Implications For Human Exposure Research Articles

Understanding cyanobacteria and cyanotoxins: implications for human exposure, toxicological risk assessment and management

Cyanobacteria, often referred to as blue-green algae, are a diverse group of photosynthetic bacteria that play a crucial role in various ecosystems. However, their proliferation and toxin production pose significant challenges to environmental, animal, and human health. In recent years, the interplay between cyanobacteria, climate change, and the production of cyanotoxins has garnered increased attention. This short note aims to delve into the intricate relationship between cyanobacteria and the production of cyanotoxins, the toxicological risks associated with exposure, and strategies for risk assessment and management.

Chlorate in foodstuffs from south China and its implication for human exposure

Chlorate, mainly used in the production of fireworks, herbicides and other products, is an inorganic pollutant, which easily dissolves in water and is difficult to degrade. Chlorate has a potential toxic risk to the thyroid function, kidneys, and blood system, which could pose a potential threat to human health. However, studies focusing on human exposure to chlorate are scarce, especially via food consumption. This study aimed to investigate the concentrations of chlorate in six types of foods (n = 531) from south China, and evaluate potential exposure risks for local residents. The detection rates of chlorate in all six types of foods were greater than 50 %, indicating the ubiquitous occurrence of chlorate in foods. Among the six types of foods, vegetables exhibited the highest concentrations of chlorate (p < 0.05), mainly attributed to the direct exposure to the environment compared with other foods. The hazard quotient (HQ) values by using EFSA reference dose (RfD) of chlorate via foods and water consumption existed greater than 1 in different age groups, indicating a potential health risks to human in south China.

Atmospheric monomethylmercury: Inferred sources constrained by observations and implications for human exposure

Monomethylmercury (MMHg) is a potent neurotoxin that poses a threat to human health. MMHg cycles in all spheres of the Earth but the sources and fate of atmospheric MMHg are unclear. Here, we develop a global model for atmospheric MMHg, which integrates the presently available data and indicates the limitations of the current study. Constrained by the observations in the atmosphere, the global atmospheric MMHg from all sources is 1009 (205–2474 as an uncertainty range) Mg/yr, with the largest sources from the in-cloud methylation of divalent mercury (475 Mg/yr) and MMHg sea spray (395 Mg/yr). MMHg has a short lifetime of 1.9 days in the troposphere due to rapid photo-demethylation. Our model indicates a net loss of marine MMHg to the atmosphere and thus a detoxifying effect on MMHg contamination in marine fish. However, it suggests additional MMHg deposition to the land, particularly in densely populated coastal areas, introducing a new risk pathway that needs to be considered in mercury exposure assessment. The atmosphere plays a non-negligible role in the biogeochemical cycle and human health, which requires further study and consideration in implementing the global Minamata Convention.

Factors Influencing Concentrations of PFAS in Drinking Water: Implications for Human Exposure

Factors Influencing Concentrations of PFAS in Drinking Water: Implications for Human Exposure

Occurrence and profiles of bisphenol A and its analogues in marine shrimps from Tianjin and their implications for human exposure

Bisphenols, a class of compounds with endocrine-disrupting characteristics, encompassing its effects on reproduction, nervous and immune systems. Diet represents the principal route of bisphenols intake, prompting concerns about dietary exposure. In this study, the occurrence and content of nine bisphenols in 96 marine shrimps from Tianjin were detected and analysed using ultra high performance liquid chromatography mass spectrometer and solid-phase extraction. The analytical method was validated to demonstrate reliable analytical performance. The results revealed that bisphenol A was detected in the majority of the samples, with the highest detection rate among the nine bisphenols, followed by bisphenol S, while the remaining bisphenols were not detected. A discernible age-related trend was identified in the assessment of dietary exposure, whereby exposure levels increased with decreasing age. Furthermore, regional discrepancies were observed, yet no gender-based distinctions were discerned. The estimated daily intake to total bisphenols through marine shrimp in this study was lower than the current tolerable daily intake set by the European Food Safety Authority, and it can be assumed that the risk of exposure to the nine bisphenols investigated through dietary is acceptable. However, given the recently proposed draft values by the European Food Safety Authority and the higher exposures observed in children and teenagers, further surveillance and dietary guidance is required. To our knowledge, this is the first study in Tianjin to evaluate the health risks associated with bisphenol A and its analogues via marine shrimp, which can monitor dietary safety and protect population health.

