Multi-scale spatial determinants of dissolved oxygen and nutrients in Qiantang River, China

This study employed spatial regression to analyze the determinants of dissolved oxygen (DO) and nutrients in the Qiantang River, China. Determinants of their spatial patterns in 1996 and 2003 as well as their dynamics during this time period were characterized at sub-basin and 500-m riparian buffer scales. Results indicated that the determinants differed by variable and by scale. Built-ups, farmland, water body, population density and gross domestic product were positive indicators for nutrient pollution and hypoxia, while distance to river source and forest were negative indicators. Higher slope variability indicates more DO and nutrients. In addition, built-up increases that were accelerated by population growth and economic development accounted for DO and nutrients dynamics to a large extent. This study highlighted that incorporation of spatial autocorrelation into regression was not only a methodological advantage but also a promising management tool.     

Investigation of dissolved uranium content in the watershed of Seine River (France)

A systematic survey of dissolved uranium activity was carried out in the Seine and the Marne over one year. A small watershed, the Grand Morin, included in the Seine one, was also investigated from stream to medium-sized rivers. The Melarchez stream exhibits low but variable dissolved 238U levels (3.3 +/- 2.0 mBq l(-1)). Thereafter, uranium activities show a rapid increase to reach, from the Grand Morin River, a rather constant range (8-11 mBq l(-1)). On the Marne before the confluence with the Seine, dissolved 238U is nearly invariable (9.1 +/- 0.8 mBq l(-1)), for flow rates comprised between 60 and 423 m3 s(-1). Dissolved 238U in the Seine corresponds to almost triple the global mean riverine uranium concentration. In the estuary of the Seine, uranium shows a gradual increase, resulting from conservative mixing of river with sea waters.     

Spatio-temporal variation of dissolved inorganic nutrients related to hydrodynamics and land use in the mangrove-fringed Segara Anakan Lagoon, Java, Indonesia

Segara Anakan is a mangrove-fringed lagoon in Java, Indonesia, which is affected by human activities in the lagoon and its hinterland. Nutrient and sediment input from the Citanduy River which drains an agriculture-dominated hinterland is thought to be an important factor for ecosystem degradation. From dry and rainy season investigations of dissolved inorganic nutrients between May 2004 and August 2006 we infer that the nutrient inventory of Segara Anakan is controlled by a complex mixture of anthropogenic and natural sources and processes. Maximum inputs into the western lagoon were supplied by the Citanduy during the rainy season while tidal exchange with the Indian Ocean dominated in the eastern lagoon with little freshwater input. During the dry season recycling in mangroves appeared to be an additional source of nutrients to the lagoon. Despite an extremely high population density and intensive agriculture in the hinterland nutrient pollution and eutrophication in the lagoon were low to moderate on a global scale. It is probably due to the short residence time of water in the shallow lagoon which indicates that major part of the land-derived nutrient input is rapidly exported to the sea. Although Segara Anakan is a highly perturbed system for decades, it appears that still natural processes exert major control on the nutrient inventory of the lagoon.     

The relationship of dissolved Pb to some dissolved trace metals (Al, Cr, Mn, and Zn) and to dissolved nitrate and phosphate in a freshwater aquatic system in Mauritius

