PURPOSE: In this study, a novel and ecological alternative have been developed to treat soils contaminated with hexavalent chromium coupling two well-known systems: electrokinetic remediation and permeable reactive biobarriers. The electric field promotes the electromigration of the hexavalent chromium oxyanions towards the anode. The biobarriers were placed before the anode electrode, in order to promote the reduction and retention of the chromium migrating in its direction. Thus, this technology provided a global treatment to soil removal without subsequent treatments of the contaminated effluents. METHODS: The electrokinetic system was coupled with two different permeable reactive biobarriers composed by Arthrobacter viscosus bacteria, supported either in activated carbon or zeolite. An electric field of 10 V was applied and two different treatment times of 9 and 18 days were tested. RESULTS: Removal values of 60% and 79% were obtained when electrokinetic treatment was coupled with zeolite and activated carbon biobarriers, respectively, for a test period of 18 day. The reduction of hexavalent chromium to trivalent chromium was around 45% for both systems. CONCLUSIONS: In this work, two types of biobarriers were efficiently coupled to electrokinetic treatment to decontaminate soil with Cr(VI). Furthermore, the viability of the new coupling technology developed (electrokinetic + biobarriers) to treat low-permeability polluted soils was demonstrated.

Perfluorinated compounds (PFCs) have been widely used in industrial and consumer products and frequently detected in many environmental media. Potential reproductive effects of perfluorooctanesulfonate (PFOS), perfluorooctanoic acid (PFOA) and perfluorononanoic acid (PFNA) have been reported in mice, rats and water birds. PFOS and PFOA were also confirmed developing toxicants towards zebrafish embryos; however, the reported effect concentrations were contradictory. Polyfluorinated alkylated phosphate ester surfactants (including FC807) are precursor of PFOS and PFOA; however, there is no published information about the effects of FC807 and PFNA on zebrafish embryos. Therefore, this study was conducted to determine the effects of these four PFCs on zebrafish embryos. Normal fertilized zebrafish embryos were selected to be exposed to several concentrations of PFOA, PFNA, PFOS or FC807 in 24-well cell culture plates. A digital camera was used to image morphological anomalies of embryos with a stereomicroscope. Embryos were observed through matching up to 96-h post-fertilization (hpf) and rates of survival and abnormalities recorded. PFCs caused lethality in a concentration-dependent manner with potential toxicity in the order of PFOS > FC807 > PFNA > PFOA based on 72-h LC₅₀. Forty-eight-hour post-fertilization pericardial edema and 72- or 96-hpf spine crooked malformation were all observed. PFOA, PFNA, PFOS and FC807 all caused structural abnormalities using early stages of development of zebrafish. The PFCs all retarded the development of zebrafish embryos. The toxicity of the PFCs was related to the length of the PFC chain and functional groups.

PURPOSE: Perfluorinated compounds (PFCs) are widely distributed from industrialized to remote locations throughout the world. This study demonstrates the spatial distributions of PFCs in water and sediments from the L’Albufera Natural Park (Valencia, Spain). METHODS: Grab water and sediment samples were collected. PFCs were extracted from sediments with acidified acetonitrile by ultrasonication and cleaned up by solid-phase extraction (SPE) and from water by SPE. Determination was carried out by liquid chromatography–tandem mass spectrometry. RESULTS: In 100% of the samples (both water and sediments), perfluorooctane sulfonate (PFOS) and perfluoroctanoic acid (PFOA) were the predominant PFCs. Among the 12 sampling sites, PFOS concentrations in sediments ranged from 0.10 to 4.80 ng/g dry weight and in water from 0.94 to 58.1 ng/L. PFOA concentrations in sediment were from 0.004 to 1.24 ng/g and in water from 0.99 to 120 ng/L. Other perfluorocarboxylic acids (C5, C6, C7, C9, and C10) and perfluorosulfonates (C4 and C10) were also identified in several locations. The sum of all 10 compounds (ΣPFCs) concentration range from 0.99 to 120 ng/L in water and from 0.25 to 17.4 ng/g in sediments. Sediment–water distribution coefficients (log K D) were in the range 2.31–4.51 and positively correlated with perfluoroalkyl chain length. CONCLUSIONS: PFC concentrations in water and sediment were both less than those able to cause acute toxicity; low but detectable PFCs pollution in the L’Albufera Natural Park in Valencia was demonstrated. These compounds are bioaccumulative; thus, the risk associated with these exposures requires a deeper evaluation of long-term chronic toxicity.

Manure products fermented underground in cow horns and commonly used as field spray (preparation 500) in the biodynamic farming system, were characterized for molecular composition by solid-state nuclear magnetic resonance [13 C cross-polarization magic-angle-spinning NMR (13 C-CPMAS-NMR)] spectroscopy and offline tetramethylammonium hydroxide thermochemolysis gas chromatography-mass spectrometry. Both thermochemolysis and NMR spectroscopy revealed a complex molecular structure, with lignin aromatic derivatives, polysaccharides, and alkyl compounds as the predominant components. CPMAS-NMR spectra of biodynamic preparations showed a carbon distribution with an overall low hydrophobic character and significant contribution of lignocellulosic derivatives. The results of thermochemolysis confirmed the characteristic highlighted by NMR spectroscopy, revealing a molecular composition based on alkyl components of plant and microbial origin and the stable incorporation of lignin derivatives. The presence of biolabile components and of undecomposed lignin compounds in the preparation 500 should be accounted to its particularly slow maturation process, as compared to common composting procedures. Our results provide, for the first time, a scientific characterization of an essential product in biodynamic agriculture, and show that biodynamic products appear to be enriched of biolabile components and, therefore, potentially conducive to plant growth stimulation.

