Characterization of The Permeation Properties of Membrane Filters and Sorption Properties of Sorbents Used for Polar Organic Chemical Integrative Samplers.

Polar organic chemical integrative samplers (POCIS) are promising devices for measuring the time-weighted average concentrations of hydrophilic compounds in aquatic environments. However, the mechanisms underlying compound uptake by POCIS remain unclear. We investigated the permeation kinetics of polyethersulfone and polytetrafluoroethylene membrane filters, and the sorption kinetics of Oasis HLB (Waters), Envi-Carb (Supelco), and Oasis WAX (Waters) sorbents.

Investigation of variability in the matrix effect on stable isotope-labeled internal standards in liquid chromatography-tandem mass spectrometry analysis of 25 pesticides in vegetables.

The matrix effects (ME) in simultaneous analysis of pesticide residue using liquid chromatography-tandem mass spectrometry (LC-MS/MS) were evaluated by comparing the slopes of matrix-matched and reagent-only calibrations of four types of vegetable samples. Both the sampling and measurement variances of the ME were also determined using one-way analysis of variance. Substantial ion suppression (ME<-20%) was observed in komatsuna, spinach, and tomato when a modified Japanese official method was implemented.

Enhancement of photodegradation of polyethylene with adsorbed polycyclic aromatic hydrocarbons under artificial sunlight irradiation.

The photodegradation of plastic waste produces microplastics (MPs) in marine environments. Plastics can adsorb hydrophobic organic pollutants such as polycyclic aromatic hydrocarbons (PAHs) and can be transported over long distances. However, the impact of adsorbed pollutants on the photodegradation remains unknown.

Development of a New Polar Organic Chemical Integrative Sampler for 1,4-dioxane Using Silicone Membrane as a Diffusion Barrier.

Efficient monitoring methods must be developed for 1,4-dioxane, which is suspected to be carcinogenic to humans and is highly mobile in aquatic environments. In this regard, polar organic chemical integrative samplers (POCIS) have been utilized extensively as passive samplers for determining time-weighted average concentrations of hydrophilic organic compounds. However, POCIS are difficult to apply to extremely hydrophilic known organic compounds with negative log octanol-water partition coefficient (K ) values due to their limited kinetic sampling time.

Photolysis of polycyclic aromatic hydrocarbons adsorbed on polyethylene microplastics.

Contaminants adsorbed on microplastics (MPs) are a potential risk to aquatic environments. Several studies have demonstrated that polycyclic aromatic hydrocarbons (PAHs), which adsorb on MPs, can be photolyzed in aqueous solutions. We investigated photolysis of PAHs on MPs under sunlight conditions to estimate their environmental fate for the first time.

Treatment of 1,4-dioxane-containing water using carriers immobilized with indigenous microorganisms in landfill leachate treatment sludge: A laboratory-scale reactor study.

1,4-Dioxane (DX) is a contaminant of emerging concern in aquatic environments, and is frequently found in landfill leachate. As a biological method applicable to landfill leachate treatment facilities, the feasibility of DX treatment using carriers immobilized with microorganisms indigenous to landfill leachate treatment sludge was explored through laboratory-scale reactor experiments by introducing carriers prepared via microorganism immobilization in the aeration tank of a leachate treatment facility. Three different carrier materials were used to immobilize microorganisms, and a model DX-containing water (10 mg/L) was treated under continuous feeding.

Development and Calibration of the Polar Organic Chemical Integrative Sampler (POCIS) for Neonicotinoid Pesticides.

Neonicotinoid pesticides are highly hydrophilic systemic insecticides that have been extensively used worldwide. To evaluate their environmental risks, the concentrations of these pesticides in the aquatic environment must be monitored. Although the polar organic chemical integrative sampler (POCIS) has proved to be a suitable passive sampler for many highly hydrophilic compounds, Oasis HLB (Waters) POCIS has shown limitations for the monitoring of neonicotinoid pesticides, such as short linear uptake ranges.

