The representativeness of soil pore water extracted by suction lysimeters in ground-water monitoring studies is a problem that often confounds interpretation of measured data. Current soil water sampling techniques cannot delineate from which soil volume a pore water sample is extracted, neither macroscopic, microscopic, or preferential flowpath. This research was undertaken to compare δ¹⁸O and Br- values of extracted suction lysimeters samples from intact soil cores with samples obtained by the direct extraction methods of centrifugation and azeotropic distillation. Also, the study was concerned with determining what portion of soil pore water is sampled by each method and explaining differences in concentrations of the extracted water from each method to allow a determination of the accuracy and viability of the three methods of extraction. Intact soil cores (30 cm diameter by 40 cm height) were extracted from two different sites. Site 1 was rapid infiltration basin number 50, near Altamonte Springs in Seminole County, Florida. Site 2 was the Missouri Management System Evaluation Area (MSEA) near Centralia in Boone County, Missouri. Isotopically (¹⁸Oδ) labeled water and bromide concentrations within water samples taken by suction lysimeters was compared with samples obtained by methods of centrifugation and azeotropic distillation. The ¹⁸Oδ water was analyzed by mass spectrometry while bromide concentration, applied in the form of KBr was measured using standard IC procedures. Water collected by centrifugation and azeotropic distillation data were about 0.25[per thousand] more negative than that collected by suction lysimeter values from a sandy soil and about 2-7[per thousand] more negative from a well structured soil. Results indicate that the majority of soil water in well-structured soil is strongly bound to soil grain surfaces and is not easily sampled by suction lysimeters. In cases where a sufficient volume of water has passed through the soil profile and displaced previous pore water, suction lysimeters will collect a representative sample of soil pore water from the sampled depth interval. It is suggested that for stable isotope studies monitoring precipitation and soil water, suction lysimeter be installed at shallow depths (10 cm). Samples should also be coordinated with precipitation events. The data also suggest that each extraction method samples a separate component of soil-pore water. Centrifugation can be used with success, particularly for efficient sampling of large areas. Azeotropic distillation is more appropriate when strict qualitative and quantitative data on sorption desorption, and various types of kinetic studies may be needed.

Aerosol samples were collected during the wintertime from Nov. 24, 1998 to Feb. 12, 1999 in Beijing, China. Chemical composition was determined using several analytical techniques, including inductive coupled plasma atomic emission spectroscopy (ICP-AES), graphite furnace atomic absorption spectroscopy (GFAAS) and flame atomic absorption spectroscopy (FAAS) for trace elements, ion chromatography (IC) for water-soluble ions and CHN elemental analyzer for organic carbon (OC) and elemental carbon (EC). The average concentration of aerosol was 375 ± 169 μg m⁻³, ranging from 136 to 759 μg m⁻³. Multilinear regression (MLR) analysis was performed and crustal matter, secondary particles and organics were identified as three major components of aerosol in wintertime in Beijing, accounting for 57.3% ± 9.8%, 13.4% ± 8.0%, and 22.8% ± 5.9% of the total concentration, respectively. Based on performance evaluation, Al, SO₄ ²⁻ and OC were selected as tracers of the three components, with the regression coefficients of 23.5, 1.78 and 1.26, respectively. A regression constant of 19.6 was obtained, which accounts for other minor components in aerosol. On average 93.5% of the total aerosol concentration, ranging from 82% to 105%, was explained by crustal matter, secondary particle and organics. Meteorological conditions are important factors that can influence the concentration level and chemical composition of aerosols. Wind would be favorable for the pollutant dilution, leading to low aerosol levels, whereas too strong a wind may cause regional soil dust and local road dust to be resuspended resulting in a high contribution of crustal matter. Circuitous air movement, high RH% and low wind speed facilitated the secondary particle formation, not only inorganic salts, such as sulfate and nitrate, but also secondary organic carbon in a similar way.

The research concerns the Wielkopolski National Park (West Poland), which suffered a huge human impact in the 1970s and 1980s owing to the nearby location of an industrial plant. Since then, fundamental technological changes that it introduced into its production of phosphate fertilizers have radically reduced the amount of pollution emitted. A three-year study (2002-2004) of fluorides in precipitation in open terrain and under tree crowns showed their concentrations to range from levels below the detection limit (0.003 mg/l) to 0.560 mg/l. Those registered under tree crowns were several times higher and indicated substantial dry deposition of fluorides on the trees. The highest values were recorded in 2003, with 43% of samples ranging from 0.01 to 0.05 mg/l, and with 51% of throughfall ranging from 0.10 to 0.50 mg/l. A strong connection was shown to exist between fluoride and sulphate concentrations in the precipitation. An analysis was made of the available data on F concentrations in the air and the dust levels around the factory, but these figures did not show an unequivocal effect on F concentrations in precipitation. A great similarity was found to occur between the fluoride content in rainwater in the Wielkopolski National Park and in the centre of the nearby Poznań metropolitan area, which indicates that there are also other F sources besides the local factory.

