Benzotriazole, Benzothiazole, and Benzophenone Compounds in Indoor Dust from the United States and East Asian Countries

Organic corrosion inhibitors (OCIs), including ultraviolet light filters, are widely used in plastics, rubbers, colorants, and coatings to increase the performance of products. Derivatives of benzotriazole (BTR), benzothiazole (BTH), and benzophenone (BP) are high-production volume OCIs that have been detected in the environment and human tissues. However, knowledge of their occurrence in indoor environments, as well as human exposure to them, is still lacking. In this study, BTR, BTH, BP and their 12 derivatives were determined in indoor dust for the first time. All three groups of OCIs were found in all 158 indoor dust samples from the U.S. and three East Asian countries (China, Japan, and Korea). The geometric mean (GM) concentration of the sum of six BTRs (GM CΣBTRs) ranged from 20 to 90 ng/g among the four countries studied, with a maximum CΣBTRs of ∼2000 ng/g found in a dust sample from China. Tolyltriazole was the major derivative of BTR measured in dust. GM CΣBTHs in indoor dust from the four countries ranged from 600 to 2000 ng/g. 2-OH-BTH was the predominant BTH in dust from the U.S., Japan, and Korea. GM CΣBPs in dust ranged from 80 to 600 ng/g, with 2-OH-4-MeO-BP and 2,4-2OH-BP, contributing to the majority of ∑BP concentrations. Based on the concentrations of three types of OCIs in indoor dust, human exposure through dust ingestion was calculated. Daily intake of OCIs through dust ingestion was higher for people in the U.S., Japan, and Korea than in China; the residents in urban China are exposed to higher levels of OCIs via dust ingestion than are those in rural China

Mass Loading and Fate of Linear and Cyclic Siloxanes in a Wastewater Treatment Plant in Greece

The occurrence and fate of 5 cyclic (D3 to D7) and 12 linear (L3 to L14) siloxanes were investigated in raw and treated wastewater (both particulate and dissolved phases) as well as in sludge from a wastewater treatment plant (WWTP) in Athens, Greece. Cyclic and linear siloxanes (except for L3) were detected in all influent wastewater and sludge samples at mean concentrations of (sum of 17 siloxanes) 20 μg L^–1 and 75 mg kg^–1, respectively. The predominant compounds in wastewater were L11 (24% of the total siloxane concentration), L10 (16%), and D5 (13%), and in sludge were D5 (20%) and L10 (15%). The distribution of siloxanes between particulate and dissolved phases in influents differed significantly for linear and cyclic siloxanes. Linear siloxanes showed higher solid–liquid distribution coefficients (log <i>K</i>_d) than did cyclic compounds. For 10 of the 16 compounds detected in influents, the removal efficiency was higher than 80%. Sorption to sludge and biodegradation and/or volatilization losses are important factors that affect the fate of siloxanes in WWTPs. The mean total mass of siloxanes that enter into the WWTP via influent was 15.1 kg per day^–1, and the mean total mass released into the environment via effluent was 2.67 kg per day^–1

Identification of Poly(ethylene terephthalate) Nanoplastics in Commercially Bottled Drinking Water Using Surface-Enhanced Raman Spectroscopy

Micro/nanoplastics have emerged as global contaminants of serious concern to human and ecosystem health. However, identification and visualization of microplastics and particularly nanoplastics have remained elusive due to the lack of feasible and reliable analytical approaches, particularly for trace nanoplastics. Here, an efficient surface-enhanced Raman spectroscopy (SERS)-active substrate with triangular cavity arrays is reported. The fabricated substrate exhibited high SERS performance for standard polystyrene (PS) nanoplastic detection with size down to 50 nm and a detection limit of 0.001% (1.5 × 1011 particles/mL). Poly­(ethylene terephthalate) (PET) nanoplastics collected from commercially bottled drinking water were detected with an average mean size of ∼88.2 nm. Furthermore, the concentration of the collected sample was estimated to be about 108 particles/mL by nanoparticle tracking analysis (NTA), and the annual nanoplastic consumption of human beings through bottled drinking water was also estimated to be about 1014 particles, assuming water consumption of 2 L/day for adults. The facile and highly sensitive SERS substrate provides more possibilities for detecting trace nanoplastics in an aquatic environment with high sensitivity and reliability

