Showing papers in "Water Air and Soil Pollution in 2004"

Arsenic and heavy metal pollution of soil, water and sediments in a semi-arid climate mining area in Mexico

Abstract: The environmental impact of arsenic and heavy metals on a 105 km2 area of the historical and recent mining site of Villa de la Paz-Matehuala, San Luis Potosi (Mexico) was evaluated. Results of soil samples reported concentrations between 19–17 384 mg kg-1 As, 15–7200 mg kg-1 Cu, 31–3450 mg kg-1 Pb and 26–6270 mg kg-1 Zn, meanwhile, the concentrations in dry stream sediment samples were found to vary between 29–28 600 mg kg-1 As, 50–2160 mg kg-1 Pb, 71–2190 mg kg-1 Cu, and 98–5940 mg kg-1 Zn. The maximum arsenic concentration in pluvial water storage ponds (265 μg L-1), near the main potential sources of pollution, exceed by 5 times the Mexican drinking water quality guideline (50 μg L-1). The arsenic concentrations in water storage ponds and stream sediments decrease as distance from the potential sources increase. A special case is the `Cerrito Blanco' area located 5 km east of Matehuala, where the highest arsenic concentration in water was found (>5900 μg L-1), exceeding by 100 times the established guideline, thus representing a severe health risk. The results suggest that arsenic and heavy metal dispersion from their pollution sources (historical and active tailings impoundments, waste rock dumps and historical slag piles), is mainly associated in this site with: (1) fluvial transportation of mine waste through streams that cross the area in W–E direction; and (2) aeolian transportation of mineral particles in SW–NE direction. Finally, control measures for pollution routes and remediation measures of the site are proposed.

Capture of Particulate Pollution by Trees: A Comparison of Species Typical of Semi-Arid Areas ( Ficus Nitida and Eucalyptus Globulus ) with European and North American Species

Abstract: Particulate pollution is a serious concern in developed countries especially in urban and suburban areas where it has adverse effects on human health, exacerbating a wide range of respiratory and vascular illnesses. Data are now available which indicate that similar problems probably occur in countries in transition and may indeed be worse where national air quality standards have been neither set nor monitored. Recently a variety of approaches using both wind tunnel and field measurements have suggested that trees can significantly reduce such adverse effects through their ability to capture pollutant particles. It is clear that species choice, planting design and location relative to pollution source are critical in determining the effectiveness of particle capture by trees. Here we present relative deposition velocities and capture efficiencies of five species used widely in woodland of urban and periurban areas of Europe (Quercus petraea (oak), Alnus glutinosa (alder), Fraxinus excelsior (ash), Acer pseudo-platanus (sycamore) and Pseudotsuga menziesii (Douglas fir)), and for two species being used increasingly in semi-arid regions, (Ficus nitida (weeping fig) and Eucalyptus. globulus (Eucalyptus)). These data are for species not previously worked on and measurements were made at three windspeeds. Deposition velocities and capture efficiencies are compared with those published for other tree species, with the values of deposition velocity ranging from 0.1 to 0.3 cm s-1 at a windspeed of 3 m s-1 to maximum values 2.9 cm s-1 at 9 m s-1 windspeed. Species with more complex stem structure and smaller leaves had greater relative deposition velocities. The use of such data in models to guide species choice and planting design in order to maximise particle removal from urban air are considered.

Removal of benzene by the indoor plant/substrate microcosm and implications for air quality

Abstract: The quality of the indoor environment has become a major health consideration, since urban-dwellers spend 80-90% of their time indoors, where air pollution can be several times higher than outdoors. ‘Indoor’ potted-plants can remove air-borne contaminants such as volatile organic compounds (VOCs), over 300 of which have been identified in indoor air. In this study a comparison was made of rates of removal of benzene, as model VOC, by seven potted-plant species/varieties. In static test-chambers, high air-borne doses of benzene were removed within 24 h, once the response had been stimulated (‘induced’) by an initial dose. Removal rates per pot ranged from 12-27 ppm d−1 (40 to 88 mg m−3 d−1) (2.5 to 5 times the Australian maximum allowable occupational level). Rates were maintained in light or dark, and rose about linearly with increased dose. Rate comparisons were also made on other plant parameters. Micro-organisms of the potting mix rhizosphere were shown to be the main agents of removal. These studies are the first demonstration of soil microbial VOC degradation from the gaseous phase. With some species the plant also made a measurable contribution to removal rates. The results are consistent with known, mutually supportive plant/soil-micro-organism interactions, and developments in microbially-based ‘biofilter reactors’ for cleaning VOC-contaminated air. The findings demonstrate the capacity of the potted-plant microcosm to contribute to cleaner indoor air, and lay the foundation for the development of the plant/substrate system as a complementary biofiltration system.

