Long-term toxicology and carcinogenicity of 2,4,6-trichlorophenol

Application of KHSO5 for remediation of soils polluted by organochlorides: A comprehensive study on the treatment's efficacy, environmental implications, and phytotoxicity

Soil pollution caused by complex organochloride mixtures has been increasing in many parts of the world in recent years; as a result, countless numbers of people are exposed to dangerous pollutions; hence, the treatment of organochlorides-polluted soils is gaining considerable attention. In this study, the potential of unactivated peroxymonosulfate (KHSO₅) in remediating soil co-contaminated with trichlorophenol, para-dichlorobenzene, and para-chloro-meta-cresol was investigated. In addition, the treatment's collateral effect on critical soil properties was explored. The result revealed that treating 10 g of soil with 20 mL of 5 mM KHSO₅ for 60 min could oxidize 70.49% of the total pollutants. The pH of the soil was decreased following the treatment. The significant decrease, (p < 0.05), in the soil organic matter following the remediation has affected cation exchange capacity, and available nitrogen. It was also observed that the treatment reduced the β-glucosidase, urease, invertase, and cellulase activities significantly, (p < 0.05). The treatment, on the other hand, brought negligible effects on available phosphorus, available potassium, and particle size distribution. The phytotoxicity tests, which included seed germination and root elongation and soil respiration tests revealed that the treatment did not leach toxins into the treated soil. The treatment method was found to be relatively ecofriendly and cost effective.

Association of bone mineral density with trichlorophenol: a population-based study

BACKGROUND

Trichlorophenols (TCPs) are metabolites of several organochlorine chemicals, including chlorobenzene, hexachlorocyclohexane, and chlorophenoxy acid, present in air, surface water, soil, and sediment. Many studies have shown that endocrine disruptors (EDs)may contribute to decreased bone mass and the increased risk of osteoporosis. However, the relationship between TCP and bone mineral density (BMD) has not been studied yet.

METHODS

We conducted a cross-sectional study by using data from the 2005-2010 National Health and Nutrition Examination Survey (NHANES). TCP levels were measured in urine samples from 3385 participants and bone mineral density was obtained by dual X-ray absorptiometry (DXA) lumbar spine and femur scanning. Multiple regression analysis, stratified analysis, curve fitting analysis, and trend tests were used to assess the relationship between TCP and BMD.

RESULT

After adjusting for confounding factors, the results of multiple regression analysis only showed that ln-2,4,5-TCP was negatively associated with BMD of lumbar spine. In stratified analyses, Male, Menstruating Female and Menopausal Female were divided into three groups for analysis. The results showed that ln-2,4,5-TCP and ln-2,4,6-TCP were not statistically associated with BMD in total femur, femoral neck, femoral tuberosity, intertrochanteric femur and lumbar spine, which was also confirmed by curve fitting analyses and trend tests.

CONCLUSION

This study demonstrated that 2,4,5-TCP and 2,4,6-TCP in urine samples were not significantly associated with BMD in the US population. Therefore, 2,4,5-TCP and 2,4,6-TCP may not be detrimental to BMD.

Assessment of the inhibition risk of chlorophenol substances on cytochrome P450 via cocktail inhibition assays

