miR-30e-5p regulates leukemia stem cell self-renewal through the Cyb561/ROS signaling pathway.

Leukemia stem cells (LSC) represent a crucial and rare subset of cells present in acute myeloid leukemia (AML); they play a pivotal role in the initiation, maintenance, and relapse of this disease. Targeting LSC holds great promise for preventing AML relapse and improving long-term outcomes. However the precise molecular mechanisms governing LSC self-renewal are still poorly understood. Here, we present compelling evidence that the expression of miR-30e-5p, a potential tumor-suppressive microRNA, is significantly lower in AML samples than in healthy bone marrow samples. Forced expression of miR- 30e effectively inhibits leukemogenesis, impairs LSC self-renewal, and delays leukemia progression. Mechanistically, Cyb561 acts as a direct target of miR-30e-5p in LSC, and its deficiency restricts the self-renewal of LSC by activating reactive oxygen series signaling and markedly prolongs recipients' survival. Moreover, genetic or pharmacological overexpression of miR-30e-5p or knockdown of Cyb561 suppresses the growth of human AML cells. In conclusion, our findings establish the crucial role of the miR-30e-5p/Cyb561/ROS axis in finely regulating LSC self-renewal, highlighting Cyb561 as a potential therapeutic target for LSC-directed therapies.

Function of serine/arginine-rich splicing factors in hematopoiesis and hematopoietic malignancies.

The serine/arginine-rich splicing factors (SRSFs) play an important role in regulating the alternative splicing of precursor RNA (pre-RNA). During this procedure, introns are removed from the pre-RNA, while the exons are accurately joined together to produce mature mRNA. In addition, SRSFs also involved in DNA replication and transcription, mRNA stability and nuclear export, and protein translation. It is reported that SRSFs participate in hematopoiesis, development, and other important biological process. They are also associated with the development of several diseases, particularly cancers. While the basic physiological functions and the important roles of SRSFs in solid cancer have been extensively reviewed, a comprehensive summary of their significant functions in normal hematopoiesis and hematopoietic malignancies is currently absent. Hence, this review presents a summary of their roles in normal hematopoiesis and hematopoietic malignancies.

Ubiquity of Synthetic Phenolic Antioxidants in Children's Cerebrospinal Fluid from South China: First Evidence for Their Penetration across the Blood-Cerebrospinal Fluid Barrier.

Synthetic phenolic antioxidants (SPAs) and relevant transformation products (TPs) are potentially neurotoxic pollutants to which humans are widely exposed. However, their penetration behavior across the brain barrier and associated exposure to the central nervous system (CNS) remain unknown. This study is the first to investigate a wide range of 30 SPAs and TPs, including emerging SPAs, in matched serum and cerebrospinal fluid (CSF) samples from children in Guangzhou, China. Sixty-two children of either sex aged <14 years with nonbloody CSF and complete clinical information were included. The findings demonstrated the ubiquitous occurrence of many SPAs and TPs, particularly BHT, 2,4-di-tert-butylphenol (DBP), AO 1010, AO 1076, BHT-Q, and BHT-quinol, not only in serum but also in the CSF. Median total concentrations of SPAs and TPs were up to 22.0 and 2.63 ng/mL in serum and 14.5 and 2.11 ng/mL in CSF, respectively. On calculating the penetration efficiencies across the blood-CSF barrier (BCSFB) (RCSF/serum, CCSF/Cserum) for selected SPAs and TPs, their RCSF/serum values (median 0.52-1.41) were highly related to their physicochemical properties, indicating that passive diffusion may be the potential mechanism of BCSFB penetration. In addition, the RCSF/serum values were positively correlated with the barrier permeability index RAlb (AlbuminCSF/Albuminserum), indicating that barrier integrity is an important determinant of BCSFB penetration. Overall, these results will improve our perception of human internal exposure to SPAs and lay a solid foundation for assessing the risk of CNS exposure to various SPAs.

Urinary Metabolites of Polycyclic Aromatic Hydrocarbons of Rural Population in Northwestern China: Oxidative Stress and Health Risk Assessment.

