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Ex situ solid phase extraction with granular activated carbon (GAC) is a promising technique to remediate contaminated sediments. The methods' efficiency depends on the rate by which contaminants are transferred from the sediment to the surface of GAC. Here, we derive kinetic parameters for extraction of polycyclic aromatic hydrocarbons (PAH) from sediment by GAC, using a first-order multi-compartment kinetic model. The parameters were obtained by modeling sediment-GAC exchange kinetic data following a tiered model calibration approach. First, parameters for PAH desorption from sediment were calibrated using data from systems with 50% (by weight) GAC acting as an infinite sink. Second, the estimated parameters were used as fixed input to obtain GAC uptake kinetic parameters in sediment slurries with 4% GAC, representing the ex situ remediation scenario. PAH uptake rate constants (kGAC) by GAC ranged from 0.44 to 0.0005 d(-1), whereas GAC sorption coefficients (KGAC) ranged from 10(5.57) to 10(8.57) L kg(-1). These values are the first provided for GAC in the presence of sediment and show that ex situ extraction with GAC is sufficiently fast and effective to reduce the risks of the most available PAHs among those studied, such as fluorene, phenanthrene and anthracene.

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In situ activated carbon (AC) amendment is a new direction in contaminated sediment management, yet its effectiveness and safety have never been tested on the level of entire food chains including fish. Here we tested the effects of three different AC treatments on hydrophobic organic chemical (HOC) concentrations in pore water, benthic invertebrates, zooplankton, and fish (Leuciscus idus melanotus). AC treatments were mixing with powdered AC (PAC), mixing with granular AC (GAC), and addition-removal of GAC (sediment stripping). The AC treatments resulted in a significant decrease in HOC concentrations in pore water, benthic invertebrates, zooplankton, macrophytes, and fish. In 6 months, PAC treatment caused a reduction of accumulation of polychlorobiphenyls (PCB) in fish by a factor of 20, bringing pollutant levels below toxic thresholds. All AC treatments supported growth of fish, but growth was inhibited in the PAC treatment, which was likely explained by reduced nutrient concentrations, resulting in lower zooplankton (i.e., food) densities for the fish. PAC treatment may be advised for sites where immediate ecosystem protection is required. GAC treatment may be equally effective in the longer term and may be adequate for vulnerable ecosystems where longer-term protection suffices.

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Sediment amendment with activated carbon (AC) is a promising technique for in situ sediment remediation. To date it is not clear whether this technique sufficiently reduces sediment-to-water fluxes of sediment-bound hydrophobic organic chemicals (HOCs) in the presence of bioturbators. Here, we report polychlorobiphenyl (PCB) pore water concentrations, fluxes, mass transfer coefficients, and survival data of two benthic species, for four treatments: no AC addition (control), powdered AC addition, granular AC addition and addition and subsequent removal of GAC (sediment stripping). AC addition decreased mass fluxes but increased apparent mass transfer coefficients because of dissolved organic carbon (DOC) facilitated transport across the benthic boundary layer (BBL). In turn, DOC concentrations depended on bioturbator activity which was high for the PAC tolerant species Asellus aquaticus and low for AC sensitive species Lumbriculus variegatus. A dual BBL resistance model combining AC effects on gradients, DOC facilitated transport and biodiffusion was evaluated against the data and showed how the type of resistance differs with treatment and chemical hydrophobicity. Data and simulations illustrate the complex interplay between AC and contaminant toxicity to benthic organisms and how differences in species tolerance affect mass fluxes from sediment to the water column.

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Addition of activated carbon (AC) to sediments has been proposed as a method to reduce ecotoxicological risks of sediment-bound contaminants. The present study explores the effectiveness of granular AC (GAC) in extracting polycyclic aromatic hydrocarbon (PAH) from highly contaminated sediments. Four candidate GAC materials were screened in terms of PAH extraction efficiency using single-step 24-h GAC extractions, with traditional 24-h Tenax extraction as a reference. Subsequently, sorption of native PAHs to the best performing GAC 1240W (0.45-1.70 mm) was studied for sediment only and for GAC-sediment mixtures at different GAC-sediment weight ratios, using 76-µm polyoxymethylene (POM) passive samplers. Granular AC sorption parameters for PAHs were determined by subtracting the contribution of PAH sorption to sediment from PAH sorption to the GAC-sediment mixture. It appears that the binding of PAHs and the effectiveness of GAC to reduce sediment porewater concentrations were highly dependent on the GAC-sediment mixing ratio and hydrophobicity of the PAH. Despite the considerable fouling of GAC by organic matter and oil, 50 to 90% of the most available PAH was extracted by the GAC during a 28-d contact time, at a dose as low as 4%, which also is a feasible dose in field-scale applications aimed at cleaning the sediment by GAC addition and removal.

