Monitoring of phytoplankton biomass and nutrients in a polluted stream

The spatial and temporal variations in the concentrations of nutrients (NH₄⁺, NO₂⁻, PO₄³⁻, SiO₄⁻) and chlorophyll a were monitored simultaneously in a slow-flowing watercourse (Saricay Stream, Turkey), which runs in a rural–urban gradient. Chlorophyll a concentrations ranged between 0.044 μg l^-1 and 206.15 μg l^-1 and, in general, the higher concentrations of chlorophyll a and ammonium were measured downstream of the raw sewage outfalls. Nitrate was by far the most abundant form of inorganic nitrogen, and its concentration ranged between 411.71 μM and 87.25 μM. Silicates and phosphates were always potentially limiting to biomass relative to nitrogen. Agricultural run-off and point discharges from urban sources greatly affected the chemical composition of the water in the Saricay Stream and drove the system towards eutrophication.     

Environmental occurrence and fate of semifluorinated n-alkanes in snow and soil samples from a ski area

Semifluorinated n-alkanes (SFAs) with carbon chain lengths of 22 to approximately 36 atoms are present in fluorinated ski waxes to reduce the friction between ski base and snow, resulting in a better glide. Semifluorinated n-alkenes (SFAenes) are byproducts in the production process of SFAs and are also found in ski waxes. Snow and soil samples from a ski area in Sweden were taken after a large skiing competition and after snowmelt, respectively, and analyzed for SFAs and SFAenes. Single analyte concentrations in snow (analyzed as melt water) ranged from a few ng L⁻¹ up to 300 μg L⁻¹. ∑SFA concentrations decreased significantly from the start to the finish of the ski trail. Single analyte concentrations in soil ranged up to 9 ng g⁻¹ dw. ∑SFA concentrations in soil did not show a trend along the ski trail. This may be due to the fact that concentrations in soil, although strongly influenced by the competition, reflect inputs during the whole skiing season. The chemical inventory in snow was greater than the inventory in soil for shorter chain SFAs (C₂₂C₂₈) and for all SFAenes. Additionally, a significant change in SFA patterns between snow and soil samples was found. These observations suggested volatilization of shorter chain SFAs and of SFAenes during snowmelt. Evidence for long-term accumulation of SFAs in surface soil over several skiing seasons was not found.     

Impact of elevated CO(2) and nitrogen fertilization on foliar elemental composition in a short rotation poplar plantation

The experiment was carried out on a short rotation coppice culture of poplars (POP-EUROFACE, Central Italy), growing in a free air carbon dioxide enriched atmosphere (FACE). The specific objective of this work was to study whether elevated CO(2) and fertilization (two CO(2) treatments, elevated CO(2) and control, two N fertilization treatments, fertilized and unfertilized), as well as the interaction between treatments caused an unbalanced nutritional status of leaves in three poplar species (P. x euramericana, P. nigra and P. alba). Finally, we discuss the ecological implications of a possible change in foliar nutrients concentration. CO(2) enrichment reduced foliar nitrogen and increased the concentration of magnesium; whereas nitrogen fertilization had opposite effects on leaf nitrogen and magnesium concentrations. Moreover, the interaction between elevated CO(2) and N fertilization amplified some element unbalances such as the K/N-ratio.     

Transformation and fate of urea in pit-toilet blackwater after discharge to environment

Environmental Science and Pollution Research - Studies on urea transformation reactions in blackwater are limited as urea rapidly hydrolyses under anaerobic condition. Since ammonium content of...     

Monitoring of polycyclic aromatic hydrocarbons in a produced water disposal area in the Potiguar Basin,Brazilian equatorial margin

Environmental Science and Pollution Research - The Potiguar Basin has oil and gas production fields offshore and onshore. All treated produced water (PW) from these fields is discharged through...     

