The mass concentration of microplastics in stools and influencing factors remain unclear. The aim was to investigate the types and mass concentrations of microplastics in the stools of young college students and to explore potential influencing factors. Twenty-six participants were recruited from colleges in each city using stratified simple sampling, including Changsha, Shanghai, and Changchun. Participants' dietary and fluid intake behavior was recorded using the 3-day 24-h dietary questionnaire and the 7-day 24-h fluid intake record, respectively. Lifestyle factor information related to microplastic exposure was collected through a microplastic exposure questionnaire. Stools were collected and detected using pyrolysis gas chromatography-mass spectrometry (Py-GCMS) method. Eventually, 78 participants completed the study. The detection rate of microplastics, including polyethylene (PE), polyvinyl chloride (PVC), polystyrene (PS), polypropylene (PP) and polyethylene terephthalate (PET), in stools was 98.7%, with a total mass concentration of 54.7 (10.1-102.7) μg/g. There were differences in the total mass concentrations of microplastics in the stools of participants in three cities, namely Changsha, Shanghai, and Changchun, which decreased sequentially (χ² = 47.819, P < 0.05). Participants with a relatively high frequency of takeaway food consumption had higher total mass concentrations of microplastics mass concentrations in stools (χ² = 7.390, P < 0.05). Participants with a relatively high frequency of consuming reheated food had a greater mass concentration of PET microplastics (χ² = 6.117, P < 0.05). The total mass concentration of microplastics, as well as the mass concentrations of PE, PVC, PP, and PA66, in the bottled water intake group were greater than those in the nonintake group (all P < 0.05). Overall, the total mass concentration of microplastics in stools was related to residential city, consumption of reheated food, and bottled water intake (all P < 0.05). Young college students generally experience microplastic exposure, with the main types being PE, PVC, PS, PP, PET, and PA66. Living location, reheated food consumption, and bottled water intake were factors influencing microplastic exposure.

This study aimed to systematically assess the total environmental exposure to microplastics and determine the internal exposure levels in the human body. A total of 26 young college students were recruited. Exposure scenario estimation methods were used to establish evaluation models. The dietary and water intake behaviors of the participants were documented with questionnaires. The food and water consumed by the participants were sampled using weight and duplicate meal methods. Furthermore, air samples from the activity regions of the participants were collected. Fasting serum, 24-h urine, and fecal samples were also collected. Pyrolysis gas chromatography/mass spectrometry (Py-GCMS) helped identify the types and determine mass concentrations of microplastics across all samples, and the internal and external exposure levels of microplastics among the population were further evaluated. Microplastics were frequently observed in food samples, with mass concentrations ranging from 2.50 to 91.30 μg/g. Water samples also contained microplastics, with concentrations ranging from 0.02 to 18.41 μg/g. Indoor and outdoor air contained PS, PE, PP, PVC, and PET. The exposure levels of young college students in Changsha to microplastics through dietary intake, water intake, and inhalation were quantified at 346.65 μg/kg bw/d, 41.17 μg/kg bw/d, and 59.57 μg/kg bw/d, respectively. Cumulatively, the total exposure to microplastics from these three sources was 460.20 μg/kg bw/d. Median microplastic levels in serum and feces samples were 20.81 μg/g and 97.36 μg/g, respectively. Additionally, urine samples indicated the presence of seven types of microplastics (PS, PE, PP, PVC, PET, PA66, and PMMA), with a median exposure level of 5.06 μg/g. Among young college students in Changsha, the primary microplastic exposure source was dietary intake, followed by air and drinking water. The internal exposure level in serum was higher than that in urine.

The fluid intake and hydration status during pregnancy may influence the health outcomes of both the mother and the fetus. However, there are few studies related to this. The aim of the present study was to investigate fluid intake behaviors among pregnant women in their second trimester, to evaluate their hydration status and pregnancy complications, and to further explore the association of fluid intake and the amniotic fluid index (AFI). Participants’ total fluid intake (TFI) levels were determined using a 7-day 24 h fluid intake questionnaire. The levels of water intake from food were not recorded or measured. Morning urine samples were collected, and both urine osmolality levels and urine specific gravity (USG) were tested to evaluate their hydration status. Fasting blood samples were also collected and measured for osmolality and complete blood count (CBC). A total of 324 participants completed the study. They were divided into four groups based on quartiles of TFI, including participants with lower (LFI₁ and LFI₂) and higher (HFI₁ and HFI₂) fluid intake levels. The median TFI was 1485 mL, and the median values of the four groups with different TFI levels were 1348, 1449, 1530, and 1609 mL, respectively. Only 3.4% of the participants attained the recommended value following an adequate water intake (1.7 L) level for pregnant women in China. Plain water was the main TFI resource (78.8~100.00%), and differences in the plain water intake levels among the four groups were evident (χ² = 222.027, p < 0.05). The urine osmolality decreased sequentially with increasing TFI values from the LFI₁ to HFI₂ group, and significant differences in the urine osmolality levels among the four groups were evident (p < 0.05). Meanwhile, the percentage of dehydrated participants decreased from 26.8% in the LFI₁ group to 0.0% in the HFI₂ group (χ² = 131.241, p < 0.05). Participants with higher TFI values had higher AFI values (χ² = 58.386, all p < 0.05), and moderate-intensity correlations were found between TFI and urine osmolality, hydration status, and AFI (all p < 0.05). A large proportion of the participants had insufficient TFIs during the second trimester of pregnancy, and a proportion of the participants were dehydrated. The preliminary analysis showed that the AFI was correlated with the TFI during the second trimester of pregnancy. A sufficient TFI is necessary for pregnant women to improve their hydration status and may have effects on their health. The results can provide appropriate scientific references for the development of beneficial recommendations concerning adequate water intake levels for pregnant women in China.