Ubiquitous occurrence of organophosphate esters in plastic-made and paper-made food contact materials and their implication for human exposure

Ubiquitous occurrence of organophosphate esters in plastic-made and paper-made food contact materials and their implication for human exposure

Synthetic Microplastics in UK tap and bottled water; Implications for human exposure

There is increasing concern for public health over inadvertent human exposure to MPs due to potential adverse health effects linked to MPs polymeric composition, toxic chemical additives, and/or harmful microorganisms adsorbing onto their surfaces. While numerous studies have reported MPs occurrence and risk in the freshwater aquatic environment and drinking water sources (e.g., rivers, lakes, and reservoirs), the current state-of-knowledge on MPs pollution in drinking water (i.e., tap water and bottled water) remains limited at a global level. This paper provides the first comprehensive study of the occurrence, concentrations, size distribution, shape, and polymer type of MPs in 177 tap water samples from 13 cities in the United Kingdom, as well as 85 samples of bottled water from 17 popular brands, with various packaging materials, on the UK market.MPs were detected in all tap water samples (range 6–100 MP/L) and bottled water samples (range 12–62 MP/L). Average MPs concentration in tap water (40 ± 16 MP/L) was statistically indistinguishable from that in bottled water (37 ± 11 MP/L). However, the average MPs particle size in tap water (32.4 μm) exceeded significantly (p < 0.05) that in bottled water (26.5 μm), indicating the various purification processes applied to bottled water may help remove larger MPs, but raises concern over the potential adverse health effects from exposure to smaller MPs. The most frequently detected polymer types were: polypropylene (PP), polyethylene (PE), and polyvinyl chloride (PVC) in tap water, and PE, PP and polyethylene terephthalate (PET) in bottled water. A strong correlation was observed (r = 0.68, P = 0.049) between the plastic cap material (PE) and the predominant polymer type in the bottled water. In terms of morphology, fragments and fibres were the most abundant MPs, together constituting 92 % and 96 % of MPs detected in tap and bottled water samples, respectively.Using EFSA (European Food Safety Authority) recommended daily water intakes, the corresponding exposures to MPs in different UK age groups were estimated. On a body weight (BW) basis, infants and toddlers were exposed (4 MP/kg BW/day) at a higher level than adults (1 MP/kg BW/day). This raises concern, given the former's incompletely developed immune/nervous systems rendering them at higher risk of adverse health effects from such exposure.

Occurrence and characterization of microplastics in bottled drinking water

Microplastics (MPs) have been identified in diverse settings, including drinking water, freshwater, food, air, and marine environments. This study employed stereomicroscopic and µ-Raman techniques to analyze water samples from ten widely consumed bottled water brands, aiming to detect and characterize MPs. Additionally, the oral consumption of MPs per capita was estimated. The average abundance of MPs ranged from 9 ± 1.00 MPs/L to 3 ± 1.73 MPs/L across all brands. Various MPs shapes were observed, including fibers, fragments, films, and pellets, with fibers being predominant (58.928%). MPs were categorized by color into five groups (red, blue, black, yellow, and transparent), with red comprising approximately 35.714% of the total count. All identified MPs were less than 500 µm in size. µ-Raman analysis validated the presence of eight different polymer types in the samples, namely Polypropylene (PP) (37.5%), Polymethyl methacrylate (PMMA) (3.571%), polystyrene (PS) (33.928%), polycarbonate (PC) (3.571%), polybutylene1 (PB1) (14.2%), Isotactic polypropylene (iPP) (7.142), Nylone 6-α polymorph (αNY6) (5.357%), and polyvinyl alcohol (PVOH) (1.785%). The estimated daily intake of MPs per person was determined to be 0.42 MPs, translating to an annual intake of 153.3 MPs per person. The origin of MPs in bottled water was likely attributed to both raw water sources and packaging materials, underscoring the need for further investigation. Given the potential health implications of human exposure to drinking water MPs, careful consideration should be given to the use of plastic packaging for potable water.

