It is widely believed that e-cigarettes are less harmful than conventional cigarettes because they have a lower nicotine content. In contrast to this notion, several in vitro studies have evaluated and demonstrated the genotoxicity associated with e-cigarette smoking. However, there is a lack of human studies on the genotoxicity of e-cigarettes. This pilot study evaluated and compared indicators of genotoxicity in e-cigarette users, cigarette smokers, and nonsmokers. A total of 84 healthy participants, including 20 e-cigarette users, 31 cigarette smokers, and 33 nonsmokers, were recruited. Genotoxicity was evaluated by measuring tail moment (TM), tail length (TL), and % tail DNA intensity (%T) using the comet assay as an indicator of DNA damage in blood and detecting micronuclei in buccal cells with the buccal micronucleus (MN) cytome assay. Bivariate analyses showed that there was no significant difference in TM and TL between e-cigarette users and cigarette smokers, but in both groups, the three parameters were significantly higher than that in nonsmokers (p<0.02). In contrast, the frequency of micronuclei in e-cigarette users (40%) was higher than that in cigarette smokers (27.5%). Our findings indicate that e-cigarettes have a similar genotoxic effect to regular cigarettes and, therefore, contradict the notion that e-cigarettes are safer than regular cigarettes.

Short-chain chlorinated paraffins (SCCPs) are persistent organic pollutants. In Japan, SCCPs are widely detected in the environment although the production and use of SCCPs have been banned. It is essential to estimate the amount and sources of SCCPs to implement countermeasures for SCCP emission. In this study, we estimated the emission and environmental concentrations of SCCP homologues in Japan from 1950 to 2050. Initially, the material flow of total SCCPs was estimated considering the material recycling process. The emission from each process during the entire life cycle of products containing SCCPs was estimated for each homologue. Volatilization factors of long-term-use products were specifically estimated from release factors and surface area, weight, and SCCP concentration of products containing SCCPs. The environmental concentrations were then estimated using the environmental fate model. In the material flow and emission estimation, parameter uncertainties, such as emission factors and SCCP application distribution, were considered, assuming each parameter follows a uniform distribution. The results of emission estimation suggested a decreasing trend of SCCP emission in recent years and continuation of this trend in the future. However, some emissions from long-term-use products may persist. In the future, products that have a long lifetime with closed-loop recycling, such as polyvinyl chloride wire-coating materials, are expected to significantly contribute to atmospheric emission. Moreover, recycled products may contain SCCPs. Based on the estimated concentration, the estimated water and sediment concentrations were within the range of the observed concentrations. Conversely, we could reduce the gap between the estimated and observed atmospheric SCCP concentrations compared with those in previous studies that did not consider the volatilization factor for each SCCP-containing product and material recycling process. However, a difference between the estimated and observed concentrations suggests that some unconsidered emission sources may exist that emit SCCPs into the atmosphere, such as SCCPs as impurities in medium-chain chlorinated paraffins, imported products containing SCCPs, and atmospheric advection from other countries. Hence, it is essential to calculate emissions from sources other than products that intentionally contain SCCPs produced in the past.

Illegal dumping of waste may directly lead to serious pollution problems because leakage and entry of chemicals into the environment are likely to occur. This article describes the environmental pollution caused by extremely large-scale illegal dumping of waste at two bordering prefecture sites in rural Japan and reviews the history and results of the implementation of technical measures to deal with the problem at one county site. The target pollutants are a wide variety of chlorinated volatile organic compounds (VOCs) and aromatic benzene due to the dumping of numerous drums containing waste solvents. From the geological characteristics and features related to the presence of contamination, site remediation was performed by applying a chemical method using lime and a combined method using pump-and-treat and bioremediation. This study describes the technical details of the soil and groundwater remediation over the years. Furthermore, we would like to consider what lessons should be learned from this long-running case of illegal dumping.