Table1_Mode of Application of Peracetic Acid-Based Disinfectants has a Minimal Influence on the Antioxidant Defences and Mucosal Structures of Atlantic Salmon (Salmo salar) Parr.DOCX

Peracetic acid (PAA) is an oxidative disinfectant with a broad spectrum of antimicrobial activity and low environmental impact. In this study, we investigated the physiological impacts of PAA application in Atlantic salmon (Salmo salar) parr reared in freshwater recirculating aquaculture systems over a 4-week period. PAA at a target concentration of 1 mg/L was administered either in pulse (every 3 days) or continuous. The group that did not receive PAA served as a control. Fish tissue samples were collected for histology, gene expression, and biochemical analyses at day 0 and after 2 and 4 weeks of exposure. The expression of genes encoding for antioxidant defence in the olfactory organs, skin, and gills changed during the trial, but the temporal effects were more pronounced than inter-treatment impacts. The glutathione group of antioxidant genes was more responsive to PAA. In most cases, an upregulation was observed. Significantly lower levels of reactive oxygen species were identified in the plasma and skin mucus of the two PAA-exposed groups at week 4; nonetheless, significantly increased levels of total antioxidant capacity were only observed in the skin mucus of fish from the continuous treatment group. Additional markers of oxidative stress (i.e., 8-oxo-2′-deoxyguanosine and o,o'-dityrosine) were analysed in the skin, gills, liver, and dorsal fins. These markers were unaffected by the two PAA treatments. Sporadic reversible structural alterations were observed in the three mucosal organs; the changes were time-dependent, and the effects of PAA treatment were minimal. The number of mucous cells varied over time but not within treatments except in the skin of the pulse group at week 4 where a reduction was observed. The ratio of acidic and neutral mucous cells in the skin and gills were affected by PAA treatments especially in the pulse group. Overall, this study revealed that Atlantic salmon parr mobilised mucosal and systemic antioxidant defences against the oxidative disinfectant PAA, but it was evident that the mode of application did not impose a strong influence. The minimal effects of PAA application on the indicators of health and welfare underscore the potential use of PAA as a routine disinfectant in recirculating aquaculture systems.</p

Synthetic Phenolic Antioxidants and Their Metabolites in Indoor Dust from Homes and Microenvironments

Synthetic phenolic antioxidants (SPAs), including 2,6-di-<i>tert</i>-butyl-4-hydroxytoluene (BHT), are extensively used in food, cosmetic and plastic industries. Nevertheless, limited information is available on human exposures, other than the dietary sources, to SPAs. In this study, occurrence of 9 SPAs and their metabolites/degradation products was determined in 339 indoor dust collected from 12 countries. BHT was found in 99.5% of indoor dust samples from homes and microenvironments at concentrations that ranged from < LOQ to 118 μg/g and 0.10 to 3460 μg/g, respectively. This is the first study to measure BHT metabolites in house dust (0.01–35.1 μg/g) and their concentrations accounted for 9.2–58% of the sum concentrations (∑SPAs). 3,5-di-<i>tert</i>-butyl-4-hydroxybenzaldehyde (BHT–CHO), 2,6-di-<i>tert</i>-butyl-4-(hydroxymethyl)­phenol (BHT–OH), 2,6-di-<i>tert</i>-butyl-1,4-benzoquinone (BHT–Q) were the major derivatives of BHT found in dust samples. The concentrations of gallic acid esters (gallates) in dust from homes and microenvironments ranged from < LOQ to 18.2 and < LOQ to 684 μg/g, respectively. The concentrations and profiles of SPAs varied among countries and microenvironments. Significantly elevated concentrations of SPAs were found in dust from an e-waste workshop (1530 μg/g). The estimated daily intake (EDI) of BHT via house dust ingestion ranged from 0.40 to 222 ng/kg/d (95th percentile)