The relationship of some dissolved trace metals (Al, Cr, Mn, Zn, and Pb) with one another and to dissolved phosphate and nitrate in a freshwater aquatic system at Flic en Flac and Grand River North West (GRNW) in Mauritius (1850 km2, 20 degrees S and 57 degrees E, Western Indian ocean) is reported following trace metal determination using inductively coupled plasma mass spectrometry (ICP-MS). Dissolved Al (<200 ng ml(-1)), Cr (<50 ng ml(-1)), Mn (<50 ng ml(-1)), Zn (< 100 ng ml(-1)), and Pb (<50 ng ml(-1)) upstream, downstream GRNW and in the marshes and rivulet at Flic en Flac were found to be below the recommended EEC maximum admissible concentrations and within the ambient drinking water quality standards in Mauritius. Dissolved Pb was significantly positively correlated to both dissolved Cr and Zn suggesting that the cycling for dissolved Pb is linked to the cycling of both dissolved Cr and Zn along GRNW. The common influential cycling of Pb and Zn was further reinforced as both dissolved Pb and Zn were significantly positively correlated to dissolved phosphate, which suggested a biological role in the cycling of Zn and Pb. The role of biological activity or adsorption to biological systems in Pb cycling along GRNW is further suggested as dissolved Pb was significantly correlated to dissolved nitrate. The apparent absence of the dissolved Al, Cr, and Mn with dissolved nitrate and phosphate could be attributed to factors such as the lower sensitivity of the GRNW to metal uptake during biological activity during the time frame considered. The cycling of dissolved Al and Mn was also not linked to the cycling of Cr, Zn, and Pb as no significant correlation was found along GRNW.     

Sediment deposition rate in the Falefa River basin, Upolu Island, Samoa

The (137)Cs method was employed to investigate the recent historical rate of sediment deposition on a lowland alluvial floodplain in the Falefa River basin, Upolu Island, Samoa. Caesium stratigraphy in the floodplain sediment profile was clearly defined, with a broad peak at 145-175 cm depth. The measured rate of vertical accretion over the last 40 years is 4.0+/-0.4 cm per year. This rate exceeds observations in humid environments elsewhere, but is similar to that recorded on other tropical Pacific Islands. Available flow data for the Vaisigano River in Samoa give a 'near-catastrophic' index value of 0.6 for flood variability. This is associated with the occurrence of tropical cyclones and storms in the Samoa area. Large floods therefore probably contribute to the high rate of floodplain sedimentation on Upolu Island. A small but growing body of evidence suggests that fluvial sedimentation rates on tropical Pacific islands are some of the highest in the world.     

Rare earth elements in the Rhine River, Germany: first case of anthropogenic lanthanum as a dissolved microcontaminant in the hydrosphere

The distribution of dissolved rare earth elements (REE) in the Rhine River, Germany, shows the anthropogenic gadolinium (Gd) microcontamination that is commonly observed in rivers in densely populated countries with a highly evolved health care system. However, the Rhine River also carries anomalously high concentrations of lanthanum (La), which produce very large positive La anomalies in normalized REE distribution patterns. These positive La anomalies first occur north of the City of Worms and then decrease in size downstream, but are still significant approximately 400 km downstream, close to the German-Dutch border. The strong La enrichment is of anthropogenic origin and can be traced back to effluent from a production plant for fluid catalytic cracking catalysts at Rhine river-km 447.4. This effluent is characterized by extremely high dissolved total REE and La concentrations of up to 52 mg/kg and 49 mg/kg, respectively. Such La concentrations are well-above those at which ecotoxicological effects have been observed. The Rhine River is the first case observed to date, where a river's dissolved REE inventory is affected and even dominated by anthropogenic La. Our results suggest that almost 1.5t of anthropogenic dissolved La is exported via the Rhine River into the North Sea per year. This reveals that the growing industrial use of REE (and other formerly "exotic" elements) results in their increasing release into the environment, and highlights the urgent need to determine their geogenic background concentrations in terrestrial surface waters.     