Artisanal small-scale gold mining (ASGM) is the largest single source of mercury (Hg) emissions globally. In this study, Hg contamination was investigated in rice, vegetables, soil, drinking water and groundwater near ASGM sites in Mandailing Natal District, North Sumatra, Indonesia to assess the human health risk of Hg to the residents. The mean Hg concentrations in the rice and vegetables were 50±33 μg/kg dw (n=20) and 2,100±2,500 μg/kg dw (n=12), respectively, and that in the paddy soil and farm soil were 5,600±12,000 μg/kg dw (n=20) and 19,000±33,000 μg/kg dw (n=12), respectively. Hg concentrations in the food, soil and drinking water samples decreased significantly with increasing distance from the amalgam burning facility to the sampling site, suggesting that the burning facility is a major source of Hg in this area. All drinking water samples were below the WHO safe value of Hg, whereas 96% of the vegetable and 82% of rice samples exceeded the safe value from the Indonesian National Standard or the FAO/WHO. The non-cancer risk calculated from the hazard quotients for the rice and vegetables exceeded 1 for children and adults. This paper provides information on Hg contamination in food and the environment in an understudied area, employing health risk assessment to evaluate long-term impacts on human health and offering insights for government decision-making regarding food quality.

The ever-increasing production, poor waste management, and persistent nature have caused plastic debris to become ubiquitous in the environment. Microplastics, usually defined as plastic particles less than 5 mm, have invaded our coasts, oceans, and seafood. Thus, there is a dire need to fully monitor and understand the global spatial distribution of microplastics in marine waters and biota, especially in commercial species. This review summarizes the microplastic abundance in the water column of both coastal and offshore areas, as well as microplastic concentrations in various biota globally. In addition, this review aims to discuss the effectiveness and limitations of various biota as bioindicators of microplastic pollution in marine environments. Coastal waters of South America, Asia, and Africa were reported to have very high abundances of microplastics, with abundances of 782,000, 19,000, and 1,200 particles/m³, respectively, possibly due to excessive input and mismanagement of plastic waste. Microplastic abundances in open oceans were significantly lower (up to three orders of magnitude) than those in coastal areas, apart from some convergence zones such as gyres. Microplastics were also detected in remote pristine areas, such as the Arctic and Antarctica, demonstrating the omnipresence and ability of microplastics to be transported long distances via atmospheric and oceanographical forces. Due to the lack of standardization, quantifiable particle size and sampling methodology were shown to greatly affect the results of microplastic abundance, making them important variables to note when comparing multiple studies. Most marine biota species were able to reflect local microplastic pollution levels to a certain extent. Filter feeders are popular bioindicator species, but their ingestion is limited to particles smaller than 1,500 μm. Although selective feeders have the capacity to ingest a larger size range of plastic particles (up to 5,000 μm or larger), their wide range of movements, ability to reject microplastics, and highly varied behaviors make them less reliable as bioindicators than filter feeders. Nonetheless, a greater variety of marine species should be monitored to ensure population health and food safety.

Neonicotinoid insecticides are exclusively used for insect control in many parts of the globe. Since early 1992, various neonicotinoid active compounds have been used for pest control in Japan. At present, all seven major neonicotinoid active compounds, imidacloprid, acetamiprid, dinotefuran, clothianidin, thiamethoxam, thiacloprid, and nitenpyram, are used in Japan, and the total shipment amount of these chemicals in the country was estimated 337.9 tons in 2022. Due to the massive neonicotinoid application in Japan, concerns have been raised about their potential infiltrations into nontarget ecosystems and their effects on human and ecological species. These concerns have inspired several studies, extensively investigating the environmental contamination levels and exposure tendencies in humans and several other invertebrate species. The current status report harmonized the up-to-date data on neonicotinoids in Japan and identified the incoherencies or knowledge gaps existing in the neonicotinoid literature reported in Japan. The report further summarized extensive neonicotinoid publications globally to illustrate the distributions of various neonicotinoid compounds in agricultural soils and surface waters and their exposures in humans and nontarget animal species. This report represents a few perspectives with detailed data from Japan into perspective.