Environmental impact and recovery at two dumping sites for dredged material in the North Sea

The environmental impact and recovery associated with the long and uninterrupted disposal of large volumes of moderately contaminated dredged material from the port of Rotterdam was studied at nearby dumping sites in the North Sea. Observations were made on sediment contamination, ecotoxicity, biomarker responses and benthic community changes shortly after dumping at the 'North' site had ceased and at the start of disposal at the new dumping site 'Northwest'. During the period of dumping, very few benthic invertebrates were found at the North site. Concentrations of cadmium, mercury, polychlorinated biphenyls (PCBs), polyaromatic hydrocarbons (PAHs) and tributyltin (TBT) in the fine sediment fraction (<63 microm) from this site were 2-3 times higher than at the reference site. In four different bioassays with marine invertebrates the sediments showed no acute toxic effects. In tissue (pyloric caeca) of resident starfish Asterias rubens, residual levels of mercury, zinc, PCBs and dioxin-like activity were never more than twice those at the reference site. Four different biomarkers (DNA integrity, cytochrome P450 content, benzo[a]pyrene hydroxylase activity and acetylcholinesterase inhibition) were used on the starfish tissues, but no significant differences were found between North and the reference site. Minor pathological effects were observed in resident dab Limanda limanda. One year after dumping had ceased at the North site, a significant increase in the species richness and abundance of benthic invertebrates and a concomitant decrease in the fine sediment fraction of the seabed were observed. After 8.2 million m3 of moderately contaminated dredged material had been dumped at the new dumping site Northwest, the species richness and abundance of benthic invertebrates declined over an area extending about 1-2 km eastwards. This correlated with a shift in sediment texture from sand to silt. The contamination of the fine sediment fraction at the Northwest location doubled. It is concluded that marine benthic resources at and around the dumping sites have been adversely affected by physical disturbance (burial, smothering). However, no causal link could be established with sediment-associated contaminants from the dredged spoils.     

Methods for sampling and analysis of tropospheric ethanol in gaseous and aqueous phases

In this paper, we report on techniques for sampling and measuring ethanol in both the gas and aqueous phases of the lower troposphere. In the gas phase, the best sampling conditions were ensured by adsorption on Hayesep Q with a Chromosorb W AW coated with LiCl dryer (method 1) or by cryogenic trapping (method 2). An intercomparison campaign showed good agreement between both methods under various conditions. Method 1 (adsorption on Hayesep Q with dryer) is easier to set up and to carry away from the laboratory. Method 2 (cryogenic trapping) requires longer sampling time (up to 60 min while method 1 requires only 10-15 min). Method 1 is adapted to high concentrations of ethanol (>20 ppb) and low relative humidity (<30%). Method 2 gives more accurate results than method 1 for low ethanol concentrations (1-20 ppb). Comparing these results to previous studies, it is clear that sampling with appropriate solid adsorbents or with stainless steel canisters (with appropriate humidified air and short storage time) is adapted to urban or industrial environments where ethanol concentrations are high. Cryogenic sampling must be preferred for remote places where ethanol concentrations are low. Three techniques were tested for sampling ethanol in the liquid phase, namely solid phase microextraction, purge and trap injection, and direct injection. Among those, the latter was chosen for field measurements of ethanol in rain samples at an urban location. These first ever results at an urban location show concentrations ranging from <1 to 5 microM in rains, which agree with the expected range of concentrations. However, the purge and trap method showed detection limits that were 50 times lower and should be preferred for liquid phase ethanol measurements in rural and remote locations. Combining cryogenic trapping for the gas phase (method 2) and direct injection for the liquid phase is convenient and well adapted for a multiphase study of ethanol in the atmosphere, where simultaneous measurements in both phases are needed.     

Removal of biocide pentachlorophenol in water system by the spent mushroom compost of Pleurotus pulmonarius

Pentachlorophenol (PCP) has been widely used as a wood preservative since 1980s. Although it has been banned worldwide, residues of PCP are still commonly found. The spent compost of oyster mushroom Pleurotus pulmonarius (SMC) which was a degraded paddy straw-based substrate, contained 25% chitin. Five percentage of the SMC could remove 89.0 +/- 0.4% of 100 mg PCPl(-1) within 2 days at room temperature predominantly by biodegradation. The maximum removal capacity was 15.5 +/- 1.0 mg g(-1) SMC. The sorption kinetics of PCP by SMC can be described by the Freundlich monolayer model with a theoretical sorption capacity similar to that found for chitin. A PCP-degradative bacterium was isolated from the SMC. Yet, biodegradation was predominantly contributed by the immobilized ligninolytic enzymes secreted by the mushroom to the SMC. Degradation of PCP involves dechlorination, methylation, carboxylation and ring cleavage as verified by GC-MSD and ion chromatography. Thus, the SMC has a potential for treating PCP-contaminated water.     

Monitoring of polychlorinated biphenyls in Belgian human adipose tissue samples

Polychlorinated biphenyls (PCBs) were monitored in Belgian human adipose tissue samples from deceased individuals (n=100). Their mean age was 52, ranging from 2 to 91 years. There were 57 men and 43 women. Other known variables were date of autopsy and place of residence. No information about diet or occupation was available. The seven marker congeners PCB 28, 52, 101, 118, 138, 153 and 180 were analysed in the samples with a GC-MS/MS method validated according to Commission Decision 2002/657/EC. Extracted fat was cleaned-up over a glass column filled with n-hexane, acid silica, deactivated alumina and anhydrous sodium sulfate. The whole procedure was subjected to a rigorous quality control programme with retention times, ion chromatograms and intensity ratios of the monitored product ions as identification criteria. The total PCB concentration ranged between 10 and 1640 ng g-1 fat, with a mean value of 658 ng g-1 fat. In the age groups of 0-9 (n=1), 10-19 (n=4), 20-29 (n=11), 30-39 (n=13), 40-49 (n=15), 50-59 (n=14), 60-69 (n=14), 70-79 (n=20), 80-89 (n=6) and 90-99 (n=2), the mean total PCB concentrations were 10, 134, 253, 445, 557, 687, 807, 962, 959, and 1191 ng g-1 fat, respectively. So, there was an increase of PCB body burden with age. For the male subjects (n=57; mean age of 53) the mean total PCB concentration was 633 ng g-1 fat. For the female subjects (n=43; mean age of 52) it was 690 ng g-1 fat. There was no significant sex-related difference in the concentrations of marker PCBs.     

