Soils that are exposed to floodwaters because of shallow groundwater and periodical wetlands are, to a large extent, exposed to contamination by organic and inorganic compounds. These are mainly compounds that have drifted along with the inflow of heavily laden floodwater and are produced within the soil profile by the anaerobic transformation of organic matter. Heavy metals and polycyclic aromatic hydrocarbon (PAH) compounds are absorbed by the soil of the floodwaters, and moving in the soil profile, they pose a threat to groundwater. What is more, after a flood, they may be absorbed by the crops. This paper focuses on the effects of Odra River (Poland) floods, heavy metals, and PAHs on soil and the possibilities of the migration of these pollutants into the soil profile. In the tested sludge samples of floodwater and soil, there were no abnormal concentrations of heavy metals, but the flooding time positively affected the amount listed in the test samples. Concentrations of PAHs increased, but they also exceeded the standards for arable soils in the case of single compounds.

In this study, the concentration-dependent joint action of chromium (Cr) and salt (NaCl), two important environmental stressors, was examined in aquatic plants. Ceratophyllum demersum L. plants were exposed to Cr (0–10 mM) for 5 days in the presence and absence of NaCl (0–500 mM). The effect of Cr, Na, and Cl accumulations on certain biological parameters (water content, ion leakage, relative growth rate, photosynthetic pigments, and protein and proline contents) was determined. Furthermore, the interactive effects of NaCl and Cr were evaluated using a mathematical model developed on the basis of the theory of probabilities. The highest Cr accumulation (0.42 mmol g⁻¹) was found in plants treated with 10 mM Cr + 125 mM NaCl. Treatment with 125 mM NaCl resulted in an increase in Cr accumulation compared with that in the control. However, 250 and 500 mM NaCl concentrations decreased Cr accumulation. Proline and water contents were not affected by increasing Cr concentration. However, NaCl did have a significant effect on any of the studied parameters. Furthermore, the interactive effects of Cr and NaCl on all studied parameters except for proline and water contents were determined. Except for photosynthetic pigments and proline content, effect of NaCl was higher than Cr on all studied parameters. The interactive effects were mostly antagonistic or additive. However, the mode of action for ion leakage was synergistic or additive. These results suggest that the coexistence of NaCl and Cr in aquatic ecosystems does not pose an additional ecological risk for aquatic plants.

Chemical stabilization is a cost-effective, environmentally friendly, in situ remediation technology based on the application of organic and/or inorganic amendments to reduce soil metal bioavailability. Our objective was to assess the early short-term effects of organic amendments (sheep manure—SHEEP, poultry litter—POULTRY, cow slurry—COW, paper mill sludge mixed with poultry litter—PAPER), in sterilized and non-sterilized form, on the microbial and chemical properties, as well as on the phytotoxicity, of a Cd, Pb and Zn contaminated soil. Our results provide useful information regarding (1) the effectiveness of amendments for chemical stabilization of mine soil and (2) the impact of microbial populations present in the amendments on soil native microbial communities. Microbial populations present in the amendments did not substantially modify soil microbial functional diversity, as reflected by Biolog EcoPlates™ data, except for PAPER-amended soils. We observed a good correlation between lettuce root elongation (phytotoxicity bioassay) and Cd, Pb, and Zn CaCl₂-extractable concentrations in soil. SHEEP and PAPER amendments were particularly effective at increasing soil pH and reducing metal bioavailability and phytotoxicity, while POULTRY and COW led to higher values of soil microbial properties (respiration and functional diversity). Beneficial effects observed under POULTRY at the beginning of the experiment, due to the presence of easily degradable organic matter, were partially lost over time. Our results emphasize the importance of the early monitoring of soil properties (microbial and chemical) and phytotoxicity to properly identify bottlenecks during amendment selection for chemical stabilization, in terms of reduction in metal bioavailability and improvement in soil health.

