The effect of copper sulphate on some biochemical parameters of rainbow trout

Copper sulphate has an adverse effect on some biochemical parameters of trout Salmo gairdneri. The main targets of damage are: (a)Tissue necrosis as demonstrated by increased ASAT and ALAT levels in blood plasma. (b)Inhibition of acetylcholinesterase activity. There is also a general stress effect as reflected by an elevated blood glucose level.     

Natural phillipsite as a matrix for a slow-release formulation of oxamyl

The performance of phillipsite as a matrix for slow-release formulation of oxamyl [N,N-dimethyl-2-methylcarbamoyl-oxymino-2-(methylthio)acetamide] was tested. The adsorption kinetics followed a first-order law, and the adsorption isotherm fitted well in a two-surface Langmuir model, suggesting a double mechanism of interaction between oxamyl and the sorbent. The sorption mechanism, studied by FTIR, provided two fractions of oxamyl. The first one is sorbed on the mineral surface, linked by H-bonding, and the second one is constituted by a multilayer of oxamyl molecules linked by a water bridge between them. The release kinetics of oxamyl from a substratum zeolite-oxamyl also follows a first-order law, with two stages that correspond to both fractions of oxamyl previously detected.     

Occupational exposure

Concentrations of polychlorinated biphenyls (PCB), polychlorinated naphthalenes (PCN), polychlorinated dibenzo-p-dioxins (PCDD), polychlorinated dibenzofurans (PCDF), hexachlorobenzene and methylsulphonyl metabolites of PCB were determined in blood plasma from potentially exposed workers and controls. Three of the potentially exposed subjects had worked with cable incineration and two were electricians. Extraction of the organochlorine compounds and lipids were performed using the lipophilic gel Lipidex. Different adsorbents and gel permeation chromatography were applied for further purification of the samples and separation of analytes. Determinations of the chlorinated compounds were made by using gas chromatography with electron-capture detection and gas chromatography-mass spectrometry. Only small differences in the concentrations of organochlorine compounds were found in the plasma from the three subject groups. Thus, specific exposure of the workers could not be confirmed.     

Evaluation of ozone-nitrogen oxides-volatile organic compound sensitivity of Cincinnati, Ohio

Ambient concentrations of ozone (O3), nitrogen oxides (NOx), total reactive nitrogen (NOy), nitric acid (HNO3), and hydrogen peroxide (H2O2) were measured during September 2003 at an urban site of Cincinnati, OH. The aim of this study was two-fold: to investigate whether O3 formation in this population exposure-type site is NOx, sensitive or volatile organic compound (VOC) sensitive and to test the practicality of using two combined observational-based methods to identify the sensitivity of O3 formation in midlevel polluted locations. The evaluation of the indicator species: NOy, O3/NOy, O3/HNO3, H2O2/ HNO3, and O3/(estimated NOx reaction products), as well as the combined hypothesis testing analysis of the weekend/weekday (WE/WD) differences of 1-hr and 8-hr average maximum O3 and of the 6:00 a.m.-9:00 a.m. average nitric oxide and NOx concentrations, show evidence that Cincinnati is likely VOC sensitive. Average WE 1-hr and 8-hr maximum O3, as well as duration of WE O3 accumulation, were not lower than the corresponding WD levels in spite of the observed significant reduction in NO, emissions on WE, a typical situation in VOC-sensitive locations. The possibility that the seasonal transition from summer to autumn could have influenced the results was also investigated through an exploratory analysis of the afternoon O3 maximum/NOx measured and of the WE/WD differences of peak O3 and morning average NO and NO, concentrations observed at this site from June through September 2003. The results suggest that a VOC-sensitive chemistry regime dominated along the summer season. The findings of this study suggest that additional reductions in regional NO, emissions in Cincinnati, a potential nonattainment area under the 8-hr O3 standard, may cause an increase in local O3. Future strategies to reduce O3 in Southwest Ohio should be further evaluated carefully. The combination of observational-based methods might provide a consistent complementary approach in the identification of the NO,-VOC sensitive characteristics of mid-to-moderate polluted urban areas.     

Effects of initial saturation on properties modification and displacement of tetrachloroethene with aqueous isobutanol

Packed column experiments were conducted to study effects of initial saturation of tetrachloroethene (PCE) in the range of 1.0-14% pore volume (PV) on mobilization and downward migration of the non-aqueous phase liquid (NAPL) product upon contact with aqueous isobutanol ( approximately 10 vol.%). This study focused on the consequences of swelling beyond residual saturation. Columns were packed with mixtures of neat PCE, water and glass beads and waterflooded to establish a desired homogeneous residual saturation, and then flooded with aqueous isobutanol under controlled hydraulic conditions. Results showed a critical saturation of approximately 8% PV for these packed column experimental conditions. At low initial PCE saturations (<8% PV), experimental results showed reduced risk of NAPL-product migration upon contact with aqueous isobutanol. At higher initial PCE saturations (>8% PV), results showed NAPL-product mobilization and downward migration which was attributed to interfacial tension (IFT) reduction, swelling of the NAPL-product, and reduced density modification. Packed column results were compared with good agreement to theoretical predictions of NAPL-product mobilization using the total trapping number, N(T). In addition to the packed column study, preliminary batch experiments were conducted to study the effects of PCE volumetric fraction in the range of 0.5-20% on density, viscosity, and IFT modification as a function of time following contact with aqueous isobutanol ( approximately 10 vol.%). Modified NAPL-product fluid properties approached equilibrium within approximately 2 h of contact for density and viscosity. IFT reduction occurred immediately as expected. Measured fluid properties were compared with good agreement to theoretical equilibrium predictions based on UNIQUAC. Overall, this study demonstrates the importance of initial DNAPL saturation, and the associated risk of downward NAPL-product migration, in applying alcohol flooding for remediation of DNAPL contaminated ground water sites.     

