Trichloroacetic Acid Concentration Research Articles

Urinary haloacetic acid concentrations in relation to sex and thyroid hormones among reproductive-aged men

Sex and thyroid hormones are critical for male reproductive health. However, the associations between haloacetic acid (HAA) exposure – a known endocrine disruptor – and sex and thyroid hormones in humans remains unclear. We thus recruited 502 male participants seeking fertility evaluation from a reproductive center. We measured concentrations of sex and thyroid hormones in a single blood sample and dichloroacetic acid (DCAA) and trichloroacetic acid (TCAA) in repeated urine samples. Multivariable linear regression models were constructed to evaluate the associations between HAA concentrations and hormone measurements. After adjusting for potential confounders and urinary creatinine concentrations, urinary concentrations of TCAA were inversely associated with serum levels of sex hormone-binding globulin (SHBG), testosterone (T), T/luteinizing hormone ratio (T/LH), and thyroid stimulating hormone (TSH) (all P for trend < 0.10). Compared with participants in the lowest quartile of TCAA concentrations, those in the highest quartile had reduced serum levels of SHGB by 14.2 % (95% CI: −26.7, −3.0 %), T by 11.1 % (95% CI: −21.7, −1.3 %), T/LH by 21.0 % (95% CI: −36.7, −7.1 %), and TSH by 19.1 % (95% CI: −39.7, −1.5 %). Additionally, we observed inverse associations between continuous measurements of urinary HAAs and serum levels of free T, bioactive T, and estradiol. Our findings suggest that male HAA exposure may be associated with disrupted sex and thyroid function.

Urinary haloacetic acid concentrations and thyroid function among women: Results from the TREE study

BackgroundDisinfection byproducts (DBPs) have been shown to impair thyroid function in experimental models. However, epidemiological evidence is scarce. MethodsThis study included 1190 women undergoing assisted reproductive technology (ART) treatment from the Tongji Reproductive and Environmental (TREE) cohort from December 2018 to August 2021. Serum thyrotropin (TSH), free triiodothyronine (FT3), and free thyroxine (FT4) were measured as indicators of thyroid function. FT4/FT3 and TSH/FT4 ratios were calculated as markers of thyroid hormone homeostasis. Dichloroacetic acid (DCAA) and trichloroacetic acid (TCAA), the two most abundant HAAs, in urine were detected to assess individual DBP exposures. ResultsAfter adjusting for relevant covariates, positive associations were observed between urinary TCAA concentrations and serum TSH and TSH/FT4 levels (e.g., percent change = 5.82 %, 95 % CI: 0.70 %, 11.21 % for TSH), whereas inverse associations were found for serum FT3 and FT4 (e.g., percent change = −1.29 %, 95 % CI: −2.49 %, −0.07 % for FT3). There also was a negative association between urinary DCAA concentration and serum FT4/FT3 (percent change = −2.49 %, 95 % CI: −4.71 %, −0.23 %). These associations were further confirmed in the restricted cubic spline and generalized additive models with linear or U-shaped dose-response relationships. ConclusionUrinary HAAs were associated with altered thyroid hormone homeostasis among women undergoing ART treatment.

Formation and control of disinfection by-products during the trichloroisocyanuric acid disinfection in swimming pool water

The increasing demand for trichloroisocyanuric acid (TCCA) in swimming pool disinfection highlights the need to evaluate its applicability in terms of disinfection by-product (DBP) formation. Nevertheless, there is limited understanding of DBP formation and control during TCCA disinfection, particularly concerning the effects of various management parameters. This study aimed to fill this knowledge gap by comprehensively investigating DBP formation during TCCA chlorination, with a particular focus on assessing the contribution and interaction of influencing factors using Box-Behnken Design and response surface methodology. Results indicated that the concentrations of trichloroacetaldehyde, chloroform, dichloroacetic acid, trichloroacetic acid, and dichloroacetonitrile produced by TCCA disinfectant were 42.5%, 74.0%, 48.1%, 94.7% and 42.6% of those by the conventional sodium hypochlorite disinfectant, respectively. Temperature exhibited the most significant impact on chloroform formation (49%), while pH played a major role in trichloroacetaldehyde formation (44%). pH2 emerged as the primary contributor to dichloroacetic acid (90%) and trichloroacetic acid (93%) formation. The optimum water quality conditions were determined based on the minimum total DBPs (pH = 7.32, Temperature = 23.7 °C, [Cl−] = 437 mg/L). Chlorine dosage and contact time exhibited greater influence than precursor concentration on chloroform, dichloroacetonitrile, trichloroacetaldehyde, trichloroacetic acid, and total DBPs. Although the interaction between water quality parameters was weak, the interaction between disinfection operating parameters demonstrated substantial effects on DBP formation (8.56–19.06%). Furthermore, the DBP predictive models during TCCA disinfection were provided for the first time, which provides valuable insights for DBP control and early warning programs.

