Application of multimedia models for understanding the environmental behavior of volatile methylsiloxanes: Fate, transport, and bioaccumulation.

Multimedia fate and transport models (MFTMs) describe how chemicals behave in the environment based on their inherent properties and the characteristics of receiving systems. We critically review the use of MFTMs for understanding the behavior of volatile methylsiloxanes (VMS). MFTMs have been used to predict the fate of VMS in wastewater treatment, rivers, lakes, marine systems, and the atmosphere, and to assess bioaccumulation and trophic transfers.

Increasing plant availability of legacy phosphorus in calcareous soils using some phosphorus activators.

Legacy phosphorus (P) in soil, accumulated over several years of fertilizer application in excess of crop demand, represents a huge and largely untapped resource. P activators can increase the availability of this P to plants by accelerating its transformation into soluble P fractions. In this study, we evaluated the potentials of four "P activators" (oxalic acid, lignin, phytase and ascorbic acid) to increase plant available P in a laboratory incubation experiment with two P-deficient calcareous soils used for wheat production.

Microbial community composition and activity controls phosphorus transformation in rhizosphere soils of the Yeyahu Wetland in Beijing, China.

Microorganisms in the rhizosphere of wetland plants can have a significant impact on phosphorus (P) interception. We investigated the seasonal pattern of microbial community structure and its relationship with different P forms in the rhizosphere of three plants Scirpus planiculmis, Zizania latifolia, and Phragmites australis from the Yeyahu Wetland, China. Chloroform fumigation-extraction was used to determine the soil microbial biomass P (SMBP) and phospholipid fatty acids (PLFA) were used to characterize microbial community composition.

Predicted persistence and response times of linear and cyclic volatile methylsiloxanes in global and local environments.

We investigated the response times of eight volatile methylsiloxanes (VMSs) in environmental systems at different scales from local to global, with a particular focus on overall loss rates after cessation of emissions. In part, this is driven by proposals to restrict the use of some of these compounds in certain products in Europe. The GloboPOP model estimated low absolute Arctic Contamination Potentials for all VMSs and rapid response times in all media except sediment.

Understanding of Cyclic Volatile Methyl Siloxane Fate in a High Latitude Lake Is Constrained by Uncertainty in Organic Carbon-Water Partitioning.

Cyclic volatile methyl siloxanes (cVMS) are emitted to aquatic environments with wastewater effluents. Here, we evaluate the environmental behavior of three cVMS compounds (octamethylcyclotetrasiloxane (D4), decamethylcyclopentasiloxane (D5) and dodecamethylcyclohexasiloxane (D6)) in a high latitude lake (Storvannet, 70°N 23°E), experiencing intermittent wastewater emissions and high latitude environmental conditions (low temperatures and seasonal ice cover). Measured cVMS concentrations in lake water were below detection limits in both March and June 2014.

Monitoring fluvial water chemistry for trend detection: hydrological variability masks trends in datasets covering fewer than 12 years.

This paper sub-samples four 35 year water quality time series to consider the potential influence of short-term hydrological variability on process inference derived from short-term monitoring data. The data comprise two time series for nitrate (NO(3)-N) and two for DOC (using water colour as a surrogate). The four catchments were selected not only because of their long records, but also because the four catchments are very different: upland and lowland, agricultural and non-agricultural.

Effects of triclosan on soil microbial respiration.

The antimicrobial substance triclosan has widespread use in personal care products and can enter the terrestrial environment if sewage sludge is applied to soil. The inhibitory effects of triclosan on basal and substrate-induced respiration (SIR) of three different soils were investigated. Soils were dosed and later redosed with four nominal triclosan concentrations, and respiration rates were measured over time.

Multimedia fate of petroleum hydrocarbons in the soil: oil matrix of constructed biopiles.

A dynamic multimedia fugacity model was used to evaluate the partitioning and fate of petroleum hydrocarbon fractions and aromatic indicator compounds within the soil: oil matrix of three biopiles. Each biopile was characterised by four compartments: air, water, soil solids and non-aqueous phase liquid (NAPL). Equilibrium partitioning in biopile A and B suggested that most fractions resided in the NAPL, with the exception of the aromatic fraction with an equivalent carbon number from 5 to 7 (EC(5-7)).

Predicting accurate and ecologically relevant regional scale concentrations of triclosan in rivers for use in higher-tier aquatic risk assessments.

Triclosan (TCS) is used in a range of domestic products and may reach aquatic environments after disposal "down-the-drain". Reach-specific TCS concentrations were predicted using the stochastic water quality model LF2000-WQX for two heavily urbanised regions in England, encompassing some of the most densely populated areas (including London and Birmingham). The model was calibrated using effluent TCS concentration data derived from a national monitoring programme which included 21 sewage treatment plants (STPs).