Occurrences and migration characteristics of photoinitiators in paper food packaging: Implication for human exposure

Photoinitiators (PIs), as an important component of UV inks, are widely used in the printing of paper food packaging. Nevertheless, there is limited information concerning the identification of PIs in food packaging and their potential migration rules under natural storage condition. In this study, 23 target PIs detected in paper food packaging were dominated by benzophenones (BZPs), followed by amine co-initiators (ACIs), thioxanthones (TXs) and phosphine oxides (POs). The concentration of ΣPIs ranged between 48.3 and 1.11 × 105 ng/g. Meanwhile, the concentration of ΣPIs were found to be significantly higher in Corrugated paper compared to Polyethylene (PE) coated paper, Composite paper and White card paper. Benzophenone (BP) was found as the dominant PI congener in Corrugated paper, with the concentration ranging from 923-3.66 × 104 ng/g. The migration quantity of ΣPIs increased in a time-dependent manner in the first 13 days and then eventually reached equilibrium. Low temperatures had a certain inhibitory effect on the migration of PIs from paper packaging to food. Under high exposure scenario, the EDIs of ΣPIs for children, adolescents, and adults were 31.4 ng/(kg bw·day), 17.2 ng/(kg bw·day), and 14.4 ng/(kg bw·day), respectively, all of which did not exceed the reference dose, indicating that dietary intake of PIs does not pose any health risks to the human body.

Presence of N, N’-substituted p-phenylenediamine quinones in Tap Water: Implication for human exposure

Monitoring studies have demonstrated the wide presence of N, N’-substituted p-phenylenediamine-derived quinones (PPDQs) in environmental matrices. The general population may be potentially exposed to PPDQs through the consumption of tap water. While, the existence of PPDQs in tap water has not been well examined. To fill this gap, in this study we collected tap water samples from Hangzhou, China, and examined seven homologues of PPDQs in collected samples. All target PPDQs were identified in the collected tap water samples, with distinct detection frequencies (38–89%). PPDQs detected in tap water was dominated by N-(1, 3-dimethylbutyl)-N’-phenyl-p-phenylenediamine (6PPDQ; mean 0.56 ng/L, < LOD–4.0 ng/L). The profiles of PPDQs concentrations in tap water from the four districts of Hangzhou city were slightly different. The daily intake (DI) was found highest for 6PPDQ (mean 14–22 pg/kg bw/day, median 10–15 pg/kg bw/day) through tap water intake. The relatively higher DIs of various PPDQs were displayed for infants (mean 10–22 pg/kg bw/day, median 6.5–15 pg/kg bw/day), relative to the children (8.0–18 pg/kg bw/day, 5.4–12 pg/kg bw/day) and adults (6.7–14 pg/kg bw/day, 4.5–10 pg/kg bw/day). These data are crucial for assessing the overall human exposure to PPDQs. This study first, to our knowledge, reveals the concentrations and profiles of PPDQs in tap water.