Association between Urinary Haloacetic Acid Concentrations and Liver Injury among Women: Results from the Tongji Reproductive and Environmental (TREE) Study.

Experimental studies have shown that disinfection byproducts (DBPs) including haloacetic acids (HAAs) can cause liver toxicity, but evidence linking this association in humans is sparse. We aimed to explore the associations between HAA exposures and liver injury. We included 922 women between December 2018 and January 2020 from the Tongji Reproductive and Environmental (TREE) cohort study in Wuhan, China. Urinary HAA concentrations including trichloroacetic acid (TCAA) and dichloroacetic acid (DCAA) and serum indicators of liver function, including alanine aminotransferase (ALT), aspartate aminotransferase (AST), and gamma-glutamyltransferase (GGT) were measured. Liver injury was defined as if any of serum indicator levels were above the 90th percentile. Multivariate logistic and linear regression models were fitted to assess the associations of urinary HAA concentrations with the risk of liver injury and liver function indicators. Stratified analyses by age, body mass index (BMI), alcohol use, and passive smoking were also applied to evaluate the potential effect modifiers. There is little evidence of associations of urinary TCAA concentrations with liver injury risk and liver function indicators. However, urinary DCAA concentrations were associated with a higher risk of liver injury [odds ratios (OR) for 1-interquartile range (IQR) increase in natural log (ln) transformed DCAA concentrations: 1.45; 95% confidence interval (CI): 1.07, 1.98]. This association was observed only among nondrinkers (). We also found that a 1-IQR increase in ln-transformed DCAA concentrations was positively associated with ALT levels (percentage ; 95% CI: 0.48%, 11.95%) and negatively associated with AST/ALT (percentage ; 95% CI: , ). In addition, urinary DCAA concentrations in relation to higher GGT levels was observed only among passive smokers (). Our findings suggest that exposure to DCAA but not TCAA is associated with liver injury among women undergoing assisted reproductive technology. https://doi.org/10.1289/EHP13386.

Exposures to drinking water disinfection byproducts and kidney function in Chinese women

BackgroundDisinfection byproducts (DBPs), the ubiquitous contaminants in drinking water, have been shown to impair renal function in experimental studies. However, epidemiological evidence is sparse. ObjectiveTo investigate exposures to DBPs in associations with renal function among women. MethodsA total of 920 women from December 2018 to January 2020 were abstracted from the Tongji Reproductive and Environmental (TREE) Study, an ongoing cohort study in Wuhan, China. Urine samples were gathered at baseline recruitment and analyzed for dichloroacetic acid (DCAA) and trichloroacetic acid (TCAA) as biomarkers of DBP exposures. Serum uric acid (UA), creatinine, and estimated glomerular filtration rate (eGFR) were measured as indicators of renal function. Multivariate linear regression and restricted cubic spline (RCS) models were conducted to assess urinary DCAA and TCAA concentrations in associations with renal function indicators. Stratified analyses by age and body mass index (BMI) were also performed. ResultsWe found null evidence of urinary TCAA in associations with renal function indicators. However, elevated urinary DCAA tertiles were related to decreased eGFR (β = −1.78%, 95% CI: 3.21%, −0.36%, comparing the upper vs. lower tertile; P for trend = 0.01). This inverse association still existed when urinary DCAA concentration was treated as a continuous variable, and the dose-response relationship was linear based on the RCS model (P for overall association = 0.002 and P for non-linear associations = 0.44). In the stratified analyses, we found an association of urinary DCAA concentration with decreased UA level among women <30 years but an association with increased UA level among women ≥30 years (P for interaction = 0.04). ConclusionUrinary DCAA but not TCAA was associated with impaired renal function among women undergoing assisted reproductive technology.

