The effect of the oil dispersant Omni-Clean on the toxicity of fuel oil no. 2 in two bioassays with the sheepshead minnow Cyprinodon variegatus

Bioassays (7-day early life stage and 96 h acute bioassays) were conducted with the sheepshead minnow, Cyprinodon variegatus, to determine the toxicity of the dispersant Omni-Clean by itself and in combination with fuel oil no. 2. Performance characteristics of both bioassay types were also compared. Bioassays used oil by itself, dispersant by itself, and oil and dispersant in various ratios. Omni-Clean was less toxic than many other dispersants, and had a relatively small effect on individual biomass. Toxicities of the oil/dispersant combinations were generally higher than expected from the toxicities of the oil and dispersant by themselves, indicating a more-than-additive effect on toxicity. The comparison of performance characteristics between the 7-day and the 96-hour bioassays showed that the early life stage test is generally more sensitive, and has the added advantage of an additional and sensitive endpoint (fish biomass).     

Beta-cyclodextrin(beta-CD) influence on the biotoxicities of substituted benzene compounds and pesticide intermediates

The acute toxicities of 19 substituted benzene compounds and intermediates of pesticides to Photobacterium phosphoreum in beta-CD aqueous solution (5 g/L) were studied and compared with those in water through luminescent bacteria toxicity test, and 15min-EC50 values were obtained. The presence of beta-CD significantly reduce biotoxicities of the low-polarity compounds, while for the higher-polarity compounds, such effect was slight. The differences of biotoxicities were correlated with Log10Kow (octanol/water partition coefficients). A significant linear relationship was obtained with some abnormal data picked out. Some explanations concerning molecular structure of chemicals as well as beta-CD were given for the relationship.     

Microbial dechlorination of polychlorinated biphenyls in anaerobic sewage sludge.

The potential of a chlorophenol (CP)-adapted consortium to dechlorinate polychlorinated biphenyls (PCBs) in sewage sludge was investigated. Results show that dechlorination rates differed significantly depending on sludge source and PCB congener. Higher total solid concentrations in sewage sludge and higher concentrations of chlorine in PCB resulted in slower dechlorination rates. No significant difference was found for 2,3,4,5-CB dechlorination from pH 6.0 to pH 8.0; however, dechlorination did not occur at pH 9.0 during a 41-day incubation period. Results show that at concentrations of 1 to 10 mg/L, the higher the PCB concentration, the faster the dechlorination rate. In addition, dechlorination rates were in the following order: methanogenic conditions > sulfate-reducing conditions > denitrifying conditions. The addition of acetate, lactate, pyruvate, and ferric chloride decreased lag times and enhanced dechlorination; however, the addition of manganese dioxide had an inhibitory effect. Dechlorination rates were also enhanced by the addition of PCB congeners, including 2,3,4-CB, 2,3,4,5-CB and 2,3,4,5,6-CB in mixture. Overall results show that the CP-adapted consortium has the potential to enhance PCB dechlorination. The optimal dechlorination conditions presented in this paper may be used as a reference for feasibility studies of PCB removal from sludge.     

Metallothionein induction and cadmium uptake in Bufo arenarum embryos following an acclimation protocol

Bufo arenarum embryos at the end of their embryonic development were acclimated to cadmium (Cd) by means of a 10-day treatment protocol. Embryos were processed for metallothionein (Mt) isolation and Cd and zinc (Zn) contents were measured. The results showed that: (1) the uptake of Cd in the experimental embryos was 7 microg/g embryo (wet weight) representing a bioaccumulation of Cd 255 times higher than in the maintaining medium; (2) a major Mt-like fraction was Cd-induced 7.8 times that in control embryos; two other protein fractions also bound Cd and Zn but were induced by Cd only about 2 and 1.4 times; (3) the Zn concentration was about 44 microg Zn/g embryo (wet weight) and did not change significantly (p>0.01) in the experimental embryos with respect to controls, but in acclimated embryos the essential metal was released from the Mts. The enhanced Mt synthesis and release of Zn from the native Mts are discussed in relation to the acclimation phenomenon.     

