To analyze a wide range of phenolic endocrine disrupting chemicals, including alkylphenols, bisphenol A (BPA) and its analogues, triclosan (TCS), thymol, and phenolic UV filters, a direct acetylation method has been developed and applied to 116 river water samples and 40 sewage treatment plant (STP) effluent samples collected in 2016–2019 in Tokyo, Japan. This method can simultaneously derivatize a range of target chemicals to inert acetylates at an early stage in the analytical procedure. In this study, nonylphenol concentrations in the Tamagawa River (median 5.7 ng/L) and the Sumidagawa River (median 13.4 ng/L) were one order of magnitude lower than those 20 years ago. Similarly, the TCS and BPA concentrations (median 27.0 ng/L and 11.0 ng/L, respectively) decreased by ~80% compared to the values obtained in studies conducted ~20 years ago. These decreases can be attributed to reduced production due to the establishment of environmental standards and industrial self-regulation. Most target chemicals had higher concentrations in the STP effluents than in river water, indicating that STP effluents are major sources of the chemicals. However, BPA in the Tamagawa River exhibited a different spatial pattern. Namely, BPA concentrations in the STP effluents (~5 ng/L) in the middle and lower reaches were lower than those in the receiving water (~15 ng/L). Meanwhile, effluents from two upstream STPs had extremely high BPA concentrations of up to 158 ng/L, revealing effluents from these STPs as major sources of BPA in the Tamagawa River. There are several landfills in the upstream STP catchment area, and their leachate is likely to contribute to the high concentrations of BPA in the STP effluents and river water. This is consistent with the composition of BPA and its alternatives, including BPAP, BPZ, BPS, BPB, BPE, BPF, BPAF, in the effluents from the STPs. The upstream STPs showed a predominance of BPA, whereas the alternatives, such as BPS and BPF, were dominant in the STPs in the middle and lower reaches. The compositional difference can be ascribed to the recent replacement of BPA with alternatives and BPA leaching from plastic products dumped in the 1980s and 1990s.
Among the plastic debris surveyed in the marine environment, a large quantity in terms of volume was found to be expanded polystyrene foam (EPS). This is due to its light weight and popularity as a packaging material. In this study, 28 compounds of polycyclic aromatic hydrocarbon (PAHs) were analyzed in both new and beached EPS collected in California, USA. In beached EPS, a variation in total PAH concentrations of up to 2 orders of magnitude was observed in the 337 to 11,800 ng/g-EPS range. Meanwhile, new EPS showed less variation in total PAH concentrations ranging from 282 to 1,194 ng/g-EPS. Most PAH species were shown to have higher concentrations in beached EPS than in new EPS, suggesting the ability of EPS to sorb PAHs from surrounding seawater. However, with anthracene, there was a significant depletion in beached EPS compared to new EPS. The fact that significant PAH concentrations were found in new unexposed EPS, including food packaging, highlights EPS as an exposure source of toxic chemicals to human food stocks upon migration, as well as to marine wildlife upon disposal. PAH concentrations and composition in new and beached EPS were consistent with those of samples from Japan, Malaysia and Australia, suggesting that the problems associated with EPS is a global issue.
Microplastics have recently been considered anthropogenic pollutants. Of the arguments to describe microplastic distributions is what mesh size should be employed. Many researchers have reported that the use of different mesh sizes causes naturally generated microplastic quantity differences. However, studies on how much specific microplastic distribution is overlooked in a large mesh remain insufficient in the aquatic environment, particularly in freshwater. Therefore, this study demonstrated qualitative and quantitative differences in microplastic distributions between 100– and 355– μm meshes from five perspectives: numerical/mass abundances, distributions along the flow direction, and microplastic features (size, shape, and polymer type). As observed, median values of numerical and mass abundances were 13.9 particles/m3 and 6.0 μg/m3, respectively, in the 100 μm mesh, then 0.4 particles/m3 and 1.0 μg/m3, respectively, in the 355 μm mesh. Although differences in mass abundances were six times between both meshes, for pristine river characteristics, the difference was ignored in this study. Results also showed that accidental irregularities discovered in the sampling analysis step affected the distribution tendency along the flow direction using the 355 μm mesh. Moreover, the 100 μm mesh showed the highest abundances in the lower sampling station, thereby reflecting the adjacent urban and its tributaries. A gradual increase in numerical fragment abundance toward a smaller size was observed with the 100 μm mesh. Additionally, results showed that cumulative probabilities relating to the minimum Feret diameter of films and fragments were divided into three parts. This division showed a 97% and 67% potential underestimation in the 355– and 100–μm meshes, respectively. Besides, although films, fibers, and fragments having seven polymers were observed in the 100 μm mesh, few shapes and polymer types were revealed in the 355 μm mesh. This finding made it was challenging to trace microplastic origins and presume bioaccumulation potentials using the 355 μm mesh. In conclusion, since the 100 μm mesh revealed completely different distributions from the 355 μm mesh, it was recommended in this study. However, viewpoints that the 355 μm mesh has an advantage in clogging the mesh exist. Therefore, a proper sampling method should be employed by establishing strategic research plans.
