The proposed and validated method for determination of ⁹⁰Sr content in environmental samples (water, soil and plant) is based on the radiochemical analytical separation of ⁹⁰Y from the sample and measuring its activity after the establishment of radioactive equilibrium with ⁹⁰Sr. Validation is the confirmation by examination and provision of objective evidence that they meet the individual requirements stipulated for a specific use. Validation of method was done based on the blank samples for water by adding ⁹⁰Sr known activity and using reference materials of soil (IAEA-326) and plant (IAEA-330). Content of ⁹⁰Sr in environmental samples was determined by α/β low level proportional counter. The accuracy and the precision of the applied method are confirmed and the method is validated and can be used for determination of ⁹⁰Sr in environmental samples. On the other hand, participations in interlaboratory comparisons are confirmed that the adequacy of the validated method is ensured.

Surface water quality monitoring is one of the responsibilities of a number of provincial and federal environmental departments in Canada. In Saskatchewan, the Ministry of Environment is responsible for the province water quality monitoring network. The sampling effort was initiated 40 years ago and has been ongoing since, with varying degrees of spatial and temporal coverage. The main objective of the Saskatchewan monitoring network is the assessment of ambient water quality status. In addition, one of the main uses of the generated water quality data is the calculation of a Water Quality Index. The adequacy of the monitoring network to perform these tasks needs to be validated. The objective of this study is to provide a statistical assessment of two of the monitoring network main aspects, the water quality variables and their sampling frequency. A new rationalization approach is applied for the assessment and reselection of water quality variables. The proposed approach provides, in a systematic way, the optimal combinations of variables to continue measuring, variables that may be redundant and could be considered for discontinuance, and variables that may need to be added to the list of variables being measured. The confidence interval around the mean is used as the main criterion for the sampling frequency assessment. A design chart is provided for the sampling frequency assessment, which is easy to use, and provides an initial assessment of the number of samples required to provide a mean value with a predefined error percentage.

The present study developed epidemic models to predict the diffusion of remediation technology. Hypotheses were derived from the models and then tested using data collected from a questionnaire survey (n = 223) and a qualitative interview (n = 28) mainly conducted in the USA, UK, and China, as well as data from the US Superfund program. Hypothesis testing results indicate that: (1) tacit knowledge in innovative remedial technologies leads to logistic rather than exponential growth in their adoption, and (2) social-economic and regulatory factors affect the adoption of remediation technologies. For specific remedial technologies adopted in the US Superfund program, it was found that in-situ bioremediation (ISB) has a higher maximum adoption rate than in-situ chemical treatment (ISC), likely due to lower cost and higher social acceptance associated with ISB. The diffusion of ISC was found to be more rapid than that of ISB due to a greater degree of tacit knowledge associated with ISB.

Preliminary analysis on dredged marine sediments from Benoi basin in Singapore was carried out showing elevated concentrations of Zn, Cu, Pb, Cd, Cr and Ni. Ethylenediamine tetraacetic acid (EDTA) thermal washing experiments were conducted for heavy metal extraction at temperature 100 °C. Results indicated the significant efficiency of thermal washing to extract Pb, Zn and Ni. However, there was little or no influence in the removal of Cu and Cr and a slight effect to Cd indicating multiple mechanisms. In addition, agitation was found to have great influence on the removal efficiency of heavy metals as experiments without agitation performed lesser or no extraction due to limited contact of the washing solution and the dredged sediment. Sequencing processes of thermal treatment followed by EDTA washing showed limited performance, likely due to thermal stabilization of the contaminants particularly at low liquid-to-soil (L/S) ratio. Furthermore, sequential extraction analysis on the metal speciation was performed before and after thermal washing. It was revealed that metals mainly extracted from fractions bound to carbonates and Fe-Mn oxides, the relative mobile fraction. On the contrary, metals in the residual fraction displayed a considerable stability.

Natural clinoptilolite from Zlatokop deposit, Serbia, was activated by microwave irradiations (10 min, 550 W) and its adsorptive efficiency for removal of crystal violet (CV) dye from aqueous solution was investigated. The process variables were specified by response surface method and the central composite design (CCD). Percentage of dye removal as a function of two numeric factors (the amount of zeolite and the concentration of crystal violet) with five values (rotatibility factor α = 0. 41) and one numeric factor (contact or agitation time) with three values (rotatibility factor α = 1. 00) at dynamic ambient conditions and pH = 6 was tested. The optimal conditions for 91.99 % decolorization were predicted to be 2 g of the zeolite in 100 ml of CV aqueous solution with concentration of 250 mg/l, and contact time of 678 s. The model was validated experimentally. Two isotherm models—Langmuir type 2 and Freundlich could describe the adsorption process with high correlation to experimental data. The calculated adsorbent capacity from the CCD (12.625 mg/g) showed a good agreement with the adsorption capacity obtained by Langmuir-2 isotherm (13.477 mg/g) and with pseudo-second-order kinetic model (12.404 mg/g).

