A quasi steady state respiration test based on Fick's law with a correction term for advective flux, for estimating petroleum hydrocarbon degradation rates, was evaluated in a full-scale (3,000 m³) biopile study. A contaminated clayey sand soil with an average TPH content of 1,421 ± 260 mg kg-¹ soil was treated in a biopile with a fixed venting and heating system. Temperature in the biopile ranged from 12.1 to 36.6°C and soil water content from 15.2 to 35.8 m³ H₂O m-³ soil. Oxygen concentrations in the biopile showed a rapid decrease with depth, before venting and reached constant atmospheric concentration during venting. Measured oxygen consumption in the biopile ranged from -0.04 to -0.68 mol O₂ m-³ soil day-¹. Average oxygen consumption rates calculated with the quasi-steady-state method were significantly (P < 0.05) lower then the oxygen consumption rates calculated with the transient method. It was suggested that the oxygen diffusion was underestimated by the diffusivity models used and that further research is needed to determine relative effective diffusion coefficients in biopiles. Although both respiration testing and petroleum hydrocarbon concentration showed a decrease of oxygen consumption in time, the estimated degradation rate was low compared to the actual decrease in petroleum hydrocarbon concentration. Additional work will have to be done to acquire a more precise knowledge of the relationship between respirometrically determined degradation rates and the actual change in petroleum hydrocarbon concentration in the soil.

We tested the efficacy of matrix based fertilizer formulations (MBF) that reduce NH₄, total phosphorus (TP), total reactive phosphorus (TRP) and dissolved reactive phosphorus (DRP) in leachate. The MBF formulations cover a range of inorganic N and P in compounds that are relatively loosely bound (MBF1) to more moderately bound (MBF2) and more tightly bound compounds (MBF3) mixed with Al(SO₄)₃ H₂O and/or Fe₂(SO₄)₃ and with the high ionic exchange compounds starch, chitosan and lignin. Glomus interadicies, a species of arbuscular mycorrhizal fungal spores that will form mycorrhizae in high nutrient environments, was added to the MBF formulations to increase plant nutrient uptake. When N and P are released from the inorganic chemicals containing N and P the matrix based fertilizers likely bind these nutrients to the Al(SO₄)₃ H₂O and/or Fe₂(SO₄)₃ starch–chitosan–lignin matrix. We tested the efficacy of the MBFs to reduce N and P leaching compared to Osmocote® 14-14-14, a slow release fertilizer (SRF) in sand filled columns in a greenhouse study. SRF with and without Al and Fe leached 78–84% more NH₄, 58–78% more TP, 20–30% more TRP and 61–77% more than MBF formulations 1, 2, and 3 in a total of 2.0 liters of leachate after 71 days. The concentration and amount of NO₃ leached among SRF and MBF formulations 1 and 2 did not differ. The SRF treatment leached 34% less NO₃, than MBF3. Total plant weight did not differ among fertilizer treatments. Arbuscular mycorrhizal infection did not differ among plants receiving SRF and MBF formulations 1, 2 and 3. Although further greenhouse and field testing are called for, results of this initial investigation warrant further investigation of MBFs.

The structural features and O₂ consumption of the epipelic biofilm in streams of the Pampean plain were explored. The study was conducted in three lowland streams subjected to different anthropic disturbances. Three sampling sites were selected in different sectors of these streams considering land use intensity (high, moderate, and low). Samples of the water and of the epipelic biofilm were taken seasonally. El Pescado stream is subjected to a low level of human impact and showed lower organic matter and nutrient contents than the Rodríguez and Don Carlos streams which are subjected to moderate and high levels of human impact. The biofilm composition of the three streams was represented by cyanophytes and diatoms but with different species composition and dominance; protozoans and nematodes were the characteristic heterotrophic groups in the three streams. The Rodríguez and Don Carlos streams showed the highest abundance of organisms. Multiple regression showed that O₂ consumption, chlorophyll a and trophic index were significantly correlated with the oxygen demands. On the other hand, the Rodríguez and Don Carlos streams exhibited significant differences with the El Pescado stream in O₂ consumption, trophic index, and chlorophyll a content. Our results demonstrated that the different biological descriptors responded to environmental variables that are influenced by the different land use intensities, being chlorophyll a, abundance of organisms, and O₂ consumption the most sensitive variables to the changes water quality.

The atmosphere over Brazilian cities is influenced by a variety of emissions sources. In this study, aerosol collection and back-trajectory analysis were used to determine the influence of local and remote sources. Aerosols were collected at three locations within the state of São Paulo: one megacity and two cities in which sugar cane burning in the surroundings is observed. We quantified the major water-soluble inorganic ions and trace metals. As expected, vehicle emissions influenced the atmosphere of the megacity heavily, and sugar cane burning influenced that of the other locations. During the period of this experiment the back-trajectory analysis revealed that air masses are transported into the state from the northeast of Brazil, where biomass burning occurs. Multivariate statistical analysis revealed that the two principal components account for 48.5% of the total data variance. We conclude that local sources have a strong impact on the concentrations of particulate matter and pollutants. Remote sources also contribute to the concentrations of aerosol pollutants.

European critical loads and novel dynamic modelling data have been compiled under the LRTAP Convention by the Coordination Centre for Effects. In 2000 9.8% of the pan-European and 20.8% of the EU25 ecosystem area were at risk of acidification. For eutrophication (nutrient N) the areas at risk were 30.1 and 71.2%, respectively. Dynamic modelling results reveal that 95% of the area at risk of acidification could recover by 2030 provided acid deposition is reduced according to present legislation. Insight into the timing of effects of exceedances of critical loads for nutrient N necessitates the further development of dynamic models.

