Chemical composition of fog and rain water was studied during a 47-day experimental period. The differences between the fog and rain water were found to be significantly for most analyzed ions. H⁺, NH₄ ⁺, NO₃ -, and SO₄ ²- made up 85% of the total median ion concentration in fog and 84% in rain water. The total mean equivalent concentration was 15 times higher in the fog than in the rain water. The fog water samples were classified according to their air mass history. The analysis of the 120 h backward trajectory led to the identification of three advection regimes. Significant differences of ion concentrations between the respective classes were found. Air masses of class I travelled exclusively over the Pacific Ocean, class II were carried over the Philippines, and class III were advected from mainland China. The turbulent fog water deposition was determined by the means of the eddy covariance method. The total (turbulent plus gravitational) fog water fluxes ranged between +31.7 mg m-² s-¹ and -56.6 mg m-² s-¹. Fog water droplets with mean diameters between 15 μm and 25 μm contributed most to the liquid water flux. The sample based nutrient input was calculated on the basis of the occult and wet deposition, and the concentrations of the simultaneously collected fog and rainwater samples, respectively. The nutrient input through wet deposition was about 13 times higher than through occult deposition.

Field study at the Cervenohorske sedlo (1,013 m a.s.l.) (Hruby Jesenik Mountains, the Czech Republic, Central Europe) during 1999-2002 has been conducted in order to analyse the chemistry of rain/snow water using bulk and throughfall collector and fog/cloud water using modified passive Grunow collector. Fog water input to coniferous forest (Picea abies) was quantified using canopy balance method. For all samples pH, and the concentrations of [graphic removed] , Ca²⁺, K⁺, Mg²⁺, Na⁺, Cl-, [graphic removed] , and [graphic removed] were measured. The volume-weighted mean pH value varied from 4.92 to 5.43 in open bulk precipitation, from 4.30 to 4.71 in throughfall and from 4.66 to 5.23 in fog water. The fog droplets generally contain higher ion concentrations than rainwater. The related enrichment factors lie between 1.1 and 10.7 for the relevant species. The fog samples exhibit higher concentrations of [graphic removed] and [graphic removed] as compared to the bulk samples during 2000-2002. [graphic removed] are 5.7-10.7 times more concentrated in fog water and [graphic removed] are 3.4-7.2 times more concentrated in fog water. These differences may result from the height and characteristics of formation of the droplets. Based on canopy balance method, the annual fog water inputs were estimated to be 22 and 19% of rain and snow annual amounts in 1999 and 2000, respectively. For [graphic removed] , [graphic removed] , and [graphic removed] , the contribution of fog deposition in total (bulk + fog) deposition is estimated as 54, 47, and 42%, respectively.

Heavy metal pollution in sediments derived from the Deûle canal and sampled at different sites not far from a smelting plant has been examined in the present work in order to identify the sources of these metals and to assess the sediment environmental quality. The total concentrations of lead, zinc, cadmium, thallium, indium and tin in the samples were determined using inductively coupled plasma-atomic emission spectroscopy (ICP-AES). Our investigations have revealed that metal pollution is readily apparent in the studied sediments, with metals contents largely exceeding those measured in the background soils: maximum values are obtained for sediments collected near the industrial zone. The chemical forms of Pb, Zn, Cd, Tl, In and Sn in these sediments have also been studied using a sequential extraction method in order to evaluate their possible mobility, bioavailability and toxicity in this aquatic environment. Overall, the averaged fractionation of Pb and Zn is dominated, in a decreasing order, by the easily reducible, oxidizable and carbonate fractions. The importance of oxidizable phase (which is assumed to be composed mainly of organic matter and sulphides) in the Pb and Zn fractionations has been confirmed by the detection of X-ray diffraction peaks ascribed to galena (PbS) and wurtzite (ZnS) in contaminated sediment samples. Anthropogenic Tl, In, and Cd are mainly retained in Fe–Mn oxides/hydroxides, whereas anthropogenic Sn predominates in aluminosilicates/clays. We suspect that elevated percentage levels of Pb, Zn, Cd and In in the reducible fraction constitute a particular potential risk to this aquatic environment in case early diagenetic phenomena (that are observed in the sedimentary material) and physical disturbances (that occur in the water column) both take place strongly in the medium.