Environmental fate of chlorothalonil in a Costa Rican banana plantation

The environmental fate of chlorothalonil (CHT) and its metabolites were studied under field-variable conditions in a commercial banana plantation in Costa Rica. Weather conditions were representative of a tropical environment and the fungicide applications were typical of those in banana production. The test plots were treated with Bravo 720 at 1.2 l ha(-1) of formulated product. Field persistence of CHT in soil and on banana leaves was measured during five consecutive months and after three aerial applications of the fungicide. Residues were analyzed in soil, sediment, water, banana leaves and drift cards by gas and liquid chromatography coupled to mass spectrometry. In soil and on the surface of banana leaves, CHT dissipated rapidly with half-lives of 2.2 and 3.9 d, respectively. Soil residues persisted and were detected 85 d after application. The main metabolite found in soil, 4-hydroxy-chlorothalonil, accounted for approximately 65% of residues detected and was measured up to 6d after application.     

Canopy leaching of nutrients and metals in a mountain spruce forest

Precipitation and throughfall fluxes of major ions, nutrients (C, N, P), and metals (Al, Fe, Mn), and the chemical composition of litter fall and living plant tissue in Norway spruce stands (the Bohemian Forest; Czech Republic), were used to evaluate how microbial processes and decay of plant tissue in canopies influence canopy leaching (CL) of elements. Proton exchange for Mg²⁺, Ca²⁺, and K⁺ in decaying biomass and co-transport of Ca²⁺ and K⁺ out of plant cells with organic acid anions were the most likely processes contributing to CL of base cations. The CL of total P and N (and also NO₃^?) was minor. Important proportions of the N and P mineral forms were transformed to organic forms by microbial processes (primary and bacterial production), with the respective CL of ?13.9 and 16.4 mmol m^?2 yr^?1 for NH₄⁺ and organic N, and ?0.33 and 0.22 mmol m^?2 yr^?1 for dissolved reactive P (DRP) and organic P. Most of particulate P and N in throughfall (～90%) originated from microbial DRP and NH₄⁺ transformations, but particulate C mostly came from the fragmentation of plant tissue (58%). Among metals, CL was not observed for Al, was small for Fe (0.3 mmol m^?2 yr^?1), and greatest for Mn (0.9 mmol m^?2 yr^?1) due to leaching from decaying tissue by acidic precipitation.     

The use of a high-FeO olivine rock as a redox buffer in a nuclear waste repository

Due to the higher stability of the spent nuclear fuel (mainly composed of UO2) under reducing conditions, and in order to enhance the retention/retardation of some key radionuclides, the olivine rock from the Lovasj?rvi intrusion has been proposed as a potential redox-active backfill-additive in deep high-level nuclear waste (HLNW) repositories. In this work, two different approaches have been undertaken in order to establish the redox buffer capacity of olivine rock: (1) The capacity of the rock to respond to changes in pH or pe has been demonstrated and the final (pH, pe) coordinates agree with the control exerted by the system Fe(II)/Fe(III). (2) The rate of consumption of oxygen has been determined at different pH values. These rates are higher than the ones reported in the literature for other solids, what would point to the possibility of using this rock as an additive to the backfill material in a HLNW.     

Monod kinetics rather than a first-order degradation model explains atrazine fate in soil mini-columns: Implications for pesticide fate modelling

Pesticide transport models commonly assume first-order pesticide degradation kinetics for describing reactive transport in soil. This assumption was assessed in mini-column studies with associated batch degradation tests. Soil mini-columns were irrigated with atrazine in two intermittent steps of about 30 days separated by 161 days application of artificial rain water. Atrazine concentration in the effluent peaked to that of the influent concentration after initial break-through but sharply decreased while influx was sustained, suggesting a degradation lag phase. The same pattern was displayed in the second step but peak height and percentage of atrazine recovered in the effluent were lower. A Monod model with biomass decay was successfully calibrated to this data. The model was successfully evaluated against batch degradation data and mini-column experiments at lower flow rate. The study suggested that first-order degradation models may underestimate risk of pesticide leaching if the pesticide degradation potential needs amplification during degradation.     