Radioactivity and elemental analysis in the Ruseifa municipal landfill, Jordan

In this study, a low background gamma-ray spectrometer based on a Hyper Pure Germanium detector was used to determine the activity concentrations of natural radionuclides in soil samples from various locations within the Ruseifa municipal landfill in Jordan. The chemical composition of the samples was also determined using a Wavelength Dispersive X-Ray Fluorescence Spectrometer. The maximum and minimum annual outdoor effective doses were found to be 103 and 36muSva(-1) in the old landfill and Abu-Sayaah village, respectively. The annual outdoor effective dose at the recent landfill site was found to be 91muSva(-1). The annual effective dose equivalents from outdoor terrestrial gamma radiation at the old landfill and the recent landfill were higher than the typical worldwide value of 70muSva(-1). Thus, some remediation of the soils on both old and recent landfills should be considered before any development for public activities. This could be achieved by mixing with clean soil from areas which are known to have lower radiation background. The concentration of heavy metals Zn, Cr, and Ba in the three sites included in this study were found to be higher than the background levels in the soil samples of the control area (Abu-Sayaah village). The enrichment factors for the above three elements were calculated and found to be: complex building site: Zn=2.52 and Ba=1.33; old landfill site: Cr=1.88, Zn=3.64, and Ba=1.26; and recent landfill site: Cr=1.57, Zn=2.19, and Ba=1.28. There was a strong negative correlation between the concentrations of the metallic elements (Mg, Al, Mn, Fe and Rb) and the concentrations of Zn, Ba, and Cr. Moreover, a strong positive correlation was found between Zn, Ba, and Cr. Thus these elements were enriched in the solid waste.     

Changes in the upper limits of tree species distribution in the Western Caucasus (Belaya River basin) related to recent climate warming

To estimate the response of tree vegetation to recent climate warming in the Western Caucasus, the population state of several tree species at the upper limit of their distribution has been estimated in three mountain massifs in the Belaya River basin. For this purpose, the average and maximum stem diameters, vitality, and age of trees have been determined in the transitional zone between middle-mountain and high-mountain beech-fir forests (1400–1700 m a.s.l.) and in crooked birch forests growing at the upper timberline (1810–2025 m). The upper limits of Acer platanoides, A. pseudoplatanus, Ulmus glabra, and Betula litwinowii have shown a tendency to rise. The upper limit of Abies nordmanniana has remained unchanged over the past few decades, which may be explained by a decrease in moisture supply during the warm season.     

Modelling radioactivity in the Irish Sea: From discharge to dose

In order to support authorised discharges of low level radioactive liquid effluent into coastal regions, mathematical models are required to robustly predict radiological impacts on critical groups of current and proposed changes to liquid discharges. The grid model presented here simulates the long term dispersion and transport of radioactivity discharged from the Sellafield site in Cumbria, UK, and the subsequent exposure of critical groups in Cumbria and across the Irish Sea in Northern Ireland. The fine grid of the model allows a good resolution of the seabed sediment distribution. This benefits the predictions for the last decades of low discharge level, when bed sediment can become a source of contamination by bringing back the legacy of past high discharges. This is highlighted by the dose comparison, where the predicted dose to Cumbria critical group follows well the dose estimated from environmental data during the low discharge level period.     

Pollutant loads from the drainage basin to the Venice Lagoon (Italy)

In order to assess the actual pollutant loads from the drainage basin, the twelve major tributaries of the Venice Lagoon were monitored and studied in the period 1998-2000 in the framework of the DRAIN project. A specific sampling scheme was designed to investigate the effects of the different regimes, including floods, in the transport of total and dissolved metals, nitrogen and phosphorous species as well as organic micropollutants. The loads were calculated from data collected during the year of 1999, since this year displayed a value close to the mean in terms of the distribution of total rainfall on the drainage basin. The annual values for the different pollutants are reported and discussed. A comparison with the estimates of previous investigations highlights the significant advancement provided by the DRAIN project results in the understanding of the drainage basin contribution to the pollution of the lagoon. Finally, the importance of flood events on the overall balance of materials and pollutants delivered to the lagoon is emphasized.     