The aim of the present study was the influence of various methods of long-term soil utilisation on the content of polycyclic aromatic hydrocarbons (PAH) in selected silty soils. Four soils were selected for the present studies, i.e.: Eutric Fluvisol originating from silty formations, Haplic Phaeozem developed from loess, Haplic Luvisol (non-uniform) developed from silt, Haplic Luvisol developed from loess. Five study sites were chosen, i.e.: apple orchards, hop gardens, fields, grasslands and natural woodland ecosystems. Samples were collected from the depth of 0-10 cm. In the samples the content of 16 PAHs was determined by means of the HPLC-UV method. The total PAHs content was at a low level. Depending on the soil and object type, the total PAHs content ranged from 72.5 to 764.0 μg·kg-¹. The pollutant level determined together with composition of individual PAHs suggested a limited anthropogenic influence relating mainly to pyrolytic processes. The total PAH content as well as the content of individual PAHs depended on agricultural land use and management. It has been shown that PAH level was influenced by environmental conditions specific for a given type of land use. In the soils in which organic carbon content differed only slightly among locations, a higher influence of the soil utilisation method on the content of individual PAHs was observed.

Rapid field-based screening methods for the semi-quantitative determination of heavy metals are desirable to support the increasing demand for the rapid characterization of contaminated sites. Single-use sensors have been fabricated using low-cost screen-printing (thick film) technology. These electrodes, coupled with differential pulse anodic stripping voltammetry (DPASV), have provided a rapid, inexpensive on site screening device for the simultaneous field-based determination of cadmium (Cd) and lead (Pb) in soil and water samples in the microgram per litre/kilogram range. A simplified soil extraction procedure, using 1 mol l-¹ aqua regia and a 3 min ultrasonic sample agitation, has been developed to allow field-based device usage. Extraction efficiency was evaluated using a soil certified reference material (CRM). Recoveries of 64% and 52% for Cd and Pb respectively were obtained, with a relative standard deviation (RSD) of <8% for both analytes (n = 10). Soil samples (82) were tested using the combined extraction-DPASV procedure and compared against standard ICP-AES analysis. Correlation coefficients of 0.9782 and 0.9728 for Cd and Pb respectively demonstrate good correlation between methods. Analytical data is also reported for copper (Cu), but significant peak distortions reduce the confidence of the method for this metal. Results indicate that the combined extraction-DPASV method yields semi-quantitative data for rapid field-based site screening purposes.

According to recent insight, the toxicity of metals in soils is better related to the free metal ion (FMI) activity in the soil solution than to the total metal concentration in soil. However, the determination of FMI activities in soil solution is a difficult and time-consuming task. An alternative is to use empirical equations (so called transfer functions (TFs)) that relate FMI activity in solution to the reactive metal concentration in the solid phase and to soil properties (pH and organic matter content). Here we test the applicability of two sets of TF for Cd and Pb using independent data from a wide range of soil types and regions that are not represented in the datasets used to derive the TFs. From these soils, soil solution was extracted using four different methods. For all these extracts, FMI activities were calculated from total concentrations in solution using the speciation program WHAM VI. In some of the soils, Cd and Pb FMI activities were also measured using a Donnan membrane technique. Most of these FMI activities deviated from the TF predictions by less than one order of magnitude and were within the 95% confidence interval of the TFs, irrespective of the method used to extract soil solution. Predictability was higher for Pb than for Cd and differed also between the two TF sets.

Stormwater runoff from urban surfaces often contains elevated levels of toxic metals. When discharged directly into water bodies, these pollutants degrade water quality and impact aquatic life and human health. In this study, the composition of impervious surface runoff and associated rainfall was investigated for several storm events at an urban site in Orlando, Florida. Total mercury in runoff consisted of 58% particulate and 42% filtered forms. Concentration comparisons at the start and end of runoff events indicate that about 85% of particulate total mercury and 93% of particulate methylmercury were removed from the surface before runoff ended. Filtered mercury concentrations showed less than 50% reduction of both total and methylmercury from first flush to final flush. Direct comparison between rainfall and runoff at this urban site indicates dry deposition accounted for 22% of total inorganic mercury in runoff.

The sampling and analysis properties of 1-stage and 2-stage filter-pack methods were studied in detail in monitoring of sulphur and nitrogen containing inorganic gases and particles (sulphur dioxide, sulphate, sum of nitric acid and nitrate and total ammonium). The limit of detection and the limit of quantitation for 24-h samples were estimated using the results of a short-term field experiment completed with available data from long-term monitoring and internal quality assurance. Furthermore, the combined expanded measurement uncertainty including sampling and analysis (Uₜₒₜ) was estimated for filter-pack methods in order to give a tool for distinguishing long-term trends in air quality from the measurement variability. Uₜₒₜ was found to be very near the analytical uncertainty when measuring higher air concentration levels, being ± 4.0% for sulphur concentrations > 1.0 μg m⁻³, ± 3.0% for sulphate concentrations > 0.5 μg m⁻³, ± 3.5% for the sum of nitrate and nitric acid concentrations > 0.3 μg m⁻³ and ± 4.5% for total ammonium concentrations > 0.8 μg m⁻³. At the lower air concentration range Uₜₒₜ increases significantly due to the field blank values. The precision of the 24-h filter-pack sample results expressed by means of modified median absolute difference (M.MAD) and coefficient of variance (CoV) gave 8.3% for sulphur dioxide and 5.4% for particulate sulphate. For the sum of gaseous nitric acid and particulate nitrate the CoV was 5.5% and for total ammonium 4.3%. In addition the suitability of the 24-h filter-pack methods in weekly sampling was proved.