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Using activated carbon (AC) for sediment remediation may have negative effects on benthic communities. To date, most AC effect studies were short-term and limited to single species laboratory tests. Here, we studied the effects of AC on the recolonization of benthic communities. Sediment from an unpolluted site was amended with increasing levels of AC, placed in trays and randomly embedded in the original site, which acted as a donor system for recolonization of benthic species. After 3 and 15 months, the trays were retrieved and benthic organisms identified. A positive trend with AC was detected for species abundance after 3 months, whereas after 15 months a negative trend with AC was detected for Lumbriculidae and Pisidiidae. On the community level, statistical analyses showed a considerable recovery in terms of species diversity and abundance in 3 months and full recovery of the community after 15 months. This was explained from migration of individuals from the donor system, followed by further migration and reproduction of the species in the next year. AC treatments explained 3% of the variance in the community data. This work suggests that AC community effects are mild as long as AC levels are not too high (1-4%).

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Adding activated carbon (AC) to contaminated sediment has been suggested as an effective method for sediment remediation. AC binds chemicals such as polycyclic aromatic hydrocarbons (PAHs), thus reducing the toxicity of the sediment. Negative effects of AC on benthic organisms have also been reported. Here, we present a conceptual model to quantify the trade-off, in terms of biomass changes, between the advantageous PAH toxicity reduction and the negative effects of AC on populations of benthic species. The model describes population growth, incorporates concentration-effect relationships for PAHs in the pore water and for AC, and uses an equilibrium sorption model to estimate PAH pore water concentrations as a function of AC dosage. We calibrated the model using bioassay data and analyzed it by calculating isoclines of zero population growth for two species. For the sediment evaluated here, the results show that AC may safely protect the benthic habitat against considerable sediment PAH concentrations as long as the AC dosage remains below 4%.

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Carbonaceous materials (CM), such as activated carbons or biochars, have been shown to significantly reduce porewater concentrations and risks by binding hydrophobic organic compounds (HOCs) present in aquatic sediments. In the present study, the authors review the current state-of-the-art use of CM as an extensive method for sediment remediation, covering both technical and ecological angles. The review addresses how factors such as CM type, particle size and dosage, sediment characteristics, and properties of contaminants affect the effectiveness of CM amendment to immobilize HOCs in aquatic sediments. The authors also review the extent to which CM may reduce bioaccumulation and toxicity of HOCs and whether CM itself has negative effects on benthic species and communities. The review is based on literature and datasets from laboratory as well as field trials with CM amendments. The presence of phases such as natural black carbon, oil, or organic matter in the sediment reduces the effectiveness of CM amendments. Carbonaceous material additions appear to improve the habitat quality for benthic organisms by reducing bioavailable HOC concentrations and toxicity in sediment. The negative effects of CM itself on benthic species, if any, have been shown to be mild. The beneficial effects of reducing toxicity at low CM concentrations most probably outweigh the mild negative effects observed at higher CM concentrations.

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Contaminated sediments can be remediated by adding carbonaceous materials (CM), e.g. activated carbons (AC). Here, we analyze published datasets from AC amendment trials to identify variation in the effectiveness of AC in reducing porewater concentrations of hydrophobic organic contaminants (HOCs). The analysis uses a model that separates the contribution of HOC sorption to AC by parameterzing the sorption contributions by amorphous organic matter and black carbon (BC). It appears that sorption to BC increased with LogK(OW), whereas sorption to AC showed a relatively narrow range of affinity properties with a median Freundlich LogK(F,)(AC) value of 7.2 (µg/kg(AC))/(µg/L)(n) (IQR = 7.0-7.5) for polychlorinated biphenyls (PCBs) and 8.6 (IQR = 8.3-8.8) for polycyclic aromatic hydrocarbons (PAHs). Estimated Freundlich exponents were n(F,)(AC) = 0.74 for PCBs and 0.82 for PAH. Sorption to AC was stronger than to BC for chemicals below LogK(OW) = 6.3-6.6. For HOC risk reduction this is favorable, because chemicals with low K(OW) show generally higher bioavailable concentrations.