Polycyclic aromatic hydrocarbon (PAH) exposure is suspected to be linked to oxidative damage. Herein, ten PAH human exposure biomarkers [hydroxylated PAH metabolites (OH-PAHs)] and five oxidative stress biomarkers (OSBs) were detected in urine samples collected from participants living in a rural area (n = 181) in Northwestern China. The median molar concentration of ΣOH-PAHs in urine was 47.0 pmol mL-1. The 2-hydroxynaphthalene (2-OHNap; median: 2.21 ng mL-1) was the dominant OH-PAH. The risk assessment of PAH exposure found that hazard index (HI) values were <1, indicating that the PAH exposure of rural people in Jingyuan would not generate significant cumulative risks. Smokers (median: 0.033) obtained higher HI values than nonsmokers (median: 0.015, p < 0.01), suggesting that smokers face a higher health risk from PAH exposure than nonsmokers. Pearson correlation and multivariate linear regression analysis revealed that ΣOH-PAH concentrations were significant factors in increasing the oxidative damage to deoxyribonucleic acid (DNA) (8-hydroxy-2'-deoxyguanosine, 8-OHdG), ribonucleic acid (RNA) (8-oxo-7,8-dihydroguanine, 8-oxoGua), and protein (o, o'-dityrosine, diY) (p < 0.05). Among all PAH metabolites, only 1-hydroxypyrene (1-OHPyr) could positively affect the expression of all five OSBs (p < 0.05), suggesting that urinary 1-OHPyr might be a reliable biomarker for PAH exposure and a useful indicator for assessing the impacts of PAH exposure on oxidative stress. This study is focused on the relation between PAH exposure and oxidative damage and lays a foundation for the study of the health effect mechanism of PAHs.

Environmental exposure to melamine and its derivatives and kidney outcomes in children.

Melamine caused acute nephrotoxicity in a past food adulteration incident, but it is unclear whether and how widespread ambient exposure to melamine and related compounds might affect pediatric kidney health. We assessed cross-sectional associations between childhood exposure to melamine and its derivatives and biomarkers of kidney injury and health and explored potential heterogeneity by sex suggested by sex-dependent differences in renal physiology. We measured melamine and its derivatives ammeline, ammelide, and cyanuric acid (CYA) in spot urine samples collected from 192 children from an urban site (Seattle, WA) and 187 children from a rural site (Yakima, WA) aged 4-8 years in the Global Alliance to Prevent Prematurity and Stillbirth (GAPPS) Study. In addition, biomarkers of kidney injury were measured in the same urine samples, including albumin, total protein, KIM-1, NAG, NGAL, and EGF. We utilized linear regressions to examine associations between individual chemical exposures and kidney biomarkers. Interaction terms examined association modification by sex, as well as potential interactions between melamine and CYA. Despite comparable exposures, girls had higher levels of many kidney injury biomarkers compared to boys. A ten-fold higher melamine concentration was associated with a 18% (95% CI: 5.6%, 31%) higher EGF in the full sample, while ten-fold higher melamine was associated with a 76% (14.1%, 173%) higher KIM-1 in boys but not in girls (-10.1% (-40.6%, 36.1%), interaction p = 0.026). Melamine exhibited significant negative interactions with CYA in association with total protein and NAG that appeared to be specific to girls. Our results suggest possible associations between melamine exposure and markers of kidney injury that may be more pronounced in boys. These findings provide novel insights into melamine and related derivative compound health effects at low levels of exposure in children and emphasize the role of sex in mediating the relationship between nephrotoxicant exposure and kidney injury.

Daily Exposure to Environmental Volatile Organic Compounds Triggers Oxidative Damage: Evidence from a Large-Scale Survey in China.