Measurement and prediction of the oxygen diffusion coefficient in unsaturated media, with applications to soil covers

Abstract: Molecular diffusion is an important mechanism for gas transport in various natural and man-made systems. This is particularly the case with soil covers installed on acid-generating mine tailings, where oxygen availability has to be controlled. One of the most important roles of such covers is to limit gas flux, which depends on the effective diffusion coefficient De of the cover materials. This paper presents an experimental procedure and results from oxygen diffusion tests performed on different types of materials, at various degrees of saturation. The determination of De in the laboratory from the test data is based on analytical and numerical solutions to Fick’s laws. The ensuing values of De are compared to values calculated from available models that relate De to basic material properties, including porosity and degree of saturation. Statistical indicators are used to evaluate the accuracy of selected models, individually and on a comparative basis. It is shown that modified versions of the Millington–Quirk (M-Q) and Millington–Shearer (M-S) models provide De values close to the measured data. A semi-empirical expression, ensuing from these models and measurements, is proposed as a simple means of estimating De.

Environmental Impacts of Farm-Scale Composting Practices

Abstract: Because of its agronomic benefits, farm-scale composting is an efficient means of recycling agricultural waste. Composting process is an aerobic degradation of fresh organic matter in mature compost. Nevertheless, according to the literature, composting may induce some environmental problems. The environmental impacts of composting will be described, along with an assessment of farm-scale composting practices which play a major role in pollution. The main environmental components potentially affected by composting pollution are air and water. Various gases released by composting, such as NH3, CH4 and N2O, can impact air quality and are therefore studied because they all have environmental impacts and can be controlled by composting management. The effect on water quality can be evaluated by considering loss of NO3 -, NH4 +, organic compounds and PO4 3-. Technical evaluation criteria for the impact of farm-scale composting on the air are determined from the physical and chemical characteristics of the raw materials, the use of additives, the turning method and frequency and the duration of the composting operations. Regarding water, the weather conditions at the beginning of the composting operation, the location of the heap, the protection against rain, the water addition during the process, the use of covers and the recovery of leaching and runoff water are also taken into account. The two main practices which control the air and water pollution from composting are: the choice of the raw material which influences gas emissions and the choice of composting location which have an high effect on losses by leaching and runoff.

Sorption of copper (ii) from aqueous solution by peat

Abstract: The use of peat for removal of copper(II) from aqueous solution has been investigated at various initial copper ion concentrations and masses of peat. The equilibrium sorption study can be described by the Langmuir equation and defined in terms of the operating lines for each batch contacting system. The mechanisms of the rate of sorption of copper(II) were analysed using the Elovich equation and a pseudo-second-order model. Both rate mechanisms provided a very high degree of correlation of the experimental sorption rate data suggesting either model could be used in design applications.

Input-Output Budgets of Inorganic Nitrogen for 24 Forest Watersheds in the Northeastern United States: A Review

Abstract: Input-output budgets for dissolved inorganic nitrogen (DIN) are summarized for 24 small watersheds at 15 locations in the northeastern United States. The study watersheds are completely forested, free of recent physical disturbances, and span a geographical region bounded by West Virginia on the south and west, and Maine on the north and east. Total N budgets are not presented; however, fluxes of inorganic N in precipitation and streamwater dominate inputs and outputs of N at these watersheds. The range in inputs of DIN in wet-only precipitation from nearby National Atmospheric Deposition Program (NADP) sites was 2.7 to 8.1 kg N ha −1 yr −1 (mean = 6.4 kg N ha −1 yr −1 ;m edian =7 .0 kg Nh a −1 yr −1 ). Outputs of DIN in streamwater ranged from 0.1 to 5.7 kg Nh a −1 yr −1 (mean = 2.0 kg N ha −1 yr −1 ;m edian =1 .7 kg Nh a −1 yr −1 ). Precipitation inputs of DIN exceeded outputs in streamwater at all watersheds, with net retention of DIN ranging from 1.2 to 7.3 kg N ha −1 yr −1 (mean = 4.4 kg N ha −1 yr −1 ;m edian =4 .6 kg Nh a −1 yr −1 ). Outputs of DIN in streamwater were predominantly NO3-N (mean = 89%; median = 94%). Wet deposition of DIN was not significantly related to DIN outputs in streamwater for these watersheds. Watershed characteristics such as hydrology, vegetation type, and land-use history affect DIN losses and may mask any relationship between inputs and outputs. Consequently, these factors need to be included in the development of indices and simulation models for predicting 'nitrogen saturation' and other ecological processes.

Heavy Metal Content of Arable Soils in Northern Belgium

Abstract: More than 600 arable soils from Flanders (Northern-Belgium) were analysed for their total acid extractable contents of As, B, Be, Cd, Co, Cr, Cu, Mn, Ni, Pb and Zn in order to determine any increase in the natural background values. Samples were taken at random in several municipalities throughout Flanders. Areas with known historical or actual sources of trace element emissions were omitted although in some cases the distance between those sources and the sampling locations was not more than 20 km. The main soil types were, ranging from north to south: sand, loamy sand, light sandy-loam, sandy-loam and loam. In the coastal area, clay soils (sea polders) were sampled. In addition to the analysis of trace elements, the soil texture class, the pH and the carbon content were determined. Macro- or mesonutrients, Ca, K, P, Mg and Na, were determined from a weak acid extract of the soil samples. Correlations between trace elements and macronutrients provide some information about fertilisation practices and heavy metal sources.A limited number of soils showed slightly enhanced levels for As, Be, Cu, Co, Cr Mn, Ni Pb and Zn. In most cases, this could be linked to the regional industrial activities. However, a clear increase for Cu and Zn, above the natural background could be distinguished in areas with low atmospheric heavy metal deposits. In these cases, the excessive use of animal manure in the past may be the reason for this enrichment. However there was no indication that the Cd content of the soil was raised by the use of large amounts of pig slurry and/or by other common agricultural activities.