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Amendment of contaminated sediment with activated carbon (AC) is a remediation technique that has demonstrated its ability to reduce aqueous concentrations of hydrophobic organic compounds. The application of AC, however, requires information on possible ecological effects, especially effects on benthic species. Here, we provide data on the effects of AC addition on locomotion, ventilation, sediment avoidance, mortality, and growth of two benthic species, Gammarus pulex and Asellus aquaticus , in clean versus polycyclic aromatic hydrocarbon (PAH) contaminated sediment. Exposure to PAH was quantified using 76 µm polyoxymethylene passive samplers. In clean sediment, AC amendment caused no behavioral effects on both species after 3-5 days exposure, no effect on the survival of A. aquaticus , moderate effect on the survival of G. pulex (LC(50) = 3.1% AC), and no effects on growth. In contrast, no survivors were detected in PAH contaminated sediment without AC. Addition of 1% AC, however, resulted in a substantial reduction of water exposure concentration and increased survival of G. pulex and A. aquaticus by 30 and 100% in 8 days and 5 and 50% after 28 days exposure, respectively. We conclude that AC addition leads to substantial improvement of habitat quality in contaminated sediments and outweighs ecological side effects.

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Properties of Ca(2+)-stimulated incorporation of amincalcohols, serine and ethanolamine, into phospholipids, and factors regulating the reaction were studied in endoplasmic reticulum membranes isolated from rat liver. In contrast to apparent K(m) values for either aminoalcohol, maximal velocities of the reaction were significantly affected by Ca2+ concentration. No competition between these two soluble substrates used at equimolar concentrations close to their K(m) values was observed, suggesting the existence of two distinct phospholipid base exchange activities. The enzyme utilizing the electrically neutral serine was not sensitive to changes of membrane potential evoked by valinomycin in the presence of KCl. On the other hand, when positively charged ethanolamine served as a substrate, the enzyme activity was inhibited by 140 mM KCl and this effect was reversed by valinomycin. The rates of inhibition of phospholipid base exchange reactions by various thiol group modifying reagents were also found to differ. Cd2+ and lipophylic p-chloromercuribenzoic acid at micromolar concentrations were most effective. It can be suggested that -SH groups located within the hydrophobic core of the enzymes molecules are essential for the recognition of membrane substrates. However, the influence of the -SH group modifying reagents on the protein-facilitated phospholipid motion across endoplasmic reticulum membranes can not be excluded, since an integral protein-mediated transverse movement of phospholipids within the membrane bilayer and Ca(2+)-mediated changes in configuration of the phospholipid polar head groups seem to be a regulatory step of the reaction. Indeed, when the membrane integrity was disordered by detergents or an organic solvent, the reaction was inhibited, although not due to the transport of its water-soluble substrates is affected, but due to modulation of physical state of the membrane bilayer and, in consequence, the accessibility of phospholipid molecules.

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In the present study the relationship between lipid peroxidation, changes in the redox state of membrane and phosphatidylethanolamine (PE) synthesis via base exchange reaction in rat liver microsomes was investigated. It was found that PE synthesis is enhanced in the presence of antioxidants, butylated hydroxytoluene (BHT), or unsaturated free fatty acids. Prooxidants, tert-butyl hydroxyperoxide (BHP), ferrous ions combined with ascorbate or NADPH (via cytochrome P450-dependent proteins), increased the amount of lipid peroxidation products in the membrane, and in consequence inhibited the reaction. The effect of BHP was fully reversed by reduced glutathione and dithiothreitol (DTT), whereas the effect of other compounds could be reversed only by BHT. In contrast, a reversal of the inhibitory effect of cadmium ions on base exchange activity was observed in the presence of DTT, but not BHT. Therefore, both the -SH/-S-S- ratio in the membrane, affected by BHP and cadmium ions, and the lipid hydroxyperoxides (rather than aldehydes), generated by ferrous ions and ascorbate or NADPH, are equally responsible for the inactivation of the ethanolamine base exchange enzyme in rat liver microsomes. This may suggest that the synthesis of PE via the base exchange reaction may be considered an element of the superfine cellular machinery involved in the repair of damage to unsaturated fatty acid chains of phospholipids caused by reactive oxygen species under oxidative stress.