Chlorophenols (CPs) are widespread pollutants in nature. CPs have raised significant concern due to their potential hepatotoxic effects on humans. This research aimed to ascertain the inhibitory potential of eleven CPs (2-CP, 3-CP, 4-CP, 2,4-DCP, 2,3,4-TCP, 2,4,5-TCP, 2,4,6-TCP, 2,3,4,5-TeCP, 2,3,4,6-TeCP, 2,3,5,6-TeCP, and PCP) on nine human CYP isoforms (CYP1A2, 2A6, 2B6, 2C8, 2C9, 2C19, 2D6, 2E1, and 3A4). The CPs that inhibit the activity of CYP isoforms were detected with human liver microsomes (HLM) using a cocktail approach in vitro. The results demonstrated that trichlorophenols, tetrachlorophenols, and PCP strongly inhibited CYP2C8 and CYP2C9. The half inhibition concentration (IC₅₀) value of 2,3,4,6-TeCP and PCP for CYP2C8 inhibition was 27.3 μM and 12.3 μM, respectively. The IC₅₀ for the inhibition of 2,4,6-TCP, 2,3,4,6-TeCP and PCP towards CYP2C9 were calculated to be 30.3 μM, 5.8 μM and 2.2 μM, respectively. 2,3,4,6-TeCP, and PCP exhibited non-competitive inhibition towards CYP2C8. 2,4,6-TCP, 2,3,4,6-TeCP, and PCP exhibited competitive inhibition towards CYP2C9. The inhibition kinetics parameters (Ki) were 51.51 μM, 22.28 μM, 37.86 μM, 7.27 μM, 0.68 μM for 2,3,4,6-TeCP-CYP2C8, PCP-CYP2C8, 2,4,6-TCP-CYP2C9, 2,3,4,6-TeCP-CYP2C9, PCP-CYP2C9, respectively. This study also defined clear structure-activity relationships (SAR) of CPs on CYP2C8, supported by molecular docking studies. Overall, CPs were found to cause inhibitory effects on CYP isoforms in vitro, and this finding may provide a basis for CPs focused on CYP isoforms inhibition endpoints.

Association between trichlorophenols and neurodegenerative diseases: A cross-sectional study from NHANES 2003-2010

PURPOSE OF THE RESEARCH

To evaluate the association of the exposure of trichlorophenols (TCPs) on the morbidity and mortality of patients with Parkinson's disease (PD) and Alzheimer's disease (AD) using the data from the National Health and Nutrition Examination Survey (NHANES) 2003-2010. Multivariable logistic regression models and COX regression were used to evaluate the association between TCP exposure and the AD and PD risk. Least Absolute Shrinkage and Selection Operator (LASSO) methods were used to screen latent covariates.

PRINCIPAL RESULTS

A total of 6333 participants over the age of 18 years were included in the analysis. After the adjustments for major confounders, participants with higher concentrations of urinary 2,4,6-TCP had higher risk of AD (odds ratios (ORs), 3.19; 95% CI: 1.07, 9.45) than the group below the limit of detection (LOD). Compared to group of below the LOD, higher urinary concentrations of 2,4,5-TCP was associated with higher risk of all-cause mortality in PD patients (log-rank P = 0.022) and all participants (log-rank P < 0.001) without adjustments for confounders. In addition, a higher risk of all-cause mortality in all participants with high urinary concentrations of 2,4,6-TCP (log-rank P = 0.001) was found without adjustments for confounders. With the adjustments for major confounders, participants with higher concentrations of urinary 2,4,5-TCP had a higher risk of death in patients with PD (hazard ratios (HRs), 53.19; 95% CI: 2.82, 1004.13) than in the group below the LOD.

MAJOR CONCLUSIONS

Exposure to high concentration of 2,4,6-TCP may increase the risk of AD, and the level of 2,4,5-TCP may be associated with the risk of death in patients with PD. Our findings reveal the potential toxicity of TCPs, highlight the potential impact of TCPs on neurodegenerative diseases, and express concerns regarding the use of organochlorine pesticides.

Humic acid promoted activation of peroxymonosulfate by Fe3S4 for degradation of 2,4,6-trichlorophenol: An experimental and theoretical study

Chlorophenols are difficult to degrade and biohazardous in the natural environment. This study demonstrated that humic acid (HA) could promote Fe₃S₄ activation of peroxymonosulfate (PMS) to degrade 2,4,6-trichlorophenol (TCP), the degradation efficiency of TCP was increased by 33%. The system of Fe₃S₄-HA/PMS produced more reactive oxygen species, and •OH was the dominant ROS. The genealogy of iron oxides together with S⁰ on the Fe₃S₄ surface inhibited PMS activation leading to the significant reduction of TCP degraded (< 70%). These problems could be solved successfully through introducing HA, which facilitated electron transfer and increased the continuous release of iron ions by 2 times. In accordance with the determined density functional theory (DFT), the degradation pathway was put forward, which indicated that TCP dechlorination and oxidation to 2,6-dichloro-1,4-benzoquinone constituted the main degradation pathway. Furthermore, the intermediates that were produced in the main degradation processes of TCP showed lower toxicity than TCP according to results that were obtained utilizing the calculations of quantitative structure-activity relationship (QSAR) together with Toxicity Estimation Software Tool (TEST). Thus, the Fe₃S₄-HA/PMS system was demonstrated to be an efficient and safe technology for organic pollutant degradation in contaminated groundwater and surface water environments.