Predicting water, sediment and NO3-N loads under scenarios of land-use and management practices in a flat watershed

Abstract: Changes in land-use or management practices may affect water outflow, sediment, nutrients and pesticides loads. Thus, there is an increasing demand for quantitative information at the watershed scale that would help decision makers or planners to take appropriate decisions. This paper evaluates by a modeling approach the impact of farming practices and land-use changes on water discharge, sediment and NO3-N loads at the outlet of a 51.29 km2 watershed of central Iowa (Walnut Creek watershed). This intensively farmed (corn-soybean rotation) watershed is characterized by a flat topography with tiles and potholes. Nine scenarios of management practices (nitrogen application rates: increase of current rate by 20, 40%, decrease of current rate by 20, 40 and 60%; no tillage) and land-use changes (from corn-soybean rotation to winter wheat and pasture) were tested over a 30 yr simulated period. The selected model (Soil and Water Assessment Tool, SWAT) was first validated using observed flow, sediment and nutrient loads from 1991 to 1998. Scenarios of N application rates did not affect water and sediment annual budgets but did so for NO3-N loads. Lessening the N rate by 20, 40 and 60% in corn-soybean fields decreased mean NO3-N annual loads by 22, 50 and 95%, respectively, with greatest differences during late spring. On the other hand, increasing input N by 20 and 40% enhanced NO3-N loads by 25 and 49%, respectively. When replacing corn-soybean rotation by winter wheat, NO3-N loads increased in early fall, immediately after harvest. Pasture installation with or without fertilization lessened flow discharge, NO3-N and sediment delivery by 58, 97 and 50%, respectively. No-tillage practices did not significantly affect the water resource and sediment loads. Finally, such realistic predictions of the impact of farming systems scenarios over a long period are discussed regarding environmental processes involved.

Influences on the Distribution of Marine Debris on the Seafloor of Shallow Coastal Areas in Greece (Eastern Mediterranean)

Abstract: The abundance and composition of marine benthic debris was investigated in shallow coastal areas of Greece (eastern Mediterranean). The mean total density of marine debris in the areas surveyed was 15 items per 1000 m2 and ranged from 0 to 251 items per 1000 m2, with plastics dominating. Much higher marine debris densities were found in this study than those found in most studies surveying the continental shelf or the deep seafloor, indicating that pollution with marine debris is more intense in coastal areas. Greater abundance of marine debris was found in bays than in open areas. Artisanal fishing activities were found to significantly contribute to marine pollution with debris. In the Saronicos Gulf, a densely populated and highly industrialized area, the abundance of marine debris was higher than the rest of the Greek areas surveyed.

Rhamnolipid Foam Enhanced Remediation of Cadmium and Nickel Contaminated Soil

Abstract: Column experiments were conducted to evaluate the feasibility of using a rhamnolipid foam to remove heavy metals (Cd and Ni) from a sandy soil contaminated with Cd (1706 ppm) and Ni (2010 ppm). Best results were obtained from the foam generated by a 0.5% rhamnolipid solution with an initial pH value of 10.0 after flushing with 20-pore-volume of solution. These conditions removed 73.2% of the Cd and 68.1% of the Ni. Removal efficiencies by foam generated by a chemical surfactant, Triton X-100, were investigated as a comparison. It removed 65.5% of the Cd and 57.3% of the Ni under the same conditions. After a 20-pore-volume liquid solution flushing, 0.5% rhamnolipid (initial pH 10.0) without foam generation removed 61.7% of the Cd and 51.0% of the Ni, whereas 0.5% Triton X-100 (initial pH 10.0) removed 52.8% of the Cd and 45.2% of the Ni. Distilled water with adjusted pH only was also used to flush through the contaminated soil column as a control. It removed 17.8% of the Cd and 18.7% of the Ni. This study shows that rhamnolipid foam technology can be an effective means for the remediation of cadmium and nickel contaminated soil.

Speciation of Metals in Sewage Sludge and Sludge-amended Soils

Abstract: This study is aimed at ascertaining the chemical partitioning ofCu, Zn, Pb, Ni, Cr and Cd in sewage sludge and agricultural soils repeatedly amended with sludge. The operationally determined speciation was investigated by using selective five steps sequential extraction method for partitioning these metals into different chemicalforms, likely to be released in solution under various environmental conditions. It provides qualitative evidence regarding the form of the association of metals and indirectly of their bioavailability. It can help to explain the process by which metals are eliminated from sewagesludge and also indicate the impact of the use of sludge on agriculturalsoils, as amendments. Data obtained by extraction procedure showed different metal distribution trend among the fractions in sewage sludgeand sludge-amended soils. Comparison of distribution pattern of metals in sludge and sludge-applied soils shows that there is possible redistribution of metals among the different phases. The sum of the metal content in the fractions compared well with the total metal content in sewage sludge, the ratios averaging 1.02, 1.04, 1.07, 0.94, 1.06, and 1.12 for Cu, Zn, Pb, Ni, Cr, and Cd, respectively. The metal recovery efficiency in sludge-amended soils was found to be: 108±6%, 102±5%, 115±8%, 111±4%, 104±7%and 124±28% for Cu, Zn, Pb, Ni, Cr and Cd, respectively.