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Preincubation of Ehrlich ascites tumour cells with millimolar concentrations of pantothenic acid, pantothenol or pantethine, but not with homopantothenic acid, at 22 degrees C or 32 degrees C, but not at 0 degrees C, makes the plasma membrane more resistant to the damaging effect of submillimolar concentrations of digitonin. It is proposed that this increased resistance is due to the increased rate of cholesterol biosynthesis. In fact, incorporation of [14C]acetate into cholesterol is by 45% increased in the cells preincubated with pantothenic acid; this probably reflects elevation of the content of CoA in such cells [Slyshenkov, V.S., Rakowska, M., Moiseenok, A.G. & Wojtczak, L. (1995) Free Radical Biol. Med. 19, 767-772].

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Preincubation of Ehrlich ascites tumor cells at 22 or 32 degrees C, but not at 0 degree C, with pantothenic acid, 4'-phosphopantothenic acid, pantothenol, or pantethine reduced lipid peroxidation (measured by production of thiobarbituric acid-reactive compounds) induced by the Fenton reaction (Fe2+ + H2O2) and partly protected the plasma membrane against the leakiness to cytoplasmic proteins produced by the same reagent. Pantothenic acid and its derivatives did not inhibit (Fe2+ + H2O2)-induced peroxidation of phospholipid multilamellar vesicles, thus indicating that their effect on the cells was not due to the scavenging mechanism. Homopantothenic acid and its 4'-phosphate ester (which are not precursors of CoA) neither protected Ehrlich ascites tumor cells against lipid peroxidation nor prevented plasma membrane leakiness under the same conditions. Incubation of the cells with pantothenic acid, 4'-phosphopantothenic acid, pantothenol, or pantethine significantly increased the amount of cellular CoA and potentiated incorporation of added palmitate into phospholipids and cholesterol esters. It is concluded that pantothenic acid and its related compounds protect the plasma membrane of Ehrlich ascites tumor cells against the damage by oxygen free radicals due to increasing cellular level of CoA. The latter compound may act by diminishing propagation of lipid peroxidation and promoting repair mechanisms, mainly the synthesis of phospholipids.

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Incorporation of [14C]serine into phosphatidylserine by the base exchange reaction in Ehrlich ascites tumor cells is inhibited by 30% by glucose and by 60% by 2-deoxyglucose (10 mM each). The inhibition by thapsigargin (0.2 microM) amounts to 80%. This inhibition is interpreted as being due to depletion of calcium stores in the endoplasmic reticulum and is compatible with the previous observation [Teplova, V. V., Bogucka, K., Czyz, A., Evtodienko, Yu.V., Duszynski, J., and Wojtczak, L. (1993) Biochem. Biophys. Res. Commun. 196, 1148-1154] that glucose and deoxyglucose elicit an increase of cytoplasmic [Ca2+] at the expense of intracellular Ca2+ stores and with the finding [Baranska, J. (1989) FEBS Lett. 256, 33-37] that the base exchange reaction requires high concentration of Ca2+ within the endoplasmic reticulum lumen.

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The procedures for purification and reconstitution of rat brain microsomal membrane protein that causes fusion of liposomes at acidic pH are described. A 1,860-fold purification was achieved, starting from the detergent-solubilized microsomal membranes. The fusion process was assayed spectrofluorimetrically by monitoring the formation of terbium-dipicolinic acid complex (Wilschut, J. et al. 1980. Biochemistry 19:6011-6021) evoked by the protein after mixing of two populations of liposomes. The fusogenic activity of the protein inserted into the membrane of Tb3+-containing vesicles was found to be strongly dependent on phospholipid composition and was higher in vesicles enriched with exogenous phosphatidylserine, phosphatidylglycerol and phosphatidylethanolamine than in those prepared with an excess of phosphatidylcholine. The vesicles enriched in negatively charged phospholipids were bound to Concanavalin A coupled to Sepharose-4B and could be released from this column only in the presence of a high concentration of alpha-methylmannopyranoside and detergent, indicating a glycoprotein nature of the fusogenic protein. Furthermore, these data show that protein inserted into membrane has its oligosaccharide chains exposed to the environment.

