-term Copper Toxicity in Apple Trees (Malus pumila Mill) and Bioaccumulation in Fruits' by Bai-Ye Sun, Shi- Hong Kan, Yan-Zong Zhang, Jun Wu, Shi-Huai Deng, Chun-Sheng Liu and Gang Yang, published online on January 15, 2010 in Wiley InterScience (www.interscience.wiley.com; DOI: 10.1002/tox.20565), has been retracted by agreement between the authors, the journal Editor in Chief, Dr. Paul Tchounwou, and Wiley Periodicals, Inc. The retraction has been agreed at the request of the authors due to overlap with 'Copper Toxicity and Bioaccumulation in Chinese Cabbage (Brassica pekinensis Rupr.)' by Zhi-Ting Xiong and Hai Wang, published in Environmental Toxicology, Volume 20, pages 188-194, 2005.

[Role of irradiance on the seasonality of Skeletonema costatum Cleve blooms in the coastal area in East China Sea].

With field culture experiments and model calculations, the role of light on why in both spring and summer Skeletonema costatum Cleve blooms can occur in the coastal area in East China Sea were studied. The results show that the growth optimal light intensity (I(opt)) of S. costatum increases gradually to a maximum of 121.6 W x m(-2) with temperature (t) up to 25 degrees C, and a rapid decline in I(opt) accompanies further increases in t beyond 25 degrees C. Such an asymmetric inverse V-shape I(opt)-t curve can be well described by Blanchard's equation. By this equation, I(opt) of each month was calculated based on monthly sea surface temperature, and though changes about 2 months later than light intensity above sea surface (I(0)), I(opt) is closely correlated with seasonal I(0) and transparency of sea water (R2 = 0.907 +/- 0.115, p < 0.001), which indicates that S. costatum adapts to the seasonality of light in sea water in the coastal area by varying I(opt) seasonally. Such an adaptive strategy leads to thick (about 6 m) light-optimal water layers for growth from early spring to late summer. The high adaptability to light and light optimum characteristics in sea water is one of the important reasons for S. costatum blooms in the both seasons in the coastal area in ECS.

[Effects of irradiance on blooms of the dinoflagellate Prorocentrum donghaiense Lu in the coastal area in East China Sea].

With field culture experiments and model calculations, the natural-light-dependent growth and the optimal light layers in sea water for growth of red tide dinoflagellate Prorocentrum donghaiense Lu were studied in order to analyze the role of light on algal blooms in the coastal area in East China Sea in spring. The results show that the relationship of growth and light can be well described by Steele's equation, and the optimal light intensity (Iopt) of P. donghaiense is (38.2 +/- 3.8) W x m(-2), which is lower than Iopt for several other red tide algae (40-133 W x m(-2)), meaning that P. donghaiense may have an advantage when developing blooms in turbid environments where solar irradiance is easily attenuated. The optimal light layers for P. donghaiense growth are thicker offshore than inshore, and the thickness of optimal light layers in the subsurface water usually in 3-15 m in depth is about 5-10 m in the red tide area. The trade-off of light and nutrient fitness results in blooms in the so-called red tide area, and the light-optimum characteristic of the subsurface water is an important factor for the subsurface bloom development in spring.