Atrazine sorption and fate in a Ultisol from humid tropical Brazil

This study combined laboratory based microcosm systems as well as field experiments to evaluate the mobility of atrazine on a Ultisol under humid tropical conditions in Brazil. Results from sorption experiments fit to the Freundlich isotherm model [K(f) 0.99 mg kg(-1)/(mg l(-1))(1/n)], and indicate a low sorption capacity for atrazine in this soil and consequently large potential for movement by leaching and runoff. Microcosm systems using (14)C-atrazine to trace the fate of the applied herbicide, showed that 0.33% of the atrazine was volatilized, 0.25% mineralized and 6.89% was recorded in the leachate. After 60 d in the microcosms, 75% of the (14)C remained in the upper 5 cm soil layer indicating atrazine or its metabolites remained close to the soil surface. In field experiments, after 60 d, only 5% of the atrazine applied was recovered in the upper soil layers. In the field experiments atrazine was detected at a depth of 50 cm indicating leaching. Simulating tropical rain in field experiments resulted in 2.1% loss of atrazine in runoff of which 0.5% was adsorbed onto transported soil particles and 1.6% was in solution. Atrazine runoff was greatest two days after herbicide application and decreased 10 fold after 15 d. The use of atrazine on Ultisols, in the humid tropics, constitutes a threat to water quality, causing surface water and ground water pollution.     

Environmental fate of rice paddy pesticides in a model ecosystem.

The distribution and metabolic fate of several rice paddy pesticides were evaluated in a modified model ecosystem. Among the three BHC isomers, beta-isomer was the most stable and bioconcentrated in all of the organisms. Alpha- and gamma-isomers were moderately persistent and degraded to some extent during the 33 day period. Disulfoton was relatively persistent due to the transformation to its oxidation products. Pyridaphenthion was fairly biodegradable. N-Phenyl maleic hydrazide derived from the hydrolysis of pyridaphenthion was not detected in the organisms though it was found in the aquarium water after 33 days. Cartap and edifenphos were considerably biodegradable, and the ratio of the conversion to water soluble metabolites was very high. There was a distinct difference in the persistence of Kitazin P and edifenphos in the aquarium water. It appeared that the hydrolysis rate of the pesticides affected their fate in the organisms. PCP appeared to be moderately biodegradable. CNP was considerably stable and stored in the organisms though the concentration in the aquarium water was relatively low. The persistence and distribution of the pesticides in the model ecosystem were dependent on their chemical structures. In spite of the limitation derived from short experimental period, the model ecosystem may be applicable for predicting the environmental fate of pesticides.     

Movement and fate of detergents in groundwater: a field study

The major cations, anions, and detergents in a plume of contaminated groundwater at Otis Air Base on Cape Cod (Mass., U.S.A.) have moved approximately 3.5 km down gradient from the disposal beds. We hypothesize that the detergents form two distinct plumes, which consist of alkyl benzene sulfonates (ABS) detergents and linear alkyl sulfonates (LAS) and sodium dodecyl sulfate (NaLS) detergents. The ABS detergents were deposited from approximately 1940 through 1965, when ABS detergents were banned. From 1965 to the present, LAS and NaLS detergents were in the sewage. The ABS detergents appear to be transported in the aquifer at the same rate as the specific conductance (major cations and anions) and boron, which are currently used as conservative tracers of the plume of contaminated groundwater. There appears to be little or no biological degradation of the ABS detergents in the aquifer, based on their concentration in the plume. On the other hand, the LAS and NaLS detergents have degraded rapidly and have been detected only 0.6 km down gradient. The roleof the detergents in the transport of other organic compounds in the plume is nuclear. There is a separation of the ABS detergent plume and the volatile organic compound plume; however, the time of entry of the detergents and the volatile organic compounds is unknown. Therefore, it is not possible to conclude on the interaction of these two classes of compounds.     