This study aimed to evaluate the types and mass concentrations of microplastics found in the stools of young college students. The underlying connections between microplastic exposure and gut microbiota were revealed. The study involved 66 participants, from whom stool samples were collected. Pyrolysis gas chromatography/mass spectrometry (Py-GCMS) was used to identify the types and mass concentrations of microplastics. Metagenomic sequencing was performed on the gut microbiota using high-throughput sequencing and metagenomic analysis techniques. Participants were divided into low group (LG) and high group (HG) based on the median mass concentration of microplastics in their stools. The differences in microbial diversity and species with significant differences between the two groups were analyzed. Spearman's correlation analysis was conducted to assess the associations between microbial characteristics and gene functions. The detection rate of microplastics in the stool samples was 98.5 %, with a median mass concentration of 54.7 μg/g. Significant differences were observed in gut microbiota between the two groups in terms of alpha and beta diversities. The relative abundance of Segatella copri was higher in the LG, while the relative abundance of Escherichia coli was higher in the HG. Compared with the LG, the gut microbiota in the HG exhibited an increase in the relative abundance of harmful bacteria, such as Dialister invisus, Clostridium fessum, and Evtepia gabavorous. The ADONIS analysis revealed that PS microplastics had a significant impact on the structure of the gut microbiota. However, no significant differences were observed among the metabolic pathways annotated in the Kyoto Encyclopedia of Genes and Genomes database between the two groups at either level I or II. Participants with higher mass concentrations of microplastics in their stools exhibited an increase in the abundance of harmful intestinal bacteria. PS microplastics had the most profound impact on the gut microbiota structure.

Background: Water intake and hydration status may potentially influence maternal and child health. However, there is little research regarding this topic. Objectives: This study aimed to investigate pregnant women’s total fluid intake (TFI) levels, hydration status, and body composition and further explore their relationship with infant birth weight. Methods: A 7-day, 24 h fluid intake recorded was applied to determine participants’ TFI levels. Morning urine samples were collected and tested to evaluate their hydration status. Maternal body compositions in their third trimester and infant birth weights were measured. Results: A total of 380 participants completed the study. The TFI was insufficient for pregnant women during their third trimester (median = 1574 mL), with only 12.1% of participants meeting the recommended adequate fluid intake level for pregnant women living in China (1.7 L per day). With the increasing TFI values, the urine osmolality decreased, which showed statistical significance among the four groups (χ² = 22.637, p < 0.05). The participants displayed a poor hydration status. Meanwhile, the percentage of participants who were in dehydrated status decreased (χ² = 67.618, p < 0.05), while body water content and basal metabolic rate increased with the increase in TFI levels (χ² = 20.784, p < 0.05; χ² = 14.026, p < 0.05). There were positive linear relationships between plain water intake, the basal metabolic rate of pregnant women and their infant birth weight (SE = 0.153, p < 0.05; SE = 0.076, p < 0.05). Conclusions: Water intake was insufficient, and poor hydration status was common among pregnant women in China. There may be potential relationships between plain water intake, basal metabolic rate, and infant birth weight.

Fluid intake and hydration status during pregnancy may have influences on maternal and infant health. However, few studies have recorded and analyzed total fluid intake (TFI) levels during the whole pregnancy. This study mainly aimed to investigate the TFI levels of pregnant women in three trimesters, and further to assess their hydration status. The relationships of TFI and hydration status were also analyzed. A convenience sampling method was used to recruit pregnant women from the Haikou Maternity and Child Health Hospital in China in this prospective cohort study. A 7-day 24 h fluid intake questionnaire was used for recording the fluid intake of the participants in their three trimesters. Fasting blood samples and first morning urine samples were also collected and tested. Hydration status was evaluated using urine osmolality. Finally, 142 pregnant women completed the study. The median TFIs in the first, second, and third trimesters were 1336, 1477, and 1584 mL, respectively. The TFI levels increased with pregnancy progression (χ² = 134.155, p < 0.05). Out of 142 participants, 100.0%, 97.2%, and 85.2% of participants did not reach the recommendation amount for an adequate TFI among Chinese pregnant women in the three trimesters, respectively (χ² = 29.840, p < 0.05). Plain water was the main source of fluid intake, accounting for 92.0%, 94.2%, and 93.4% of TFI, respectively. The median values of dairy product intake were 61, 57, and 59 mL in the three trimesters. The frequency of participants without an optimal hydration status in the three trimesters was 71.8%, 76.1%, and 83.1%, respectively (χ² = 29.909, p < 0.05). The participants of each trimester were divided into four groups according to quartiles of TFI, including participants with a lower fluid intake (LFI₁ and LFI₂) and higher fluid intake (HFI₁ and HFI₂). As the TFI values increased from the LFI₁ group to the HFI₂ group, the urine osmolality decreased (all p < 0.05). Moderate-intensity negative correlations were found between urine osmolality, hydration status, and TFI (all p < 0.05). It is suggested that fluid intake strategies should be promoted and health education should be conducted to improve the hydration status of pregnant women.