Investigation of the Heavy Metal Sources in Relation to Automobiles

Abstract: In order to investigate the sources of roadside heavy metal pollution, auto tire, gasoline, gas oil, kerosene, paint for road markings (white, yellow and red), the soot from the discharge spout, auto tire rubber, asphalt pavement, gray paint and anticorrosive on the guardrail were gathered together and analyzed. As a consequence, Pb may be originally from yellow and red road markings, and gray paint or anticorrosive. Hg is mainly emitted from the combustion of premium gasoline and diesel soot is an important source of As, Ni and Zn. Cd and Zn are mainly emitted from the abrasion of tire rubber. The wear of asphalt pavement is considered to be a source of Ni and V.

Reclamation of polluted soil: phytoremediation potential of crop-related brassica species

Abstract: Soils polluted by heavy metals can be reclaimed using a number of expensive tactics that either remove the contaminants or stabilize them within the soil. The value of metal accumulating plants for environmental remediation has recently been appreciated and promising results have been obtained. This paper reports a study on the behavior of Brassica napus, Brassica juncea, Raphanus sativus and Brassica carinata grown on a substrate contaminated by several heavy metals caused by the use of contaminated irrigation water. Data on carbon dioxide assimilation, biomass growth and the bioconcentration and translocation factor of each metal in each species were measured. The polluted substrate caused only a small variation in photosynthesis, however transpiration was more affected by the experimental substrate and in all three species of the genus Brassica the presence of metals in the substrate resulted in higher transpiration levels.

Magnetic signature of industrial pollution of stream sediments and correlation with heavy metals: case study from south france

Abstract: Industrial pollution is one of the most important environmentalthreats, with serious consequences for the future. Thus, its detailed study is of great importance. Apart from expensive andtime-consuming chemical methods, several rapid and cheap proxymethods have been developed recently, one of them being based on rock-magnetic parameters. In the present paper we examine the use of rock-magnetic methods designed to assess the degree of pollution of recent stream sediments taken from the Arc river (Provence, France). The aim was to identify industrially-derived magnetic particles and to link this `magnetic pollution' to concentrations of heavy metals. Geological basements allow the easy determination of magnetic particles of industrial origin. Our results clearly demonstrate that magnetic anomalies, observed in the stream sediments along the river, can be explained by human activities, as they correlate well with concentrations of lead, zinc, iron and chromium.

Hydrous Ferric Oxide (HFO)—a Scavenger for Fluoride from Contaminated Water

Abstract: Groundwaters contaminated with excess fluoride (above 1.5 mg/L) posed some risks to the public health in India. Methods available for fluoride contaminated water treatment are cogaulation–filtration using alum + lime + bleaching powder (Nalgonda technique) and adsorption using activated alumina. Use of aluminium compounds for water treatment purpose needs replacement on neurological health problem. Objective to this, the synthesis and fluoride adsorption behavior of hydrous ferric oxide (HFO) are reported here. It is seen that fluoride adsorption density varies as a function of pH, contact time, aging time, drying temperature and particle size of HFO. Highest adsorption density for fluoride is found to be at pH 4.0. Effects of competing anions in removing fluoride from solution were tested. Arsenite, arsenate, phosphate and sulfate show strong interfering effect at high anions to fluoride molar ratio in solution. Adsorption of fluoride on HFO follows the Freundlich isotherm and the Lagergren first-order kinetic model. It was also determined that HFO is a better adsorbent in removing fluoride from high fluoride groundwater than some other adsorbents. Regeneration of fluoride-rich HFO results showed that 1.0 M NaOH solution could be used up to a maximum of 75% regeneration.

N2O, NO, and NH3 emissions from soil after the application of organic fertilizers, urea and water

Abstract: Agricultural soil is a major source of nitrous oxide (N2O), nitric oxide (NO) and ammonia (NH3). Little information is available on emissions of these gases from soils amended with organic fertilizers at different soil water contents. N2O, NO and NH3 emissions were measured in large-scale incubations of a fresh sandy loam soil and amended with four organic fertilizers, [poultry litter (PL), composted plant residues (CP), sewage sludge pellets (SP) and cattle farm yard manure (CM)], urea fertilizer (UA) or a zero-N control (ZR) for 38 days. Fertilizers were added to soil at 40, 60 or 80% water-filled pore space (WFPS). The results showed that urea and organic fertilizer were important sources of N2O and NO. Total N2O and NO emissions from UA ranged from 0.04 to 0.62%, and 0.23 to 1.55% of applied N, respectively. Total N2O and NO emissions from organic fertilizer treatments ranged from 0.01 to 1.65%, and <0.01 to 0.55% of applied N, respectively. The lower N2O and NO emissions from CP and CM suggested that applying N is these forms could be a useful mitigation option. Comparison of the NO-N/N2O-N ratio suggested that nitrification was more dominant in UA whereas denitrification was more dominant in the organic fertilizer treatments. Most N was lost from PL and UA as NH3, and this was not influenced significantly by WFPS. Emissions of NH3 from UA and PL ranged from 62.4 to 69.6%, and 3.17 to 6.11% of applied N, respectively.