High mortality rates due to predation from fish may reduce densities of preferred prey animals. Predation may also depress the rate of recovery from environmental stress. In an alpine ecosystem damaged by acidification, we compared three different techniques of monitoring the recovery of two large species of crustaceans, the amphipod Gammarus lacustris and the notostrachan Lepidurus arcticus. The methods used were: (1): benthic littoral kick samples, (2): artificial substrate in the form of jute bags, (3): examination of brown trout stomachs. The monitoring took place in two limed lakes at the Hardangervidda mountain plateau in Central Norway, L. Svartavatn and L. Svartavasstjørni. Brown trout, Salmo trutta, is the only fish species in the lakes. Liming as a water quality improvement measure was started in 1994. All stomach samples were negative with respect to Gammarus and Lepidurus during the period 1987-1998. In 1999, the first records of both species were done in trout stomachs collected from Lake Svartavatnet. In Lake Svartavasstjørni, Lepidurus and Gammarus reappeared in fish stomachs in 2001 and 2002, respectively. During the period of monitoring, no records of these crustaceans were done in benthic samples and on artificial substrate in any of the two lakes. In an unacidified reference site, Lake Skiftesjøen, both benthic samples and the jute bags indicated a dense population of Gammarus. Our results strongly indicate that studies of fish stomachs are the best method for monitoring low-density populations of attractive fish food animals.

The long-term monitoring of precipitation and its chemical composition are important for identifying trends in rain quality and for assessing the effectiveness of pollution control strategies. A statistical test has been used to the atmospheric concentrations measured in the French rural monitoring network (MERA) in order to bring out spatio-temporal trends in precipitation quality in France over the period 1990-2003. The non-parametric Mann-Kendall test which has been developed for detecting and estimating monotonic trends in the time series was used and applied in our study at annual values of wet-only precipitation concentrations. The emission data suggest that SO₂ and NO x emissions decreased (-3.3 and -2.0% year-¹, respectively) contrary to NH₃ emissions that increased slightly (+0.2% year-¹) over the period 1990-2002 in France. On the national scale, the pH values have a significant decreasing trend of -0.025 ± 0.02 unit pH year-¹. [graphic removed] and [graphic removed] concentrations in precipitation have a significant decreasing trend, -3.0 ± 1.6 and -3.3 ± 0.6% year-¹, respectively, corresponding with the downward trends in SO₂ emissions in France (-3.3% year-¹). A good correlation (R ² = 0.84) between SO₂ emissions and [graphic removed] concentrations was obtained. The decreasing trend of [graphic removed] was more significant (-5.4 ± 5.2% year-¹) than that of [graphic removed] (-1.3 ± 2.4% year-¹). Globally, the concentration of the major ions showed a clear downward trend including marine and alkaline ions. In addition, the relative contribution of HNO₃ to acidity precipitation increased by 51% over the studied period.

Vegetation both physically and biochemically influences denitrification in wetlands. Litter from various plant species supplies various amounts and qualities of organic carbon to denitrifying bacteria, and may thus affect denitrification capacity. We explore whether there is seasonal variation in the denitrification potential in stands of Glyceria maxima, Phragmites australis, Typha latifolia, and Potamogeton pectinatus (the stands differed in terms of which species was predominant). Experiments and measurements investigated whether denitrification potential was related to organic matter and its availability to denitrifying bacteria, suitability for bacterial growth, and amount in the wetland. Availability of organic material, as measured in the slurries, was highest in the G. maxima and P. pectinatus samples, with the highest availability in May and August. However, when the samples were closer to wetland conditions, i.e., intact sediment cores containing litter and organic sediment, the denitrifying capacity was highest in the cores from G. maxima stands, but lowest in P. pectinatus cores. In addition, the denitrification potential of the intact cores was highest in November. Differences in denitrification capacity between the slurries and intact sediment cores, considering the organic material of the plant species and the seasonal pattern, were attributed to differences in the amount of plant litter generated.

