Optimisation of pressurised liquid extraction for elimination of sulphur interferences during determination of organotin compounds in sulphur-rich sediments by gas chromatography with flame photometric detection

A simple method for species-selective analysis of organotin compounds (OTCs) (butyl and phenyl) in sediments was developed. The sample preparation procedure was specifically optimised for sulphur-rich sediments to eliminate interferences from elemental sulphur and organosulphur compounds. Tin species were extracted from sediment samples using pressurised liquid extraction technique (PLE), ethylated - with simultaneous extraction to isooctane - in aqueous phase with sodium tetraethylborate (NaBEt(4)) and separated/detected by gas chromatography with flame photometric detection (GC-FPD). PLE operational variables (extraction temperature and pressure, solvent composition and number of static extraction steps) and extract handling routine were fine-tuned to minimise the amount of extracted interferents while keeping OTCs recovery at an acceptable level. Best results were obtained after extraction of sediment samples with methanol/water (75% v/v methanol) solution of acetic acid/sodium acetate with tropolone addition (0.6 g l(-1)). Derivatisation of low temperature, high-pressure (50 degrees C, 13.8 MPa) extracts gives isooctane extracts which are clean enough to be directly analysed by GC-FPD without any further cleanup. Interferences from elemental sulphur were completely eliminated while concentrations of other interferents were reduced to the level not impairing quantitation of OTCs under the study. No negative effects in terms of chromatographic column deterioration were observed after repeated injections of such extracts. Two certified reference materials, BCR646 and PACS-2, were analysed to assess performance of the method. Recoveries of all OTCs under the study, except MBT, were in the range of 91-114%. MBT extraction efficiency was low (34-47%) therefore the method is unsuitable for precise determinations of this compound.     

Concentration of bioactive compounds in mussels Mytilus galloprovincialis as an indicator of pollution

The polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and organotins were analyzed in mussels Mytilus galloprovincialis from polluted and unpolluted sites from Mokpo Bay, Korea. The total PAH's concentrations (10(-3)mgkg(-1)) measured by GC-MS were in the range from 31+/-23 to 1+/-1. Among the eight PAHs the predominant ones were fluoranthene, phenanthrene and pyrene and accounted approximately 63% of the total PAHs. Among the four detected PCBs the highest content was of PCB 153, which accounted about 47% of the total PCBs. The main organotin compounds were dibutyltindichloride (DBT) and tributyltinchloride (TBT) and their composition was approximately 33% and 24%. PAHs, PCBs and organotins were found only in the mussels from polluted site. The antioxidant activity by ABTS [2,2'-azinobis (3-ethylbenzothiazoline-6-sulfonic acid)] test was higher in mussels from polluted than from unpolluted sites (P<0.05). It was found a correlation between the determined compounds (PAHs, PCBs and organotins) and the antioxidant activity of the mussel tissue from polluted site and the correlation coefficients were 0.96, 0.92 and 0.80, respectively. Such correlation can be explained by the properties of mussels. Since the mussel cell wall and tissues are hydrophobic, they can concentrate a number of hydrophobic pollutants like PAHs and PCBs from the marine environment by solubility rules. On the other hand, proteins are lipophilic compounds having antioxidant properties. Certain amino acid residues and thiol (-SH) groups, contained in proteins, respond to the ABTS antioxidant activity assay. Thus there may be a correlation between the total antioxidant activity of the organism and the PAH-PCB pollutants which were concentrated from its environment. The studied properties of mussels from polluted site can be used as an additional indicator of pollution.     

Empirical Estimation of Virtual Point Source Height Over a Bank of Coke Ovens

This paper addresses an empirical method of assessment of the height of a virtual point source. In order to achieve such assessment, three planes defining the location of a virtual point source in a space are created and formulas describing the geometry of observer’s sight and plume orientation are used. Data for calculations are obtained on a basis of plume photographs. The final position of a virtual emission point is described by a set of its coordinates in the Cartesian coordinate system. Presented method may be applied as a means to verify and validate the existing formulas describing the rise of plume above the stack exit or as a tool enabling acquisition of information for the sake of creating new formulas of this type. The calculation of the location of a virtual point source ascribed to the point emission from the roof of the bank of coke oven is presented and illustrated with photographs which reveal position of plume, adequate planes, axes and characteristic objects.     