Response of Six Australian Plant Species to Heavy Metal Contamination at An Abandoned Mine Site

Abstract: This investigation was carried out to assess the potential suitability of certain Australian plants for use in the phytoremediation of derelict mine sites. The plant species studied were native to the area surrounding a silver mine at Yerranderie in NSW, Australia, which has been derelict now for over 70 years. The contamination on this site is typical of that caused by acid mine drainage, with very low soil and water pH, and large areas devoid of topsoil and vegetation. Soil metal concentrations exceeded the Australian and New Zealand Environment and Conservation Council (ANZECC) 1992 guidelines for soil quality in several locations. Corresponding topsoil and upper plant samples were collected along three transects crossing the path of drainage from the mine wastes. Six plant species were dominant on the site, including Juncus usitatus (common rush), Lomandra longifolia (spiny-headed mat rush), Cynodon dactylon (couch), Pteridium esculentum (bracken fern), Acacia decurrens (black wattle) and Melaleuca alternifolia (teatree). Of these species, C. dactylon, J. usitatus and L. longifolia were identified as of potential use in phytostabilisation programs, due to tolerance of acid soils and tolerance and/or accumulation of significantly higher concentrations of Pb and Cd than other plant species present on the site.

Hydrocarbons and Metals in Atmospheric Deposition and Roof Runoff in Central Paris

Abstract: Hydrocarbons (aliphatic and aromatic) and metals (heavy metals and major elements) were measured in both atmospheric deposition and roof runoff in central Paris (France). Atmospheric deposition (wet and dry) was collected from December 2001 to October 2002 and roof runoff was sampled on three buildings with different covering materials, i.e., slate tiles and zinc sheets. This paper gives an overview of the results on the flux and distribution points of view for both atmospheric deposition and roof runoff. Results show that atmospheric fluxes of hydrocarbons and major elements increase during cold seasons, due to residential heating occurrence, while heavy metals, whose major sources have constant emission fluxes, exhibit steady atmospheric loads throughout the year. Moreover, hydrocarbon fingerprints reveal mainly biogenic and pyrolytic origins for aliphatic and aromatic hydrocarbons, respectively. The results about roof runoff contamination suggest that the scavenging processes for hydrocarbons and metals are dependent on rainfall amount rather than on the rain event characteristics (number, intensity, duration), and dry deposition weakly contributes to the pollutant loads in roof runoff. Results also highlight that both metallic and slate roofs do not act as a source of hydrocarbons and major elements - exclusively originating from atmospheric deposition - while they act as a source of some heavy metals. Zinc-covered roofs largely release Zn and Ti, while slate roofs mainly release Pb, Ti and Cu. Whatever the material used for roof covering, roof runoff presents high Ni and V loads due to the vicinity of the chimney stacks of heating boilers.

Cellular Impact of Metal Trace Elements in Terricolous Lichen Diploschistes muscorum (Scop.) R. Sant. – Identification of Oxidative Stress Biomarkers

Abstract: The purpose of this research is to present toxic effects of some heavy metals (cadmium, lead and zinc) on lichen physiology. In the North of France, those metals are concentrated for example in industrial polluted soils near metallurgic plants and waste dumps. Our investigations were conducted on Diploschistes muscorum (Scop.) R. Sant, a terricolous lichen growing on previously quoted soils as well as on non-contaminated ones. Different stress parameters were investigated as potassium leakage – which is related to the loss of membrane integrity – and oxidative stress through following parameters: malondialdehyde (MDA), glutathione (GSH) and superoxide dismutase (SOD). It seems, therefore, that heavy metals induce oxidative stress in this lichen, in which we found membrane damage and enhancement of SOD activity and GSH concentrations. With regard to very high concentrations of Cd, Pb and Zn, a resistance involving antioxidant mechanisms limits the expected damage. Those mechanisms involve GSH, SOD as well as secondary metabolites, which have this resistance property. This study is a first step of investigation to use – in the future– physiological parameters as tool for environment assessment.