In order to gain insight into the community structure and the biodegradative potential of bacteria residing in a BTEX-contaminated field site, with benzene as main pollutant, an investigation strategy with a variety of cultivation-independent and -dependent approaches was undertaken. Based on 16S ribosomal DNA sequence analysis, sampling stations in the center of the pollution plume were found to be dominated by a bacterial consortium affiliated with various members of the class of Proteobacteria and Firmicutes, including different sporulating and non-sporulating sulfate-reducing bacteria and members of the genus Geobacter. Non-polluted samples retrieved from outside the plume revealed several phylotypes which were also observed in the centre of the plume. Bacterial sequences retrieved from the fringe of the plume were dominated by several genera of beta Proteobacteria subclass which were not associated with other phylotypes obtained in this study. All sampling stations were tested positive for catechol 2,3-dioxygenase genes, indicating the presence of microorganisms with the genetic potential degrading aromatic compounds via the meta-cleavage pathway. The groundwater system at the down-gradient edge of the plume was characterized, in contrast to all other sampling stations in the center and outside the plume, by high numbers of cultivable bacteria and cultivable aerobic benzene and toluene degraders. These findings are also in accordance with the investigations based on fluorescent in situ hybridization (FISH) with rRNA-targeted oligonucleotide probes, suggesting the presence of an actively benzene degrading bacterial community of beta Proteobacteria at the fringe of the pollution plume.

The main factors determining the geochemical fate of copper in urban freshwaters affected by raw sewage discharges were investigated in this work. Water samples from the Iraí and Iguaçu rivers were collected monthly during a 1-year period at two points located upstream and downstream from the city of Curitiba, in Brazil. Results revealed that raw sewage discharges from the heavily urbanized area caused an enhancement of humic-coated suspended solids in the Iguaçu River. In these waters copper is predominantly associated with the humic-coated particles whereas in the Iraí River copper was found primarily in the aqueous phase. The transfer of copper from the aqueous to the solid phase changed its physical speciation along the watercourse. Thus, aspects related to the overall transport of trace metals in watercourses become an important issue to be considered in further studies concerning the effect of sewage discharges on the geochemical speciation and fate of trace metals in urban rivers.

A complete record derived from the core from the Daihai Lake in a remote area provides new insights into the changing atmospheric heavy metal deposition associated with historical industrial activities, the Asian monsoon, long-range transport, and the chemical composition of matter derived from weathering of catchment. The fluctuation of lithogenic element concentration in the lake sediments can readily be explained by a particle sorting effect induced by the Asian monsoon. The variation of atmospheric deposition of Cu and Pb shows a similar profile in the lower part of the core sediments, and coincides with environmental change, with high atmospheric deposition coupled with wet, temperate period; while low deposition with dry, cold period, indicating a transport variation of heavy metal pollutants entrained by the Asian summer monsoon. From the beginning of nineteenth century, the atmospheric deposition of Cu and Pb decreased and then slowly increased. This may be associated with the destroyed industry induced by long-term wars in China and the less heavy metal pollutants relative to the weak Asian summer monsoon in this period. Comparison between atmospheric-derived metal and sediment trap metal using Ga as the reference element shows that atmospheric Cu and Pb budgets do not exceed the fluvially-induced Cu and Pb budgets in the indirectly disturbed area. On average, there have been approximately 5.4 mg m-² yr-¹ of Cu and 5.1 mg m-² yr-¹ of Pb atmospherically deposited in the region.

The removal of 4-chlorophenol from aqueous solutions by both a Mexican clinoptilolite-heulandite zeolitic rock and the modified zeolitic material with the surfactant hexadecyltrimethylammonium bromide (HDTMABr), using batch and packed-bed (column) configurations, was investigated. The unmodified zeolitic rock did not show any adsorption of 4-chlorophenol. The effects of pH, contact time and concentration of 4-chlorophenol on the adsorption process by the surfactant modified material were examined. The sorption of 4-chlorophenol was not affected by the pH range from 4 to 9.5. 4-chlorophenol retention reached equilibrium in about 18 h and the rate of 4-chorophenol adsorption by the modified material was faster in the first 10 h than later. The experimental data were treated with the models: pseudo-first order, pseudo-second order, fractional power and Elovich models. Although, the last three gave correlation coefficients higher than 0.96, the pseudo-second order model was the best to describe the reaction rate. The experimental data follow a linear isotherm which is characteristic for sorption of organic solutes by the partition mechanism. The Bed Depth-Service Time Model was applied to the sorption results in order to model the column operation. The results showed that the surfactant modified zeolitic rock could be considered as a potential adsorbent for 4-chlorophenol removal from aqueous solutions.