Developed fungal–bacterial biofilms as a novel tool for bioremoval of hexavelant chromium from wastewater

Remediation measures for hexavalent chromium [Cr(VI)] are required for a safe environment. As a recent development in microbiology, bacterial biofilms are being studied as effective bioremediation agents. When bacteria are in fungal surface-attached biofilm mode, they are called fungal–bacterial biofilms (FBBs). They have not been tested for bioremediation so far. Hence, this study was conducted to develop FBBs and glass-wool-attached bacterial biofilms (BBs), and to evaluate Cr(VI) tolerability and removal of bacterial monocultures, BBs and FBBs. FBBs showed a significantly high level of Cr(VI) tolerance and resistance compared with its BBs or monocultures. After 10 days, up to 90% of Cr(VI) had been removed, which was significantly higher than that of BBs or its monocultures. Thus, it is clear that FBBs can be used as a novel tool to decontaminate Cr(VI) both in situ and ex situ.     

Perfluorinated organic compounds in human blood serum and seminal plasma: a study of urban and rural tea worker populations in Sri Lanka

Concentrations and accumulation of 13 fluorinated organic compounds (FOCs) in human sera and seminal plasma were measured in an Asian developing country, Sri Lanka. Six of the FOCs, PFOS (perfluorooctanesulfonate), PFHS (perfluorohexanesulfonate), PFUnA (perfluoroundecanoic acid), PFDA (perfluorodecanoic acid), PFNA (perfluorononanoic acid) and PFOA (perfluorooctanoic acid), were detected in all of the sera samples. Measurable quantities of two main perfluorosulfonates, PFOS and PFHS, were found in all seminal plasma samples. The detection frequency of the predominant perfluoroalkylcarboxylate, PFOA, in seminal plasma was >70%. Accumulation of PFOS in sera was significantly positively correlated with PFOA, PFHS and PFNA. Positive linear regressions were also found between PFNA and PFUnA and PFNA and PFDA suggesting that these compounds may have a similar origin of exposure and accumulation. Significantly positive associations were observed for partitioning of both PFOS and PFNA between sera and seminal plasma. The accumulation of FOCs was not significantly different in sera from Colombo (urban population) and Talawakele (rural conventional tea workers). However, the Haldummulla population (rural organic tea workers) had relatively lower exposure to FOCs compared to the other two groups, urban and rural conventional tea workers. Concentrations of FOCs in Sri Lanka were similar to those reported for industrialized countries suggesting that human exposure to such chemicals is widespread even in developing countries. The novel finding of FOCs in human seminal plasma implies that further studies are needed to determine whether long-term exposure in humans can result in reproductive impairments.     

Correction to: Contrasting effects of engineered carbon nanotubes on plants: a review

Environmental Geochemistry and Health - Unfortunately, in the original publication of the article, Prof. Yong Sik Ok’s affiliation was incorrectly published. The author’s affiliation is...     

Contrasting effects of engineered carbon nanotubes on plants: a review

Rapid surge of interest for carbon nanotube (CNT) in the last decade has made it an imperative member of nanomaterial family. Because of the distinctive physicochemical properties, CNTs are widely used in a number of scientific applications including plant sciences. This review mainly describes the role of CNT in plant sciences. Contradictory effects of CNT on plants physiology are reported. CNT can act as plant growth inducer causing enhanced plant dry biomass and root/shoot lengths. At the same time, CNT can cause negative effects on plants by forming reactive oxygen species in plant tissues, consequently leading to cell death. Enhanced seed germination with CNT is related to the water uptake process. CNT can be positioned as micro-tubes inside the plant body to enhance the water uptake efficiency. Due to its ability to act as a slow-release fertilizer and plant growth promoter, CNT is transpiring as a novel nano-carbon fertilizer in the field of agricultural sciences. On the other hand, accumulation of CNT in soil can cause deleterious effects on soil microbial diversity, composition and population. It can further modify the balance between plant-toxic metals in soil, thereby enhancing the translocation of heavy metal(loids) into the plant system. The research gaps that need careful attention have been identified in this review.