Plant litter and organic sediments are a main sink for metals and metalloids in aquatic ecosystems. The effect of invertebrate shredder (a key species in litter decay) on metal/metalloid fixation by organic matter is described only under alkaline water conditions whereas for slightly acidic waters nothing can be found. Furthermore, less is known about the effect of invertebrate shredders on the quality of dissolved organic carbon (DOC) and nitrogen (DON) released during litter decay. We conducted an experiment to investigate the impact of invertebrate shredder (Gammarus pulex) on metal/metalloid fixation/remobilization and on the quality of DOC/DON released under slightly acidic water conditions. During decomposition of leaf litter, invertebrate shredder facilitated significantly the emergence of smaller particle sizes of organic matter. The capacity of metal fixation was significantly higher in smaller particles (POM 2,000–63 μm) compared to original leaf litter and litter residues. Thus, G. pulex enhanced metal fixation by organic partition of sediments by increasing the amount of smaller particle of organic matter in aquatic ecosystems. In contrast, the capacity of metal/metalloid fixation in the smallest fraction of POM (<63 μm) was lower compared with leaf residues in treatment without invertebrates. Remobilization of metals and metalloids was very low for all measured elements. A significant effect of invertebrates on quantitative formation of DOC/DON was confirmed. The quality of released DOC/DON, which may affect metal/metalloid remobilization, was also significantly affected by invertebrate shredders (e.g., more carboxylates). Hence, invertebrate shredder enhanced significantly the fixation of metals/metalloids into POM in slightly acidic environments.

OBJECTIVE: In this work, continuous and size-segregated aerosol measurements at Mt. Krvavec, Slovenia, during the Eyjafjallajökull volcanic eruption were performed. Based on chemical and morphological characteristics of size-segregated particles, the presence of the volcanic aerosols after long-range transport to Slovenia was to be confirmed. RESULTS AND CONCLUSIONS: Continuous measurements with the aethalometer and SMPS indicated the suspected volcanic ash plume passing over the sampling site. The aerosols collected by discrete sampling showed a chemical signature similar to the known elemental signature of the Icelandic volcanic ash. Coarse particles showed a composition typical for silicates rich in metals; in many cases also S was present. Morphological analysis showed particles with features indicative of an explosive volcanic eruption, e.g., pumice and pumice shards, glass shards, minerals, evidence of steam condensation, etc. The high sulfate concentration associated with the fine particles resulted in sulfate crystallization within the cascade impactor leading to the formation of large structures resembling a “fern”. Mass size distributions for Fe, Ti, Mn, Ca, Na, and Mg showed one primary peak (for Fe, Mn, and Ti at 2.8 μm; for Ca, Na, and Mg at ca. 4 μm), which supports the fact that most of the particles in the coarse sizes were silicates rich in metals. The size distribution of the water-soluble SO 4 2− showed a maximum peak at 0.75 μm, which also confirms the high sulfate concentration in the fine particles. Chemical and morphological characterization of aerosols collected at Mt. Krvavec indeed confirmed that volcanic ash plume passed over Slovenia.

BACKGROUND, AIM, AND SCOPE: Olive oil mill wastewater (OMW), a by-product of the olive oil extraction process, is annually produced in huge amounts in olive-growing areas and represents a significant environmental problem in Mediterranean areas. We studied the impact of OMW dilutions (1:20 and 1:10) on spinach plants in order to evaluate OMW dilutions as a low-cost alternative method for the disposal of this waste. MATERIALS AND METHODS: The effects of OMW dilutions were evaluated on seed germination, shoot and root elongation, biomass production, nutrient uptake and translocation, ascorbic acid content, polyphenols, photosynthetic pigments, and photosynthetic performance of spinach. RESULTS: Plant biomass was more affected than plant height and total chlorophyll; carotenoid and ascorbic acid content progressively decreased with decreasing OMW dilution. Exposure to both OMW dilutions resulted in overaccumulation of total polyphenols, which were negatively correlated to plant biomass and nutrients. Nutrient (Fe, Ca, and Mg) content was insufficient leading to reduced growth. Water use efficiency decreased mainly due to decreased CO2 assimilation rate rather than to a decline of transpiration rate. Disturbances in photosystem II (PSII) photochemical efficiency could be better envisaged by the ratio between variable fluorescence and initial fluorescence (Fv/Fo), which showed much greater amplitude than the maximal photochemical efficiency of PSII photochemistry (Fv/Fm). CONCLUSIONS: From the data obtained, it is suggested that 1:20 OMW dilutions are still phytotoxic and that higher OMW dilutions should be used in order to use this waste for the irrigation of spinach plants.