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We enriched liver microsomes in lipid classes and molecular species disrupting membranes with octyl glucoside and reassembling them by detergent removal. Phosphatidylethanolamine incorporated into membranes better than phosphatidylserine or phosphatidylcholine. In addition, the degree of incorporation depended on the unsaturation of fatty acyl-chains. The enrichment of the membranes with phosphatidylserine or phosphatidylcholine inhibited serine base-exchange, whereas the addition of phosphatidylethanolamine usually stimulated it. The effect of exogenous lipids also depended on molecular species; egg yolk phosphatidylcholine and dipalmitoyl phosphatidylcholine inhibited base-exchange whereas the effect of palmitoyl-oleoyl phosphatidylcholine depended on the incorporated amount. The degree of unsaturation also modulated the effect of phosphatidylethanolamine.

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The addition of fiveFusarium species, cultured on wheat grain, to the standart chicken diet DKA starter, caused atrophic changes in the thymus and testes, as observed in the microscopic picture of these organs. The degree of lesions were depended on theFusarium species and its amount added to the standart diet.

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Microdochium nivale (Fusarium nivale) was found to be frequently occuring in Poland pathogen of small grain cereals heads, causing symptoms similar to those observed after infection ofFusarium species. In consecutive years since 1985 till 1989 the following percentage of wheat and rye ears infected withM. Nivale and withFusarium head blight symptoms was found: 34%, 21%, 42%, 9%, 46% (wheat) and 57%, 43%, 65%, 4%, 47% (rye) heads.However, in naturally infected rye and wheat samples (kernels and chaff), we did not detect toxins usually present in samples infected with fungi of genusFusarium - such as deoxynivalenol and derivatives. TypicalFusarium trichothecene metabolites were also not present in cultures of 11M. nivale strains, growing 3-5 weeks on rice (45% water content) at 20°C. Cultures of two typical isolates on wheat grain (strain KF 1124) and on rice (KF 245) were found to be non toxic to broiler chickens when present in amount 20-40% in their diet. It can be concluded thatM. nivale (F. nivale) representatives in Poland did not produce toxic metabolites neither under laboratory condition nor after cereal ears infection under field conditions.

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Six pigs of initial weight 40 +/- 1.7 kg with a T-piece cannula fitted at the terminal ileum were given diets composed of 96.3% of rye, barley or triticum grains ground to pass the 2.6 mm mesh, 3.3% mineral and vitamin mixture and 0.4% Cr2O3. Each diet was given to all pigs in a Latin square design, and faeces and ileal digesta were collected on 7, 8, 9 and 10, 11 and 12 day of feeding each diet, respectively. The grains varied widely in the content of pentosans, polyuroids, beta-glucan and monosaccharides. The antitrypsin activities were 0.84, 2.73 and 1.62 TUI/g in barley, rye and triticum, respectively. Ileal and faecal apparent digestibilities of nitrogen and amino acids were higher (P less than or equal to 0.01) in Triticum than in barley and rye. The digestibility of carbohydrates (pentosans, beta-glucan, polyuroids and non-structural carbohydrates) were lower in pigs fed a rye diet than of those fed a Triticum diet. The results are discussed with respect of the role to non starch polysaccharides, especially pentosans in digestibility of nitrogen and energy in animals receiving a rye diet.

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Ethanol, hexobarbital, chlorpromazine and haloperidol had no effect on the composition and total amount of gangliosides in rat and mouse brains. The gangliosides seemed to be resistant to ethanol and the above mentioned drugs. None of them either in single or repeated doses had a major effect on the sialic acid-containing glycosphingolipids. The results of this study are at variance with those reported by Klemm & Foster (Life Sci., 1986, 39, 897-902) who described a sharp decrease of the total level of brain gangliosides after injection of a single dose of ethanol.

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