Dynamics of Organic C Mineralization and the Mobile Fraction of Heavy Metals in a Calcareous Soil Incubated with Organic Wastes

Abstract: Organic wastes such as sewage sludge and compost increase the input of carbon and nutrients to the soil. However, sewage sludge-applied heavy metals, and organic pollutants adversely affect soil biochemical properties. Therefore, an incubation experiment lasting 90 days was carried out to evaluate the effect of the addition of two sources of organic C: sewage sludge or composted turf and plant residues to a calcareous soil at three rates (15, 45, and 90 t of dry matter ha−1) on pH, EC, dissolved organic C, humic substances C, organic matter mineralization, microbial biomass C, and metabolic quotient. The mobile fraction of heavy metals (Zn, Cd, Cu, Ni, and Pb) extracted by NH4NO3 was also investigated. The addition of sewage sludge decreased soil pH and increased soil salinity to a greater extent than the addition of compost. Both sewage sludge and compost increased significantly the values of the cumulative C mineralized, dissolved organic C, humic and fulvic acid C, microbial biomass C, and metabolic quotient (qCO2), especially with increasing application rate. Compared to compost, the addition of sewage sludge caused higher increases in the values of these parameters. The values of dissolved organic C, fulvic acid C, microbial biomass C, metabolic quotient, and C/N ratio tended to decrease with time. The soil treated with sewage sludge showed a significant increase in the mobile fractions of Zn, Cd, Cu, and Ni and a significant decrease in the mobile fraction of Pb compared to control. The high application rate of compost resulted in the lowest mobility of Cu, Ni, and Pb. The results suggest that biochemical properties of calcareous soil can be enhanced by both organic wastes. But, the high salinity and extractability of heavy metals, due to the addition of sewage sludge, may limit the application of sewage sludge.

Spatial and temporal variation of PM10 mass concentrations within the greater area of Athens, Greece

Abstract: This study presents the results of a yearlong PM10 measurement campaign, conducted at four sampling sites, within the Greater Athens Area, between June 2001 and May 2002. Daily average PM10 concentrations were determined using reference samplers installed in two urban locations (Maroussi and Aristotelous), a mixed urban–industrial location (Elefsina) and a background location (Thrakomacedones). The 24-h and annual PM10 average concentrations were calculated and compared to the corresponding air quality standards, promulgated by the European Union, revealing severe exceedances of the limit values. The mean concentrations for the sampling periods were 73.8, 83.2, 32.9 and 54.9 μg/m3 for Maroussi (MAR), Aristotelous (ARI), Thrakomacedones (THR) and Elefsina (ELE), respectively. The spatial variation of PM10, was investigated resulting at a coefficient of variation of 0.36 within the study area and correlation coefficients ranging from 0.57 to 0.84. In addition, strong associations between PM10 and other primary gaseous pollutants were found. Regression analysis of PM10 against NOx (used as an indicator for road traffic emissions) revealed significant vehicular contributions to the measured PM10 concentrations. Higher PM10 levels were recorded during prevailing winds of the S–SW sectors, while lower levels were observed during strong northerly flows. The overall results allowed a first assessment of the severity of PM10 air pollution in the Athens basin, and of the potential sources responsible for it. The control of traffic-related particle emissions appears to be a principal objective, for the confrontation of the PM10 pollution problem affecting the area.

The effect of climate warming on the hydrochemistry of alpine lakes

Abstract: The hydrochemistry of mountain lakes is highly conditioned by the chemicalcomposition of atmospheric deposition and by climate characteristics. Consequently these ecosystems have proved to be sensitive to long-term changes in both factors. Climate warming seems to be particularly pronounced in the Alpine region. A reduction of snow cover in space and time, due to less precipitation and higher temperatures, means a greater exposure of rocks and soils in the watersheds, which enhances weathering processes. In this paper we aim to evaluate the possible effect of these processes on long-term changes in the chemistry of alpine lakes. Recent climate changes affecting the study area were investigated through a data series referring to temperature, precipitation, snow depth and duration at some stations in the Ossola Valley. Chemical data of 35 lakes located in the Ossola and Sesia Valleys (Central Alps) were used. Lakes were sampled both in the late summer of 2000 and 2001 in the framework of two European Projects and the results compared with previous data (1984–1987). Two lakes (Boden Superiore and Inferiore, 2343 and 2334 m a.s.l., respectively), located in the northern part of the study area, have been sampled more or less continuously since the late 70s, enabling us to evaluate the trends of the main chemical variables. For lakes lying in catchments with highly soluble rocks, a comparison between the two data sets shows an increase of solute contents in the last few years. This result could be attributed to increased weathering rates due to climate warming.

Suitability of soil microbial parameters as indicators of heavy metal pollution

Abstract: Several microbial parameters (microbial biomass, respiration, dehydrogenase, phosphatase, sulphatase, glucosidase, protease and urease activities) were measured in soils from five sites located in urban green areas close to roads differing in traffic density. Our aims were to evaluate the suitability of such parameters as field biomarkers of stress induced by heavy metal pollution, and to compare results obtained by single microbial parameters with results given by an index expressing the average microbial (AME) response of the microbial community. Data showed that all parameters were significantly reduced in the sites characterized by the highest load of metals in soil. Dehydrogenase, sulphatase, glucosidase activities and respiration, declined exponentially with increasing metal concentration, whereas phosphatase activity and AME decreased following a sigmoidal type relationship. In contrast, protease, urease and microbial biomass were not significantly correlated with soil metal concentration. Microbial parameters differed both in sensitivity to critical metal concentrations and in the rate of decline at increasing metal loads in soil. Due to the complex interplay of chemical, physical and biological factors which influence microbial activities and biomass, the proposed index (AME) appeared more suitable than single microbial parameters for a biomonitoring study of this type.

The Effect of Fire on Mercury Cycling in the Soils of Forested Watersheds: Acadia National Park, Maine, U.S.A.

