Immobilizing materials such as lherzolite could reduce metal bioavailability but the effectiveness of lherzolite on the extractability and bioavailability of cadmium (Cd) and zinc (Zn) is rarely investigated. We conducted a greenhouse experiment to investigate the effect of 5% application of lherzolite to a contaminated soil on the chemical fractionation of Cd and Zn and their uptake by radish (Raphanus sativus L.) and Japanese mustard spinach (Brassica rapa L. var. perviridis). Both plants were grown in a highly contaminated (with Cd and Zn) sandy loam soil. Plants were cultivated consecutively three times in the same pots. After the third cultivation, soil samples were collected and analyzed by sequential extraction procedure into five operationally defined fractions (F1—exchangeable, F2—carbonate-bound, F3—oxides-bound, F4—bound with organic matter, and F5—residual). Addition of lherzolite to soil decreased 50% of exchangeable (F1) Cd but it increased the carbonate (F2), oxide (F3), and organic (F4) fraction Cd. For Zn, application of lherzolite resulted into the reduction of both F1 (87%) and F2 (33%) fractions but it increased the F3, F4, and F5 fractions. The reduction in exchangeable fraction of Cd and Zn in the soil resulted in higher plant growth and lower concentrations of both Cd (64% to 92%) and Zn (78% to 99%) in plant tissues of both plant species grown. We may thus conclude that application of lherzolite resulted into lower availability of these metals in the soil leading to lower uptake of Cd and Zn by plant roots, lower toxicity, and ultimately higher plant growth.

Nonpoint source pollution management initiated by the Ministry of Environment (MOE) in Korea resulted to the construction of 25 pilot facilities termed Best Management Practices (BMPs) until 2005. The national nonpoint sources control projects were employed to fulfill the Total Maximum Daily Load programs. The long-term monitoring being conducted at the sites which began in 2006 is providing detailed insight into the performance of the BMPs. The experience and performance data will be used to better understand and implement similar structural BMPs in the future as well as to assist the MOE in developing the design and maintenance guidelines of BMPs. This study presents the results gathered from the monitoring field tests and experiments over 22 rainfall events between the June 2006 and September 2008 period investigating the pollutant removal efficiency of the infiltration trench BMP that is one of the 25 pilot projects of the MOE. In addition, it includes the development of simple linear regression models to estimate constituent event mean concentration. The results reveal high treatment efficiencies for total suspended solids (89%); biochemical oxygen demand, chemical oxygen demand, and dissolved organic carbon (89-93%); oil and grease (100%); cadmium, lead, and zinc (89-93%); total nitrogen (84%); and total phosphorus (82%). The monitoring data and results will represent a step forward to a better prediction of impacts in the environment and to the national development of BMPs for sustainable watershed management in the country.

The effectiveness of persulfate oxidation for the destruction of tetrachlorobiphenyl a representative polychlorobiphenyl (PCB), in spiked subsurface soils was evaluated in this study. Kaolin and glacial till soils were selected as representative low permeability soils; both soils were spiked with 50 mg PCB per dry kilogram of soil. Activation of persulfate oxidation was necessary to achieve effective destruction of PCBs in soils. As persulfate oxidation activators, temperature and high pH were used in order to maximize PCB destruction. In addition, the effect of oxidant dose and reaction time was investigated. The optimal dose for persulfate was found to be 30% for maximum oxidation. The persulfate activation with temperature of 45°C was superior to persulfate activation with high pH (pH 12), where higher PCB destructions were observed for kaolin and glacial till soils. PCB destruction increased with reaction time, where maximum degradation was achieved after 7 days. The highest PCB destruction was achieved with temperature activation at 45°C using a dosage of 30% persulfate at pH 12 for kaolin and glacial till soils after 7 days.