Discovery of perfluoroalkyl sulfonyl quaternary ammonium substances in the environment and their environmental behaviors

A variety of per- and polyfluoroalkyl substances (PFASs) have been released into the environment via wastewater treatment plant (WWTP) effluent, with current target and nontarget analytical methods typically focusing on negatively ionized PFASs while largely overlooking positively ionized ones. In this study, five cationic PFASs, perfluoroalkyl sulfonyl quaternary ammonium substances (PFAQASs), were first identified in surface water impacted by the WWTP effluent, applying a metabolomics-based nontarget analysis method. Environmental behaviors of identified novel PFAQASs were further investigated. In surface water, sediment, and fish (Coilia mystus) samples collected from the Yangtze River, 8:3 PFAQA was consistently the predominant PFAQASs, with the mean concentrations of 90 ng/L (< LOD−558 ng/L), 92 ng/g dw (< LOD−421 ng/g dw), and 2.3 ng/g ww (< LOD−4.6 ng/g ww), respectively. This study highlights the necessity to discover other cationic PFASs in the environment. Among PFAQASs, 8:4 PFAQA (4.2, range 3.4 − 4.6) had the highest mean sediment-water partitioning coefficient (log Koc), followed by 8:3 PFAQA (3.9, 2.8 − 4.5) and 6:3 PFAQA (3.7, 3.3 − 4.1). The log Koc of PFAQASs showed a general increase trend with the increasing carbon chain length. Mean bioaccumulation factor (BAF) values of PFAQASs calculated in the collected fish from the Yangtze River ranged from 1.9 ± 0.32 (4:3 PFAQA) to 2.9 ± 0.34 (8:4 PFAQA). The mean BAF values of PFAQASs generally increased with the carbon chain length. Further studies are warranted to elucidate the environmental fate, potential toxicity, and human exposure implications for these identified novel PFASs.

Discovery and analysis of microplastics in human bone marrow

The health implications of human exposure to microplastics (MPs) have raised significant concerns. While evidence indicates MPs can accumulate in closed human organs like the heart, placenta, and blood, there is no available data on MP exposure specifically within the human bone marrow. To fill the research gap, this study detected the concentration of microplastics (MPs) in bone marrow samples by pyrolysis gas chromatography-mass spectrometry (Py-GC/MS) and assessed the size range and morphological characteristics of MPs by Laser Direct Infrared Spectroscopy (LD-IR) and scanning electron microscopy (SEM). Our study shows that MPs were present in all 16 bone marrow samples, with an average concentration of 51.29 µg/g ranging from 15.37 µg/g to 92.05 µg/g. Five polymer types-polyethylene (PE), polystyrene (PS), polyvinyl chloride (PVC), polyadiohexylenediamine 66 (PA66), and polypropylene (PP), were identified. PE was the most frequent polymer detected in the bone marrow, with an average concentration of 30.02 µg/g ranging from 14.77 µg/g to 52.57 µg/g, with a detection rate of 93.75 %. PS had the highest detection rate at 100 % of bone marrow samples, while PVC and PA66 were found in 75 % of samples each. LD-IR analysis revealed the identification of 25 polymer types, with an average abundance of 19.72 particles/g. Of these, 89.82 % of the MPs were smaller than 100 µm. In summary, this study has, for the first time, demonstrated the presence of MPs are deeply embedded within human bone marrow, providing a basis for future investigations into their potential toxicological effects and underlying mechanisms affecting the hematopoietic system.

Per- and polyfluoroalkyl substances in Chinese commercially available red swamp crayfish (Procambarus clarkii): Implications for human exposure and health risk assessment

