The use of two new ligands, (1Z)-1-(4-aminophenyl) ethan-1-one semicarbazone (L¹) and (1Z)-1-(4-nitrophenyl)ethan-1-one semicarbazone (L²), was evaluated for their potential use as chelators in increasing phytoremediation effectiveness. The uptake of heavy metals by Teddy Bear sunflowers increased when L¹ added at 0.1 and 0.3 g/kg. Metal uptake selectivity was Cr > Ni ≫ Cd for each treatment. The 0.1-g/kg L¹ ligands produced a significant uptake of metals in Sundance sunflowers. The 0.3-g/kg L¹ level increased the metal uptake, but it was lower than 0.1-g/kg L¹ treatment. The uptake selectivity with L² ligand was Cr > Ni > Cd, with the majority of metals retained in the roots. L¹ ligand was better compared in comparison to L² ligand for enhancing uptake of metals.

Phytoextraction is a soil remediation technique involving plants that concentrate heavy metals in their shoots, which may be removed from the area by harvest. The application of synthetic chelants to soil increases metal solubility, and therefore enhances phytoextraction. However, synthetic chelants degrade poorly in soil, and metal leaching poses a threat to human and animal health. The aim of this study is to assess the use of two biodegradable chelants (citric acid and nitrilotriacetic acid (NTA)) for Pb phytoextraction by maize from a soil contaminated by battery-casing disposal. In order to assess the behavior of a non-degradable chelant, ethylenediaminetetraacetic acid (EDTA) was also included in the experiment. The chelants NTA and EDTA were applied to soil pots at rates of 0, 3, 5, 7, and 10 mmol kg⁻¹ of soil. The rates used to citric acid were 0, 5, 10, 15, and 30 mmol kg⁻¹. Maize plants were grown for 72 days and chelants were applied 9 days before harvest. Soil samples were extracted with CaCl₂ to assess the Pb solubility after chelants application. The results showed that NTA was more efficient than citric acid to solubilize Pb from soil; however, citric acid promoted higher net removal of Pb (120 mg pot⁻¹) than NTA (57 mg pot⁻¹). Thus, the use of citric acid, a biodegradable organic acid, could be feasible for enhancing the phytoextraction of Pb from the site studied with no environmental constraints.

Reductive dechlorination of tetrachloroethylene (PCE) by green rust modified with copper (GR(Cu)) was investigated using a batch reactor system. Four different forms of GRs (GR-Cl, GR-SO₄, GR-CO₃, and GR-F) were synthesized by partial air oxidation of Fe(OH)₂ and used in reductive dechlorination. The addition of Cu(II) into GRs produced 100-nm particles on the surface of GRs, which were considered to be metallic Cu and transformed a portion of GR to magnetite. Concentration of Fe(II) in the liquid phase increased and concentration of Fe(II) in the solid phase decreased during the modification process and the extent of these changes was dependent on the amount of Cu(II) added. The most reactive of the modified GRs was GR-F(Cu), which reacted with PCE at a rate that was 80 times faster than that of GR-Cl(Cu). The rate of PCE degradation by GR-F(Cu) was strongly dependent on pH with higher rates at higher pH over the range of pH 7.5-11. Increasing concentrations of Cu(II) over the range of 0 to 5 mM increased rate constants. The rate of dechlorination of PCE by GR-F(Cu) showed surface saturation behavior with respect to PCE concentration.

Diverting the infiltrating water away from the zone of N application can reduce nitrate-nitrogen (NO₃-N) leaching losses to groundwater from agricultural fields. This study was conducted from 2001 through 2005 to determine the effects of N-application methods using a localized compaction and doming (LCD) applicator and spoke injector on NO₃-N leaching losses to subsurface drainage water and corn (Zea mays L.)-soybean (Glycine max L.) yields. The field experiments were conducted at the Iowa State University's northeastern research center near Nashua, Iowa, on corn-soybean rotation plots under chisel plow system having subsurface drainage ‘tile' system installed in 1979. The soils at the site are glacial till derived soils. The N-application rates of 168 kg-N ha⁻¹ were applied to corn only for both the treatments each replicated three times in a randomized complete block design. For combined 5 years, the LCD N-applicator in comparison with spoke injector showed lower flow weighted NO₃-N concentrations in tile water (16.8 vs. 20.1 mg L⁻¹) from corn plots, greater tile flow (66 vs. 49 mm), almost equivalent NO₃-N leaching loss with tile water (11.5 vs. 11.3 kg-N ha⁻¹) and similar corn grain yields (11.17 vs. 11.37 Mg ha⁻¹), respectively, although treatments effects were found to be non-significant (p = 0.05) statistically. The analysis, however, revealed that amount and temporal distribution of the growing season precipitation also affected the tile flow, NO₃-N leaching loss to subsurface drain water, and corn-soybean yields. Moreover, the spatial variability effects from plot to plot in some cases, resulted in differences of tile flow and NO₃-N leaching losses in the range of three to four times despite being treated with the same management practices. These results indicate that the LCD N-applicator in comparison with spoke injector resulted in lower flow weighted NO₃-N concentrations in subsurface drain water of corn plots; however, strategies need to be developed to reduce the offsite transport of nitrate leaching losses during early spring period from March through June.