Abstract: This study compares mercury (Hg) and methylmercury (MeHg) distribution in the soils of two forested stream watersheds at Acadia National Park, Maine, U.S.A. Cadillac Brook watershed, which burned in 1947, has thin soils and predominantly deciduous vegetation. It was compared to the unburned Hadlock Brook watershed, with thicker soil and predominantly coniferous vegetation. Soils in both watersheds were primarily well drained. The fire had a significant impact on the Cadillac watershed, by raising the soil pH, altering the vegetation, and reducing carbon and Hg pools. Total Hg content was significantly higher (P > 0.05) in Hadlock soils (0.18 kg Hg ha-1) compared to Cadillac soils (0.13 kg Hg ha-1). Hadlock O horizon had an average Hg concentration of 134±48 ng Hg g-1 dry weight, compared to 103±23 ng Hg g-1 dry weight in Cadillac O horizon. Soil pH was significantly higher in all soil horizons at Cadillac compared to Hadlock soils. This difference was especially significant in the O horizon, where Cadillac soils had an average pH of 3.41±0.22 compared to Hadlock soils with an average pH of 2.99±0.13.To study the mobilization potential of Hg in the O horizons of the two watersheds, batch adsorption experiments were conducted, and the results were modeled using surface complexation modeling. The results of Hg adsorption experiments indicated that the dissolved Hg concentration was controlled by the dissolved organic carbon (DOC) concentration. The adsorption isotherms suggest that Hg is more mobile in the O horizon of the unburned Hadlock watershed because of higher solubility of organic carbon resulting in higher DOC concentrations in that watershed.Methylmercury concentrations, however, were consistently higher in the burned Cadillac O horizon (0.20±0.13 ng Hg g-1 dry weight) than in the unburned Hadlock O horizon (0.07±0.07 ng Hg g-1 dry weight). Similarly, Cadillac soils possessed a higher MeHg content (0.30 g MeHg ha-1) than Hadlock soils (0.16 g MeHg ha-1). The higher MeHg concentrations in Cadillac soils may reflect generally faster rates of microbial metabolism due to more rapid nutrient cycling and higher soil pH in the deciduous forest. In this research, we have shown that the amount of MeHg is not a function of the total pool of Hg in the watershed. Indeed, MeHg was inversely proportional to total Hg, suggesting that landscape factors such as soil pH, vegetation type, or land use history (e.g., fire) may be the determining factors for susceptibility to high Hg in biota.

Nitrogen deposition and nitrate leaching at forest edges exposed to high ammonia emissions in Southern Bavaria

Abstract: The atmospheric deposition of air pollutants was studied by means of monitoring canopy throughfall at six forest stands. The investigation was carried out in Norway spruce (Picea abies L. Karst.) forests in Southern Bavaria with high ambient ammonia concentrations due to either adjacent intensive agriculture or poultry housing. Five monitoring plots transected the forest edges and forest interior from the edge, at 50, 150, about 400 m and about 800m to the interior. Additionally, nutrient concentration in soil solution was sampled with suction cups at each plot, and C/N ratio of the humus layer was also determined. The variation of ambient ammonia concentration between three of the six investigated sites was estimated using diffusive samplers. In order to compare the effects of atmospheric deposition on European beech (Fagus sylvatica L.) and Norway spruce additional monitoring plotswere installed under each of these species in a mixed beech and spruce stand. Bulk deposition and soil water samples were analysed for major ions (NO3 -, NH4 +, SO4 2-, Cl-, Na+, K+, Mg2+, Ca2+M).The results show a substantial increase of deposition towards the forest edges for all ions. This so called 'edge effect' continued in most cases until a distance from 50 to 150 m from edge. For both ambient ammonia concentrations and nitrogen deposition, it can be concluded that increased dry deposition is the main reason for the edge effect. Over 76% of the nitrogen ratios in throughfall deposition between the edge and 50 m distance into the spruce forest exceed 1.0. Except for potassium, beech generally showed lower ratios than spruce.Due to high nitrogen deposition the forest floor, C/N ratios were lower at stand edges when compared to their interior. In contrast to the increase of nitrogen deposition at the edge, nitrate export below the main rooting zone was lower at the edge. Nitrate export was generally lower under beech than spruce. Nitrogen budgets of some plots were negative, indicating a reduction of total ecosystem nitrogen stock.The results show that forest edges, especially in areas with high air pollution, receive much more atmospheric deposition than the interior parts of closed forest stands. As many deposition studies in forests were conducted at field stations in the central parts of forests the estimated deposition for the whole forest may be underestimated. This may be important to consider in geo-statistical studies and models aiming to estimate spatial critical deposition values, especially with an increasing fragmentation of the forest cover.

