Cumulative risk assessment and exposure characteristics of parabens in the general Taiwanese using multiple hazard indices approaches

Simultaneous and sensitive detection of methylparaben and its metabolites by using molecularly imprinted solid-phase microextraction fiber array technique

BACKGROUND

Methylparaben (MP), a commonly used antibacterial preservative, is widely used in personal care products, foods, and pharmaceuticals. MP and its metabolites are easy to enter the water environment, and their exposure and accumulation have negative effects on the ecological environment and human health, and have endocrine disrupting activity and potential physiological toxicity. It is still the primary issue of environmental analysis and ecological risk assessment to develop simple and reliable methods for simultaneous sensitive detection of these compounds in environmental water.

RESULTS

In this paper, a flexible molecularly imprinted fiber array strategy is proposed for simultaneous enrichment and detection of trace MP and its four main metabolites. The experimental results showed that the three-fiber imprinted fiber array constructed by MP imprinted fiber had the best effect on the simultaneous enrichment of these five target analytes. The enrichment capacity of the imprinted fiber array was 214-456 times, 314-1201 times and 38-685 times that of commercial PA, PDMS and PDMS/DVB fiber arrays, respectively. The limit of detection (LOD) of this method was 0.033 μg L-1. The spiked recovery rate was 86.78-113.96 %, and RSD was less than 9.17 %. In addition, this molecularly imprinted SPME fiber array has good stability, long service life and can be used repeatedly at least 100 times.

SIGNIFICANCE

This molecularly imprinted fiber array strategy can flexibly assemble different molecularly imprinted SPME fibers together, effectively improve the enrichment ability and detection sensitivity, and achieve simultaneous selective enrichment and detection of several analytes. This is an easy, efficient and reliable method for monitoring several trace analytes simultaneously in intricate environmental matrices.

Exposure characteristics and cumulative risk assessment of bisphenol A and its substitutes: the Taiwan environmental survey for toxicants 2013

Introduction

Ever since the use of bisphenol A (BPA) has been restricted, concerns have been raised regarding the use of its substitutes, such as bisphenol S (BPS) and bisphenol F (BPF). Meanwhile, the EU European Food Safety Authority (EFSA) issued the new tolerable daily intake (TDI) after the latest re-risk assessment for BPA, which enforced the need for cumulative risk assessment in the population. This study was conducted to identify BPA and its substitute's exposure characteristics of the general Taiwanese population and estimate the cumulative risk of bisphenol exposure.

Methods

Urine samples (N = 366 [adult, 271; minor, 95]) were collected from individuals who participated in the Taiwan Environmental Survey for Toxicants 2013. The samples were analyzed for BPA, BPS, and BPF through ultraperformance liquid chromatography-tandem mass spectrometry. Daily intake (DI) levels were calculated for each bisphenol. Hazard quotients (HQs) were calculated with the consideration of tolerable DI and a reference dose. Additionally, hazard index (HI; sum of HQs for each bisphenol) values were calculated.

Results

Our study found that the median level of BPA was significantly higher in adults (9.63 μg/g creatinine) than in minors (6.63 μg/g creatinine) (p < 0.001). The DI of BPS was higher in female (0.69 ng/kg/day) than in male (0.49 ng/kg/day); however, the DIs of BPF and BPS were higher in boys (1.15 and 0.26 ng/kg/day, respectively) than in girls (0.57 and 0.20 ng/kg/day, respectively). Most HI values exceeded 1 (99% of the participants) after EFSA re-establish the TDI of BPA.

Discussion

Our study revealed that the exposure profiles and risk of BPA and its substitute in Taiwanese varied by age and sex. Additionally, the exposure risk of BPA was deemed unacceptable in Taiwan according to new EFSA regulations, and food contamination could be the possible source of exposure. We suggest that the risk of exposure to BPA and its substitutes in most human biomonitoring studies should be reassessed based on new scientific evidence.

