Evaluation of passive sampling polymers and nonequilibrium adjustment methods in a multiyear surveillance of sediment porewater PCBs.

Polymeric passive sampling devices are increasingly used to measure low-level, freely dissolved concentrations of hydrophobic organic contaminants in environmental waters. A range of polymers have been used for this purpose, and several different methods of accounting for nonequilibrium using performance reference compounds (PRCs) have been proposed. The present study explores the practical impacts of these decisions in an applied context using results from a multiyear passive sampling surveillance of polychlorinated biphenyl concentrations in sediment porewater at a contaminated marsh amended with activated carbon (AC) sorbent materials.

Persistent reductions in the bioavailability of PCBs at a tidally inundated Phragmites australis marsh amended with activated carbon.

In situ amendment of sediments with highly sorbent materials like activated carbon (AC) is an increasingly viable strategy to reduce the bioavailability of persistent, sediment-associated contaminants to benthic communities. Because in situ sediment remediation is an emerging strategy, much remains to be learned about the field conditions under which amendments can be effective, the resilience of amendment materials toward extreme weather conditions, and the optimal design of engineered applications. We report the results of a multiyear, pilot-scale field investigation designed to measure the persistence and efficacy of AC amendments to reduce the bioavailability of polychlorinated biphenyls (PCBs) in an intertidal Phragmites marsh.

Polybrominated diphenyl ethers: Residence time in soils receiving biosolids application.

Polybrominated diphenyl ethers (PBDEs) may enter the environment because of accumulation in biosolids followed by application to agricultural lands. No published dissipation studies are available for PBDEs in agricultural soils after biosolids application. Therefore, we conducted a 3-year study to examine the fate of PBDEs in a small-scale 0.

Organic amendments for risk mitigation of organochlorine pesticide residues in old orchard soils.

Performance of compost and biochar amendments for in situ risk mitigation of aged DDT, DDE and dieldrin residues in an old orchard soil was examined. The change in bioavailability of pesticide residues to Lumbricus terrestris L. relative to the unamended control soil was assessed using 4-L soil microcosms with and without plant cover in a 48-day experiment.

Long-term trends of PBDEs, triclosan, and triclocarban in biosolids from a wastewater treatment plant in the Mid-Atlantic region of the US.

In the US, land application of biosolids has been utilized in government-regulated programs to recycle valuable nutrients and organic carbon that would otherwise be incinerated or buried in landfills. While many benefits have been reported, there are concerns that these practices represent a source of organic micropollutants to the environment. In this study, biosolids samples from a wastewater treatment plant in the Mid-Atlantic region of the US were collected approximately every 2 months over a 7-year period and analyzed for brominated diphenyl ethers (BDE-47, BDE-99, and BDE-209), triclosan, and triclocarban.

Fate of microconstituents in biosolids composted in an aerated silage bag.

Although most composting studies report pathogen concentrations, little is known about the fate of Endocrine Disruptor Chemicals (EDCs) during composting. In this study, a positively aerated polyethylene bag composting system was filled with a mixture of woodchips and limed biosolids from a large Waste Water Treatment Plant (WWTP) to study the removal efficiency of two different groups of EDCs. Two antibacterial compounds, Triclocarban (TCC) and Triclosan (TCS), and a TCS byproduct, Methyltriclosan (MeTCS), as well as seven congeners of flame retardants known as PBDEs (Polybrominated Diphenyl Ethers) were studied during two phases of composting: 1) a thermophilic phase, in which positive mechanical aeration, pushing air into and through the materials matrix, was conducted for 2 months; and 2) a curing and stabilization phase in which no mechanical aeration was provided and the bag was opened to ambient passive aeration to simulate storage conditions for seven months.

Utilizing thin-film solid-phase extraction to assess the effect of organic carbon amendments on the bioavailability of DDT and dieldrin to earthworms.

Improved approaches are needed to assess bioavailability of hydrophobic organic compounds in contaminated soils. Performance of thin-film solid-phase extraction (TF-SPE) using vials coated with ethylene vinyl acetate was compared to earthworm bioassay (Lumbricus terrestris). A DDT and dieldrin contaminated soil was amended with four organic carbon materials to assess the change in bioavailability.

Persistence of polybrominated diphenyl ethers in agricultural soils after biosolids applications.

This study examines polybrominated diphenyl ethers (PBDE) levels, trends in biosolids from a wastewater treatment plant, and evaluates potential factors governing PBDE concentrations and the fate in agricultural soils fertilized by biosolids. The mean concentration of the most abundant PBDE congeners in biosolids ( summation operatorBDE-47, BDE-99, and BDE-209) generated by one wastewater treatment plant was 1250 +/- 134 microg/kg d.w.