Polycyclic aromatic hydrocarbons (PAHs); their derivatives nitro, and methyl-PAHs; n-alkanes; and organic acids were investigated in the aerosol samples collected during two field campaigns conducted at three sampling stations in an industrialized city in southern Italy. The main sources affecting the atmosphere and its toxicity were investigated by means of the diagnostic ratios of: specific particulate-phase PAHs, marker compounds among nitro-PAHs, alkanes, and acids, the dominant wind direction, daily and seasonal abundance of carcinogenic organic substances. The potential importance of the non-regulated pollutants to assess the air quality was confirmed; in fact the carcinogenic organic compounds showed to have scarce correlation with particulate matter (PM) concentration. An exceptionally high variability of toxic compounds at a daily scale was due to meteorological condition causing periods of extremely high pollution levels.

There is evidence in the literature that the ratio of mass of sorbent (M) to volume of solution (V) affects the results of batch tests with soils and sediments. This restricts the use of such data to conditions with the same M/V ratio they were derived with, unless its influence is corrected. To find a correction, we conducted batch tests with soil and zinc solution using four M/V ratios. For each ratio, the experiments produced a different relationship between the mass of zinc sorbed per unit mass of soil (a s) and the zinc concentration in the solution after shaking and removal of the solid phase (C det), which is usually taken as the equilibrium concentration (C eq). A theoretical analysis revealed that the M/V effect can be accounted for by dividing C det by the M/V ratio, if it is caused by the presence of a “third phase”. The relationship between a s and C det×V/M is the same for all ratios then.

The current study investigated the sorption of sulfadimethoxine (SMT), sulfamethoxazole (SMX), tetracycline (TET), and oxytetracycline (OTC) to Na-rich montmorillonite clay in synthetic effluent (SE) and field wastewater effluent (FE). Both SMT and SMX showed a low sorption capacity and are therefore likely to be highly mobile in the environment, while the sorption of TET to clay in environmental pH range (6.5-7.5) showed similarly high adsorption capacity. Differences in sorption capacities of TET and OTC to SE or FE were attributed to the various concentrations of divalent cations in the effluents. In addition, differences in sorption of OTC or TET to SE were attributed to their different molecular structure. Moreover, the adsorption of TET in SE and FE showed linear adsorption isotherms and fitted to Freundlich model. Further experiments showed that addition of humic acid or SE to TET sorbed to clay did not enhance or suppress the sorption of TET to clay.

Thermogravimetry (TG) was used to investigate the pollution on marine sediments close to urban and industrial sites. Sediment weight loss when heated (TG) was performed under oxidizing conditions from 250°C to 900°C. The first derivative of TG curves was used to generate a Cartesian diagram for sediments cataloging, in a quick way, according to their organic matter and grain size contents. Thus, sediment placed at the right of the diagram were characterized by a prevalence of the thin fraction and high organic matter content, while on the left side, samples were characterized by large sandy fractions, and, in general, low organic matter contents. Two references materials and metal pollution index were used to validate the Cartesian diagram obtained.

An ozone forecasting system has been developed based on the CALGRID photochemical dispersion model. The system is implemented as an experimental operational web service at the LaMMA Consortium to forecast ozone pollution over Tuscany region, Italy. It takes advantage of two daily forecasts, one reproducing the meteorology over Tuscany and the other providing chemical boundary conditions. Meteorological forecasts are performed by the Weather Research and Forecasting Nonhydrostatic Mesoscale Model (WRF-NMM) mesoscale model, which is operative at LaMMA for the daily forecasting service. Calculated at a 10-km resolution, WRF-NMM outputs are downscaled to the 4-km system's final resolution through the CALMET diagnostic model. Daily boundary conditions are forecast by the CHIMERE dispersion model of the PREV'AIR European air quality forecasting system. Since CHIMERE uses the MELCHIOR chemical mechanism, a suitable species conversion was required to the SAPRC-90 mechanism implemented in CALGRID. Emission data are provided by the Regional Inventory of the Sources of Emissions of the Tuscan Regional Authority. Each day, a 96-h simulation is run starting from 00 UTC of the preceding day, used to merely initialize the system, resulting in a 3-day forecast of ozone from today issued to the web in terms of ozone daily mean and maximum concentrations over Tuscany. The system was experimentally run over May to September 2007, resulting in a good accuracy compared to station observations.

This study aimed at determining the water quality of River Sirimon and River Kongoni, Ewaso Ng'iro North Basin, Kenya. Water quality analysis of these two rivers was done for a period of 5 months between November 2005 and February 2006. Portable Palintest equipment was used for the chemical analysis. The study established that there were sulphates concentrations of 22 mgL⁻¹ in the Kongoni River water associated with the use of commercial fertilisers as compared to mean values of 7 mgL⁻¹ along Sirimon River; phosphate concentrations were 1.3 mgL⁻¹ in Kongoni and 0.15 mgL⁻¹ in Sirimon and salinity 3 mgL⁻¹ in Kongoni and 0.47 mgL⁻¹ in Sirimon. On average, mean nitrates concentrations of 1.7 mgL⁻¹ were recorded for Kongoni River, which were higher than those recorded for Sirimon River (0.033 mgL⁻¹). These concentration levels were however within the standard levels set by WHO for example 50 mgL⁻¹ for nitrates (WHO 2008). River Kongoni has two major irrigated horticultural farms across it which were likely polluting the river during the time of this study.