Emission and fate assessment of methyl tertiary butyl ether in the Boston area airshed using a simple multimedia box model: comparison with urban air measurements

Expected urban air concentrations of the gasoline additive methyl tertiary butyl ether (MTBE) were calculated using volatile emissions estimates and screening transport models, and these predictions were compared with Boston, MA, area urban air measurements. The total volatile flux of MTBE into the Boston primary metropolitan statistical area (PMSA) airshed was calculated based on estimated automobile nontailpipe emissions and the Universal Quasi-Chemical Functional-Group Activity Coefficient computed abundance of MTBE in gasoline vapor. The fate of MTBE in the Boston PMSA was assessed using both the European Union System for the Evaluation of Substances, which is a steady-state multimedia box model, and a simple airshed box model. Both models were parameterized based on the meteorological conditions observed during air sampling in the Boston area. Measured average urban air concentrations of 0.1 and 1 microg/m3 MTBE during February and September of 2000, respectively, were comparable to corresponding model predictions of 0.3 and 1 microg/m3 and could be essentially explained from estimated temperature-dependent volatile emissions rates, observed average wind speed (the airshed flushing rate), and reaction with ambient tropospheric hydroxyl radical (*OH), within model uncertainty. These findings support the proposition that one can estimate gasoline component source fluxes and use simple multimedia models to screen the potential impact of future proposed gasoline additives on urban airsheds.     

Wetland influence on mercury fate and transport in a temperate forested watershed

The transport and fate of mercury (Hg) was studied in two forest wetlands; a riparian peatland and an abandoned beaver meadow. The proportion of total mercury (THg) that was methyl mercury (% MeHg) increased from 2% to 6% from the upland inlets to the outlet of the wetlands. During the growing season, MeHg concentrations were approximately three times higher (0.27ng/L) than values during the non-growing season (0.10ng/L). Transport of Hg species was facilitated by DOC production as indicated by significant positive relations with THg and MeHg. Elevated concentrations of MeHg and % MeHg (as high as 70%) were found in pore waters of the riparian and beaver meadow wetlands. Groundwater interaction with the stream was limited at the riparian peatland due to the low hydraulic conductivity of the peat. The annual fluxes of THg and MeHg at the outlet of the watershed were 2.3 and 0.092microg/m2-year respectively.     

The fate and importance of organics in drinking water treatment: a review

In the pioneer days, the main driving forces for research of organics in drinking water treatment (DWT) were human health risks and optimisation of technology. The focus was on natural organic matter (NOM) structure, disinfection by-products (DBPs) formation, NOM removal by means of coagulation, adsorption, and oxidation, and development of the most efficient water treatment trains. Surprisingly, after decades of research, rapid development of analytical techniques and progress in risk assessment, the same driving forces are still in the limelight — although the topics have changed slightly. The attention switched from trihalomethanes to a new generation of DBPs. The definition of hydrophilic/hydrophobic NOM depends on the technique used for characterisation. It has become evident that numerous organic compounds can threaten water supply sources. Some of them had been ignored or overlooked in the past, but have recently been detected by advanced analytical tools even in drinking water. Prioritisation becomes priority per se. As far as processes are concerned, mainstream research has been following three lines: fouling mechanisms, application of hybrid processes and interactions between synthetic organic chemicals, other water constituents and materials used in DWT. Significant development has been made in membrane technology. This paper presents a broad overview of the recent organics research. Although the state-of-the-art technologies seem to have an answer to each and every question raised, it is still necessary to deal with specific problems on a case-by-case basis mainly due to the unique nature of NOM and different xenobiotics that may appear in various types of waters. In the end, human health risk, which derives from the presence/absence of organics, is only the tip of the iceberg — underneath lies a whole new universe — the socio-economic aspect of water treatment and quality that deserves much more attention.     