The aim of this study was to demonstrate that zebrafish embryos subjected to a priming exposure provided by one environmental stressor (low-dose alpha particles) can induce an adaptive response against a subsequent challenging exposure provided by another environmental stressor (heavy metal Cd). The effect thus identified would be an antagonistic multiple stressor effect. The effects of alpha particle radiation and/or Cd on whole embryos were studied through quantification of apoptotic signals at 24 h post-fertilization (hpf). Embryos were stained with the vital dye acridine orange, followed by counting the stained cells. For each set of experiments, 30 dechorionated embryos were divided into three groups, each having ten embryos. The three groups of embryos were referred to as (A) the control group, which received no more further treatments after dechorionation, (B) Cd-treated group, which did not receive any priming exposure and would receive a challenging exposure at 10 hpf and (C) (alpha + Cd)-treated group, which would receive both priming and challenging exposures. We defined the normalized net number of apoptotic signals in the (alpha + Cd)-treated group as N C * = [(apoptotic signals for (alpha + Cd)-treated group − average apoptotic signals for the corresponding control group)/average apoptotic signals for the corresponding control group] and that in the Cd-treated group as N B* = [(apoptotic signals for Cd-treated group − average apoptotic signals for the corresponding control group)/ average apoptotic signals for the corresponding control group]. By using the non-parametric Mann–Whitney U statistic, we were able to show that N C * was significantly smaller than N B *(p = 0.006). These demonstrated an antagonistic multiple stressor effect between ionizing radiation and Cd through the induction of an adaptive response by the ionizing radiation against subsequent exposures to Cd.

PURPOSE: Dechlorination of polychlorinated biphenyls (PCBs) by nanoscale zerovalent iron (NZVI) is often strongly hindered by increased pH because large amounts of H+ ions were consumed during the surface reaction. The main objective of this work was to evaluate the effect of pH control in acid on the dechlorination processes of PCBs and to compare the dechlorination efficiency between 2,4,4′-trichlorobiphenyl (2,4,4′-CB) and the extracted PCBs from the field PCBs-contaminated soil in this system. METHODS: The reaction solution pH was controlled to be weakly acid (4.90–5.10) with an automatic pH control system, in which the dechlorination of 2,4,4′-CB and extracted PCBs from a PCBs-contaminated soil by NZVI and palladized nanoscale zerovalent iron (NZVI/Pd) was investigated. RESULTS: To control the reaction solution pH to be acid actually increased the dechlorination rate of PCBs by NZVI and NZVI/Pd. The observed normalized pseudo-first-order dechlorination rate constants (k obs) of 2,4,4′-CB increased from 0.0029 min−1 (no pH control) to 0.0078 min−1 (pH control) by NZVI and from 0.0087 min−1 (no pH control) to 0.0108 min−1 (pH control) by NZVI/Pd. In the case of NZVI/Pd, the chlorines in the para position were much more easily dechlorinated than ortho position, and biphenyl was the dominating product. As the solution pH was controlled at 4.90–5.10, the dechlorination rate constants of PCB congeners extracted from soil (k obs) were 0.0027–0.0033 min−1 and 0.0080–0.0098 min−1 by NZVI and NZVI/Pd, respectively. CONCLUSIONS: To keep the reaction solution to be weakly acid markedly increased the dechlorination rate of PCBs, which may offer a novel technology in the remediation of PCBs-contaminated soil.

BACKGROUND, AIM AND SCOPE: The environmental presence of polybrominated diphenyl ethers (PBDEs), among which BDE-47 and BDE-99 are particularly abundant, makes toxicity data necessary to assess the hazard risk posed by PBDE to aquatic organisms. This study examines the effects of BDE-47 and BDE-99 on embryo-larval stages of the marine flatfish turbot. MATERIALS AND METHODS: The turbot embryos were exposed at nominal concentrations of BDE-47 and BDE-99 for 6 days. Selected dose levels were relevant for investigating sublethal and lethal effects. RESULTS: Both tested compounds caused lethal toxicity as well as non-lethal malformations during embryo development. We found a high toxic potency of BDE-47 compared to BDE-99 (LC50 values for embryos and larvae, respectively, BDE-47: 27.35 and 14.13 μg L−1; BDE-99: 38.28 and 29.64 μg L−1). DISCUSSION: The present study shows high sensitivity of fish early life stages (ELS) to PBDE compounds. Based on environmental concentrations of dissolved PBDEs from various aquatic ecosystems, waterborne BDE-47 and BDE-99 pose little risk of acute toxicity to marine fish at relevant environmental concentrations. CONCLUSIONS: Turbot fish ELS proved to be an excellent model for the study of ecotoxicity of contaminants in seawater. The results demonstrate harmful effects of PBDE on turbot ELS at concentrations in the range of parts per billion units. RECOMMENDATIONS AND PERSPECTIVES: In the perspective of risk assessment, ELS endpoints provide rapid, cost-effective and ecologically relevant information, and links should be sought between these short-term tests and effects of long-term exposures in more realistic scenarios.