Associations of exposure to disinfection by-products with blood coagulation parameters among women: Results from the Tongji reproductive and environmental (TREE) study

BackgroundExperimental studies have shown that disinfection byproducts (DBPs) induce coagulotoxicity, but human evidence is scarce. ObjectiveThis study aimed to explore the relationships of DBP exposures with blood coagulation parameters. MethodsAmong 858 women from the Tongji Reproductive and Environmental (TREE) study, urinary dichloroacetic acid (DCAA) and trichloroacetic acid (TCAA) were detected as internal biomarkers of DBP exposures. We measured activated partial thromboplastin time (APTT), fibrinogen (Fbg), international normalized ratio (INR), prothrombin time (PT), and thrombin time (TT) as blood coagulation parameters. Multivariable linear regression models were utilized to estimate the relationships between urinary DCAA and TCAA and blood coagulation parameters. The effect modifications by demographic and lifestyle characteristics were further explored. ResultsElevated tertiles of urinary DCAA concentrations were associated with increased PT and INR (11.29%, 95% CI: 1.66%, 20.92% and 0.99%, 95% CI: 0.08%, 1.90% for the third vs. first tertile, respectively; both P for trends < 0.05). Stratification analysis showed that the positive associations were only observed among younger (< 30 years), leaner (body mass index < 24.0 kg/m2), and non-passive smoking women. Moreover, elevated tertiles of urinary TCAA concentrations in positive associations with PT and INR were observed among younger women (17.89%, 95% CI: 2.50%, 33.29% and 1.82%, 95% CI: 0.34%, 3.30% for the third vs. first tertile, respectively; both P for trends < 0.05) but not among older women (both P for interactions < 0.05). ConclusionHigher levels of urinary DCAA and TCAA are associated with prolonged clotting time among women.

Measurement of haloacetic acids in human urine samples from six megacities of China using a refined detection method

Haloacetic acids (HAAs) are common disinfection by-products in chlorine disinfected water. Humans are extensively exposed to them. However, nationwide biomonitoring data were not available for any country. This study developed a labor-efficient and sensitive method for the detection of urinary HAAs, including trichloroacetic acid (TCAA) and dichloroacetic acid (DCAA), and conducted an exposure assessment in a Chinese population. A total of 850 first-morning-void urine samples were collected from adults in six megacities in China: Wuhan (central), Lanzhou (northwest), Chengdu (southwest), Taiyuan (north), Shanghai (east), and Dalian (northeast). Each participant (n = 425) provided a pair of urine samples during the warm (September to October 2018) and cold (December 2018 to January 2019) seasons. The detection method achieved good retention of the target analytes using a Fluoro-Phenyl column and excellent selectivity using in-source fragmentation ions as precursor ions in multiple reaction monitoring. The detection rate of urinary TCAA in Chinese populations was high (78.5%) but varied among different regions (54.0% to 98.0%). DCAA was rarely detected (<10%). The overall median value of specific gravity adjusted TCAA concentrations was 5.70 μg/L in the warm season and 3.87 μg/L in the cold season, respectively. Higher urinary TCAA concentrations were more likely to occur in Wuhan (Yangtze River Basin), urban areas, and during the warm season. The upstream region of the Yangtze River Basin (Chengdu) typically has lower TCAA concentrations. TCAA formation in coastal cities such as Shanghai and Dalian may be impacted by seawater intrusion. Estimated daily intakes of TCAA were lower than its chronic reference dose of 20 μg/kg-bw/day. This detection method can be applied to future biomonitoring of urinary HAAs. More attention should be paid to the highly exposed subgroups when exploring the health effects of long-term TCAA exposure.

Associations between Urinary Concentrations of Disinfection Byproducts and in Vitro Fertilization Outcomes: A Prospective Cohort Study in China.