Microbial Degradation of Fipronil in Clay Loam Soil

Abstract: Fipronil, (±)-5-amino-1-(2,6-dichloro-∝,∝,∝-trifluoro-p-tolyl)-4-trifluoromethysulfinylpyrazole-3-carbonitrile, is used as an effective insecticide for the control of rice pests in China. Although many studies examining the fate of fipronil in the soilenvironment have been conducted, there are no studies on the microbial degradation of fipronil in the soil environment. Fipronil was degradedby microorganisms in the non-sterile clay loam soil, which resulted in the formation of metabolite, MB45950. The degradation of fipronil in non-sterile clay loam soil was mainly influenced by the soil microbes. The half-lives in non-sterile clay loam soil were 9.72 and 8.78 d at 25 and 35 °C, respectively compared to 33.51 and 32.07 d at 25 and 35 °C, respectively in the sterile soil. The microbial viability test showed that non-sterile clay loam soil had viable microorganisms throughout the experiment. Fipronil did not adversely affect the microbes once soil microbes adapted to the presence of fipronil in the clay loam soil.

Relative Effect of Temperature and pH on Diel Cycling of Dissolved Trace Elements in Prickly Pear Creek, Montana

Abstract: Diel (24 hr) cycles in dissolved metal and As concentrations have been documented in many northern Rocky Mountain streams in the U.S.A. The cause(s) of the cycles are unknown, although temperature- and pH-dependent sorption reactions have been cited as likely causes. A light/dark experiment was conducted to isolate temperature and pH as variables affecting diel metal cycles in Prickly Pear Creek, Montana. Light and dark chambers containing sediment and a strand of macrophyte were placed in the stream to simulate instream temperature oscillations. Photosynthesis-induced pH changes were allowed to proceed in the light chambers while photosynthesis was prevented in the dark chambers. Water samples were collected periodically for 22 hr in late July 2001 from all chambers and the stream. In the stream, dissolved Zn concentrations increased by 300% from late afternoon to early morning, while dissolved As concentrations exhibited the opposite pattern, increasing 33% between early morning and late afternoon. Zn and As concentrations in the light chambers showed similar, though less pronounced, diel variations. Conversely, Zn and As concentrations in the dark chambers had no obvious diel variation, indicating that light, or light-induced reactions, caused the variation. Temperature oscillations were nearly identical between light and dark chambers, strongly suggesting that temperature was not controlling the diel variations. As expected, pH was negatively correlated (P < 0.01) with dissolved Zn concentrations and positively correlated with dissolved As concentrations in both the light and dark chambers. From these experiments, photosynthesis-induced pH changes were determined to be the major cause of the diel dissolved Zn and As cycles in Prickly Pear Creek. Further research is necessary in other streams to verify that this finding is consistent among streams having large differences in trace-element concentrations and mineralogy of channel substrate.

Nitrogen Isotope Ratios of Synthetic and Organic Sources of Nitrate Water Contamination in Spain

Abstract: This work aims to identify the sources of nitrogencontamination in nitrate vulnerable zones (NVZs) of Spain by means of the nitrogen isotope method. Three categories of nitrogen sources (synthetic fertilisers, animal wastes, and sludges and effluents from waste-water treatment plants) from three NVZs were analysed for their nitrogen isotopic composition (δ15N) in order to assess the applicability of the method to the identification of these N sources. The mean δ15N values were: +1.48‰ for synthetic fertilisers, +15.98‰ for animal wastes and +11.52‰ for sludges and effluents. The synthetic fertiliser sources were significantly different from the organic sources and so, the method can be used for their identification. The highest variability was found within the animal waste category. The range of values found for the different kinds of animal wastes (+5.86 to +36.74) was very wide and overlappedthe range found for sludges and effluents from waste-water treatmentplants (+4.57 to +20.18). Accordingly, these two nitrogen sources areisotopically indistinguishable.

Trace Metals in the Water Columns of the Red Sea and the Gulf of Aqaba, Egypt

Abstract: Seawater samples were collected from the northern Red Sea and the Gulf of Aqaba at different depths during February 1999 and analyzed for iron, zinc, manganese, nickel, copper, cadmium, cobalt and lead to determine the existing concentration of these metals, their distribution patterns and where contamination has occurred. The concentrations of Fe, Zn, Mn, Ni, Cu, Cd, Co, Pb were scatteredin the ranges: (0.56–4.44; mean 1.67±0.9 μg L-1), (0.13–1.17; mean 0.24±0.12 μg L-1), (0.06–0.21; mean 0.13±0.03 μg L-1), (0.05–0.52; mean 0.16±0.06 μg L-1), (0.07–0.29; mean 0.14±0.06 μg L-1), (0.02–0.78; mean 0.49±0.14 μg L-1), (0.06–0.29; mean 0.15±0.04 μg L-1), and (0.02–0.68; mean 0.31±0.13 μg L-1), respectively. The results revealed a small range of variation and regional irregularities. It also indicated significant higher concentrations for Fe, Cd and Pb compared to other metals. Compared to the northern Red Sea, significant higher concentrations for Ni and Cd are measured at the Gulf of Aqaba. Other metals, i.e. Fe, Zn, Mn, Cu, Co, and Pb are not significantly different in both areas indicating no distinct concentration gradients. Except for Pb, the distribution patterns indicated significantly lower concentrations at surface layer in both regions, then increasing to their maximum values at the sub-surface layers which followed by a decrease in deep water. The study indicated also that the mean concentrations of trace metals examined here are much lower than those reported for the Mediterranean Sea and typical of open ocean water.