Cadmium-contaminated soils can be re-used and also produce biomass energy if we plant soybeans or other biomass crops in the contaminated sites. In this study, two soils with pH values of 5.9 and 6.7 were artificially spiked to make their final total concentration as CK (about 1.0), 3.0, and 5.0 mg Cd kg⁻¹. Different amendments were mixed with these artificially Cd-contaminated soils to study the effect on the growth and Cd uptake of soybean, which include control (without amendment addition), powder-activated carbon (1%), and biosolids (sludge, 5%), respectively. Three kilograms of the treated soils was added into each pot and sowed 10 seeds of soybean (Leichardt species). The experiment was conducted in a 25°C greenhouse and controlled the soil water contents in the levels of 50-70% water holding capacity during the experimental period. Plants were harvested after growing for 90 days, and their fresh weights, dry weights, and plant heights were determined and recorded. Compared with the lower pH soil (5.9), soybeans were higher and have higher fresh weights and dry weights when growing in the higher pH soil (6.7). For most of the treatments, the two amendments had no significant effects on the plant heights of soybeans. For 3.0 or 5.0 mg Cd kg⁻¹ soil, the application of biosolids has significant effect on increasing the fresh weights and dry weights of soybeans (p < 0.05). However, there were no specific effects of applying activated carbons on the fresh weights and dry weights of soybeans.

Purpose Contamination with petroleum hydrocarbons (PHC) is a global problem with environmental implications. Physico-chemical treatments can be used for soil cleanup, but they are expensive, and can have implications for soil structure and environment. Otherwise, biological remediation treatments are cost-effective and restore soil structure. Several remediation experiments have been carried out in the lab and in the field; however, there is the challenge to achieve as good or better results in the field as in the laboratory. In the ambit of a project aiming at investigating suitable biological remediation approaches for recovering a refinery contaminated soil, we present here results obtained in bioremediation trials. The approaches biostimulation and bioaugmentation were tested, in parallel, and compared with natural attenuation. For this purpose, mesocosm experiments were carried out inside the refinery area, which constitutes a real asset of this work. Methods Soil contaminated with crude oil was excavated, re-contaminated with turbine oil, homogenised and used to fill several 0.5 m³ high-density polyethylene containers. The efficiency of procedures as follows: (1) natural attenuation; (2) manual aeration; (3) biostimulation by adding (3.1) only nutrients; and (3.2) nutrients and a non-ionic surfactant; and (4) bioaugmentation in the presence of added (4.1) nutrients or (4.2) nutrients and a non-ionic surfactant were evaluated after a 9-month period of experiment. For bioaugmentation, a commercial bacterial product was used. In addition to physico-chemical characterization, initial and final soil contents in total petroleum hydrocarbons (TPH) (by Fourier transform infrared spectrophotometry) and the total number of bacteria (by total cell counts) were carried out. For TPH degradation evaluation the soil was divided in four fractions corresponding to different depths: 0-5; 5-10; 10-15; and 15-20 cm. Mean values of percentages of PHC degradation varied between 20 and 50% at surface and between 10 and 35% below 5-cm depth. Natural attenuation was as efficient as most of the tested treatments (about 30% TPH degradation) being exceeded only by bioaugmentation combined with nutrient and surfactant amendments (about 50% TPH degradation). Higher TPH degradation at surface suggests that a combination of sufficient dioxygen, propitious for aerobically degradation, with sunlight required for production of strong photochemical oxidants like ozone, contributed for enhancing degradation. Indeed, the atmosphere of the refineries is relatively rich in volatile organic compounds and nitrogen dioxide (a side-product of the combustion of residual volatile PHC released by the chimneys), which are precursors of O₃ and other photochemical oxidants produced in sunny days, which are very common in Portugal. The fact that natural attenuation was as efficient as most of the soil treatments tested was very probably a result of the presence, in the initial soil, of physiologically adapted native microorganisms, which could be efficient in degrading PHC. Conclusions A cost-effective way to reduce half-life for the degradation of PHC of contaminated soil of the refinery will be a periodic revolving of the soil, like tillage, in order to expose to the oxidative atmosphere the different layers of contaminated soil. A combination of soil revolving with bioaugmentation together with nutrients and surfactant amendments may result in an additional improvement of PHC degradation rate. However, this last procedure will raise markedly the price of the remediation treatment.

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.