Biodeterioration of cardboard-based liquid containers collected for fibre reuse

Liquid packaging board (LPB) collected in Germany is processed in Finland as recycled fibre and as plastic reject for incineration. The chemical, biological and physical changes occurring in recycled LPB bales were monitored during storage of six and 18 months. The moisture content in the core of the bales ranged from 7% to 53%, and pH values varied from 6.0 to 8.5. The average amount of mesophilic bacteria per container was 1.5 x 10(7) - 5 x 10(8), which means that recycled LPB pulp cannot be recommended for sanitary use. The concentration of CO2 inside the bale is an indicator of the activity of aerobic microorganisms and might be suitable for identifying deteriorated bales and removing them from the production line. Insects were found in some bales and the more deteriorated the bale was the more species of insects were found. The results showed the conversion of cellulose into humic acids to be clearly underway in some recycled LPB bales. The bale samples were extracted into hot water and into fulvic acids and humic acid (HA) fractions. The concentration of the humic acid fraction varied in the range 0.3-0.6% of the organic matter in fresh bales and 2.2% in one old bale. During aging nitrogen was enriched in all fractions.     

Degradation pathways of PCBs upon UV irradiation in hexane.

The photodegradations of eight individual PCB congeners (5, 31, 52, 77, 87, 126, 138, 169) in hexane have been investigated employing a mercury lamp. All degradation reactions of the above mentioned PCB congeners are of the pseudo first order. The principal products of PCB decomposition are the less chlorinated biphenyls, and no PCB-solvent adducts are found. Symmetrical and coplanar PCB congeners show lower photoreactivities. The reactivities of the chlorine atoms at various positions of PCB rings are generally in the order: ortho > meta > para. Photodechlorinations occur mainly on the more substituted rings, when the numbers of chlorine atoms on the two phenyl rings are unequal. During photodegradation, some coplanar PCB congeners are formed, which make the TEQ of solutions to decrease slowly or even to increase.     

Sorption of arsenate and arsenite anions by iron(III)-poly(hydroxamic acid) complex

Iron(III)-poly(hydroxamic acid) resin complex has been studied for its sorption abilities with respect to arsenate and arsenite anions from an aqueous solution. The complex was found effective in removing the arsenate anion in the pH range of 2.0 to 5.5. The maximum sorption capacity was found to be 1.15 mmol/g. The sorption selectivity showed that arsenate sorption was not affected by chloride, nitrate and sulphate. The resin was tested and found effective for removal of arsenic ions from industrial wastewater samples.     

Variation of toxaphene indicator compounds in fish from single fishing grounds: conclusions for sampling

The levels of three toxaphene indicator compounds were determined in individual lots of herring, redfish, Greenland halibut and farmed salmon. Concentration levels of the three marine fish species were characterised by a right-skewed frequency distribution whereas residue concentrations in farmed salmon were normally distributed. The toxaphene concentrations in the edible part of redfish, herring and Greenland halibut were found to be positively correlated to the sizes and thus to age. As results show, for representative sampling of a landed catch, not more than 10 individual fishes from typical size classes of a lot are necessary for a pooled sample.     

Off-site forensic determination of waterborne elemental emissions: a case study at a secondary lead smelter

A multi-element, multi-media analysis of waterborne sediments downstream from a secondary lead smelter is presented. Sediments were collected from a closed municipal storm water drain, an open private storm water conveyance, and a channelized river. Characteristic ratios of lead, antimony, arsenic, and cadmium were found in the samples, which were similar to air and soil samples taken at the same site. Additional elements, some associated with lead-acid batteries and some not, were also found. Significant correlation was found among the concentrations of the majority of these elements.     

Effect of manganese on the concentration of amino acids in different regions of the rat brain

The present study was designed to determine if chronic exposure of weanlings and adult rats to Mn produces significant alterations in amino acid concentrations in different regions of the rat brain. Weanling (30 day old) and adult (90 day old) male rats were exposed to 10 and 20 mg Mn/kg body weight per day, by gavage, for 30 days. Forty-eight hours after the last dose, animals were sacrificed by decapitation and brains were dissected into different regions to determine the concentration of amino acids by HPLC/EC. A dose dependent decrease in body weight gain was found in the adult, but not in the weanling rats. Significant increases occurred in concentrations of aspartate, glutamate, glutamine, taurine and gamma-aminobutyric acid (GABA) in the cerebellum of the adult rats dosed with 20 mg/kg per day, Mn. A significant decrease in the concentration of glutamine was observed in caudate nucleus and hippocampus of weanling rats dosed with 10 mg/kg, Mn. These data suggest that chronic Mn exposure can produce a decrease in body weight gain in adult rats and alterations in amino acids in different regions of weanling and adult rat brains.