In vivo toxicity evaluations of halophenolic disinfection byproducts in drinking water: A multi-omics analysis of toxic mechanisms

Halophenolic disinfection byproducts (DBPs) in drinking water have attracted considerable concerns in recent years due to their wide occurrence and high toxicity. The liver has been demonstrated as a major target organ for several halophenolic DBPs. However, little is known about the underlying mechanisms of liver damage caused by halophenolic DBPs. In this study, 2,4,6-trichlorophenol (TCP), 2,4,6-tribromophenol (TBP) and 2,4,6-triiodiophenol (TIP) were selected as representative halophenolic DBPs and exposed to C57BL/6 mice at an environmentally-relevant concentration (0.5 μg/L) and two toxicological concentrations (10 and 200 μg/L) for 12 weeks. Then, a combination of histopathologic and biochemical examination, liver transcriptome, serum metabolome, and gut microbiome was adopted. It was found that trihalophenol exposure significantly elevated the serum levels of alkaline phosphatase and albumin. Liver inflammation was observed at toxicological concentrations in the histopathological examination. Transcriptome results showed that the three trihalophenols could impact immune-related pathways at 0.5 μg/L, which further contributed to the disturbance of pathways in infectious diseases and cancers. Notably, TBP and TIP had higher immunosuppressive effects than TCP, which might lead to uncontrolled infection and cancer. In terms of serum metabolic profiles, energy metabolism pathway of citrate cycle and amino acid metabolism pathways of valine, leucine, and isoleucine were also significantly affected. Integration of the metabolomic and transcriptomic data suggested that a 12-week trihalophenol exposure could prominently disturb the glutathione metabolism pathway, indicating the impaired antioxidation and detoxification abilities in liver. Moreover, the disorder of the intestinal flora could interfere with immune regulation and host metabolism. This study reveals the toxic effects of halophenolic DBPs on mammalian liver and provides novel insights into the underlying mechanisms of hepatotoxicity.

Determination of 19 chlorophenols in fish by QuEChERS-gas chromatography-mass spectrometry

大量含氯农药、次氯酸消毒水以及水产品杀虫剂和杀菌剂的广泛使用,使鱼类容易受到氯酚类化合物的污染,因而建立鱼肉中氯酚类化合物的检测方法十分重要。建立了QuEChERS结合气相色谱-质谱法同时检测鱼肉中19种氯酚类化合物的分析方法。19种氯酚类化合物选用DB-5MS毛细管色谱柱(30 m×0.25 mm×0.25 μm),载气流速1 mL/min进行分离,可以得到很好的峰形。前处理采用改良的QuEChERS方法,通过对提取剂的种类和剂量、净化剂的种类和剂量,以及衍生条件中的衍生温度、衍生时间和衍生剂用量等进行优化,确定最优的前处理方法。选择10 mL乙酸乙酯作为提取剂,500 mg的C₁₈作为净化剂,加入3 g氯化钠和5 g无水硫酸镁,过0.22 μm的有机滤膜,加入50 μL的硅烷化衍生剂在45 ℃条件下衍生30 min,用EI源测定,选择离子监测模式,以外标法定量。19种氯酚类化合物在0.4~10 μg/L范围内具有良好的线性关系,相关系数R²大于0.998,方法定量限为0.04~0.16 μg/kg。空白基质不同加标水平的回收率为70.6%~115.0%,相对标准偏差为2.6%~10.5%。将建立的方法应用于实际样品的检测分析,结果显示,各种鱼肉中均有不同程度的氯酚类化合物检出,其中,黄花鱼检出的氯酚类化合物总量最大,为8.74 μg/kg;其次为鲫鱼7.59 μg/kg;米鱼的检出量最少,为1.59 μg/kg。所建立的方法简化了样品的前处理步骤,操作简单,方法灵敏度高、重复性好,可满足鱼肉中19种氯酚类化合物的高通量检测要求,能显著提高氯酚类化合物的检测效率。