Remobilization of polychlorinated biphenyls from sediment and its consequences for their transport in river waters

A laboratory experiment was performed to examine the remobilization of indicator polychlorinated biphenyls (iPCBs) from sediments and its results were applied to the real-world data for explaining the transport of PCBs in river. Seven PCB concentrations were determined in three series of model water–sediment systems (3 g of river sediment, three different volumes of distilled water (0.5, 0.25, and 0.15 ml), and 5 mg of biocide) after 11 days of incubation. Solid-phase extraction was used for separation of analytes from the aqueous phase and solvent extraction for isolation of analytes from the sediments, respectively. The extracts were analyzed for individual iPCB congeners using gas chromatography–mass spectrometry method. For each series of the experiment, the concentrations of PCBs in aqueous phase were similar. The average sediment/water partition coefficient value was 10⁴?l/kg. The solubility of individual PCB congeners in water did not influence the desorption of PCBs from the sediment. Although the dominant form of PCBs in a water–sediment system occurs as suspended and colloidal fractions, these compounds are transported mostly in a dissolved form. Suspended and colloidal matter is a major sink for PCBs in low-energy aquatic environments. In contrast, the dissolved PCBs are readily transported in running waters. The mobilization of PCBs from sediments to aqueous phase, with respect to their solubility in water, seems to be limited, thus reducing the risk of secondary pollution.     

Horizontal and vertical variabilities of mercury concentration and speciation in sediments of the Gdansk Basin,Southern Baltic Sea

The mercury compounds introduced to the environment because of anthropogenic activity are accumulated, mainly, in marine sediments. Both distribution of mercury in the Baltic Sea and factors affecting it are remain largely unknown. Due to its complex chemistry and variable conditions in the Baltic Sea bottom sediments, mercury may be reemitted to the overlaying water, and thus to the environment.The aim of this study was twofold. Total mercury contents were measured in sediments of the Gdansk Basin along a Vistula mouth (main source)--Gdansk Deep (deposition area) transect in order to assess spatial distribution of the element. Soft and sandy bottom sediment cores were collected and cut into slices. The mercury measurements consisted of acid digestion followed by CV-AAS determination. A five-step sequential extraction procedure involving measurements of mercury species water soluble, bound to humic substances and insoluble, was employed in order to investigate mercury speciation. On the basis of speciation results stability and remobilisation potential was assessed. The second aim was demonstrating that mercury gradients in vertical profiles of the investigated sediment cores exist.Total mercury contents varied in range from 28 ng/g x dw to 844 ng/g. Mercury associated with organic matter and sulphides, (respectively 39% and 49%) were the dominant species of the element. The results indicated that the river run-off is a source of mercury in the area. Vertical gradients of both total content and speciation of mercury in the soft sediments were attributed to both remobilisation from sediments, and decreasing trend in the anthropogenic load of the element deposited to sediments.     

Effect of treated swimming pool water on the levels of trihalomethanes in swimmer's urine

Swimming pools are considered to be the prime source for public exposure to trihalomethanes (THMs), mainly chloroform, because of their use for hygienic purposes. High doses of chlorine are easily perceptible by smell. The aim of this study was to measure simultaneously the THM levels in urine and blood of swimmers and in pool water itself (from city and university swimming pool), in order to investigate further the relationship between substances in different matrices at known environmental levels with uptake of these substances in indoor swimming pools. Volatile analytes were isolated and preconcentrated from the samples by thin layer headspace analysis (TLHS) with autogenous generation of the liquid sorbent. Chloroform, bromodichloromethane and dibromochloromethane were detected in the urine of all persons attending a swimming pool. Concentrations of THM compounds varied in the case of each swimmer. The research confirmed that approximately 10% of the volatile haloorganic compounds are excreted in urine in the unchanged form.     