Volatile organic compounds (VOCs) are ubiquitous environmental pollutants and have been implicated in adverse health outcomes. In this study, concentrations of 11 VOC metabolites (mVOCs) and three oxidative stress biomarkers (8-oxo-7,8-dihydro-2'-deoxyguanosine, 8-oxo-7,8-dihydro-guanosine, and dityrosine) were determined in 205 urine samples collected from 12 cities across mainland China. Urinary ∑11mVOC concentrations ranged from 498 to 1660 ng/mL, with a geometric mean (GM) value of 1070 ng/mL. The factorial analysis revealed that cooking, solvents, and vehicle emissions were the three primary sources of VOC exposure. A significant regional variation was clearly found in ∑11mVOC concentrations across four regions in China, with high urine VOC concentrations found in North and South China (GM: 1450 and 1340 ng/mL). The multiple linear regression model revealed that most mVOCs were significantly positively correlated with three oxidative stress markers (ß range: 0.06-0.22). Mixture effect regression showed that isoprene, crotonaldehyde, acrolein, and benzene were the strongest contributors to oxidative stress. Approximately 80% of the participants have HQ values greater than 1.0 for 1,3-butadiene and benzene, suggesting that their exposure doses were close to potential adverse health effects. Our findings provide comprehensive information on human exposure and potential health risks of VOCs in China.

Eight novel brominated flame retardants in indoor and outdoor dust samples from the E-waste recycling industrial park: Implications for human exposure.

As alternatives for legacy brominated flame retardants, novel brominated flame retardants (NBFRs) have a wide array of applications in the electronic and electrical fields. The shift of recycling modes of electronic and electrical waste (e-waste) from informal recycling family workshop to formal recycling facilities might come with the change the chemical landscape emitted including NBFRs, however, little information is known about this topic. This study investigated the occurrence characteristics, distribution, and exposure profiles of eight common NBFRs and their derivatives in an e-waste recycling industrial park in central China and illustrated the differences in various functional zones in the recycling park. The highest level of ΣNBFRs in dust samples was found in e-waste storage area at median concentration of 27,400 ng/g, followed by e-waste dismantling workshops (23,300 ng/g), workshop outdoor area (7770 ng/g), and residential area outdoor (536 ng/g). In the e-waste dismantling associated dust samples, tetrabromobisphenol A bis(2,3-dibromopropyl ether) (TBBPA-BDBPE), tetrabromobisphenol A (TBBPA) and 2,4,6-tris(2,4,6-tribromophenoxy)-1,3,5-triazine (TTBP-TAZ) were the predominant components. This paper presented the first evidence regarding the occurrence characteristic and distribution of tetrabromobisphenol S (TBBPS), tetrabromobisphenol A bismethyl ether (TBBPA-BME) and tetrabromobisphenol S bis(2,3-dibromopropyl ether) (TBBPS-BDBPE) in the e-waste associated dust samples. By comparing with previous studies performed in China, this paper also noticed the significant decrease of TBBPA concentrations in the dust probably due to the shift of e-wastes sources and recycling modes. We further assessed the risk of occupational workers exposure to NBFRs. The median EDI (estimated daily intake) value of ΣNBFRs among e-waste dismantling workers was 9.71 ng/kg BW/d with the maximum EDI value being 19.6 ng/kg BW/d, hundreds of times higher than those exposed by general population. The study raises great concern for the health risk of occupational exposure to NBFRs in the e-waste recycling industrial park.

First evidence of occupational and residential exposure to bisphenols associated with an e-waste dismantling site: A case study in China.

Bisphenol A and its structural analogues (BPs) are widely used chemicals in electronics devices. To get insight into the occupational exposure to the full-time employees compared with the residents, urinary BPs in workers dismantling e-waste and in nearby residents were compared. Only 4 BPs among the tested 8 congeners, bisphenol AF (BPAF), bisphenol A, bisphenol S (BPS), and bisphenol F (BPF), were extensively detected with the detection frequencies of 100%, 99%, 98.7%, 51.3%. The median concentration of bisphenol A was 8.48 ng/mL, followed by BPAF (1.05 ng/mL), BPS (0.115 ng/mL), and BPF (0.110 ng/mL). The 4 detected BPs had a median concentration (Σ4BPs) ranging from 0.950 to 64.5 ng/mL in all volunteers, with a median value of 10.2 ng/mL. Result indicated the median concentration of ∑4BPs in worker's urine was significantly higher (14.2 ng/mL) than those in residents in nearby towns (4.52 ng/mL and 5.37 ng/mL) (p < 0.05), suggesting a BPs' occupational exposure risk related to e-waste dismantling. Besides, urinary ∑4BPs' median concentrations for the employees in family workshops (14.5 ng/mL) were significantly higher than those in plants with centralized management (9.36 ng/mL). Among volunteers, higher ∑4BPs were observed in groups of aged above 50 years, males, or body weight under average with no significant correlations. The estimated daily intake of bisphenol A did not exceed the reference dose (50 µg/kg bw/day) recommended by the U.S. Food and Drug Administration. In this research, excess levels of BPs were recorded for the full-time employees in e-waste dismantling sites. Strengthened standards could support public health initiatives for full-time worker protection and reduce take-home BPs to family members.