In this study critical load functions and target load functions of nitrogen and sulphur deposition with respect to acidity and minimum base cation to aluminium ratio were calculated with the SAFE model using three different averaging strategies: (1) averaging based on current forest generation, (2) averaging based on next generation and (3) averaging based on the entire simulation period. From the results it is evident that although target load calculation and indeed critical load calculation is straight forward, there is a problem in translating a predicted recovery according to the target load calculation back to a site-specific condition. We conclude that a policy strategy for emission reductions that ensures recovery, according to calculated target load functions, is likely to be beneficial from an ecosystem point of view. However, such a strategy may not be sufficient to achieve actual non-violation of the chemical criteria throughout the seasonal or rotational variations. To address this issue we propose a method for calculating dynamic critical loads which ensures that the chosen criteria is not violated.

The health of near shore marine ecosystems has long been a concern because of its importance to coastal areas. Jiaozhou Bay (JZB) is one such marine ecosystem experiencing rapid water quality degradation in the last several decades. From the area surrounding the bay, the nutrients discharged into the bay through surface water and groundwater has been greatly changed. The thickness of the aquifers and the permeability is relatively high, the concentrations of nutrients in the groundwater are generally high, and so the groundwater discharged into JZB is very significant. However, no attempt has ever been made to evaluate the amount of nutrients discharged into the bay area via groundwater. In this study, the cross-section method and water balance method were used to estimate the amount of groundwater and nutrients discharged into JZB via the subsurface. Groundwater was monitored and sampled at aquifers surrounding the bay area, and some previously available data was also analyzed. The results indicated that groundwater from the Baisha Aquifer east of JZB now is the major source of nutrients (nitrate, dissolved SiO₂) being discharged into the bay. The concentrations of nutrients in the groundwater have been increasing with intensive agricultural land use. However, Dagu Aquifer, the largest aquifer north of JZB, only provides limited nutrients to the bay area because of the construction of a low permeability subsurface dam. Historically, during the 1970s to the 1990s, the Baisha Aquifer experienced seawater intrusion due to excessive groundwater withdrawal. The same was true for the Dagu Aquifer from the 1980s to the 1990s. Because of this, no significant nutrients were discharged into the bay.

Emissions of sulphur and oxidized nitrogen compounds in Europe have been reduced following a series of control measures during the last two decades. These changes have taken place during a period in which the primary gases and the wet deposition throughout Europe were extensively monitored. Since the end of the 1970s, for example land based sulphur emissions declined by between 90 and 70% depending on the region. Over the same period the total deposition of sulphur and its partitioning into wet and dry deposition have declined, but the spatial pattern in the reduction in deposition differs from that of emission and has changed with time. Such non-linearities in the emission-deposition relationship are important to understand as they complicate the process of assessing the effects of emission reduction strategies. Observed non-linearities in terrestrial sulphur emission-deposition patterns have been identified in north west Europe due to increases in marine emissions, and are currently slowing the recovery of freshwater ecosystems. Changes in the relative amounts of SO₂ and NH₃ in air over the last two decades have also changed the affinity of terrestrial surfaces for SO₂ and have therefore changed the deposition velocity of SO₂ over substantial areas. The consequence of this effect has been the very rapid reduction in ambient SO₂ concentration in some of the major source areas of Europe, where NH₃ did not change much. Interactions between the different pollutants, generating non-linearities are now being incorporated in long-range transport models to simulate the effects of historical emission trends and to provide projections into the future. This paper identifies non-linearities in emission deposition relationships for sulphur and nitrogen compounds in Europe using data from the EMEP long-rang transport model and measured concentration fields of the major ions in precipitation and of SO₂ and NO₂ in surface air.

This study qualifies and quantifies the effects of pH, hardness, alkalinity, salinity and bone calcination temperature related with the adsorption of As(V) onto biogenic hydroxyapatite (HAPb) obtained from cow-charred bones. Arsenic contamination of surface and subsurface waters is widely extended in Argentina. It is a problem of major concern, particularly in rural and suburban areas where there are not water treatment plants for supplying of drinking water. HAPb is a natural material, whose absorbent properties can be used for the design of low-cost technologies for As(V) abatement in water. In this work HAPb has been characterized by physical and chemical analysis (XRD, SEM, EDAX, BET, and electrophoretic mobility). A Plackett–Burman screening experimental design allowed us to determine the main variables affecting the efficiency of As(V) sorption onto HAPb. Based on these variables and with a design of higher order we developed a model of the system to study its behaviour. Data collection was planned through a Doehlert experimental design and a back propagation artificial neural network was used to work it out. Results showed that salinity is the major variable affecting the efficiency of the As(V) immobilization process but pH and hardness should be taken into account because of associations among them.

The quantification of arsenic biovolatilization by microscopic filamentous fungi Aspergillus clavatus, A. niger, Trichoderma viride and Penicillium glabrum under laboratory conditions is discussed in this article. The fungi were cultivated on a liquid medium enriched with inorganic arsenic in pentavalent form (H₃AsO₄). Filamentous fungi volatilized 0.010 mg to 0.067 mg and 0.093 mg to 0.262 mg of arsenic from cultivation systems enriched with 0.25 mg (5 mg.l-¹ of arsenic in culture media) and 1.00 mg of arsenic (20 mg.l-¹ of arsenic in culture media), respectively. These results represent the loss of arsenic after a 30-day cultivation from cultivation systems. The production of volatile arsenic derivatives by the A. niger and A. clavatus strains was also determined by hourly sorption using the sorbent Anasorb (CSC) on the 29th day of cultivation.