Occurrence profiling, risk assessment, and correlations of antimicrobials in surface water and groundwater systems in Southwest Nigeria

The presence of antimicrobials in water has grown into a major global health concern. This study thus focused on the presence, ecological implications, and potential health risks associated with nine antimicrobials: five antibiotics (ampicillin, chloramphenicol, ciprofloxacin, metronidazole, and tetracycline) and four parabens (methylparaben, ethylparaben, propylparaben, and butylparaben) in surface water and groundwater samples collected from three Southwestern States in Nigeria (Osun, Oyo, and Lagos States). These antimicrobials were widely detected across the three States with ciprofloxacin being the most dominant having maximum average concentrations of 189 μg L-1 and 319 μg L-1 in surface water and groundwater respectively. The range of average concentrations of antibiotics in surface water are 47.3-235 μg L-1 (Osun), 27.9-166 μg L-1 (Oyo) and 52.1-159 μg L-1 (Lagos). For groundwater, it is 35.3-180 μg L-1 (Osun), 26.5-181 μg L-1 (Oyo) and 32.3-319 μg L-1 (Lagos). The average concentrations of all parabens were 32.4-153 μg L-1, 53.4-80.1 μg L-1, and 83.2-132 μg L-1 for surface water and 46.7-55.7 μg L-1, 53-117 μg L-1, and 62.4-118 μg L-1 for groundwater in Osun, Oyo, and Lagos States respectively. Methylparaben was most frequently detected paraben with average concentrations of 153 μg L-1 and 117 μg L-1 in surface water and groundwater respectively. The measured environmental concentrations of these antimicrobials pose a significant ecological risk while those of ciprofloxacin and ampicillin pose a high health risk to all population groups studied. The average concentrations of antibiotics investigated in this study exceeded their threshold values for Predicted No-Effect Concentrations (PNEC) associated with resistance selection, except for tetracycline.

The occurrence and probabilistic risk of exposure to parabens from bottled and hand-shaken teas in the general adult population of Taiwan

Parabens (PBs) are esters of p-hydroxybenzoic acid, and there are growing concerns due to their potential to disrupt endocrine function and their wide use as preservatives in foodstuffs, including beverages. The consumption of bottled and hand-shaken teas is gradually replacing traditional tea consumption through brewing. However, no study has reported PB concentrations in different types of teas or packaging and their associated health risks. Our aim was to determine the concentration of PBs (methyl- (MetPB), ethyl- (EthPB), propyl- (PropPB), butyl-paraben (ButPB)) in green, black, and oolong teas in two varieties of products (bottled and hand-shaken teas), using UPLC-MS/MS. Additionally, we estimated the health risks associated with tea consumption in the general adult population of Taiwan. A Monte Carlo simulation was applied to estimate the distribution of daily PB intake through bottled (n = 79) and hand-shaken (n = 71) tea consumption. Our findings revealed geometric mean concentrations in bottled green/black/oolong teas were 714.1/631.2/532.1 ng/L for MetPB, 95.2/ 30.5/14.9 ng/L for EthPB, 77.9/28.3/non-detected (ND) ng/L for PropPB, and 69.3/26.6/ND ng/L for ButPB. Hand-shaken green/black/oolong teas exhibited concentrations of 867.5/2258/1307 ng/L for MetPB, 28.5/28.8/14.5 ng/L for EthPB, 25.4/18.3/17.8 ng/L for PropPB, and 30.3/18.0/15.5 ng/L for ButPB. The median MetPB concentrations in hand-shaken black (2333 ng/L) and oolong teas (1215 ng/L) were significantly higher than those in bottled black (595.4 ng/L) and oolong teas (489.3 ng/L). Conversely, median concentrations of EthPB, PropPB, and ButPB in bottled teas were significantly higher than those in hand-shaken teas. MetPB was the predominant PB, constituting 73.2-91.9% in bottled teas and 85-94% in hand-shaken teas. Our results showed no health risks associated with bottled or hand-shaken tea consumption based on reference doses. However, the study highlights the importance of continued vigilance given the potential chronic exposure to PBs from various sources, necessitating ongoing concern despite the absence of immediate risks from tea consumption.