The evaluation of electrical energy per order (E(Eo)) for photooxidative decolorization of four textile dye solutions by the kinetic model

Photooxidative decolorization of four textile dyestuffs, C.I. Acid Orange 7 (AO7), C.I. Acid Orange 8 (AO8), C.I. Acid Orange 52 (AO52) and C.I. Acid Blue 74 (AB74), by UV/H2O2 was investigated in a laboratory scale photoreactor equipped with a 15 W low pressure mercury vapour lamp. The decolorization of the dyes was found to follow pseudo-first-order kinetics, and hence the figure-of-merit electrical energy per order (E(Eo)) is appropriate for estimating the electrical energy efficiency. The E(Eo) values were found to depend on the concentration of H2O2, concentration and basic structure of the dye. This study shows that these textile dyes can be treated easily and effectively with the UV/H2O2 process with E(Eo) values between 0.4 and 5 kW h m-3 order-1, depending on the initial concentrations of dyes and H2O2. The kinetic model, based on the initial rates of degradation, provided good prediction of the E(Eo) values for a variety of conditions.     

Bioavailability of contaminants estimated from uptake rates into soil invertebrates

It is often argued that the concentration of a pollutant inside an organism is a good indicator of its bioavailability, however, we show that the rate of uptake, not the concentration itself, is the superior predictor. In a study on zinc accumulation and toxicity to isopods (Porcellio scaber) the dietary EC(50) for the effect on body growth was rather constant and reproducible, while the internal EC(50) varied depending on the accumulation history of the animals. From the data a critical value for zinc accumulation in P. scaber was estimated as 53 microg/g/wk. We review toxicokinetic models applicable to time-series measurements of concentrations in invertebrates. The initial slope of the uptake curve is proposed as an indicator of bioavailability. To apply the dynamic concept of bioavailability in risk assessment, a set of representative organisms should be chosen and standardized protocols developed for exposure assays by which suspect soils can be evaluated.     

Temporal trends in spheroidal carbonaceous particle deposition derived from annual sediment traps and lake sediment cores and their relationship with non-marine sulphate

Spheroidal carbonaceous particles (SCPs) provide an unambiguous indication of atmospherically deposited contamination from industrial sources. SCP data from a 12 year annual sediment trapping and coring programme at 14 lakes based on the UK Acid Waters Monitoring Network, were used to consider temporal trends in deposition and to compare these with measured non-marine sulphate fluxes. Results show good temporal coherence across a broad area of northern UK and that SCP deposition levels and are now at their lowest since the 1940s, in agreement with modelled sulphate data. SCP fluxes show reasonable linearity with measured non-marine sulphate depositional fluxes from the nearest UK Acid Deposition Monitoring Network sites, especially over the post-flue-gas desulphurisation period, but comparisons prior to 1972 are not possible due to lack of data. We speculate on whether palaeolimnological SCP data might be used to reconstruct the history of non-marine sulphate fluxes from industrial sources.     

Availability of heavy metals for uptake by Salix viminalis on a moderately contaminated dredged sediment disposal site

Extractability of Cd, Cr, Cu, Ni, Pb, and Zn in a dredged sediment disposal site was assessed using single extraction procedures (H2O; 0.01 M CaCl2; 1 M NH4OAc; NH4OAc-EDTA; CaCl2-TEA-DTPA). Only Cd and Zn were found to exceed statutory threshold values for total content. The field was planted with Salix viminalis "Orm" and accumulation of heavy metals in bark, leaves, roots, and wood was evaluated at seven sampling locations along an observed gradient in texture and pollution. Biomass production was high, ranging from 13.2 to 17.8 t ha(-1) y(-1) dry weight. Metal accumulation in aboveground plant parts was low, amounting to the following annually extracted mass of metals per ha: 5034 g Zn, 83 g Cd, 145 g Cu, 83 g Pb, 12 g Ni and 6 g Cr. The use of accumulating clones and the use of soil amendments might enhance extraction efficiency in future research.     

The degradation of endocrine disruptor di-n-butyl phthalate by UV irradiation: a photolysis and product study

The direct photolysis of an important endocrine disruptor compound, di-n-butyl phthalate (DBP), has been investigated under monochromatic UV irradiation at 254 nm over a wide pH range (3-11). The investigation was carried out under idealized conditions and has considered both reaction kinetics and the degradation mechanism. It was found that more than 90% of DBP can be degraded within an hour of irradiation in water. A simple model has been developed and used to predict the initial DBP photolysis rate constant at different pH values and initial DBP concentrations. The major decomposition mechanism of DBP is believed to involve the hydrolytic photolysis of the carbon in the alpha and/or beta-position of the ester chain with the production of aromatic carboxylic derivatives. Additionally, multi-degradation pathways are proposed for acid-catalyzed hydrolytic photolysis (pH 3-5), which was found to be useful in explaining the photo-degradation of DBP under acidic conditions. The use of 254 nm UV to photo-degrade DBP was found to be a relatively fast and clean process, especially in neutral to basic conditions.