Experimental studies show that disinfection byproducts (DBPs) can inhibit oocyte maturation, decrease fertilization capacity, and impair embryo development, but human evidence is lacking. We aimed to evaluate the associations between exposure to drinking water DBPs and in vitro fertilization (IVF) outcomes. The study included 1,048 women undergoing assisted reproductive technology (ART) treatment between December 2018 and January 2020 from a prospective cohort study, the Tongji Reproductive and Environmental study in Wuhan, China. Exposure to DBPs was assessed by dichloroacetic acid (DCAA) and trichloroacetic acid (TCAA) in up to four urine samples, which were collected on the day of both enrollment and oocyte retrieval. Multivariable generalized linear mixed models, accounting for multiple IVF cycles per woman, were applied to evaluate the associations between urinary biomarkers of DBP exposures and IVF outcomes. Stratified analyses were used to explore the potential effect modifiers. The included 1,048 women underwent 1,136 IVF cycles, with 960 (91.6%), 84 (8.0%), and 4 (0.4%) women contributing one cycle, two cycles, and three cycles, respectively. We found that elevated quartiles of urinary DCAA and TCAA concentrations were associated with reduced numbers of total oocytes and metaphase II oocytes and that urinary DCAA concentrations with a lower proportion of best-quality embryos (all p for ). Moreover, elevated quartiles of urinary DCAA concentrations were associated with decreased proportions of successful implantation, clinical pregnancy, and live birth (14%, 15%, and 15% decreases in adjusted means comparing the extreme quartiles, respectively; all p for ). Stratification analyses showed that the inverse associations of urinary TCAA concentrations with multiple IVF outcomes were stronger among women y of age (p for ). Exposure to drinking water DBPs was inversely associated with some IVF outcomes among women undergoing ART treatment. Further study is necessary to confirm our findings. https://doi.org/10.1289/EHP12447.

Electrocatalytic dechlorination of aqueous trichloroacetic acid by Vitamin B12 modified iron electrode

Haloacetic acids (HAAs) are ubiquitously detected in drinking water and even persistent after boiling due to their stability and nonvolatility, which leads to risk exposure to human. To minimize the risk, HAAs removal through electrocatalytic reduction easily utilized in point-of-use household devices is proposed. Trichloroacetic acid (TCAA) as a typical target, was investigated using laboratory-prepared metal electrode modified with Vitamin B12 (VB12) by the drop coating method. The dechlorination performance and effects of influencing factors on the TCAA dechlorination by VB12/metal composite cathode were studied. Under the conditions of 10.0 mg VB12 loading and 7.0 mA/cm2 current density, 92.9% TCAA removal efficiency was achieved within 5 h at 25 °C in neutral water solution. The degradation processes followed the first-order kinetic model. The results show that VB12/iron (Fe) electrode presented the superior electrocatalytic activity than VB12/aluminium and VB12/copper. The dechlorination efficiency of TCAA was promoted by higher VB12 loadings and current density; inhibited by alkaline condition and higher initial concentration of TCAA. The synergistic effect between atomic H* and VB12 occurred during the TCAA dechlorination process through the electron transfer. The proposed pathway elucidated that TCAA was dechlorinated to form dichloroacetic acid (DCAA) and monochloroacetic acid (MCAA), with acetic acid and chloride as ultimate products. This electrocatalysis system with VB12/Fe composite electrode exhibits high reaction efficiency, targeted dehalogenation, and environmental friendliness. This work is expected to provides a new way for the removal of halogenated DBPs at the tap and the safeguard drinking water for consumers.