Performance of a narrow buffer strip in abating agricultural pollutants in the shallow subsurface water flux

The performance of a narrow buffer strip in abating dissolved P, electrical conductivity and herbicides (terbuthylazine, alachlor, nicosulfuron, pendimethalin, linuron) in subsurface water coming from cropland was tested in an experiment carried out on the low plains of the Veneto Region (NE Italy). The experiment lasted from December 1997 to June 1999, monitoring subsurface water quality entering and exiting a buffer composed of a grass strip (5 m wide) and 1 m wide row of trees. Dissolved phosphorus concentrations were reduced by almost 100% passing through the buffer and in most cases exiting water satisfied the limit for avoiding eutrophication. A positive effect was also detected on ECW (reduced by 20%), while pH was not significantly altered. Herbicide concentration abatement varied between 60 and 90%, depending on the chemical and the time elapsed since application.     

The study of distribution and fate of nitrobenzene in a water/sediment microcosm

In November 2005, an explosion occurred at a petrochemical plant of the Jilin Petrochemical Corporation in Jilin Province, China. A nearby water body was seriously polluted with a large spill of toxic substances made up of a mixture of benzene, aniline, and nitrobenzene (NB). To understand the long term impact of NB on public health and ecosystem around the Songhua River, it was necessary to investigate its fate in the environment. In this study, a microcosm was used to mimic the polluted water system and to study the transport and fate of NB in the river water body. The volatility and biodegradation of NB was investigated and a Markov model was applied to predict the fate of NB in the environment. The simulated results matched very well with the results obtained from the microcosm experiment. The model indicated that at room temperature and after around 500 h, there was only residual NB in the water and sediment. Most of the NB (around 82%) evaporated into the air and 18% was degraded by microorganisms.     

Effect of photosensitizer riboflavin on the fate of 2,4,6-trinitrotoluene in a freshwater environment

The effect of riboflavin (1 microM) on the fate of TNT (20 mg/l) in a natural water environment was studied. The relative contribution of photolysis, microbial assemblages and freshwater matrix to TNT degradation was examined. The rates, extent and products of TNT and riboflavin transformation were compared under different experimental conditions. It was found that riboflavin significantly enhanced the degradation of TNT in natural water environment. Thus it is a potentially useful photosensitizing agent for the treatment of TNT-contaminated surface water. Furthermore, in the presence of riboflavin, two new intermediates with max. absorption wavelength of 230 nm were found, demonstrating that transformation of TNT in the presence of riboflavin undergoes different pathways.     

Distribution and fate of metals in the dispersion plume of a major municipal effluent

The environmental impacts of municipal wastewater discharges on receiving waters are numerous and inputs of contaminants such as metals can cause toxicity to organisms in receiving waters. The effluents generated by the treatment plant of the city of Montreal, Canada, the largest such facility in the St. Lawrence Valley, was investigated to determine the environmental fate of trace metals in the receiving waters. Total and extractable metal concentrations were determined and physico-chemical parameters were measured to characterize the receiving waters and evaluate their influence on the fate and behaviour of metals released from the urban effluent. Our results showed that particulate metals near the effluent discharge point are highly reactive and their distribution seems to be significantly influenced by the abundance of HCl-reactive iron and manganese, which act as trace-metal carriers. The partitioning of metals between dissolved and particulate phases varies along the effluent dispersion plume and therefore could strongly influence the exposure routes for aquatic organisms that are exposed to the various contaminants released from the effluent.     

Monitoring of organochlorine pesticides residues in green mussels (Perna viridis) from the coastal area of Thailand

The utilization of organochlorine pesticides for pest control chemical has been of great interest on residue contamination from biological organisms in the environment. Green mussel (Perna viridis) samples were monitored as bioindicators for assessment of the water quality in coastal waters along the Gulf of Thailand. Thirty-six samples were collected from 12 stations during 1997-1999 and analysed for 26 organochlorine pesticide compounds. This paper focuses on the contamination of organochlorine pesticide residues in green mussel (P. viridis) during 1997-1999. The limit of detection of all organochlorine pesticides compounds was at the range of 0.1-8.3 ng g(-1) wet weight and recovery 75-95%. The concentration of organochlorine pesticides residues in green mussel was lower than the maximum residue limit for aquatic animals as recommended by the Ministry of Public Health of Thailand. The trend of organochlorine pesticide residue contamination in this area decreased from 1989 to 1999.