Concentrations of fipronil and its degradates (fipronil sulfone, fipronil sulfide, and fipronil deslfinyl: collectively “fipronils” hereafter) were measured with a liquid chromatography-tandem mass spectrometry in influent and effluent samples of a small-scale municipal wastewater treatment plant (WWTP) in Japan, which were monthly sampled for a year, and stream water samples to which the WWTP effluent is discharged. Stream water was sampled from upstream and downstream points of the WWTP. Fipronil was detectable in all the WWTP samples with the median being 1.8 and 2.3 ng/L for influent and effluent, respectively, while the degradates were less frequently detectable (detection frequency: 0-33%). Detection of intact fipronil in influent indicated the use of fipronil insecticide in household. There was no statistical difference between fipronils concentrations in influent and effluent samples indicating that removal of fipronils was inefficient during the treatment process. Fipronil was frequently detectable in stream waters but with lower median concentration by one order of magnitude (0.22 and 0.41 ng/L for upstream and downstream) than WWTP samples. Detection of degradates was more frequent in stream water (25-80%) than in WWTP samples indicating occurrence of degradation products of agriculture-derived fipronil in the environment. There was no statistical difference between fipronils concentrations in upstream samples and those in downstream samples indicating that the discharge of this particular WWTP does not influence stream fipronils concentrations.

Recently, there has been a concern about specific increases in Gd concentrations in environmental waters compared with other rare earth elements. Hydrophilic interaction liquid chromatography coupled with ICP-MS is used for speciation analysis of Gd contrast agents. Here, we aimed to detect these agents by general specification ICP-MS for environmental analysis using an ion exchange column with an aqueous solvent. Using GL-science SYPRON AX-1 and a carbonate-bicarbonate buffer, four Gd contrast agents ―Gd-DTPA-BMA, Gd-BT-DO3A, Gd-DTPA, and Gd-EOB-DTPA― were separated by stepwise elution (switching between two different concentration solvents). The method detection limit (MDL) for a river water sample of Gd contrast agents is similar to that previously reported (Gd-DTPA-BMA: 2.7 ng of Gd/L, Gd-BT-DO3A: 4.4 ng of Gd/L, Gd-DTPA: 1.3 ng of Gd/L and Gd-EOB-DTPA: 3.3 ng of Gd/L), and applicable to environmental river water samples. On the other hand, some issues were observed in the MDL for sea water samples due to the influence of coexisting salts.

The elution order of all 209 polychlorinated biphenyls (PCBs) on two capillary columns, DB-17ms and VF-17ms, is presented. In addition, the interference on dioxin-like PCBs by polychlorinated dibenzo-p-dioxins was clarified.

This study addresses the behavior of hexavalent chromium (Cr(VI)) in contaminated soils and the challenges of remediation, with a specific focus on the impact of trace elements coexisting with chromium. Cr(VI), a toxic and highly mobile form, is commonly reduced to the less toxic trivalent chromium (Cr(III)) through various remediation methods such as treatment with Fe(II). However, Cr(VI) has been observed to reappear in treated soils over time, posing ongoing environmental risks. This research examines the role of 31 trace elements in influencing Cr(VI) reduction and potential reoxidation of Cr(III). The study identified four elements—V(IV), Mn(II), As(III) and Sb(III)—that may significantly alter Cr behavior due to their varied oxidation states. Through experiments, the results showed that Mn(II) and V(IV) contribute to Cr(III) reoxidation, a process that can revert Cr to its more toxic form, Cr(VI). Additionally, As(III) was found to potentially enhance Cr(III) dissolution, suggesting a pathway by which Cr(III) could return to a soluble, reactive state in alkaline conditions. This study suggests that coexisting trace elements, often neglected in traditional remediation approaches, may play a crucial role in the stability of Cr(VI) remediation. Addressing these interactions can inform more robust and effective strategies for managing Cr contamination in environmental settings, particularly where industrial waste has led to diverse element contamination. The findings emphasize the importance of considering trace element effects to prevent Cr(VI) re-emergence and improve the remediation technologies.

We detected 216~225 Bq/kg-raw of radiocesium in the muscle of seabass (Lateolabrax japonicus) collected in October 2024 at the Kuma River estuary in the evacuation zone in Okuma town, Fukushima Prefecture. In the stomach contents of the seabass, 386 Bq/kg-raw of radiocesium was detected. Some seabass has the characteristic of including the estuarine areas in their feeding behavior, and it is assumed that the radioactivity specific to seabass was caused by their feeding behavior. We pointed out that the case may be one of the causes of the variations of radioactivity of radiocesium in seabass caught off the coast of Fukushima Prefecture.

There is a concern about the sudden release of hazardous chemical substances into the environment during natural disasters and accidents. To enhance responsiveness to this concern, we published Chemical Risk Assessment and Management Resource Core for Disaster and Emergency (D.Chem-Core), a web-based information system. In this study, a tabletop exercise was conducted with staff from local environmental research institutes to evaluate the usability of this system, which is designed to support in responding to such unexpected events. We assessed usability in two ways: how the system contributed to the planning of environmental surveys, and how participants perceived it. During group work in the tabletop exercise, each group independently decided a chemical release accident scenario, discussed how they would respond to the situation, and documented the decision-making process. For system evaluation, we identified eleven items related to environmental surveys and summarized whether each group was able to obtain the necessary information. The useful ratios, the ratios of the number of groups that could obtain the necessary information, were at least 0.5 for all items except the one for which there was no demand. According to the survey, approximately 90% of respondents expressed their willingness to use the system in response to disasters and accidents. As a result, we confirmed that the system demonstrates strong usability in such situations.

Dioxins present in various environmental media were quantified using a DB-17ms column with dimensions of 80 m × 0.18 mm ID, 0.18 μm film thickness. The analytical results obtained with this column showed good agreement with those acquired using the conventional multi-column method. These findings demonstrate that all 29 TEF congeners can be effectively separated and quantified in a single injection using the longer, narrower column.