Analysis of metabolites in green tea during the roasting process using non-targeted metabolomics.

BACKGROUND: Roasting plays an important role in the formation of flavor of roasted green tea; however, the changes in chemicals during this process have not been systematically studied until now. To reveal the dynamic changes in chemicals in green tea during roasting, non-targeted metabolomics, coupled with chemometrics, was employed. RESULTS: A total of 101 non-volatile metabolites were identified in tea samples, and 29 metabolites were identified as characteristic metabolites of roasting. A significant increase in catechins and their derivatives, organic acids, and flavonoid glycosides was observed, while the content of some amino acids and their derivatives decreased over 50% during roasting. The content of theanine glucoside increased dramatically (by 21.23-fold at the roasting stage), and Maillard-derived compounds also increased to varying degrees. CONCLUSION: Glycosylation, oxidative polymerization, and pyrolysis were important reactions responsible for the formation and transformation of flavor compounds in roasted green tea during roasting. © 2022 Society of Chemical Industry.

Neonicotinoid Insecticides and Their Metabolites Can Pass through the Human Placenta Unimpeded.

Studies on neonicotinoid (NEO) exposure in pregnant women and fetuses are scarce, and transplacental transfer of these insecticides is unknown. In this study, parent NEOs (p-NEOs) and their metabolites (m-NEOs) were determined in 95 paired maternal (MS) and cord serum (CS) samples collected in southern China. Imidacloprid was the predominant p-NEO in both CS and MS samples, found at median concentrations of 1.84 and 0.79 ng/mL, respectively, whereas N-desmethyl-acetamiprid was the most abundant m-NEO in CS (median: 0.083 ng/mL) and MS (0.13 ng/mL). The median transplacental transfer efficiencies (TTEs) of p-NEOs and m-NEOs were high, ranging from 0.81 (thiamethoxam, THM) to 1.61 (olefin-imidacloprid, of-IMI), indicating efficient placental transfer of these insecticides. Moreover, transplacental transport of NEOs appears to be passive and structure-dependent: cyanoamidine NEOs such as acetamiprid and thiacloprid had higher TTE values than the nitroguanidine NEOs, namely, clothianidin and THM. Multilinear regression analysis revealed that the concentrations of several NEOs in MS were associated significantly with hematological parameters related to hepatotoxicity and renal toxicity. To our knowledge, this is the first analysis of the occurrence and distribution of NEOs in paired maternal-fetal serum samples.

First Evidence of Prenatal Exposure to Emerging Poly- and Perfluoroalkyl Substances Associated with E-Waste Dismantling: Chemical Structure-Based Placental Transfer and Health Risks.

Limited information is available about prenatal exposure to per- and polyfluoroalkyl substances (PFAS) in electronic waste (e-waste) recycling sites. In this study, we determined 21 emerging PFAS and 13 legacy PFAS in 94 paired maternal and cord serum samples collected from an e-waste dismantling site in Southern China. We found 6:2 fluorotelomer sulfonate (6:2 FTSA), 6:2 chlorinated polyfluorinated ether sulfonate (6:2 Cl-PFESA), and perfluorooctanephosphonate (PFOPA) as the major emerging PFAS, regardless of matrices, at median concentrations of 2.40, 1.78, and 0.69 ng/mL, respectively, in maternal serum samples, and 2.30, 0.73, and 0.72 ng/mL, respectively, in cord serum samples. Our results provide evidence that e-waste dismantling activities contribute to human exposure to 6:2 FTSA, 6:2 Cl-PFESA, and PFOPA. The trans-placental transfer efficiencies of emerging PFAS (0.42-0.94) were higher than that of perfluorooctanesulfonic acid (0.37) and were structure-dependent. The substitution of fluorine with chlorine or hydrogen and/or hydrophilic functional groups may alter trans-placental transfer efficiencies. Multiple linear regression analysis indicated significant associations between maternal serum concentrations of emerging PFAS and maternal clinical parameters, especially liver function and erythrocyte-related biomarkers. This study provides new insights into prenatal exposure to multiple PFAS in e-waste dismantling areas and the prevalence of emerging PFAS in people living near the sites.