Associations between paraben exposure, thyroid capacity, homeostasis and pituitary thyrotropic function in the general Taiwanese: Taiwan Environmental Survey for Toxicants (TEST) 2013

Several studies have suggested that some endocrine disruptors such as synthetic phenols, parabens and phthalates may disrupt thyroid hormone signaling and associated negative feed-backs with the central hypothalamic-pituitary-thyroid (HPT) axis. Therefore, we investigated urinary paraben and blood thyroid hormone levels in the Taiwanese population. Our sample comprised 264 adults (aged 18-97 years) and 75 minors (aged 7-17 years) from Taiwan Environmental Survey for Toxicants 2013. Urinary levels of methylparaben (MeP), ethylparaben (EtP), propylparaben (PrP), and butylparaben (BuP) were assessed. Hormones of particular interest include: thyroid-stimulating hormone (TSH), triiodothyronine (T3), and thyroxine (T4). We sought integrated parameters to describe the transfer of thyroid hormones in homeostatic models. The geometric mean urinary paraben levels of the adults were higher than those of the minors (adults vs. minors; MeP: 383 vs. 62.4 ng/mL; PrP: 109 vs. 8.00 ng/mL; EtP: 39.5 vs. 2.38 ng/mL, and BuP: 6.36 vs. 2.13 ng/mL). In the male adults, we discovered that 0.253% (p = 0.032), 0.256% (p = 0.041) and 0.257% (p = 0.037) decreases in the TSH, TSH/T4 and TSH/FreeT4 ratio was associated with 1% EtP increases, respectively. In the female minors, 0.093% (p = 0.044), 0.072% (p = 0.047) and 0.156 (p = 0.004) increases in the TSH ratios were associated with a 1% MeP, EtP and BuP increase, respectively. Moreover, 0.151% (p = 0.008) and 0.177% (p = 0.001) increases in TSH/T4 and TSH/free T4 ratios were associated with a BuP 1% increase, respectively. Finally, EtP was positively associated with SPINA-GT (β: 15.66, p = 0.036) in the male adults. By contrast, EtP were positively associated with Jostel's TSH index and sTSHI (β: 0.072, p = 0.049; β: 0.107, p = 0.049) in the female minors. The Taiwanese population is commonly exposed to parabens, which can potentially lead to alteration of thyroid hormone homeostasis.

Methylparaben toxicity and its removal by microalgae Chlorella vulgaris and Phaeodactylum tricornutum

The widespread occurrence of methylparaben (MPB) has aroused great concern due to its weak estrogenic endocrine-disrupting property and potential toxic effects. However, the degradation potential and pathway of MPB by microalgae have rarely been reported. Here, microalgae Chlorella vulgaris and Phaeodactylum tricornutum were used to investigate their responses, degradation potential and mechanisms towards MPB. MPB showed low-dose stimulation (by 86.02 ± 0.07% at 1 mg/L) and high-dose inhibition (by 60.17 ± 0.05% at 80 mg/L) towards the growth of C. vulgaris, while showed inhibition for P. tricornutum (by 6.99 ± 0.05%-20.14 ± 0.19%). The degradation efficiencies and rates of MPB were higher in C. vulgaris (100%, 1.66 ± 0.54-5.60 ± 0.86 day^-1) than in P. tricornutum (4.3-34.2%, 0.04 ± 0.01-0.08 ± 0.00 day^-1), which could be explained by the significantly higher extracellular enzyme activity and more fluctuation of the protein ratio for C. vulgaris, indicating a higher ability of C. vulgaris to adapt to pollutant stress. Biodegradation was the main removal mechanism of MPB for both the two microalgae. Furthermore, two different degradation pathways of MPB by the two microalgae were proposed. MPB could be mineralized and completely detoxified by C. vulgaris. Overall, this study provides novel insights into MPB degradation by microalgae and strategies for simultaneous biodegradation and detoxification of MPB in the environment.