Oxidative dehalogenation of trichlorophenol catalyzed by a promiscuous artificial heme-enzyme

The miniaturized metalloenzyme Fe(iii)-mimochrome VI*a (Fe(iii)-MC6*a) acts as an excellent biocatalyst in the H₂O₂-mediated oxidative dehalogenation of the well-known pesticide and biocide 2,4,6-trichlorophenol (TCP). The artificial enzyme can oxidize TCP with a catalytic efficiency (k_cat/K^TCP_m = 150 000 mM⁻¹ s⁻¹) up to 1500-fold higher than the most active natural metalloenzyme horseradish peroxidase (HRP). UV-visible and EPR spectroscopies were used to provide indications of the catalytic mechanism. One equivalent of H₂O₂ fully converts Fe(iii)-MC6*a into the oxoferryl-porphyrin radical cation intermediate [(Fe(iv) Created by potrace 1.16, written by Peter Selinger 2001-2019 ]]> O)por˙⁺], similarly to peroxidase compound I (Cpd I). Addition of TCP to Cpd I rapidly leads to the formation of the corresponding quinone, while Cpd I decays back to the ferric resting state in the absence of substrate. EPR data suggest a catalytic mechanism involving two consecutive one-electron reactions. All results highlight the value of the miniaturization strategy for the development of chemically stable, highly efficient artificial metalloenzymes as powerful catalysts for the oxidative degradation of toxic pollutants.

The artificial metalloenzyme FeMC6*a is able to perform the H₂O₂-mediated dechlorination of 2,4,6-trichlorophenol with unrivalled catalytic efficiency, highlighting its potential application for the removal of toxic pollutants.

Inclusion Complexation of Organic Micropollutants with β-Cyclodextrin

Recently, β-cyclodextrin (βCD)-based polymers with enhanced adsorption kinetics and high removal capacity of organic micropollutants (OMPs) and uptake rates have been synthesized and tested experimentally. Although the exact physical–chemical mechanisms via which these polymers capture the various types of OMPs are not yet fully understood, it is suggested that the inclusion complex formation of OMPs with βCD is very important. In this study, the inclusion complex formation of OMPs with βCD in an aqueous solution is investigated by using the well-established attach–pull–release method in force field-based molecular dynamics simulations. A representative set of OMPs is selected based on the measured occurrences in surface and ground waters and the directives published by the European Union. To characterize the formation of the inclusion complex, the binding free energies, enthalpies, and entropies are computed and compared to experimental values. It is shown that computations using the q4md-CD/GAFF/Bind3P force field combination yield binding free energies that are in reasonable agreement with the experimental results for all OMPs studied. The binding enthalpies are decomposed into the main contributing interaction types. It is shown that, for all studied OMPs, the van der Waals interactions are favorable for the inclusion complexion and the hydrogen bond formation of the guest with the solvent and βCD plays a crucial role in the binding mechanism. Our findings show that MD simulations can adequately describe the inclusion complex formation of βCD with OMPs, which is the first step toward understanding the underlying mechanisms via which the βCD-based polymers capture OMPs.

Chlorination of Phenols Revisited: Unexpected Formation of α,β-Unsaturated C4-Dicarbonyl Ring Cleavage Products

Despite decades of research on the fate of phenolic compounds when water is disinfected with hypochlorous acid (HOCl), there is still considerable uncertainty regarding the formation mechanisms and identity of ring cleavage products, especially at higher chlorine doses. This study focuses on the formation of electrophilic ring cleavage products-a class of compounds that poses potential health risks at relatively low concentrations-from the reactions of phenols with chlorine. By monitoring the formation of products of reactions between ring cleavage products and the model nucleophile N-α-acetyl-lysine, we identified the α,β-unsaturated dialdehyde 2-butene-1,4-dial (BDA) and its chlorinated analogue, chloro-2-butene-1,4-dial (Cl-BDA), after the chlorination of phenol, para- and ortho-substituted chlorophenols (2-Cl, 4-Cl, 2,4-diCl-, 2,6-diCl, and 2,4,6-triCl-phenol), and 3,5-di-Cl-catechol. Maximum yields of BDA were observed when chlorine was present in large excess (HOCl/phenol ratios of 30:1 to 50:1), with yields ranging from 18% for phenol to 46% for 3,5-diCl-catechol. BDA and Cl-BDA formation was also observed during the chlorination of brominated phenols. For methyl-substituted phenols, the presence of methyl substituents in both positions ortho to the hydroxy group inhibited BDA and Cl-BDA formation, but the chlorination of cresols and 2,3-dimethylphenol yielded methyl- and dimethyl-BDA species. This study provides new insights into the formation of reactive and toxic electrophiles during chlorine disinfection. It also provides evidence for the importance of phenoxy radicals produced by one-electron transfer reactions initiated by chlorine in the production of dicarbonyl ring cleavage products.