Mercury in Precipitation at an Urbanized Coastal Zone of the Baltic Sea (Poland)

Wet deposition is an important source of metals to the sea. The temporal variability of Hg concentrations in precipitation, and the impact of air masses of different origins over the Polish coastal zone were assessed. Samples of precipitation were collected (August 2008–May 2009) at an urbanized coastal station in Poland. Hg analyses were conducted using CVAFS. These were the first measurements of Hg concentration in precipitation obtained in the Polish coastal zone. Since Poland was identified as the biggest emitter of Hg to the Baltic, these data are very important. In the heating and non-heating season, Hg concentrations in precipitation were similar. Hg wet deposition flux dominated in summer, when the production of biomass in the aquatic system was able to actively adsorb Hg. Input of metal to the sea was attributed to regional and distant sources. Maritime air masses, through transformation of Hg(0), were an essential vector of mercury in precipitation.     

Volatile organohalogen compounds in human urine: the effect of environmental exposure

The paper presents the results of determination of volatile organohalogen compounds (VOX) in urine samples from subjects exposed to these compounds in their workplaces and through consumption of chlorinated tap water. The analytes were isolated and preconcentrated from the complex urine samples using the thin layer headspace (TLHS) technique with autogenous generation of the liquid sorbent. Final gas chromatographic determination was carried out by direct aqueous injection with electron capture detection (DAI-ECD). The results indicate that only a small fraction (<4%) of the VOX input is excreted with urine in the non-metabolized form. A positive correlation was found between the occupational levels of VOX in the workplace and their levels in urine. VOX levels in the urine of subjects not exposed to them in the workplace were significantly lower. Their presence in the organisms was most probably related to consumption of tap water produced by chlorination of surface waters.     

Emissions of ammonia, hydrogen sulfide, and odor before, during, and after slurry removal from a deep-pit swine finisher

It is a common practice in the midwestern United States to raise swine in buildings with under-floor slurry storage systems designed to store manure for up to one year. These so-called "deep-pit" systems are a concentrated source for the emissions of ammonia (NH3), hydrogen sulfide (H2S), and odors. As part of a larger six-state research effort (U.S. Department of Agriculture-Initiative for Future Agriculture and Food Systems Project, "Aerial Pollutant Emissions from Confined Animal Buildings"), realtime NH3 and H2S with incremental odor emission data were collected for two annual slurry removal events. For this study, two 1000-head deep-pit swine finishing facilities in central Iowa were monitored with one-year storage of slurry maintained in a 2.4 m-deep concrete pit (or holding tank) below the animal-occupied zone. Results show that the H2S emission, measured during four independent slurry removal events over two years, increased by an average of 61.9 times relative to the before-removal H2S emission levels. This increase persisted during the agitation process of the slurry that on average occurred over an 8-hr time period. At the conclusion of slurry agitation, the H2S emission decreased by an average of 10.4 times the before-removal emission level. NH3 emission during agitation increased by an average of 4.6 times the before-removal emission level and increased by an average of 1.5 times the before-removal emission level after slurry removal was completed. Odor emission increased by a factor of 3.4 times the before-removal odor emission level and decreased after the slurry-removal event by a factor of 5.6 times the before-removal emission level. The results indicate that maintaining an adequate barn ventilation rate regardless of animal comfort demand is essential to keeping gas levels inside the barn below hazardous levels.     

Temperature modeling in activated sludge systems: a case study.

A model of temperature dynamics was developed as part of a general model of activated-sludge reactors. Transport of heat was described by the one-dimensional, advection-dispersion equation, with a source term based on a theoretical heat balance over the reactor. The model was compared to several reference models, including a tanks-in-series model and the dispersion model with heat components neglecting biochemical-energy inputs and other activated-sludge, heat-balance terms. All the models were tested under steady-state and dynamic conditions at a full-scale facility, the Rock Creek wastewater treatment plant in Hillsboro, Oregon, using meteorological data from a station located 16 km from the plant. The dispersion model and tanks-in-series model matched in situ temperature data with absolute-mean errors less than 0.1 degrees C. Neglecting biochemical-heat-energy inputs in the activated-sludge reactor underestimated temperatures by up to 0.5 degrees C. The biochemical-heat-energy inputs accounted for 30 to 40% of the total heat flux throughout the year.