Particle size distribution and its elemental composition in the ambient air of Delhi

This study examines the chemical composition of PM10, the thoracic fraction of the atmospheric particulate matter. An eight-stage Anderson impactor is used to separate the PM10 from other fractions with different aerodynamic behaviour at three different area representative sites in Delhi from February to May 1998. PM10 particulate are subdivided into two fractions, coarse (> 2.1-10 microns) and fine (< 2.1 microns). The concentrations of major heavy metals such as Pb, Zn, Cd, Ni, and Fe are determined by atomic absorption spectrophotometer. The average concentration of coarse fraction of PM10 is found to be 68.3 +/- 17 micrograms/m3 while the fine fraction of PM10 is 71.3 +/- 15 micrograms/m3 for Delhi. Metal concentration (except Fe) in fine fraction exceeds by a factor of up to 6, as compared to that in the coarse fraction. In order to identify the major sources of fine and coarse fraction of PM10, principle component analysis (PCA) was undertaken and three major sources were identified, namely vehicular emissions, industrial emission, and soil resuspension.     

Spatially differentiated management-revised discharge scenarios for an integrated analysis of multi-realisation climate and land use scenarios for the Elbe River basin

A spatially differentiated, management-revised projection of natural water availability up to 2053 was requested for a basin-wide scenario study about the impact of global change in the Elbe River basin. Detailed discharge and weather information of the recent years 1951–2003 were available for model calibration and validation. However, the straightforward “classic” approach of calibrating a hydrological model on observed data and running it with a climate scenario could not be taken, because most observed river runoffs in Central Europe are modified by human management. This paper reports how the problem was addressed and how a major projection bias could be avoided. The eco-hydrological model SWIM was set up to simulate the discharge dynamics on a daily time step. The simulation area of 134,890?km2 was divided into 2,278 sub-basins that were subdivided into more than 47,500 homogeneous landscape units (hydrotopes). For each hydrotope, plant growth and water fluxes were simulated while river routing calculation was based on the sub-basin structure. The groundwater module of SWIM had to be extended for accurate modelling of low flow periods. After basin-scale model calibration and revisions for known effects of lignite mining and water management, evapotranspiration and groundwater dynamics were adjusted individually for more than 100 sub-areas largely covering the entire area. A quasi-natural hydrograph was finally derived for each sub-area taking into account management data for the years 2002 (extremely wet) and 2003 (extremely dry). The validated model was used to access the effect of two climate change scenarios consisting of 100 realisations each and resembling temperature increases of 2 and 3?K, respectively. Additionally, four different land use scenarios were considered. In all scenario projections, discharge decreases strongly: The observed average discharge rate in the reference period 1961–1990 is 171?mm/a, and the scenario projections for the middle of the twenty-first century give 91–110?mm/a, mainly depending on the climate scenario. The area-averaged evapotranspiration increases only marginally within the scenario period, e.g., from about 570 to about 580?mm/a for the temperature increase of 2?K, while potential evapotranspiration increases considerably from about 780 to more than 900?mm/a. Both discharge and evapotranspiration changes vary strongly within the basin, correlating with elevation. The runoff coefficient that globally decreases from 0.244 to 0.160 in the 2?K scenario is locally governed primarily by land use; 68% of the variance of the decreases can be attributed to this factor.     

Sediment accumulation rate and radiological characterisation of the sediment of Palmones River estuary (southern of Spain)

Chemical analyses and radioecological methods were combined in order to estimate the sediment accumulation rate in the upper 20 cm depth of the Palmones River estuary. Organic matter, total carbon, C:N and (137)Cs vertical profiles showed changes at 13 cm depth. These changes could be associated with the decrease in river input since 1987 when a dam situated in the upper part of the estuary started to store water. Using 1987 as reference to date the sediment, accumulation rate was 1.2 cm yr(-1). As alternative method, two layer model of (210)Pb(xs) vertical distribution showed a sedimentation rate of 0.7 cm yr(-1) with a surface mixing layer of 7 cm thickness. The high ammonium, potassium and sodium content in pore water and the strong correlation between (137)Cs activities and organic matter in dry sediment suggests that (137)Cs (the only anthropogenic product detected) is mainly accumulated in the estuary associated with the particulate organic material from the catchment area.     