Exposure to Contemporary and Emerging Chemicals in Commerce among Pregnant Women in the United States: The Environmental influences on Child Health Outcome (ECHO) Program.

Prenatal chemical exposures can influence maternal and child health; however, few industrial chemicals are routinely biomonitored. We assessed an extensive panel of contemporary and emerging chemicals in 171 pregnant women across the United States (U.S.) and Puerto Rico in the Environmental influences on Child Health Outcomes (ECHO) Program. We simultaneously measured urinary concentrations of 89 analytes (103 total chemicals representing 73 parent compounds) in nine chemical groups: bactericides, benzophenones, bisphenols, fungicides and herbicides, insecticides, organophosphate esters (OPEs), parabens, phthalates/alternative plasticizers, and polycyclic aromatic hydrocarbons (PAHs). We estimated associations of creatinine-adjusted concentrations with sociodemographic and specimen characteristics. Among our diverse prenatal population (60% non-Hispanic Black or Hispanic), we detected 73 of 89 analytes in ≥1 participant and 36 in >50% of participants. Five analytes not currently included in the U.S. biomonitoring were detected in ≥90% of samples: benzophenone-1, thiamethoxam, mono-2-(propyl-6-carboxy-hexyl) phthalate, monocarboxy isooctyl phthalate, and monohydroxy-iso-decyl phthalate. Many analyte concentrations were higher among women of Hispanic ethnicity compared to those of non-Hispanic White women. Concentrations of certain chemicals decreased with the calendar year, whereas concentrations of their replacements increased. Our largest study to date identified widespread exposures to prevalent and understudied chemicals in a diverse sample of pregnant women in the U.S.

Determinants of phthalate exposures in pregnant women in New York City.

Previous studies have provided data on determinants of phthalates in pregnant women, but results were disparate across regions. We aimed to identify the food groups and demographic factors that predict phthalate exposure in an urban contemporary pregnancy cohort in the US. The study included 450 pregnant women from the New York University Children's Health and Environment Study in New York City. Urinary concentrations of 22 phthalate metabolites, including metabolites of di-2-ethylhexylphthalate (DEHP), were determined at three time points across pregnancy by liquid chromatography coupled with tandem mass spectrometry. The Diet History Questionnaire II was completed by pregnant women at mid-pregnancy to assess dietary information. Linear mixed models were fitted to examine determinants of urinary phthalate metabolite concentrations. Using partial-linear single-index (PLSI) models, we assessed the major contributors, among ten food groups, to phthalate exposure. Metabolites of DEHP and its ortho-phthalate replacement, diisononyl phthalate (DiNP), were found in >90% of the samples. The sum of creatinine-adjusted DiNP metabolite concentrations was higher in older and single women and in samples collected in summer. Hispanic and non-Hispanic Black women had lower urinary concentrations of summed metabolites of di-n-octyl phthalate (DnOP), but higher concentrations of low molecular weight phthalates compared with non-Hispanic White women. Each doubling of grain products consumed was associated with a 20.9% increase in ∑DiNP concentrations (95%CI: 4.5, 39.9). PLSI models revealed that intake of dried beans and peas was the main dietary factor contributing to urinary ∑DEHP, ∑DiNP, and ∑DnOP levels, with contribution proportions of 76.3%, 35.8%, and 27.4%, respectively. Urinary metabolite levels of phthalates in pregnant women in NYC varied by age, marital status, seasonality, race/ethnicity, and diet. These results lend insight into the major determinants of phthalates levels, and may be used to identify exposure sources and guide interventions to reduce exposures in susceptible populations.

Investigating particle-size-induced changes in composition, physical, rheological, and bioactive properties of black tea powder.

