As a consequence of increasing industrial applications, thousand tons of polyphosphonates are introduced every year into the environment. The inherent stability of the C–P bond results in a prolonged half-life. Moreover, low uptake rates limit further their microbial metabolization. To assess whether low detergent concentrations were able to increase polyphosphonate utilization by the cyanobacterium Spirulina platensis, tolerance limits to the exposure to various detergents were determined by measuring the growth rate in the presence of graded levels below the critical micellar concentration. Then, the amount of hexamethylenediamine-N,N,N′,N′-tetrakis(methylphosphonic acid) that is metabolized in the absence or in the presence of sublethal detergent concentrations was quantified by ³¹P NMR analysis on either P-starved or P-fed cyanobacterial cultures. The strain tolerated the presence of detergents in the order: nonionic > anionic > cationic. When added to the culture medium at the highest concentrations showing no detrimental effects upon cell viability, detergents either improved or decreased polyphosphonate utilization, the anionic sodium dodecyl sulfate being the most beneficial. Metabolization was not lower in P-fed cells—a result that strengthens the possibility of using, in the future, this strain for bioremediation purposes.

In the last decade, various molecular methods (e.g., fluorescent hybridization assay, sandwich hybridization assay, automatized biosensor detection, real-time PCR assay) have been developed and implemented for accurate and specific identification and estimation of marine toxic microalgal species. This review focuses on the recent quantitative real-time PCR (qrt-PCR) technology developed for the control and monitoring of the most important taxonomic phytoplankton groups producing biotoxins with relevant negative impact on human health, the marine environment, and related economic activities. The high specificity and sensitivity of the qrt-PCR methods determined by the adequate choice of the genomic target gene, nucleic acid purification protocol, quantification through the standard curve, and type of chemical detection method make them highly efficient and therefore applicable to harmful algal bloom phenomena. Recent development of qrt-PCR-based assays using the target gene of toxins, such as saxitoxin compounds, has allowed more precise quantification of toxigenic species (i.e., Alexandrium catenella) abundance. These studies focus only on toxin-producing species in the marine environment. Therefore, qrt-PCR technology seems to offer the advantages of understanding the ecology of harmful algal bloom species and facilitating the management of their outbreaks.

Chlorophenols, like many other synthetic compounds, are persistent problem in industrial areas. These compounds are easily degraded in certain natural environments where the top soil is organic. Some studies suggest that mineral soil contaminated with organic compounds is rapidly remediated if it is mixed with organic soil. We hypothesized that organic soil with a high degradation capacity even on top of the contaminated mineral soil enhances degradation of recalcitrant chlorophenols in the mineral soil below. We first compared chlorophenol degradation in different soils by spiking pristine and pentachlorophenol-contaminated soils with 2,4,6-trichlorophenol in 10-L buckets. In other experiments, we covered contaminated mineral soil with organic pine forest soil. We also monitored in situ degradation on an old sawmill site where mineral soil was either left intact or covered with organic pine forest soil. 2,4,6-Trichlorophenol was rapidly degraded in organic pine forest soil, but the degradation was slower in other soils. If a thin layer of the pine forest humus was added on top of mineral sawmill soil, the original chlorophenol concentrations (high, ca. 70 μg g⁻¹, or moderate, ca. 20 μg g⁻¹) in sawmill soil decreased by >40 % in 24 days. No degradation was noticed if the mineral soil was kept bare or if the covering humus soil layer was sterilized beforehand. Our results suggest that covering mineral soil with an organic soil layer is an efficient way to remediate recalcitrant chlorophenol contamination in mineral soils. The results of the field experiment are promising.