High formation of trichloroacetic acid from high molecular weight and ultra-hydrophilic components in freshwater raphidophytes upon chlorination

Raphidophytes are flagellate unicellular algae that causes algal blooms in drinking water sources. In Japan, it was recently reported that the concentration of trichloroacetic acid (TCAA), a major chlorinated disinfection byproduct (DBP), increased dramatically in drinking water when the source water contained raphidophytes. Additionally, raphidophytes produced haloacetic acid (HAA) precursors, especially TCAA precursors, in high concentrations. However, their properties are still unknown, and thus, well-designed countermeasures against DBP formation have not yet been established. Therefore, in this study, the HAA precursors originated from raphidophytes in natural water collected from the algal blooms in Muro Dam (Nara Prefecture, Japan) and Gonyostomum semen (G. semen), a raphidophyte species, cultivated in the laboratory, were characterized to provide the information for establishing suitable treatment strategies. Using several high-performance liquid chromatography columns, solid-phase extraction cartridges, and ultrafiltration devices, and the spectral profiles, we discovered that the HAA precursors are highly hydrophilic and high-molecular-weight compounds with acidic and phenolic functional groups. Further characterization of the high-molecular-weight fraction (> 3 kDa) from the G. semen culture showed that the HAA precursors had a molecular weight of ~10–60 kDa, and that they were not protein molecules despite containing a large amount of nitrogen atoms. Furthermore, the TCAAFP of the fraction (310 ± 25 μg/mg C) were as high as phenol, known as a reactive TCAA model precursor. The presence of unique and unreported DBP precursors was confirmed.

Adsorption of trichloroacetic acid from drinking water using polyethylene terephthalate waste carbon and periwinkle shells–based chitosan

Abstract Toxins are formed because of massive anthropogenic activities, polluting freshwater bodies. Most disinfectants used in water purification produce disinfection by-products (DBPs) such as trichloroacetic acid (TCA). TCA is a strong acid, and TCA uptake could harm gastrointestinal tract tissues or result in systemic acidosis. Activated carbons were investigated to remove TCA from drinking water in this study. Elemental and Energy Dispersive X-ray (EDX) and scanning electron microscope methodologies were employed to characterize the surface morphological features of the activated carbons (SEM). Activated carbons’ chemical functional groups were identified through using Fourier transform-infrared (FT-IR) spectroscopy technique. Using a UV-vis spectrophotometer, the TCA concentrations in water samples were examined at 530 nm. The levels of TCA in raw and conventionally treated water were 0.9900 and 2.8900 mg/L, respectively. The polyethylene terephthalate activated carbon (PETAC), polyethylene terephthalate modified activated carbon (PETMAC), and commercial activated carbon (CAC) gave mean TCA removal efficiencies of 80.80%, 90.90%, and 90.90% for raw water and 95.16%, 96.13%, and 100% for conventionally treated water, respectively. The reusability efficiencies of PETAC and PETMAC were 78.4% and 82.4%, respectively. The PETAC with R 2 = 0.9377 showed that Langmuir model best fit the TCA adsorption in the isotherm models. According to the findings, PETAC was effective at removing TCA from water sources and could be improved by incorporating chitosan.

Characterization and chlorine reactivity of particulate matter released by bathers in indoor swimming pools

Disinfecting swimming pool water is essential for preventing waterborne diseases. An unforeseen consequence of treating water with disinfectants is the formation of disinfection by-products (DPBs) that can cause harmful effects to health through the interactions between the added disinfectant and organic matter in the water. The present work focuses on the chlorine reactivity with particles released by bathers. Such particles are collected in the filter backwash water of swimming pools and this study intends to distinguish DPBs generated from dissolved chemicals from those formed by particulate matter. Therefore, filtered and unfiltered backwash waters were collected from several swimming pools, analysed physicochemically and chemically, and then chlorinated as is (79 mgL−1) and as diluted suspensions (36.2 and 11.9 mgL−1) at varying concentrations of chlorine (1.2 mg and 24 mgCl2L−1). Utilizing a DPD colorimetric technique and GC-ECD, respectively, the kinetics of chlorine consumption and DPBs production have been investigated. Up to 25.7 μgL−1 of chloroform was produced within 96 h at 1.2 mgCl2L−1, followed by haloacetic acids (HAAs) and haloacetonitriles (HANs). Within 96 h, the concentration of trichloroacetic acid reached a maximum of 231.8 μgL−1 at a chlorine concentration of 231.8 μgL−1. The formations of 0.13 μmol THMs, 0.31 μmol HAAs, and 0.04 μmol HANs per mg of dissolved organic carbon (DOC) were finally determined by correlating the organic content of particles with the nature of the DBPs generated. Comparing the quantities of DBPs generated in filtered and unfiltered samples helps us conclude that ∼50% of DBPs formed during the chlorination of swimming pool water are derived from particles brought by bathers.