Over 70 wood chemical plants operated in northern Pennsylvania between ca. 1890 and 1950, all located within 72 km of the New York state border. Their original purpose was to salvage the small unwanted hardwood trees left behind by the lumber mills, and to make charcoal, calcium acetate and methanol for a number of industrial uses via destructive distillation. At many old wood chemical plant sites, unknown quantities of wood tar remain as a residual contaminant and pose a pollution threat to aquatic life in nearby streams. Research on the composition and properties of residual wood tars from five abandoned industrial sites in Pennsylvania are described. Weathered wood tars were more viscous and contained fewer volatile and semivolatile organic compounds than did soil-buried tars. Phenol, 2-methylphenol (o-cresol), 4-methylphenol (p-cresol), and 2, 4-dimethylphenol were found in all sampled tars. These water-soluble phenolic compounds were released quasi-instantaneously in aqueous solution, followed by a slower rate of release, consistent with the behavior of similar compounds in other dense non-aqueous liquids. Air-exposed wood tar deposits developed a hard crust, which contained fewer volatiles and semivolatiles and had a higher softening point than other samples. These tars eroded to form a powdered soil colonized by lichens and mosses. Residual wood tar material found at one site was shown to be thermally altered, likely during the historical destruction of the chemical plant by fire. Recovered wood tar wastes have a relatively high heating value and may have use as a potential, but limited, alternate energy source.

GOALS, SCOPE AND BACKGROUND: Anaerobic digestion of organic household waste can lead to an increase in dioxin-like content, as determined by dioxin-specific bioassays. This may be a result of bioactivation of Ah receptor (AhR) agonists into more potent congeners. Work towards identifying the contributing compound groups is important in order to understand the mechanisms and to assess the relevance behind this increase in dioxin-like toxicity, since the residue can be used as a soil fertilising agent. The aim with the present work was to identify compound groups with AhR agonistic properties that caused the previously reported increase in dioxin-like activity after anaerobic biodegradation METHODS: Firstly, chemical fractionation combined with dioxin bioassay testing was used to find bioactive classes of compounds. Secondly, batch digestion experiments with an externally added polychlorinated biphenyl (PCB) mixture (Clophen A50) and with decabrominated diphenyl ether (decaBDE), respectively, were studied as a possible process for transformation of precursors into more potent, dioxin-like compounds. Mesophilic (37ºC) and thermophilic (55ºC) anaerobic digestion were studied. Two different dioxin-specific bioassays were used to analyse AhR agonists in the biodegraded material, the CELCAD and the DR-CALUX. RESULTS AND DISCUSSION: AhR agonist activity was detected in both di- and polyaromatic fractions of digestate extracts, which indicated that a diverse mixture of compounds contributed to the bioassay responses. No quantifiable activities were induced by the monoaromatic fractions. Further fractionation based on planarity revealed higher concentrations of AhR agonists than what was detected after the first fractionation, probably due to non-additive biological interactions of compounds in the extract that were removed in the second fractionation. These results showed significant activity in the non-planar diaromatic fractions and in the co-planar fractions of both diaromates and polyaromates. In the batch experiment with externally added PCB, an increase in dioxin-like activity was seen after 21 days of digestion at mesophilic conditions. After completed digestion, the content of AhR agonists was equal to the start concentration. PCB analysis with GC-MS indicated that dehalogenation of PCBs occurred in the digestors. The batch experiment with decaBDE showed no significant changes in TEQ-concentrations over time. CONCLUSIONS: The results show that the previously reported increase of AhR agonists during mesophilic anaerobic digestion is probably due to an accumulation of several different groups of AhR agonists, both diaromatic and polyaromatic, and both co-planar and non-planar. Batch experiments with externally added PCBs and decaBDE, respectively, did not result in any accumulation of AhR agonist activity after completed digestion, even though chemical analysis indicate a dechlorination of PCBs. Complex, unfractionated extracts were difficult to test using the bioassay approach. Removal of AhR antagonists or otherwise interacting compounds during fractionation may yield bio-TEQ values that are much higher than in the original extract. RECOMMENDATIONS AND PERSPECTIVE: Our results indicate that the environmental risk that AhR agonists may pose concerning large-scale anaerobic digestion of organic household waste probably depends on the efficiency of the digester and the sludge residence time. In order to obtain reliable results with the bioassays, an extensive cleanup and fractionation procedure is necessary. Without clean up and fractionation, there is a risk for false negatives and misleading conclusions. DR-CALUX and CELCAD were both suitable for these kinds of studies, provided that suitable fractionation methods are used.