BACKGROUND: People brew tea to drink an infusion that only contains 25% water-soluble constituents, leading to most of the insoluble materials being wasted. Tea powder could be drunk directly by mixing with water without producing any waste. Tea powder can also be used as a natural additive to improve the flavour and taste in beverages and foods. Much detailed information on the particle properties of tea powder is required with its increasing consumption. The aim of this study was to investigate the effects of particle size ranging from median diameter D50  = 4.32 to 26.59 µm on the composition, physical, rheological, and bioactive properties of black tea powder. RESULTS: The results indicate that large powder sizes had high bulk density and flowability, whereas small powder sizes possessed good swelling ability and wettability. The contents of water extract, total polyphenols, crude fibre, catechins, and thearubigins reduced with a decrease in particle size. To change the particle size and concentration could adjust the elastic modulus and the viscous modulus of the black tea powder suspension. Moreover, black tea powder with small particle size could regulate blood lipids in a hyperlipidaemic rat model by lowering triacylglycerols and elevating high-density lipoprotein cholesterol, whereas large particles presented an advantage in reducing body weight. CONCLUSION: Our investigation extended the knowledge of commercial black tea powder in composition, physical, rheological, and bioactive properties. These results lay the foundation for future exploration of the use of tea powder in the food industry. © 2022 Society of Chemical Industry.

Effect of red light on the composition of metabolites in tea leaves during the withering process using untargeted metabolomics.

BACKGROUND: Red light withering significantly improves the sensory flavor qualities of tea, although changes in metabolites during this process have not been systematically studied until now. The present study comprehensively analyzes metabolites in withered tea leaves at 2-h intervals up to 12 h under red light (630 nm) and dark conditions using ultra performance liquid chromatography-high resolution mass spectrometry (untargeted metabolomics). RESULTS: Ninety-four non-volatile compounds are identified and relatively quantified, including amino acids, catechins, dimeric catechins, flavonol glycosides, glycosidically-bound volatiles, phenolic acids and nucleosides. The results show that amino acids, catechins and dimeric catechins are most affected by red light treatment. Ten free amino acids, theaflavins and theasinensin A increase after red light irradiation, whereas epigallocatechin gallate and catechin fall. CONCLUSION: The present study provides a comprehensive and systematic profile of the dynamic effects of red light on withering tea and a rationale for its use in tea processing quality control. © 2021 Society of Chemical Industry.

Profiles of parabens and their metabolites in paired maternal-fetal serum, urine and amniotic fluid and their implications for placental transfer.

Six parabens and their four metabolites were measured in paired maternal serum (MS) and cord serum (CS) samples collected from 95 pregnant women to elucidate placental transfer of this class of compounds. Matched maternal urine (MU) and amniotic fluid (AF) collected from 13 of 95 pregnant women were also analyzed to examine partition of these chemicals between maternal and fetal tissues. The placental transfer rates (PTRs; concentration ratio of parabens between CS and MS) of methyl- (MeP), ethyl- (EtP), propyl-parabens (PrP) were 0.81, 0.63, and 0.60, respectively. Furthermore, the PTRs of OH-MeP (0.93) and OH-EtP (1.8) were higher than those of their corresponding parent parabens, which suggested that hydroxylation increased placental transfer rates of parabens. Structure-dependent placental transfer mechanisms were observed. A significant negative correlation between molecular weights (or log Kow) of MeP, EtP, PrP, and p-hydroxy benzoic acid (4-HB) and PTRs suggested passive diffusion as a mechanism of placental transfer of these chemicals. Nevertheless, other hydroxylated metabolites (OH-EtP, OH-MeP, and 3,4-dihydroxy benzoic acid (3,4-DHB)) showed a positive correlation between molecular weight (or log Kow) and PTRs, which suggested that the placental transfer is mediated by protein binding of these metabolites. The MU to MS concentration ratios of MeP (MU/MSMeP) and PrP (MU/MSPrP) were 71 and 81, respectively, and MU/MSMeP was two orders of magnitude higher than that found for the metabolite (MU/MSOH-MeP: 0.35), suggesting that hydroxylation metabolite reduced urinary elimination of parabens. To our knowledge, this is the first time to report the occurrence and distribution of parabens and their metabolites in paired maternal-fetal serum, urine, and AF samples in China. Our results provide novel information on placental transfer of parabens and their metabolites.