One of the most important sources of solid waste in the Mediterranean Basin ecosystem originated from the phosphate fertilizer industries, which discharge phosphogypsum (PG) directly into aquatic environments or are stacked on stockpiles. The present study investigates metal release from PG under the influence of variable pH, increasing PG mass content, and complexing organic matter ligands. Major ions from PG leachates, grain size and charge, main functional groups along with metal leachability (Pb, Cd, Cr, Cu, and Zn) were determined using ion chromatography, laser diffraction, zetameter, Fourier transform infrared spectroscopy, and atomic absorption spectroscopy, respectively. The complete dissolution of PG recorded is at 2 g/L. Saturation and supersaturation with respect to PG may occur at concentrations of 3 and 4 g/L, respectively, revealing a clustering phenomenon leading to heavy metal encapsulation within the aggregates. Organic ligands such as citrate may trigger the cationic exchange within the PG suspension leading to ion release. As these factors are considered as specific process involving the release of contaminants from PG during storage under natural conditions, this study could set the foundations for PG remediation in aquatic environment. Organic ligands under controlled pH conditions could be utilized in treating fertilizer industrial wastes by taking into consideration the particularity of the receiving area, thus decreasing metal hazardous impact on natural media.

This work described a novel method for the synthesis of high-ferromagnetism nanoparticles (FeO/CNTs) to efficiently remove Cr(VI) from aqueous solution. The FeO/carbon nanotubes (CNTs) were prepared by in situ reduction with post-oxidation method by using cheap and environmentally friendly precursor under mild condition. Magnetic hysteresis loops revealed that FeO/CNTs had superior saturation magnetization (152 emu/g), enabling the highly efficient recovery of FeO/CNTs from aqueous solution by magnetic separation at low magnetic field gradients. FTIR, Raman, XPS, and TEM observations were employed to characterize the physical-chemical properties of FeO/CNTs, demonstrating that CNTs were successfully coated with iron oxide matrix. The adsorption equilibrium of Cr(VI) on FeO/CNTs was reached within 30 min. Langmuir, Freundlich, and Dubinin-Radushkevich isotherm were chosen to analyze the equilibrium data. The results indicated that Langmuir model can well describe the equilibrium data with the maximum adsorption capacity of 47.98 mg/g at room temperature and 83.54 mg/g at 353 K. The adsorption capacity of FeO/CNTs for Cr(VI) was greatly improved as compared to raw CNTs and other similar adsorbents reported. The pseudo-second-order kinetic model provided the best description of Cr(VI) adsorption on FeO/CNTs. Most importantly, possible synthesis mechanism and Cr(VI) removal mechanism were explored. The results suggest that large amounts of Cr(VI) were adsorbed on FeO/CNTs surface by substituting the surface position of -OH and then reducing it to Cr(OH) and CrO.

Water quality degradation in river systems has caused great concerns all over the world. Identifying the spatial distribution and sources of water pollutants is the very first step for efficient water quality management. A set of water samples collected bimonthly at 12 monitoring sites in 2009 and 2010 were analyzed to determine the spatial distribution of critical parameters and to apportion the sources of pollutants in Wen-Rui-Tang (WRT) river watershed, near the East China Sea. The 12 monitoring sites were divided into three administrative zones of urban, suburban, and rural zones considering differences in land use and population density. Multivariate statistical methods [one-way analysis of variance, principal component analysis (PCA), and absolute principal component score—multiple linear regression (APCS-MLR) methods] were used to investigate the spatial distribution of water quality and to apportion the pollution sources. Results showed that most water quality parameters had no significant difference between the urban and suburban zones, whereas these two zones showed worse water quality than the rural zone. Based on PCA and APCS-MLR analysis, urban domestic sewage and commercial/service pollution, suburban domestic sewage along with fluorine point source pollution, and agricultural nonpoint source pollution with rural domestic sewage pollution were identified to the main pollution sources in urban, suburban, and rural zones, respectively. Understanding the water pollution characteristics of different administrative zones could put insights into effective water management policy-making especially in the area across various administrative zones.