Particulate matter in the Cairo atmosphere. 1. Dustfall and its chemical constituents

Dustfall, sampled in different parts of Cairo, has been analysed for selected constituents in soluble and insoluble fractions. We show that the rate of total particulate deposition over Cairo increased from 27 g/m² · 30 days during 1962 to 57 g/m² · 30 days in 1983; the highest rates of deposition were recorded during winter and spring months, while the maximum concentrations of soluble compounds were found during the summer season. The high concentrations of ammonium and sulphates detected in dustfall over Cairo during summer indicates that atmospheric chemical reactions play an important role in this increase of soluble compounds concentration. The rate of deposition in different districts and the chemical composition indicate that particulate matter in Cairo atmosphere is influenced by urban activities and winds loaded with dust from the industrial areas north and south of the city. Furthermore, i.r. spectroscopic analysis show absorption bands at about 2950, 2920, 2820, 2720, 1720, 1465, 1385, 1300 and 1100 cm⁻¹ which are characteristic bands for aliphatic hydrocarbons, aldehydes, and ketones. The presence of these compounds and the high concentration of tarry matter confirm the role of combustion processes in polluting the atmosphere of Cairo.     

Mass balance approach to estimating radionuclide loads and concentrations in edible fish tissues using stable analogues

Humans can consume a number of types of biota tissues, which have varying propensities to accumulate radionuclides. As a result, depending upon the biota species, the radionuclide and the tissue under consideration, it may be necessary to estimate the percent radionuclide load in specific edible tissues, and in cases where whole organisms are consumed, to estimate the radionuclide load in the whole body of an organism, based on data that have been collected for individual tissues. To accomplish this, data were compiled that can be used to estimate the partitioning patterns and percent loads of various groups of elements in edible tissues of freshwater fishes. General trends in partitioning, such as those provided in this paper, can be used to predict radionuclide transfer to humans and the corresponding potential radiological dose to humans via dietary pathways, in this case following the consumption of fish.     

Freshwater discharge from the drainage basin to the Venice Lagoon (Italy)

The twelve major tributaries of the Venice Lagoon (accounting for the 97% of the inputs from the drainage basin) were monitored in the framework of the DRAIN project (1998-2000) in order to obtain a detailed knowledge on the hydrological regimes and to measure the mean annual freshwater discharge from surface runoff. The study represents an essential step in the estimate of the pollutant load delivered to the lagoon that must necessarily be based on a solid understanding of the fluxes of material out of the drainage basin. Due to the influence of the tide in the majority of the gauging sections, a specific methodology for the measurement of the discharge was developed. The main results of the study are described, underlining the differences in the regime of the investigated streams. A rainfall-runoff analysis evidenced the different characteristics of the monitored tributaries, in terms of specific hydrological features, morphology of the individual sub-basins, management of the water resource and spatial distribution of rainfall. An estimate of the maximum peak discharge from the drainage basin is finally obtained from data of an extreme flood event occurred in November 1999.     

Particulate matter and black smoke concentration levels in central Athens, Greece

This study presents the statistical analysis of PM(10) and PM(2.5) concentrations (measured at a central site, in the Athens area), along with black smoke (BS) data, for a 2-year period. The biennial average concentrations of PM(10) and PM(2.5) were 75 and 40 microg m(-3). The respective average concentration of BS, as estimated by the OECD method, was 108 microg m(-3). Severe exceedances of the PM(10) air quality standards were recorded. The seasonal variation of PM(10) and BS was less pronounced than the variation of PM(2.5), which concentration was elevated by 14.2% during the cold period. Concentrations of all three pollutants were significantly lower during weekends; however, PM(2.5) and BS displayed a more uniform weekly distribution pattern. PM(10) particles were found to be almost equally comprised by PM(2.5) and PM(10-2.5) particles (PM(2.5)/PM(10) ratio=0.53+/-0.09 microg/m(3)). The average PM(10)/BS value was found lower than unity revealing the inappropriateness of the used reflectance conversion method, for the estimation of mass-equivalent BS concentrations, in the study area, where diesel-powered vehicles mainly control emissions of light-absorbing substances. Important reductions in concentrations were observed during days when drivers of diesel-powered taxies and transportation buses went on strike (reaching 40% for BS). Calm wind conditions were found to have an incremental effect on particle concentrations and were also associated with the appearance of persistent episodic events. Increased PM levels were also observed during southern-southwestern wind flows while significantly lower-than-average concentrations were measured during precipitation events. Separate regression analyses were performed for PM(10), PM(2.5) with BS and NO(x) as independent variables, in an attempt to estimate the relative contribution of specific source types (diesel-powered vehicles) to measured particle levels. The contribution of the diesel-exhaust component to PM(10) mass was estimated at 49.9%, while the corresponding contributions to PM(2.5) mass concentrations was 53.8%. These results may have important implications with the oncoming decision of national authorities to allow the purchase of diesel-powered private cars to the residents of the Greater Athens Area, which was forbidden up to this day.     

