Despite common knowledge that the metal content adsorbed by fine particles is relatively higher compared to coarser particles, the reasons for this phenomenon have gained little research attention. The research study discussed in the paper investigated the variations in metal content for different particle sizes of solids associated with pollutant build-up on urban road surfaces. Data analysis confirmed that parameters favourable for metal adsorption to solids such as specific surface area, organic carbon content, effective cation exchange capacity and clay forming minerals content decrease with the increase in particle size. Furthermore, the mineralogical composition of solids was found to be the governing factor influencing the specific surface area and effective cation exchange capacity. There is high quartz content in particles >150 μm compared to particles <150 μm. As particle size reduces below 150 μm, the clay forming minerals content increases, providing favourable physical and chemical properties that influence adsorption.

A molecular study on how the abundance of the dechlorinating culture KB-1 affects dechlorination rates in clay till is presented. DNA extracts showed changes in abundance of specific dechlorinators as well as their functional genes. Independently of the KB-1 added, the microbial dechlorinator abundance increased to the same level in all treatments. In the non-bioaugmented microcosms the reductive dehalogenase gene bvcA increased in abundance, but when KB-1 was added the related vcrA gene increased while bvcA genes did not increase. Modeling showed higher vinyl-chloride dechlorination rates and shorter time for complete dechlorination to ethene with higher initial concentration of KB-1 culture, while cis-dichloroethene dechlorination rates were not affected by KB-1 concentrations. This study provides high resolution abundance profiles of Dehalococcoides spp. (DHC) and functional genes, highlights the ecological behavior of KB-1 in clay till, and reinforces the importance of using multiple functional genes as biomarkers for reductive dechlorination.

Uptake and elimination kinetics of metals in soil invertebrates are a function of both soil and organism properties. This study critically reviewed metal toxicokinetics in soil invertebrates and its potential use for assessing bioavailability. Uptake and elimination rate constants of different metals are summarized. Invertebrates have different strategies for essential and non-essential metals. As a consequence, different types of models must be applied to describe metal uptake and elimination kinetics. We discuss model parameters for each metal separately and show how they are influenced by exposure concentrations and by physiological properties of the organisms. Soil pH, cation exchange capacity, clay and organic matter content significantly affect uptake rates of non-essential metals in soil invertebrates. For essential metals, kinetics is hardly influenced by soil properties, but rather prone to physiological regulation mechanisms of the organisms. Our analysis illustrates that toxicokinetics can be a valuable measurement to assess bioavailability of soil-bound metals.

The microbial community and the nirS- and nirK-encoding denitrifiers in the intertidal sediments along Laizhou Bay in China were studied using pyrosequencing and real-time quantitative PCR (qPCR), respectively. There were three primary intertidal zones: Laizhou (La), Weifang Harbor (We), and Dongying (Do). Significant differences in composition and abundances at the different taxonomic levels were observed among the three bacterial communities. The qPCR results indicated that the nirS gene abundance varied from 8.67×105 to 5.68×106copies/gwet weight (ww), whereas the nirK gene abundance varied from 1.26×105 to 1.89×106copies/gww. The canonical correlation analysis (CCA) indicated that the sand percentage was the most important factor in shaping the bacterial community followed by silt percentage, NO2−, TOC, DO, pH, and clay percentage, whereas the clay percentage, pH, NO3−, DO, NO2−, TOC, silt percentage, and sand percentage were the most important factors associated with regulating the abundance of nirS- and nirK-encoding denitrifiers.

The interaction of dispersed oil droplets with large diameter suspended particulate materials (SPM) has been little studied. In the current study, particle size, oil characteristics and chemical dispersant significantly influence the adsorption of oil droplets to SPM in seawater. Sediments with a smaller particulate size (clay) approaching that of the oil droplets (2–20μm) adsorbed more oil per gram than sediments with large particle size (sand). Heavier, more polar oils with a high asphaltene content adsorbed more efficiently to SPM than lighter, less polar oils. A decrease in the smaller, more water soluble oil components in the sediment adsorbed oil was observed for all oil types. Addition of chemical dispersant decreased the adsorption of oil droplets to suspended carbonate sand in an exponential-like manner. No change in the relative distribution of compounds adsorbed to the sediment was observed, indicating dispersants do not alter the dissolution of compounds from oil droplets.

The level of mercury (Hg) concentration in soils can be estimated using certain predictors such as the content of organic carbon (Cₒᵣg) or the fine fractions (FFs) such as silt and clay. This study was focused on the potential use of Cₒᵣgand FF contents as the predictors of Hg concentration at the spatial meso-scale in forest soils derived from Triassic sandstones and claystones, Quaternary sands derived from weathering sandstones and Quaternary sands of fluvioglacial origin. To understand the importance of Cₒᵣgand FF contents for Hg retention in mineral soil, the allocation of Hg in physically separated fractions of soil samples was also tested. The experiment was designed over a regular 200 × 200-m grid, where 275 plots were established. The results implied that the concentration of total Hg in mineral soil may vary by several orders of magnitude because of the natural variation in Cₒᵣgcontent. The model where the Cₒᵣgcontent was the only variable explained 44 % of Hg concentration variability in soil, and other significantly correlated variables were the FF content and the C/N ratio. Detailed analysis revealed that the particulate organic matter fraction accumulated more Hg per unit of Cₒᵣgthan in the organic matter associated with FF. The content of Cₒᵣg, FF and C/N ratio allowed, for the local soils, a satisfactory prediction of the spatial distribution and the magnitude of total Hg concentration in soils.