Simultaneous analysis of seven neonicotinoid pesticides in agricultural products involving solid-phase extraction and surrogate compensation using liquid chromatography-tandem mass spectrometry.

This study proposes a practical and precise method for the simultaneous analysis of seven neonicotinoid pesticides in agricultural products using liquid chromatography-tandem mass spectrometry from two different approaches. First, the applicability of a cleanup cartridge, comprised of a polymer sorbent consisting of a styrene-divinylbenzene copolymer with N-containing polar groups and methacrylate, in food samples was demonstrated for the first time. Second, applying an internal standard (IS) calibration method at a lower cost was considered by changing the timing of the IS addition and selecting the minimum number of ISs by referring on the matrix effect.

Reduced bioavailability of polycyclic aromatic hydrocarbons (PAHs) in sediments impacted by carbon manufacturing plant effluent: Evaluation by ex situ passive sampling method.

Potential risks of polycyclic aromatic hydrocarbons (PAHs) in sediments of a Japanese bay contaminated by carbon manufacturing plant effluent were evaluated by calculating toxicity units (TUs). TUs calculated from the measured whole-sediment concentrations (C) were often higher than or close to 1, signaling a possible toxicity concern to benthic organisms. In contrast, TUs based on the freely dissolved pore water concentrations (C) measured by an ex-situ passive sampling method with polyethylene strips were 0.

Carbon sources that enable enrichment of 1,4-dioxane-degrading bacteria in landfill leachate.

1,4-Dioxane (DX) is a recalcitrant cyclic ether that has gained attention as an emerging pollutant in the aquatic environment. Enrichment of indigenous DX-degrading bacteria, which are considered to be minor populations even in DX-impacted environments, is the key for efficient biological DX removal. Therefore, this study aimed to explore carbon sources applicable for the enrichment of DX-degrading bacteria present in landfill leachate, which is a potential source of DX pollution.

Determining the suitability of a polar organic chemical integrated sampler (POCIS) for the detection of pesticide residue in the Ishikawa River and its tributary in Osaka, Japan.

The monitoring of pesticide concentrations in Japanese rivers was conducted a grab sampling method and a passive sampling method using the polar organic chemical integrated sampler (POCIS). The results showed that cumulative detections were 84 with grab sampling and 98 with the POCIS. All of the pesticides detected by grab sampling could be quantified with a POCIS except for one (although its traces were detected).

Impact of aerobic acclimation on the nitrification performance and microbial community of landfill leachate sludge.

Nitrogenous pollution of water is regarded as a global environmental problem, and nitrogen removal has become an important issue in wastewater treatment processes. Landfill leachate is a typical large source of nitrogenous wastewater. Although the characteristics of leachate vary according to the age of the landfill, leachates of mature landfill have high concentrations of nitrogenous compounds.

Comparing polyethylene and polyoxymethylene passive samplers for measuring sediment porewater concentrations of polychlorinated biphenyls: Mutual validation and possible correction by polymer-polymer partition experiment.

Two sediment passive samplers, polyethylene (PE) and polyoxymethylene (POM), were compared and mutually validated for measuring freely dissolved concentrations (C) of polychlorinated biphenyls (PCBs) in sediment porewater. PE and POM strips in commonly used dimensions (30 and 76 μm in thickness, respectively) were exposed to sediment slurries for 28 d. The C values calculated using literature polymer-water partition coefficients were consistently higher for PE than for POM by a factor of 2 on average.

Temperature dependence on the pesticide sampling rate of polar organic chemical integrative samplers (POCIS).

Laboratory experiments were performed to determine the sampling rates of pesticides for the polar organic chemical integrative samplers (POCIS) used in Japan. The concentrations of pesticides in aquatic environments were estimated from the accumulated amounts of pesticide on POCIS, and the effect of water temperature on the pesticide sampling rates was evaluated. The sampling rates of 48 pesticides at 18, 24, and 30 °C were obtained, and this study confirmed that increasing trend of sampling rates was resulted with increasing water temperature for many pesticides.