A simple method to purify intrinsically disordered proteins by adjusting trichloroacetic acid concentration

Late embryogenic abundant proteins (LEA) are a group of proteins that accumulate during the desiccation phase of the seed and in response to water deficit in the plant. Most LEA proteins are highly hydrophilic and have physicochemical characteristics similar to those of intrinsically disordered proteins (IDPs). Although the function of LEA proteins is not fully understood, there is evidence indicating that these proteins have an important role in reducing the effects caused by water limitation. The analysis of the biochemical and physicochemical characteristics of LEA proteins is crucial to determine their function, for which it is necessary to obtain large amounts of pure protein. Within this current work, we have improved our previous TCA purification method used for basic recombinant LEA proteins to obtain acidic IDPs, the method reported here is fast and simple and is based on the enrichment of the protein of interest by boiling of the bacterial extract followed by a precipitation with different concentrations of TCA and salt. This protocol was applied to acidic and basic IDPs, represented by eight recombinant LEAs, resulting in milligram quantities of highly enriched proteins, which keep their in vitro functionality.

Simultaneous Detection and Analysis of Free Amino Acids and Glutathione in Different Shrimp.

An amino acid analyzer method for the simultaneous determination of 20 free amino acids (FAAs) and glutathione (GSH) in Penaeus vannamei (PV), Penaeus vannamei, Penaeus hidulis (PH) and Penaeus japonicus (PJ) were developed. The effects of different concentrations of trichloroacetic acid (TCA) and ethanol on the extraction of free amino acids were investigated, and 120 g·L−1 TCA was found to be ideal. The target analytes were eluted in sodium citrate buffer B1 (pH = 3.3) containing 135 mL·L−1 ethanol and 1 mol·L−1 sodium hydroxide (7 mL) and at the optimizing conversion time of sodium citrate buffer B2 (pH = 3.2) and sodium citrate buffer B3 (pH = 4.0) of 5.6 min, and the effective separation was achieved within 29.5 min. The developed method showed good linearity (R2 ≥ 0.9991) in the range of 1–250 µg·mL−1 with good intra-day and inter-day precision (relative standard deviations ≤ 2.38%) and spike recovery (86.42–103.64%). GSH and cysteine were used to identify marine prawn and freshwater shrimp. Hydroxyproline and serine were used to distinguish PV and Macrobrachium nipponense (MN) from others, respectively. The highest content of the total FAAs was found in PV, and principal component analysis revealed that PV had the highest comprehensive score for FAAs and GSH. Arginine was found to have the greatest influence on shrimp flavor.

Determination of Optimum TBARS Conditions for Evaluation of Cow and Sheep Milk Oxidative Stability

Having a complex fatty acid profile, milk is the subject of several oxidation processes that are different to those in other food matrices. Considering this, is important to appreciate the degradation status of milk using rapid and simple methods to quantify the main degradation products. The aim of this study was to adapt a simple and rapid method for determination of milk oxidative stability and to quantify malondialdehyde, one of the lipid oxidation products. Four parameters (trichloroacetic acid concentration—TCA, antioxidant type, incubation time, and thiobarbituric acid—TBA concentration) were modified to establish the best experimental sequence. It was concluded that the relevant results were obtained by precipitating milk proteins using 20% TCA; incubating samples for 90 min with 0.8% TBA, without adding antioxidant; and registering absorbance at three different wavelengths (450, 495, and 532 nm). This method was successfully applied to cow and sheep milk samples and the absorbance values obtained provided information about degradation of fatty acids for both milk types. The Pearson correlation showed a positive relationship between the fatty acid profiles of milk samples and the absorbance values that characterized their oxidation pattern during storage.

