Fluoride, a common phytotoxic air, water and soil pollutant is commonly released to the environment by a number of industrial processes. Agricultural soils high in fluoride are common due to long term accumulation of fluoride from multi-sources and extensive application of phosphate fertilizers. The effect of sodium fluoride (0, 50,100,150 mM) on growth, pigments content, changes in biochemical parameters, along with fluoride and other ions accumulation was investigated in Salicornia brachiata grown in solution cultures under controlled conditions. With fluoride treatment growth as fresh or dry mass accumulation increased marginally. However, higher concentrations decreased the biomass and shoot tip became blunt; margin of the shoot changed its colour to reddish brown and developed necrotic spots. Photosynthetic pigments (chlorophylls and carotenoids) content decreased, while, anthocyanin content increased significantly with fluoride treatment. Peroxidase (POX), superoxide dismutase (SOD), ATPase and acid phosphate activities were negatively regulated. In addition F-, Na⁺, Mn²⁺ and Fe²⁺ ions concentration increased while, K⁺, Ca²⁺ and Mg²⁺ contents decreased with fluoride treatment. To our knowledge this is the first report on fluoride tolerance in a marshy halophytes using as high as 150 mM concentration and the results suggest that S. brachiata is a moderately fluoride tolerant annual halophyte and may be useful to vegetate the fluoride contaminated marshy lands.

Sediments from 18 different road runoff detention systems, located on the Swedish West Coast, were assessed for their ecological hazard potential. Thirteen of the sites were detention ponds, three were manholes within the same sedimentation construction, and two were detention basins handling wash water from road tunnels. Sediments from all sites were analysed for a range of physico-chemical parameters and contaminants, and screened for acute toxicity using Hyalella azteca (sediment), Daphnia magna (elutriate), and Ceriodaphnia dubia (elutriate) as the test organisms, and for chronic toxicity using C. dubia as the test organism. The benthic fauna of the thirteen detention ponds was also studied. Sediment quality guidelines probable effect levels were exceeded for one or several contaminants at half of the sites, and one third revealed toxicity in some of the bioassays. Most of the detention ponds were dominated by tolerant taxa indicating low biological quality. Relationships between contaminant concentrations, toxicity in bioassays, and benthic fauna were, however, found to be weak. Extractable organic Zn, which was used as a tire wear marker, correlated with Zn, Cu, presumably from brake linings, and W, a common component of tire studs. The highest concentration, which was found in the manholes (14 mg kg⁻¹ ds), corresponds to a tire wear concentration of 11 g kg⁻¹ ds. The results of the present study have shown that traffic related contaminants accumulate in the studied runoff treatment systems, and, therefore, the maintenance of them is crucial in order to prevent contamination of surrounding waters.

While hydrophilic compounds are degraded easily in Trickling bed air biofilters (TBABs), hydrophobic compounds are retarded until biological cultures produce a sufficient RNA or enzyme/protein to utilize this compound. Hydrophobic compounds are not readily bio-available which makes them reluctant to biodegradation as mass transfer between the gas and liquid phases is a rate limiting step. To enhance the destruction of hydrophobic compounds in TBABs, the utilization of surfactant was introduced to increase the solubility which helps overcoming the rate limiting step. The surfactant was used as well to limit the growth of excess biomass ensuring smooth flow through the biofilter bed and preventing short circuits. Two different non-ionic non-toxic surfactants were used in this study: Triton X-100 and Tomadol® 25-7. Two lab-scale controlled TBABs were operated for investigating the performance difference for n-Hexane as an example of hydrophobic volatile organic compound (VOC) with and without the addition of surfactant. Operating conditions in both TBABs were as follows: nutrient feed rate (2L/day), air flowrate (1.4L/min), bed depth (60cm), empty bed retention time (120s), bed material (diatomaceous earth pellets) and room-temperature. The inlet concentration was changed from 50 to 100ppmv. Acclimation period, removal profile along biofilter depth, nitrogen consumption, and CO₂ production were compared under continuous loading operation condition. The optimum concentration of surfactant in the nutrient feed was determined by a batch experiment. The effect of different surfactant concentrations on VOC water solubility with time was studied by considering different VOC concentration sets within the TBAB loading rate range.