We examined the effectiveness of rhizoaugmentation for treating water contaminated with the nitrophenols (NPs), 2-NP, 3-NP, 4-NP, and 2,4-dinitrophenol (2,4-DNP) using NP-degrading bacteria. We used 2-NP-degrading Pseudomonas sp. (strain ONR1), 3-NP-degrading Cupriavidus sp. (MFR2), 4-NP-degrading Rhodococcus sp. (PKR1), 2,4-DNP-degrading Rhodococcus sp. (DNR2), and giant duckweed (Spirodela polyrhiza). The four bacterial strains readily colonized Spirodela roots, as approximately 1 × 10⁵colony-forming units [CFUs] plant⁻¹to 10⁶–10⁷ CFU plant⁻¹. The higher populations remained stable through five sequential 2-day degradation cycles and completely removed all four NPs within each cycle. The root–bacteria association also successfully treated wastewater effluent contaminated with NPs; 52–71 % of 2-NP and 100 % of 3-NP, 4-NP, and 2,4-DNP were removed within each of five 2-day cycles. These results demonstrate the potential of rhizoaugmentation to achieve efficient and sustainable treatment of NP-contaminated waters.

Treated and untreated rice straw extensively exists in the soil. In order to elucidate its possible effect on the fate of organic pollutants, sorption of pyrene by rice straw and its main constituents (lignin, cellulose, and hemi-cellulose) were studied, as single solute and in the presence of other co-existing organic pollutants, phenanthrene (Phen), benzo[a]pyrene (BaP), phenol, and pentachlorophenol (PCP). Pyrene showed the greatest sorption on lignin with greater aromaticity and smaller polarity, and the sorption coefficient was almost two orders of magnitude greater than those on cellulose and hemi-cellulose. Bi-solute sorption results showed that Phen, BaP and PCP exhibited apparent competitive sorption with pyrene on the four sorbents; while the existence of phenol promoted the sorption of pyrene on rice straw and lignin but inhibited the sorption on cellulose and hemi-cellulose. For the two polycyclic aromatic hydrocarbon (PAH) co-solutes and PCP, hydrophobicity and molecular size played important roles in competition, suggesting the direct competition for hydrophobic sorption sites and pore blockage mechanisms. In contrast, the polar co-solute, phenol showed different effects on pyrene sorption onto the four sorbents, suggesting that multiple interactions between polar organic compounds and sorbents are involved in the sorption.

This study assessed runoff losses following laboratory rainfall simulation on a grassland soil at two time intervals (48 and 216 h) after a single application of biosolids and meat and bone meal (MBM). The treatments were, a soil-only control, three types of biosolids (lime-stabilised (LS), thermally dried (TD) and anaerobically digested (AD)) and two types of MBM (low ash and high ash content) all applied at two rates (the maximum and double the maximum legal application rate currently permitted in Ireland). Results showed that treatment, time interval and their interactions all had significant effects on dissolved reactive P (DRP), total P (TP) and total dissolved P (TDP) concentrations. Time interval had the greatest effect for DRP and TP concentrations, while treatment was more significant for TDP. All treatments released DRP concentrations in excess of 30 μg DRP L⁻¹. Anaerobically digested biosolids released the least amount of DRP into surface runoff for both application rates at both time intervals. Low ash content MBM, applied at the maximum legal rate, released the most DRP at both time intervals, and the TD biosolids released the most DRP when applied at double the maximum rate. Lime-stabilised biosolids released the most TP in runoff at both application rates. Runoff comprised of >50 % particulate P for all treatments. Besides TD biosolids, all treatments, applied at both rates, released lower concentrations of suspended solids (SS) during the second time interval than the first. Soil-specific effects were also evident, although the soil was non-calcareous and had a low pH and high amounts of available aluminium and iron, high organic matter ensured low levels of P adsorption.

A bentonite-based hydrogel was chemically modified to prepare a new effective adsorbent for the removal of phosphate from aqueous solutions using batch equilibrium experiments at the laboratory scale. The efficiency of the phosphate adsorption by the modified adsorbents followed the order: Al-Fe-hydrogel > Al-hydrogel > Fe-hydrogel > Rewoquate surfactant-hydrogel ≅ Irasoft surfactant-hydrogel > raw hydrogel. The amount of Fe and Al, as determined in proportion to the cation exchange capacity (CEC) of the hydrogel, was the most important parameter for optimizing the modification process by pillaring solutions. The results showed that the phosphate adsorption was rapid and pH independent. The removal of phosphate reached up to 99 % at the optimized conditions. The adsorption data were well fitted by Langmuir and Freundlich models. According to the Langmuir model, the maximum adsorption capacity of the phosphate on the Fe-Al-hydrogel was 14.29 mg L⁻¹. The removal of phosphate from an urban wastewater using the modified adsorbent was more than 99 %. The Fe-Al-hydrogel selectively adsorbed the phosphate from the solutions containing sulphate, bicarbonate, chloride, and nitrate. Based on the obtained results, the synthesized adsorbent could be used effectively to decontaminate the phosphate polluted water.

Ombrotrophic peatlands are highly sensitive to atmospheric heavy metal deposition. Previous attempts to quantify peatland lead pollution have been undertaken using the inventory approach. However, there can be significant within-site spatial heterogeneity in lead concentrations, highlighting the need for multiple samples to properly quantify lead storage. Field portable x-ray fluorescence (FPXRF) continues to gain acceptance in the study of contaminated soil, but has not thus far been used to assess peatland lead contamination. This study compares lead concentrations in surface peat samples from the South Pennines (UK) derived using (a) FPXRF in the field, (b) FPXRF in the lab on dried samples and (c) ICP-OES analysis. FPXRF field and lab data are directly comparable when field measurements are corrected for water content, both can be easily used to estimate acid extractable lead using regression equations. This study is a successful demonstration of FPXRF as a tool for a time- and cost-effective means of determining the lead content of contaminated peatlands, which will allow rapid landscape scale reconnaissance, core logging, surface surveys and sediment tracing.