Disinfection byproducts in chlorinated or brominated swimming pools and spas: Role of brominated DBPs and association with mutagenicity

Although the health benefits of swimming are well-documented, health effects such as asthma and bladder cancer are linked to disinfection by-products (DBPs) in pool water. DBPs are formed from the reaction of disinfectants such as chlorine (Cl) or bromine (Br) with organics in the water. Our previous study (Daiber et al., Environ. Sci. Technol. 50, 6652; 2016) found correlations between the concentrations of classes of DBPs and the mutagenic potencies of waters from chlorinated or brominated swimming pools and spas. We extended this study by identifying significantly different concentrations of 21 individual DBPs in brominated or chlorinated pool and spa waters as well as identifying which DBPs and additional DBP classes were most associated with the mutagenicity of these waters. Using data from our previous study, we found that among 21 DBPs analyzed in 21 pool and spa waters, the concentration of bromoacetic acid was significantly higher in Br-waters versus Cl-waters, whereas the concentration of trichloroacetic acid was significantly higher in Cl-waters. Five Br-DBPs (tribromomethane, dibromochloroacetic acid, dibromoacetonitrile, bromoacetic acid, and tribromoacetic acid) had significantly higher concentrations in Br-spa versus Cl-spa waters. Cl-pools had significantly higher concentrations of Cl-DBPs (trichloroacetaldehyde, trichloromethane, dichloroacetic acid, and chloroacetic acid), whereas Br-pools had significantly higher concentrations of Br-DBPs (tribromomethane, dibromoacetic acid, dibromoacetonitrile, and tribromoacetic acid). The concentrations of the sum of all 4 trihalomethanes, all 11 Br-DBPs, and all 5 nitrogen-containing DBPs were each significantly higher in brominated than in chlorinated pools and spas. The 8 Br-DBPs were the only DBPs whose individual concentrations were significantly correlated with the mutagenic potencies of the pool and spa waters. These results, along with those from our earlier study, highlight the importance of Br-DBPs in the mutagenicity of these recreational waters.

Associations of Urinary Trichloroacetic Acid Concentrations with Spermatozoa Apoptosis and DNA Damage in a Chinese Population.

Exposure to trichloroacetic acid (TCAA) has been associated with impaired semen quality; however, its association with spermatozoa apoptosis and DNA damage remains unclear. We, therefore, collected single semen and repeated urine samples from male partners of couples attending a reproductive center, which were measured for spermatozoa apoptosis and DNA damage parameters and TCAA concentrations, respectively. Multivariable linear regression models were used to explore the associations between urinary TCAA concentrations and spermatozoa apoptosis (n = 462) and DNA damage parameters (n = 512). After adjusting for potential confounders, positive dose-response relationships were found between urinary TCAA concentrations and percentage of tail DNA (tail%) and tail-distributed moment (TDM) (both p for trend <0.10). Compared with men in the lowest tertile of urinary TCAA concentrations, men in the highest tertile had a greater tail% and TDM of 6.2% (95% CI: 0.7, 12.2%) and 8.9% (95% CI: -1.9, 20.5%), respectively. Urinary TCAA concentrations were unrelated to spermatozoa apoptosis parameters in a dose-response manner. However, urinary TCAA concentrations were positively associated with the percentage of Annexin V+/PI- spermatozoa (apoptotic cells), when urinary TCAA concentrations were modeled as continuous variables. Our results suggest that exposure to TCAA at concentrations in real-world scenarios may be associated with spermatozoa apoptosis and DNA damage.

Associations between drinking water disinfection byproducts and menstrual cycle characteristics: A cross-sectional study among women attending an infertility clinic.