Sulfonamide antibiotics can enter agricultural soils by fertilisation with contaminated manure. While only rough estimations on the extent of such applications exist, this pathway results in trace level contamination of groundwater. Therefore, we studied the transport of three sulfonamides in leachates from field lysimeters after application of a sulfonamide-contaminated liquid manure. In a 3-year period, the sulfonamides were determined in 64% to 70% of all leachate samples at concentrations between 0.08 to 56.7 µg L⁻¹. Furthermore, sulfonamides were determined in leachates up to 23 months after application, which indicated a medium- to long-term leaching risk. Extreme dry weather conditions resulted in highest dislocated amounts of sulfonamides in two of the three treatments. Furthermore, soil management such as tillage and cropping affected the time between application and breakthrough of sulfonamides and the intra-annual distribution of sulfonamide loads in leachates. Although the total sulfonamide leaching loads were low, the concentrations exceeded the limit value of the European Commission of 0.1 µg biocide L⁻¹ in drinking water in more than 50% of all samples. Furthermore, the medium-term mean concentration of the sulfonamides ranged from 0.08 and 4.00 µg L⁻¹, which was above the limit value of the European Commission in 91 out of 158 samples. Therefore, sulfonamides applied to soils in liquid manure under common agricultural practice may cause environmental and health risks which call for a setting up of more long-term studies on the fate of antibiotics.

A method that utilizes solid-phase microextraction (SPME) coupled with gas chromatography (GC) and chemical ionization tandem mass spectrometry (MS/MS) was developed for analyzing a group of emerging pollutants, N-nitrosamines, in water. The developed analytical method requires a water sample of less than 5 ml and only 1.5 h for complete analysis. The method detection limits for N-nitrosodimethylamine (NDMA), N-nitrosodiethylamine, and N-nitrosodi-n-propylamine were in the range of 3.2 to 3.5 ng/l; for N-nitrosomorpholine, it was 15.2 ng/l. The method was successfully employed to measure the N-nitrosamine concentration at trace levels of nanogram per liter in four water treatment plants (WTPs) and one water distribution system. In the WTPs, only NDMA was detected in the treatment processes. Within the treatment train, NDMA was observed after chlorination. The level of NDMA significantly declined after slow sand filtration due presumably to microbial degradation. The NDMA concentration collected from consumer tap water was about 40% higher on average than that in the finished water. The excellent performance of the SPME/GC/MS/MS method in various water matrices as well as the shorter analysis time and smaller sample volume compared to currently used extraction techniques makes it an alternative means for the analysis of N-nitrosamine in drinking water, wastewater, and laboratory research with small reactors.

The adsorption and photocatalytic degradation of methyl orange (MO) aqueous solution under visible light illumination by polythiophene/titanium dioxide (PTh/TiO₂) composite particles were studied. The experimental observations from UV-vis spectrophotometer indicate that MO molecules were degraded in a different degree during the visible light-induced photocatalysis reaction. We propose a new degradation mechanism of MO during the photocatalytic reaction, based on blue shift of UV-vis absorption spectra of MO solution and other researches. The data from total organic carbon analyzer definitely prove that MO can be mineralized to CO₂ and H₂O, and some intermediate products are generated during the photocatalysis degradation of MO.

Amine-functionalized SiO₂/TiO₂ photocatalytic films have been synthesized using the peroxo titanic acid (PTA) approach coupled with the sol-gel dip-coating method. The 3-aminopropyl-trimethoxysilane (APTMS) and methyltrimethoxysilane (MTMOS) were employed as the amine functional groups and silica precursor. The effects of the ratio of APTMS/MTMOS, PTA refluxed time, and pH of prepared sol on the characteristics and the formaldehyde degradation efficiency were investigated. Physicochemical properties of prepared photocatalysts were characterized with nitrogen adsorption-desorption isotherm measurement, SEM, X-ray diffraction (XRD), UV-vis spectrophotometer, and Fourier transform infrared (FTIR) spectroscopy. The XRD and FTIR results indicated that the obtained photocatalysts consisted of -NH₂ groups, SiO₂, and anatase TiO₂. The photocatalytic films showed high transmittance of 80-90% in the visible light region. The obtained film prepared with the APTMS/MTMOS ratio of 0.03, pH of 1.8, and 10 h of refluxed time possessed high specific surface area (604.0 m² g⁻¹) and 85% formaldehyde degradation efficiency. The enhancement of formaldehyde degradation efficiency was observed when increasing the PTA refluxed time. The repeatability of photocatalytic film was also tested, and the degradation efficiency was 92.0% of initial efficiency after seven cycles.