The adsorption of microcystin-LR (MCLR) by biochar has never been well understood. For the first time, the unconventional adsorption of hydrophilic MCLR on wood-based biochars was comprehensively investigated as a function of biochar properties, environmental temperature, solution pH, coexisting dissolved organic matter (DOM), and polar organic competitors. High-temperature-prepared biochar from 700 °C (BC-700) and low-temperature-prepared biochar from 300 °C (BC-300) were characterized with significantly different surface areas but similar alkaline nature. Despite a very low surface area, BC-300 exhibited very high adsorption capacity, which implies the important contribution of surface groups to biochar. MCLR adsorption on biochars was pH dependent and was strongly reduced by macromolecular DOM. Polycarboxylic aliphatic acids and 2-(2-hydroxyethyl) guanidinium cation, which are similar to specific structural groups in MCLR, exhibited an evident competitive effect. The results indicated that both carboxylic and guanidino groups of MCLR serve significant functions in MCLR adsorption to biochar. The adsorption mechanisms may be primarily related to the columbic attractions and the hydrogen bonding interactions between MCLR and biochar surface. In particular, the irreversible adsorption enhancement of MCLR was observed on BC-700, which suggests that biochar amendment can aid in immobilizing MCLR from water to sediment, thereby prolonging MCLR environmental fate in biochar-amended sediment.

The genotoxic effects of four heavy metal mixtures on Drosophila melanogaster were investigated with reference to gene expressions of heat shock proteins (HSP26, HSP60, HSP70 and HSP83), DNA profiles, and mitochondrial NADH dehydrogenase sequence. Adult D. melanogaster flies were treated with a mixture of four (Fe, Cu, Cd and Pb) heavy metals (HMs) in three different concentrations, which were selected based on one higher dose (HM3) and one lower dose (HM1) relative to the permitted limits (HM2) in drinking water at 1st, 5th and 10th days. It was determined that the amount of the accumulated heavy metals and the expressions of the HSP genes were changed with increasing exposure time. The accumulations of Cd and Pb were increased with increasing exposure time; additionally, the HSP expression patterns were determined as HSP70 > HSP60 > HSP26 > HSP83 HM1 (5th day), HM2 (5th day and 10th day), and HM3 (all exposure times). It was also determined that the application of the heavy metal mixture affected the random amplified polymorphic DNA (RAPD) profiles and the mitochondrial NADH dehydrogenase sequence of D. melanogaster. The highest base pair changes (9 bp) were determined at the HM2 concentration (permissible limits in drinking water) on the 1st day of treatment. Therefore, it was shown that mixture of four heavy metals caused a genotoxic effect and D. melanogaster is a useful model organism for heavy metal-induced genotoxicity studies.

Lacustrine sedimentation and trace metal accumulation are naturally occurring processes that can be altered by anthropogenic activities. Indices of sediment or metal dynamics are important for the management and operational use of man-made reservoirs and their drainage basins. In this study, we compared two reservoirs in Virginia, USA, to quantify the effect of varying watershed characteristics on sediment and metal fluxes. Lake Pelham is a human-impacted reservoir surrounded by agricultural fields and anthropogenic developments, whereas Lake Moomaw is an undeveloped reservoir surrounded by moderate to extremely sloping forested landscapes. Three sediment cores were taken from each reservoir to estimate²¹⁰Pb-based sediment accumulation rates, organic matter content, and indices of trace metal enrichment and accumulation. The average²¹⁰Pb-based sediment accumulation rates were 0.348 ± 0.053 and 0.246 ± 0.043 g cm⁻² year⁻¹for Lake Pelham and Lake Moomaw, respectively. The sediment trace metal results showed strong correlation with sediment organic content, and both reservoirs had moderate to high enrichment of Cu and little enrichment of Zn and Pb. Overall, Lake Moomaw had relatively low sediment accumulation and metal enrichment. Comparatively, Lake Pelham had significantly greater metal concentrations, which were highest in the upper reaches of the reservoir. Lake Pelham also had higher sediment accumulation rates and higher metal enrichment, reflecting the impact of human development within the greater watershed. Results from this study suggest that urbanization can increase reservoir sediment and metal fluxes, but atmospheric deposition is also important in forested watersheds that have not undergone anthropogenic land-use change.

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.