This study evaluated the effects of reducing the exposure concentration and the human health damage of alternative plasticizers to di(2-ethylhexyl) phthalate (DEHP) by a novel relative and quantitative risk assessment framework. The framework combines semivolatile organic compounds (SVOC) consumer exposure tools and damage functions. The used exposure tools were the consumer exposure models (CEM) of the US Environmental Protection Agency (US EPA) and DustEx of the Dutch National Institute for Public Health and the Environment (RIVM). These were used in the chemical substance management systems of the Toxic Substances Control Act (TSCA) and the Registration, Evaluation, Authorization and Restriction of Chemicals (REACH). Concerning plasticizers, we determined the rational values for the main parameters and estimation accuracy which have not been informed sufficiently to users. We also identified the key parameters for operating the exposure tools. The indoor concentrations of DEHP were predicted using a simple box model, and the estimation accuracies of CEM and DustEx were evaluated by comparing predicted DEHP concentrations with actual measured values. For the DEHP concentration in house dust, both CEM and DustEx had an estimation accuracy of Factor 3−1–3. In particular, in the region of LogKoa <12, DustEx tended to provide higher estimations of the dust phase concentration compared with CEM. The material/air partition coefficient Kma was the most sensitive and crucial parameter for both exposure tools. Compared with DEHP, the predictions of both exposure tools showed that the alternative plasticizers had lower exposure concentrations of 86.8%–4.5% in air and 75.5%–4.4% in dust. In addition, the damage functions for nonphthalates were newly determined, and the human health damage amount was calculated by multiplying the determined damage function by the estimated exposure concentration. The total amount of human health damage of alternative plasticizers was 59−1–655−1 compared with DEHP, indicating that the nonphthalate di(2-ethylhexyl) terephthalate (DEHT) had the highest risk reduction effect.
Open dumping and burning of waste contaminated with mercury are known mercury emission sources in the environment, especially in developing countries. However, little data are available to understand the actual situation. The results of a survey—implemented by the Ministry of the Environment, Japan—were analysed to examine the effectiveness and challenges of the survey methodologies. Mercury levels in ambient air, solid waste, emission flux, leachate water and human hair at waste disposal facilities in Cameroon, Indonesia, Kenya, Myanmar and Nigeria were analysed.
Ambient mercury levels at waste disposal facilities, where spontaneous waste combustion was observed, fluctuated significantly, although the average with the continuous monitoring was below 50 ng m−3. The factors for these fluctuations might be waste conditions, wind directions, distance from the waste combustion point, and others. The level was well below the guideline value for the workplace environment of the World Health Organization. Thus, it is unlikely for the site workers to develop adverse health effects caused by inhaling the ambient air.
The proportion of mercury emitted from waste disposal facilities, the quotient of daily mercury emission from the surface and daily mercury input to the facility were calculated. The results are 0.075%–1.32%, which indicated that less percentage of mercury input was emitted to the atmosphere and that the remaining will be accumulated in the facilities.
The methylmercury levels in hair were mostly below 1 μg g−1, which is below the equivalent to tolerable intake both for adults (4.4 μg g−1) and pregnant women (2.2 μg g−1). Thus, it is of no special concern for onsite workers regarding dietary mercury intake. Total mercury levels for most samples were also sufficiently low, but a few samples showed elevated mercury. The elevated levels might have been caused due to the application of personal care products containing mercury or accidental contact with other products containing mercury.
The survey has provided some useful insights into the mercury situation in waste landfill facilities in developing countries. The enhancement of mercury levels when and where open burning of waste is occurring needs further evaluation.
Mercury concentrations in ambient air at solid waste landfill facilities in developing countries with and without spontaneous waste combustion