The extensive utilization of per- and polyfluoroalkyl substances (PFASs) has led to their pervasive presence in the environment, resulting in contamination of aquatic products. Prolonged exposure to PFASs has been linked to direct hepatic and renal damage, along with the induction of oxidative stress, contributing to a spectrum of chronic ailments. Despite the recent surge in popularity of red swamp crayfish as a culinary delicacy in China, studies addressing PFASs' exposure and associated health risks from their consumption remain scarce. To address this gap, our study investigated the PFASs’ content in 85 paired edible tissue samples sourced from the five primary red swamp crayfish breeding provinces in China. The health risks associated with dietary exposure were also assessed. Our findings revealed widespread detection of PFASs in crayfish samples, with short-chain perfluoroalkyl carboxylic acids (PFCAs) exhibiting the highest concentrations. Notably, the total PFAS concentration in the hepatopancreas (median: 160 ng/g) significantly exceeded that in muscle tissue (5.95 ng/g), as did the concentration of every single substance. The hazard quotient of perfluorohexanesulfonic acid (PFHxS) via consuming crayfish during peak season exceeded 1. In this case, a potential total non-cancer health risk of PFASs, which is mainly from the hepatopancreas and associated with PFHxS, is also observed (hazard index>1). Thus, it is recommended to avoid consuming the hepatopancreas of red swamp crayfish. Greater attention should be paid to governance technology innovation and regulatory measure strengthening for short-chain PFASs.

Flame Retardant Exposure in Vehicles Is Influenced by Use in Seat Foam and Temperature.

Flame retardants (FRs) are added to vehicles to meet flammability standards, such as US Federal Motor Vehicle Safety Standard FMVSS 302. However, an understanding of which FRs are being used, sources in the vehicle, and implications for human exposure is lacking. US participants (n = 101) owning a vehicle of model year 2015 or newer hung a silicone passive sampler on their rearview mirror for 7 days. Fifty-one of 101 participants collected a foam sample from a vehicle seat. Organophosphate esters (OPEs) were the most frequently detected FR class in the passive samplers. Among these, tris(1-chloro-isopropyl) phosphate (TCIPP) had a 99% detection frequency and was measured at levels ranging from 0.2 to 11,600 ng/g of sampler. TCIPP was also the dominant FR detected in the vehicle seat foam. Sampler FR concentrations were significantly correlated with average ambient temperature and were 2-5 times higher in the summer compared to winter. The presence of TCIPP in foam resulted in ∼4 times higher median air sampler concentrations in winter and ∼9 times higher in summer. These results suggest that FRs used in vehicle interiors, such as in seat foam, are a source of OPE exposure, which is increased in warmer temperatures.

Phthalate alternatives and their monoesters in indoor dust from several regions, China and implications for human exposure

Household products, in response to regulations, increasingly incorporate phthalate (PAE) alternatives instead of traditional PAEs. However, limited information exists regarding the fate and exposure risk of these PAE alternatives and their monoesters in indoor environments. The contamination levels of PAE alternatives and their monoesters in indoor dust might vary across regions due to climate, population density, industrial activities, and interior decoration practices. By analyzing indoor dust samples from six geographical regions across China, this study aims to shed light on concentrations, profiles, and human exposure to 12 PAE alternatives and 9 their monoesters. Bis(2-ethylhexyl) benzene-1,4-dicarboxylate (DEHTP), tributyl 2-acetyloxypropane-1,2,3-tricarboxylate (ATBC), and tris(2-ethylhexyl) benzene-1,2,4-tricarboxylate (TOTM) were the main PAE alternatives in dust across all regions. The total concentrations of 12 PAE alternatives ranged from 0.125 to 4160 μg/g in indoor dust. High molecular weight PAE alternatives had significantly correlated concentrations (p < 0.05) based on Spearman analysis, suggesting their co-use in heat-resistant plastic products. A collective of nine monoesters were identified in most samples, with total concentrations ranging from 0.048 to 29.6 μg/g. The median concentrations of PAE alternatives were highest in North China (66.8 μg/g), while those of monoesters were highest in Southwest China (6.93 μg/g). A significant correlation (p < 0.05) between the concentrations of DEHTP and its monoester suggested that degradation could be a potential source of monoesters. Although hazard quotients (HQs) have been calculated to suggest that the current exposure is unlikely to pose a significant health risk, the lack of toxicity threshold data and the existence of additional exposure pathways necessitate a further confirmation.