An open limestone channel (OLC) was constructed within an existing drain to treat the acidic and metal-rich drainage waters generated from an acid sulfate soil (ASS) catchment. The OLC was constructed downstream of a catchment pump and it consisted of a series of ponds and limestone sections. The accumulation of sediment over the limestone, preventing contact of limestone with acidic water, was the greatest problem impacting the OLC in its first year of operation. The continuous or sporadic operation of the catchment pump (at 120 l/s) was not sufficient to flush sediment from the limestone. The accumulation of large amounts of sediment onto the limestone reduced the amount of alkalinity and calcium released into solution. However, if the sediment is removed by agitating the limestone then an equivalent or greater amount of alkalinity may be added to solution and more metals removed from solution compared to fresh limestone. The coating on the limestone had a high concentration of manganese oxides in addition to slightly lower concentrations of aluminium and iron. Removal of these metals from the water was due to the increase in pH produced by limestone dissolution in addition to sorption reactions of the existing coating which had natural microbial activity.

In this study, we evaluated the relative contribution of atmospheric particulate mercury (Hg(p)) and divalent reactive gaseous mercury (RGM) to mercury dry deposition in Japan. The dry deposition fluxes (on a water surface sampler) and atmospheric PM concentrations of Hg, Cd, Cu, Mn, Ni, Pb and V, which were measured concurrently from April 2004 to March 2006 at 10 sites across the nation, were used in this evaluation. We considered that Hg(p) and RGM, but not Hg⁰, are deposited on the water surface, and that our method of sampling Hg(p) without the use of KCl-coated annular denuders enables the exclusion of a significant amount of RGM artifact. The monthly average dry deposition velocities (= deposition flux/atmospheric PM concentration) of Cd and Pb were found to be similar to each other (Cd/Pb deposition velocities = 1.06 ± 0.58). It was assumed that the deposition velocity of Hg(p) is identical to the mean deposition velocity of Cd and Pb, because the particle size distribution of Hg(p) is likely similar to those of both elements. Using this deposition velocity, the monthly dry deposition flux of Hg(p) was calculated. The average contribution (±1σ) of Hg(p) to the annual deposition flux at ten sites was 26 ± 15%. The mercury dry deposition flux increased generally from spring to early summer, which was attributed mostly to the deposition of RGM. This seasonal change correlated to that in photochemical oxidant (primarily O₃) concentration in air at most sites. These suggest that mercury dry deposition in Japan is predominantly deposition of RGM, which was formed via oxidation of Hg⁰ by O₃ in the atmosphere.

The enrichment factor, multivariate analysis and metal speciation studies were used to identify degree, source and dispersal of metal contamination in Khli Ti watershed, Thailand. Topsoil samples were collected throughout the watershed, analyzed for total metal concentration. Sequential extraction was also carried out to determine geochemical phases of metals which were identified as exchangeable and bound to carbonates, Fe–Mn oxides, organic matter and residuals. Soil characteristics including pH, total organic carbon, redox potential, cation exchange capacity and texture were also analyzed. Principal component analysis yielded three metal groups which explained 83% of the variance. The concentrations of metals which were derived from lithogenic origin, such as Co, Cr, Fe, Ni and V were in natural background levels and were mostly bound to the residual phase. The remaining elements (i.e. Ba, Cd, Cu, Pb, Sb and Zn) were associated with the contamination from previous activities of the Pb-ore concentrator and Zn–Pb mining. Anthropogenic contamination mainly increased Pb and Zn bound to Fe–Mn oxides at the expense of residual fraction. Even though low exchangeable Pb contents in Khli Ti soils indicated low availability to plants, Pb bound to Fe–Mn oxides fraction might increase its mobility under reducing conditions.