Modelling the extra and intracellular uptake and discharge of heavy metals in Fontinalis antipyretica transplanted along a heavy metal and pH contamination gradient

Samples of the aquatic bryophyte Fontinalis antipyretica Hedw. were transplanted to different sites with the aim of characterizing the kinetics of the uptake and discharge of heavy metals in the extra and intracellular compartments. The accumulation of metals in extracellular compartments, characterized by an initial rapid accumulation, then a gradual slowing down over time, fitted perfectly to a Michaelis-Menten model. The discharge of metals from the same compartment followed an inverse linear model or an inverse Michaelis-Menten model, depending on the metal. In intracellular sites both uptake and discharge occurred more slowly and progressively, following a linear model. We also observed that the acidity of the environment greatly affected metal accumulation in extracellular sites, even when the metals were present at relatively high concentrations, whereas the uptake of metals within cells was much less affected by pH.     

The combined use of chemical and biochemical markers to assess water quality along the Ebro River

Carp (Cyprinus carpio) and barbel (Barbus graellsii) were collected from five sites along the Ebro River. The study was designed to assess levels of persistent organic pollutants and metals bioaccumulated by fish, and some biochemical responses (cytochrome P450 system, phase II activities, and metallothioneins) against those pollutants. The highest levels of PCBs and DDTs were detected in carp from industrialised areas, which also showed high levels of mercury and cadmium in the liver, and high levels of nonylphenol in bile. Significant alterations in some biochemical markers were observed and associated to combined exposure to pollutants. The activity 7-ethoxyresorufin O-deethylase ranged from 69 pmol/min/mg protein in carp from the reference site to 415 pmol/min/mg protein in those from polluted sites. Carp from the Ebro Delta, an agricultural area, had depressed acetylcholinesterase in muscle tissue. Metallothionein concentrations were positively correlated with copper residues, but no significant differences among sampling points were observed.     

Decolourization of synthetic dyes by Trametes hirsuta in expanded-bed reactors

The present paper studies the decolourization of different synthetic dyes (Indigo Carmine, Bromophenol Blue, Methyl Orange and Poly R-478) by the white-rot fungus Trametes hirsuta at bioreactor scale under solid-state conditions, operating with ground orange peelings as a support-substrate. Dye decolourization was performed in both batch and continuous mode. Batch cultivation led to high decolourization percentages in a short time (100% for Indigo Carmine in 3h and 85% for Bromophenol Blue in 7 h). As for continuous cultivation, different hydraulic retention times (HRT) were studied (0.8, 1, 1.5 and 3d). The highest decolourization percentages were obtained operating at a HRT of 3d, especially for the dyes Methyl Orange and Poly R-478 (81.4% and 46.9%, respectively). This is a very interesting result, since there are few studies dealing with the continuous decolourization of dyes at bioreactor scale by fungal laccases.     

Modeling lead bioavailability and bioaccumulation by Lumbriculus variegatus using artificial particles. Potential use in chemical remediation processes

Artificial particles, specifically a diverse selection of chromatographical resins, have been recommended and used as a useful experimental model to predict the bioavailability and bioaccumulation of sediment-bound organic chemicals. In this work the same experimental model was adopted to investigate the bioavailability and bioaccumulation of lead by the freshwater oligochaete Lumbriculus variegatus. Particle-water partition coefficients were also determined. Sand particles and the anionic exchange resin promoted a similar uptake and bioaccumulation of lead. Instead, in the presence of the cationic exchanger the metal was not detected in the animals. For neutral particles, the uptake and accumulation depended on the chemistry of the functional groups at the active sites. In addition, a significant negative correlation was found between bioaccumulation and the particle-water partition coefficients. These studies may help to develop alternative methods for chemical remediation of lead-contaminated aquatic systems.     

Effect of chromium on the fatty acid composition of two strains of Euglena gracilis

The effect of hexavalent chromium on fatty acid composition was studied in two strains of Euglena gracilis; UTEX 753 (from the Culture Collection of Algae of Texas University, USA) and MAT (isolated from a highly polluted River). Both were grown in photoauxotrophic and photoheterotrophic conditions and exposed to two metal concentrations, one below and one above IC50. The high malondialdehyde (MDA) levels (3 to 7-fold) obtained with chromium concentration above IC50, suggested the existence of metal-induced lipid peroxidation. Total lipid content increased only with concentration below IC50, whereas it was inhibited by higher metal concentration. Photoheterotrophic control strains exhibited a significantly higher proportion of saturated and polyunsaturated fatty acids. Polyunsaturated acids were most affected by chromium, especially those related to chloroplast structures. Ultra-structure studies showed clear thylakoid disorganization in all treated cells. The results indicate that hexavalent chromium affects levels of fatty acids, especially those related to photosynthetic activity.