Aerosolization of micro- and nanoplastics via sea spray: Investigating the role of polymer type, size, and concentration, and potential implications for human exposure

Micro- and nanoplastics (MNPs) can enter the atmosphere via sea spray aerosols (SSAs), but the effects of plastic characteristics on the aerosolization process are unclear. Furthermore, the importance of the transport of MNPs via these SSAs as a possible new exposure route for human health remains unknown. The aim of this study was two-fold: (1) to examine if a selection of factors affects aerosolization processes of MNPs, and (2) to estimate human exposure to MNPs via aerosols inhalation.A laboratory-based bubble bursting mechanism, simulating the aerosolization process at sea, was used to investigate the influence of MNP as well as seawater characteristics. To determine the potential human exposure to microplastics via inhalation of SSAs, the results of the laboratory experiments were extrapolated to the field based on sea surface microplastic concentrations and the volume of inhaled aerosols.Enrichment seemed to be influenced by MNP size, concentration and polymer type. With higher enrichment for smaller particles and denser polymers. Experiments with different concentrations showed a larger range of variability but nonetheless lower concentrations seemed to result in higher enrichment, presumably due to lower aggregation. In addition to the MNP characteristics, the type of seawater used seemed to influence the aerosolization process. Our human exposure estimate to microplastic via inhalation of sea spray aerosols shows that in comparison with reported inhaled concentrations in urban and indoor environments, this exposure route seems negligible for microplastics. Following the business-as-usual scenario on plastic production, the daily plastic inhalation in coastal areas in 2100 is estimated to increase but remain far below 1 particle per day.This study shows that aerosolization of MNPs is a new plastic transport pathway to be considered, but in terms of human exposure it seems negligible compared to other more important sources of MNPs, based on current reported environmental concentrations.

Perchlorate and chlorate in aquatic products from Shenzhen, China, and their implications for human exposure

Perchlorate and chlorate are chemically stable species with high solubility and are widely distributed in various foods. Dietary intake is considered to be the main route of human exposure to these chemicals. Aquatic products are an important component of residents' daily diets. However, there is still a lack of a complete research report on perchlorate and chlorate contamination in aquatic products. Thus, this study investigated the concentration of perchlorate and chlorate in shellfish, freshwater fish, freshwater shrimp, sea fish, and sea shrimp from Shenzhen and assessed human exposure risks. The detection frequency of chlorate was low, and the incidence of perchlorate was significantly lower than previous studies, demonstrating a substantial reduction in perchlorate contamination in Shenzhen waters. However, certain samples exhibited relatively elevated concentrations. The highest concentration of chlorate (43.1 µg kg−1) and perchlorate (14,865 µg kg−1) were both found in sea shrimp. Notably, the 95th percentile estimated daily intake (EDI) value of perchlorate derived from sea shrimp and shellfish surpassed the reference dose (RfD), while the EDI values of chlorate were all below the RfD. Therefore, Shenzhen residents are advised to consume sea shrimp and shellfish with caution to minimize the possible health risks linked to perchlorate and chlorate exposure.

Emerging organophosphite and organophosphate esters in takeaway food and the implications for human exposure.

Takeaway food has become a prominent component of the diet in urban areas of China, especially for young people. Although dietary intake is a major pathway to contaminants for human exposure, studies on emerging organophosphite antioxidants (OPAs) and organophosphate esters (OPEs) in food are scarce. Here, we investigated four OPAs and 19 OPEs in takeaway foods (n = 99) and paired takeaway food packaging (n = 50) in China. AO168=O (mean: 14.9 ng/g ww), TPPO (mean: 1.05 ng/g ww), and TCIPP (mean: 0.579 ng/g ww) were dominant in the takeaway food. Some OPEs had significant correlations in takeaway food. Emerging OPAs and OPEs in takeaway food varied significantly depending on the packaging materials and food types. AO168 and AO168=O were widespread in the paired takeaway food packaging. The migration efficiencies of emerging OPAs and OPEs were low in takeaway food packaged in aluminum foil. Although the actual contamination of emerging OPAs and OPEs in takeaway food significantly differed from those of in food simulants migrated from paired takeaway food packaging, the results imply that food itself and takeaway food packaging are potential contamination sources of emerging OPAs and OPEs in takeaway food. The average estimated dietary intakes of emerging OPAs and OPEs were 465 ng/kg body weight (bw)/day and 91.9 ng/kg bw/day, respectively. The exposure risk of emerging OPAs and OPEs through takeaway food intake is low in China.