Spatial and temporal distributions of hexabromocyclododecanes in surface soils of Jinan, China.

Contamination by hexabromocyclododecanes (HBCDDs) in the soil environment is an ongoing concern because of their "specific exemption" on the production and use in China. In this study, spatial distribution, temporal trend, and diastereoisomer profiles of HBCDDs were examined in surface soils collected in Jinan, China. Concentrations of ΣHBCDD (sum of α-, ß-, and γ-HBCDDs) in soils ranged from 1.70 to 228 ng/g dry weight (dw), with a mean value of 26.1 ng/g dw. Soils collected from e-waste dismantling sites (mean 146 ng/g dw) contained significantly higher concentrations of ΣHBCDD than those of urban (15.5 ng/g dw) and farmland soils (3.86 ng/g dw) (p < 0.01). The temporal trend suggested that ΣHBCDD levels in the industrial area rose significantly between 2014 and 2019 (p < 0.05), with an annual increase of 12%. An increase in ΣHBCDD levels was also observed in urban and farmland soil samples during the study period, although it did not reach a significant level (p > 0.05). All surface soils were dominated by γ-HBCDD (mean 60.7% of total concentrations); however, the proportions of α-isomer increased from 28.7% in urban and rural soils to 43.4% in industrial soils. The calculated risk quotients of HBCDDs present in soils were at least 25-fold lower than the threshold limit value. The mean mass inventory of HBCDDs was approximately 2501 kg in the cultivated land of Jinan City; further studies are needed to discern the uptake of HBCDDs by crops and the fate of these chemicals in agricultural ecosystems.

Occurrence of Melamine and Its Derivatives in Breast Milk from the United States and Its Implications for Exposure in Infants.

Melamine received public and regulatory attention in 2008 following a scandal that involved the adulteration of milk and infant formula in China that affected tens of thousands of infants. Little is known about human exposure and the food chain transfer of melamine and its derivatives. In this study, melamine, cyanuric acid, ammeline, and ammelide were analyzed in 100 human milk samples collected from the United States during the period of 2009-2012. ∑Melamine (sum of melamine and its three derivatives) was found in breast milk at concentrations that ranged from 0.176 to 10.0 ng/mL (median: 1.40 ng/mL). Cyanuric acid was the major derivative, accounting for 73% of the total concentrations, followed by melamine (21%). No remarkable associations were noted between melamine and cyanuric acid concentrations and maternal/infant characteristics. The cumulative daily intakes of melamine (16.9-30.6 ng/kg bw/day) and cyanuric acid (88.8-161 ng/kg bw/day) were calculated for breast-fed infants and were found to be 1-2 orders of magnitude below the current tolerable daily intake. This is the first study to report the distribution of melamine and its derivatives in breast milk from the United States.

Occurrence and Profiles of Melamine and Cyanuric Acid in Bovine Feed and Urine from China, India, and the United States.

Melamine and cyanuric acid have been reported to occur in animal products. Nevertheless, information that pertains to the occurrence of melamine and cyanuric acid in cattle feed and urine is lacking. In this study, the occurrence of melamine and its three derivatives (i.e., cyanuric acid, ammeline, and ammelide) was determined in 183 bovine urine and 29 matched feed samples collected from China, India, and the United States. ∑Melamine (sum of four target compounds) was found in all urine samples at concentrations that ranged from 4.2 to 5280 ng/mL (median: 370 ng/mL); cyanuric acid was the major derivative, accounting for 97% of the total concentrations, followed by melamine (2.2%). The ubiquitous occurrence of ∑Melamine in feed (21-6230 ng/g) suggests that it is the major source of melamine and its derivatives in bovines. Urinary concentrations of melamine and cyanuric acid varied significantly among the three countries, with samples from China as having the highest concentrations, followed by the United States and India. The calculated cumulative daily intakes of melamine and cyanuric acid were at least 10-fold below the current tolerable daily intake recommended for humans. Our study provides evidence-based data on exposure patterns and sources of melamine and cyanuric acid in cattle.