Determination of thorium, uranium and potassium elemental concentrations in surface soils in Cyprus

A comprehensive study was conducted to determine thorium, uranium and potassium elemental concentrations in surface soils throughout the accessible area of Cyprus using high-resolution gamma-ray spectrometry. A total of 115 soil samples was collected from all over the bedrock surface of the island based on the different lithological units of the study area. The soil samples were air-dried, sieved through a fine mesh, sealed in 1000-ml plastic Marinelli beakers, and measured in the laboratory in terms of their gamma radioactivity for a counting time of 18 h each. From the measured gamma-ray spectra, elemental concentrations were determined for thorium (range from 2.5 x 10(-3) to 9.8 microg g(-1)), uranium (from 8.1 x 10(-4) to 3.2 microg g(-1)) and potassium (from 1.3 x 10(-4) to 1.9%). The arithmetic mean values (A.M. +/- S.D.) calculated from all samples are: (1.2+/-1.7 microg g(-1)), (0.6+/-0.7) microg g(-1), and (0.4+/-0.3%), for thorium, uranium and potassium, respectively, which are by a factor of three-six lower than the world average values of 7.4 microg g(-1) (Th), 2.8 microg g(-1) (U) and 1.3% (K) derived from all data available worldwide. The best-fitting relation between the concentrations of Th and K versus U and also of K versus Th, is essentially of linear type with a correlation coefficient of 0.93, 0.84 and 0.90, respectively. The Th/U, K/U and K/Th ratios (slopes) extracted are equal to 2.0, 2.8 x 10(3) and 1.4 x 10(3), respectively.     

Changes in the sex structure of pine populations related to temperature anomalies

The results of ten-year observations on fluctuations in the sex of individual trees and the sex structure of tree stands in two insular pine forests in the south of Central Siberia are presented. It is noted that the ratio of sex types of pine trees has markedly changed since 1998–1999. Significant correlations between the sex structure of stands and anomalies of the annual average air temperature have been recorded since the early 1990s. The male generative sphere of pine has changed to the greatest extent. Periodicity and delay in the change of shoot sexualization in response to changes in temperature are discussed.     

Estimation of critical loads for radiocaesium in Fennoscandia and Northwest Russia

The application of the critical loads methodology for radioactive contamination of Arctic and sub-arctic ecosystems, where natural and semi-natural food products are important components of the diet of many people, is proposed and discussed. The critical load is herein defined as the amount of radionuclide deposition necessary to produce radionuclide activity concentrations in food products exceeding intervention limits. The high transfer of radiocaesium to reindeer meat gives this product the lowest critical load, even though the intervention limit is relatively high compared with other products. Ecological half-lives of radiocaesium in natural and semi-natural products are often very long, and it is therefore important to take account of contamination already present in the event of an accident affecting areas where such products are important. In particular, the long ecological half-life for radiocaesium in moose meat means that the critical load is highly sensitive to prior deposition. An example of the potential application of the method for emergency preparedness is given for the Chernobyl accident.