This study evaluates the degree of pollution of marine sediments using two methods: standard (physico-chemical parameters) and instrumental techniques: thermogravimetric analysis (TG) and infrared spectroscopy (ATR-FTIR). ATR-FTIR proved to be a tool capable of identifying the organic and inorganic compounds in sediments such as organic carbon, clay, and carboxylate groups which can bind metal contaminants. TG results of 14 sediment samples were compared with organic matter (OM), organic carbon (OC), total nitrogen (TN), clay, and carbonate (CaCO₃) contents obtained by standard methods. The results showed that weight losses for a specific range of temperatures are closely correlated with the content of OM (R ² = 0.92), OC (R ² = 0.82), TN (R ² = 0.96), clay content (R ² = 0.87), and CaCO₃ (R ² = 0.9) for sediment samples. It is concluded that TG and ATR-FTIR allows a simultaneous, rapid, and reliable screening of sediment properties.

The paper reports ultraviolet matrix-assisted laser desorption/ionization mass spectroscopy (UVMALDI-MS) protocol for determination of complex heterogeneous emulsion or suspension formulations. The active agents and surfactants are morpholine fungicide fenpropimorph (1), amorolfine (2), tridemorph (mixture of 2,6-dimethyl-4-alkylmorpholins 3–6), 2,6-dimethyl-4-[2-methyl-3-(6-methyl-decahydro-naphthalen-2-yl)-propyl]-morpholine (7), dodemorph (8), main metabolite of 1 fenpropimorph acid (9), sodium dodecyl sulfate (10), and stearate (11). The full method and techniques validation as well as method performance parameters are discussed in terms of their maximal representativeness toward real environmental and foodstuff assay problems. These are additionally complicated by heterogeneous laterally, vertically, and time distribution of pesticide contaminants and their major metabolites in environmental samples. The real environmental heterogeneous distribution is elucidated, studying sterilized soil fractions with particle size 2.0 μm, clay content 11.5 %, silt 23.0 %, sand 8.1 %, and pH ∈ 6.0–8.1. A statistical sampling cluster approach is used. The method performance parameters are concentration LODs of 0.026 mg kg⁻¹(res. LOQs 0.08666 mg kg⁻¹). Concentration linear dynamic ranges are ∈ 0.025–7.3 mg kg⁻¹(r² = 0.99822 and 0.99421) and ∈ 2.3–7.4 mg kg⁻¹(level of confidence of 99.33₁ %) for complex spiked heterogeneous soil samples. The data illustrates the great capability of method and its promising application for environmental contamination monitoring and controlling programs for assessment.

Recycling irrigation water is a common practice at ornamental plant nurseries for conserving water; however, it poses the risk of sourcing and dispersing waterborne plant pathogens, especially species of Phytophthora. Slow sand filtration is a water treatment process that can remove pathogens from water, but the slow rate of water treatment may limit its application at nursery operations. In this study, four novel substrates (crushed brick, calcined clay, polyethylene beads, and Kaldnes® medium) in addition to sand were examined to determine how effective each substrate was at removing zoospores of Phytophthora nicotianae from water. The effects of substrate physical parameters, substrate depths (0, 5, 10, 20, 40, and 60 cm), and microbe density (after nursery effluent was recirculated through each substrate for 21 days) on zoospore removal by each substrate were quantified. Sand was the most effective physical filter and supported development of the best biological filter for removing zoospores. Sand columns 40 and 60 cm deep removed zoospores completely using physical filtration alone, and zoospore removal by sand at 10- and 20-cm depths was increased with the addition of biological filtration. Kaldnes® medium and polyethylene beads were the least effective filtration substrates under all conditions tested. After 21 days of recirculating nursery effluent through substrate columns, microbe density in and zoospore removal by all substrates increased. With further optimization, crushed brick may have potential to be utilized as a recycled material for a slow filtration system focused on removing plant pathogens from irrigation water.

Management strategies that prevent the onset of nuisance and noxious cyanobacteria blooms are needed to preserve the integrity and safety of freshwater resource uses. Scientifically defensible data are needed regarding efficacy of proactive approaches in order to assist water resource managers in making informed decisions. As phosphorus availability has been indicated as a crucial aspect of cyanobacteria presence/dominance in freshwater systems, the integration of novel technologies to inactivate phosphorus is a critical component to achieve improved water quality. Phoslock (Phoslock Water Solutions, Ltd.) phosphorus locking technology is composed of the element lanthanum in a bentonite clay matrix that has a high specificity to bind and inactivate soluble reactive phosphorus. This research evaluated the phosphorus binding efficiency of Phoslock in aqueous and sediment matrices and the consequent impact on algae assemblage composition and water quality parameters. Laguna Niguel Lake in California afforded an opportunity to evaluate the operational effectiveness of Phoslock in a system historically plagued by high phosphorus concentrations, potentially toxic cyanobacteria (Aphanizomenonflos-aquae dominant), and lake closures. Phoslock was able to rapidly (<2 weeks) and significantly (p < 0.0005) decrease total (>80 %) and free reactive (>95 %) phosphorus in the water column and shift potentially releasable sediment phosphorus fractions to residual forms after treatment. Despite documented cyanobacteria blooms and high pretreatment cell densities, cyanobacteria levels remained below or near detection limits and only comprised a small fraction of the algae assemblage following Phoslock application. This study provides water resource managers an information on operational implementation and efficacy of a phosphorus binding technology.