To develop an efficient bio-immobilization approach for the remediation of heavy metal pollution in soil, a mutant species of Bacillus subtilis (B38) was obtained by ultraviolet irradiation and selection under high concentration of cadmium (Cd) in a previous study. In the present study, to check the applicability of this mutated species to the sorption and immobilization of other metals, the sorption of four heavy metals, Cd, chromium (Cr), mercury (Hg), and lead (Pb), on living and nonliving B38 in single- and multiple-component systems under different conditions was investigated using batch experiments. Rapid metal binding occurred on both living and nonliving B38 during the beginning of the biosorption. The sorption kinetics followed the exponential equation for living biomass and the pseudo-first-order Lagergren model for nonliving biomass, with r (2) values in the range of 0.9004-0.9933. The maximum adsorptive quantity of the heavy metals on B38 changed with the solution pH, temperature, biomass dose, and ionic strength. The nonliving biomass generally showed greater or similar adsorptive capacities as compared with the living biomass and was not likely to be affected by the solution parameters. The bacterium had a stronger affinity to the cationic heavy metals than to the anionic one, and the equilibrium sorption amounts were 210.6, 332.3, and 420.9 mg/g for Cd(II), Hg(II), and Pb(II), respectively. The results of binary and ternary sorption experiments indicated that the metals with the higher sorption capacity in the single-component systems showed greater inhibitory effects on the biosorption of other metal ions in the multiple-component systems, but the sorption sites of Hg and Cd or Pb are likely to be different. The results of this study illustrated that the mutant species is a promising biosorbent for the remediation of multiple heavy metals.

Metal concentrations (Al, Ba, Ca, K, Li, Mg, Na, Se, Sr and Ti) in submerged macrophytes and corresponding water and sediments were studied in 24 eutrophic lakes along the middle and lower reaches of the Yangtze River (China). Results showed that these eutrophic lakes have high metal concentrations in both water and sediments because of human activities. Average concentrations of Al and Na in tissues of submerged macrophytes were very high in sampled eutrophic lakes. By comparison, Ceratophyllum demersum and Najas marina accumulated more metals (e.g. Ba, Ca, K, Mg, Na, Sr and Ti). Strong positive correlations were found between metal concentrations in tissues of submerged macrophytes, probably because of co-accumulation of metals. The concentrations of Li, Mg, Na and Sr in tissues of submerged macrophytes significantly correlated with their corresponding water values, but not sediment values.

The generation and emission of particulate matter from abrasion industry are subjects of the pollution monitoring by multidisciplinary study involving earth sciences and engineering disciplines. This work investigates the correlation between textural properties of in situ rock with class size distribution and morphology of particles generated after rock comminution and particles emitted in the air. A special comminution-dust sampling architecture was realised. The combined use of scanning electron microscopy and particle size analyser was considered in performing digital image analysis on both crushed products and airborne particles collected onto membrane filters. The results show that the size and morphology of crushed particles are linked to the petrographic rock properties. In particular, particles with fibrous morphology are prominent in rocks showing foliated textures where elongated minerals occurred, with implication for asbestos-bearing rocks. For what concerns the airborne particles, the results show that their aerodynamic diameters are independent of the crusher operating conditions. External parameters probably intervene in the distribution of the airborne particles emission, including the dynamic air fluxes, or environmental conditions. By applying mathematical models, the morphology and size range of airborne particles following the comminution processes can be predicted, and results has implication for pollutants contamination due to particulate matters emitted by crush stone industry.

Soybean stover-derived biochar was used to immobilize lead (Pb) in military firing range soil at a mass application rate of 0 to 20 wt.% and a curing period of 7 days. The toxicity characteristic leaching procedure (TCLP) was performed to evaluate the effectiveness of the treatment. The mechanism responsible for Pb immobilization in military firing range soil was evaluated by scanning electron microscopy-energy dispersive x-ray spectroscopy (SEM-EDX) and x-ray absorption fine structure (XAFS) spectroscopy analyses. The treatment results showed that TCLP Pb leachability decreased with increasing biochar content. A reduction of over 90 % in Pb leachability was achieved upon treatment with 20 wt.% soybean stover-derived biochar. SEM-EDX, elemental dot mapping and XAFS results in conjunction with TCLP leachability revealed that effective Pb immobilization was probably associated with the pozzolanic reaction products, chloropyromorphite and Pb-phosphate. The results of this study demonstrated that soybean stover-derived biochar was effective in immobilizing Pb in contaminated firing range soil.