Istanbul, housing a population over ten million and with population increase rate of approximately twice that of Turkey, is one of the greatest metropolitan cities of the world. As a consequence of rapid population growth and industrial development, Omerli watershed is highly affected by wastewater discharges from the residential areas and industrial plants. The main objective of this study is to investigate the temporal assessment of the land-use/cover of the Omerli Watershed and the water quality changes in the Reservoir. The study is mainly focused on the acquisition and analysis of the Satellite Probatoire de l'Observation de la Terre (SPOT) (1993), Indian Remote Sensing satellite (IRS) (1996 and 2000) and Landsat Thematic Mapper (TM) (2004, 2005, and 2006) satellite images that reflect the drastic land-use/cover changes utilizing the ground truth measurements. The rapid, uncontrolled, and illegal urbanization coupled with insufficient infrastructure has caused the deterioration of the water quality within the past two decades in the Omerli watershed. The water quality analysis of the drinking water Reservoir within the watershed is investigated using 2006 dated Landsat TM satellite digital data. The results are compiled and compared with the water quality measurements of parameters like total nitrogen (TN), the total phosphorus (TP), chlorophyll a (CL) and total dissolved solids (TDS). The observed reflectance shows a strong relationship with the water quality parameters and thus, the satellite data proved to provide a useful index of TN, TP, CL and TDS. Moreover, the linkage between the water quality parameters and the individual band reflectance values are supported by multiple regression analysis.

The phytoremediation potential of water hyacinth, Eichhornia crassipes (Mart.) Solms, was examined in two independent studies under nitrogen (N) rates of 0, 40, 80, 100, 150, 200, and 300 ppm. A modified Hoagland solution was added to ponds containing water hyacinths which were rated and measured weekly for 4 weeks. The hyacinths accounted for 60–85% of the N removed from solution. Net productivity, as measured by dry matter gain, increased with an increase in N rate until 80 ppm. Above that level dry matter productivity was similar. Tissue N increased linearly with dry matter gain, but total nitrogen removal from the water increased exponentially with net dry matter gain or with an increase in canopy cover. The relation between total N in plant tissue and N removal from the water was similar for the two experiments.

Different nitrogen (N) fractions from 14 sediments from the shallow lakes in the middle and lower reaches of Yangtze River area before and after N release experiments were investigated, and the content of different N fractions, and contribution of different N fractions to the N released from sediments were also studied. Ion-exchangeable form (IEF-N), carbonate form (CF-N), iron-manganese oxide form (IMOF-N) and organic matter-sulfide form (OSF-N) accounted for 2.72~17.67%, 0.47~4.43%, 1.18~3.49% and 31.05 to 71.61% to total N, respectively. The N released was higher than 50% from IEF-N, approximately 35% from OSF-N, 6 and 8% from CF-N and IMOF-N on the average. Approximately 27.32~70.02% of IEF-N, 10.37~32.11% of CF-N, 11.37~33.43% IMOF-N and 2.02~8.19% OSF-N were released. For the sediments that were slightly polluted, IEF-N was the main N fraction that may be released and its contribution to total N released was more than 63.07%, for the sediments that TN was higher than 3,540.27 mg·kg-¹, OSF-N would become the main N fraction that can be released and its contribution to total N released was more than 45%.

This study investigated particulate matter (PM) granulometry delivered in source area runoff as a function of hydrologic transport and settling. At a Baton Rouge, LA paved urban watershed, event runoff volume and PM load were “fully captured” and recovered in settling tanks. Events were differentiated as mass-limited (ML) or flow-limited (FL) and PM differentiated into suspended (1 to ~25 μm), settleable (~25 to 75 μm), sediment (75 to 4,750 μm) fractions; and also particle size distributions (PSDs). Suspended sediment concentration (SSC)-turbidity relationships were unique for FL events compared to ML events; while 60 min of quiescent settling produced a single distinct relationship across all events. ML events transported higher proportions of settleable and sediment mass compared to higher suspended mass for FL events. Event-based ratios of settled and unsettled turbidity as well as SSC mass were statistically different for ML and FL events. For the same settling conditions, treatment of ML and FL events were statistically different. Results demonstrated that PM separation by a unit operation was a deterministic function of granulometry, hydrodynamics, unit operation mechanisms and loads, but significantly influenced by the indeterminate nature of local climate; and hydrology which drives PM delivery and is not known a priori. Combining the influences of scour and lack of maintenance, unit operation performance is non-stationary and cannot be described by a single value. Treatment should be tied to an effluent concentration; granulometry and load.