Occurrence of microplastics and metals in European seabass produced in different aquaculture systems: Implications for human exposure, risk, and food safety

Microplastics (MPs) are emerging contaminants of increasing concern as they may cause adverse effects and carry other contaminants, which may potentially compromise human health. Despite occurring in aquatic ecosystems worldwide, the knowledge about MP presence in different aquaculture systems and their potential impact on seafood products is still limited. This study aimed to determine the levels of MPs in water, feed, and European seabass (Dicentrarchus labrax) from three relevant aquaculture systems and estimate human exposure to MPs and metals through seabass consumption. The recirculating aquaculture system (RAS) had the highest MP occurrence in water and feed. MP levels in seabass followed the aquaculture system's levels in water and feed, with RAS-farmed fish presenting the highest MP load, both in the fish gastrointestinal tract (GIT) and muscle, followed by pond-, and cage-farmed fish. MPs' characteristics across aquaculture systems and fish samples remained consistent, with the predominant recovered particles falling within the MP size range. The particles were visually characterized and chemically identified by micro-Fourier Transform Infrared Spectroscopy (μFTIR). Most of these particles were fibres composed of man-made cellulose and PET. MP levels in GIT were significantly higher than in muscle for pond- and RAS-farmed fish, MPs' bioconcentration factors >1 indicated bioconcentration in farmed seabass. Metal concentrations in fish muscle were below permissible limits, posing low intake risks for consumers according to the available health-based guidance values and estimated dietary scenarios.

P-Phenylenediamine Derivatives in Tap Water: Implications for Human Exposure

Human exposure to p-phenylenediamine derivatives (PPDs) may induce hepatotoxicity and altered glycolipid metabolism. Recent studies have demonstrated the wide presence of PPDs in environmental matrixes. However, until now, the occurrence of PPDs in tap water has not been well known. This study analyzed nine PPDs in tap water collected from Hangzhou and Taizhou, China. The results showed that seven PPDs were detected in tap water samples from Hangzhou (n = 131), with the concentration of total detected PPDs ranging from 0.29 to 7.9 ng/L (mean: 1.6 ng/L). N-(1, 3-dimethylbutyl)-N′-phenyl-p-phenylenediamine (6PPD; mean: 0.79 ng/L, &lt;LOD−5.7 ng/L) was the predominant PPD in tap water from Hangzhou, followed by N, N′-di-2-butyl-p-phenylenediamine (44PD; 0.39 ng/L, &lt;LOD−2.2 ng/L) and N-isopropyl-N′-phenyl-1, 4-phenylenediamine (IPPD; 0.31 ng/L, &lt;LOD−1.4 ng/L). Five PPDs were detected in tap water collected from Taizhou (n = 30). N-phenyl-N′-cyclohexyl-p-phenylenediamine (CPPD; mean: 1.0 ng/L, &lt;LOD−4.2 ng/L) was the predominant PPD in tap water from Taizhou, followed by 6PPD (0.93 ng/L, &lt;LOD−2.6 ng/L) and 44PD (0.78 ng/L, &lt;LOD−1.8 ng/L). The mean daily intake (DI) of PPDs for adults and children in Hangzhou was estimated to be 4.9–24 and 6.4–32 pg/kg bw/day, respectively. Meanwhile, the mean DI of PPDs for adults and children living in Taizhou was 11–31 and 14–40 pg/kg bw/day, respectively. To our knowledge, this study provides the first data on the occurrence of PPDs in tap water, which is vital for human exposure risk assessment.