Disinfection byproducts (DBPs) have been shown to alter ovarian steroidogenesis and cause estrous cyclicity disturbance and prolongation in experimental studies, however human studies are lacking. We aimed to evaluate the cross-sectional associations between drinking water DBPs and menstrual cycle characteristics. A total of 1078 women attending an infertility clinic in Wuhan, China were included between December 2018 and January 2020. Characteristics of menstrual cycle were collected by questionnaires. Concentrations of dichloroacetic acid (DCAA) and trichloroacetic acid (TCAA) were measured in urine as biomarkers of drinking water DBPs. Multivariate logistic and linear regression models were used to evaluate the associations between urinary DCAA and TCAA concentrations and menstrual cycle characteristics. Higher urinary DCAA concentrations were associated with increased odds ratios (ORs) of irregular menstrual cycle (OR=1.80; 95% CI: 0.97, 3.33 for the highest vs. lowest quartile; P for trend=0.05) and long menstrual cycle (OR=1.62; 95% CI: 0.97, 2.70 for the highest vs. lowest quartile; P for trend=0.06), as well as prolonged variation in cycle length (β=1.27 days; 95% CI: -0.11, 2.66 for the highest vs. lowest quartile; P for trend=0.04). Higher urinary TCAA concentrations were associated with prolonged bleeding duration (β=0.23 days; 95% CI: -0.06, 0.51 for the highest vs. lowest quartile; P for trend=0.07). These results suggest that exposure to drinking water DBPs is associated with menstrual cycle disturbances. These findings are warranted to confirm in other studies.

A model to understand postinflammatory hyperpigmentation better

British Journal of DermatologyVolume 186, Issue 3 p. e113-e113 Plain Language SummaryFree Access A model to understand postinflammatory hyperpigmentation better First published: 07 March 2022 https://doi.org/10.1111/bjd.20987AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Abstract Linked Article: Vellaichamy et al. Br J Dermatol 2022; 186:508–519. Postinflammatory hyperpigmentation (PIH) is an extremely common disease that involves the development of dark spots on the skin at sites of previous injury or disease. This is the result of overproduction of melanin in the skin (the pigment that gives skin its normal colour). There are limited options for treating it and this is because not very much is known about how it develops. PIH can have a significant impact on patient’s quality of life, especially in individuals with skin of colour. In this study, we test and refine a model we had previously developed in order to understand this disease better. Based in the USA, we recruited 29 patients to test our model, which includes light- and colour-based technology to assess the amount of pigmentary response in the skin. We induced pigmentation using trichloroacetic acid (TCA) and assessed the response using a variety of measures. Our findings suggest that in future studies investigating how PIH develops and looking at potential agents that might be used to treat it the best concentration of TCA to apply is 30%. We found that our model could demonstrate a dose–response relationship between the degree of insult and the severity of the resulting pigmentation. This study also shows that microRNAs (small pieces of genetic material that play an essential role in a large number of biological processes) can be helpful tools in our quest for a better understanding of this disease and also, possibly, as targets for treatment. Volume186, Issue3March 2022Pages e113-e113 RelatedInformation

A novel electrochemical sensor based on autotropic and heterotrophic nitrifying biofilm for trichloroacetic acid toxicity monitoring

Trichloroacetic acid (TCA), a toxic substance produced in the disinfection process of wastewater treatment plants, will accumulate in the receiving water. The detection of TCA in the water can achieve the purpose of early warning. However, currently there are few reports on microbial sensors used for TCA detection, and the characteristics of their microbial communities are still unclear. In this work, a toxicity monitoring microbial system (TMMS) with nitrifying biofilm as a sensing element and cathode oxygen reduction as a current signal was successfully constructed for TCA detection. The current and nitrification rate showed a linear relationship with low TCA concentration from 0 to 50 μg/L (R2current = 0.9892, R2nitrification = 0.9860), and high concentration range from 50 to 5000 μg/L (R2current = 0.9883, R2nitrification = 0.9721). High-throughput sequencing revealed that the TMMS was composed of autotrophic/heterotrophic nitrifying and denitrifying microorganisms. Further analysis via symbiotic relationship network demonstrated that Arenimonas and Hyphomicrobium were the core nodes for maintaining interaction between autotropic and heterotrophic nitrifying bacteria. Kyoto Encyclopedia of Genes and Genomes analysis showed that after adding TCA to TMMS, the carbon metabolism and the abundance of the tricarboxylic acid cycle pathway were reduced, and the activity of microorganisms was inhibited. TCA stress caused a low abundance of nitrifying and denitrifying functional enzymes, resulting in low oxygen consumption in the nitrification process, but more oxygen supply for cathode oxygen reduction. This work explored a novel sensor combined with electrochemistry and autotrophic/heterotrophic nitrification, which provided a new insight into the development of microbial monitoring of toxic substances.