Anthropometric measures at age 3 years in associations with prenatal and postnatal exposures to chlorophenols

BACKGROUND

Chlorophenols (CPs), suspected as endocrine disrupting chemicals, exposure during early life may contribute to body size. However, limited human data with inconsistent findings have examined the developmental effects of CPs exposure.

OBJECTIVE

To explore associations between prenatal and postnatal CPs exposure and anthropometric parameters in children aged 3 years.

METHODS

A subset of 377 mother-child pairs with urinary five CP concentrations were enrolled from a prospective birth cohort. Generalized linear models were conducted to evaluate associations of CPs exposure with children's anthropometric measures.

RESULTS

Maternal urinary 2,4,6-trichlorophenol (2,4,6-TCP) concentrations were significantly negatively associated with weight z scores [regression coefficient (β) = -0.51, 95% confidence interval (CI): -0.96, -0.05; p = 0.01], weight for height z scores (β = -0.54, 95% CI: -1.02, -0.06; p = 0.01) and body mass index (BMI) z scores (β = -0.53, 95% CI: -1.03, -0.03; p = 0.01) of children aged 3 years, after adjustment for potential confounders and postnatal CPs exposure. In the sex-stratified analyses, these inverse associations remained among boys, while in girls, positive associations of prenatal 2,4,6-TCP exposure with weight for height z scores and BMI z scores were observed. Postnatal exposure to 2,5-diclorophenol (2,5-DCP) was positively associated with weight z scores (β = 0.26, 95% CI: 0.02, 0.50; p = 0.04), after controlling for possible confounders and maternal CPs exposure during pregnancy. Considering potential sex-specific effects, these associations were only observed in girls.

CONCLUSIONS

Our findings indicate that prenatal 2,4,6-TCP exposure and postnatal 2,5-DCP exposure may have adverse and sex-specific effects on children's physical development.

A comparative evaluation of the immunotoxicity and immunomodulatory effects on macrophages exposed to aromatic trihalogenated DBPs

Objective: 2,4,6-trichlorophenol (TCP), 2,4,6-tribromophenol (TBP), and 2,4,6-triiodophenol (TIP) are three aromatic halogenated disinfection byproducts (DBPs) identified in chlorinated saline effluents. This study aimed to evaluate and compare their immunotoxicity and immunomodulatory effects on macrophages. Materials and methods: CCK-8 assay was used to evaluate cytotoxicity of TCP, TBP, and TIP in mouse macrophage RAW264.7 cells. A light microscope and digital camera were used to record the morphological changes of RAW264.7 cells. qRT-PCR was used to measure the mRNA levels of polarization markers and secreted cytokines. Cytokine production was also detected by ELISA. Flow cytometry was performed to analyze the expression of M1 and M2 markers on macrophages. Results: TCP, TBP, and TIP had different cytotoxic effects on macrophages. The rank order of cytotoxicity was TIP > TBP > TCP. Furthermore, the three halogenated DBPs displayed different preferences for macrophage polarization. Intriguingly, 200 μM TIP remarkably induced the M2-dominant polarization of macrophages, while 200 μM TCP induced an M1-dominant polarization of macrophages. TBP has a moderate ability in inducing M1 and M2 polarization compared with TCP and TIP. Conclusions: TIP displayed higher cytotoxicity against macrophages than TBP and TCP, its brominated and chlorinated analogs. Since M1 and M2 macrophages facilitate the inflammatory and anti-inflammatory responses, respectively, the discrepancy of TCP, TBP, and TIP in inducing macrophage polarization may lead to distinct immunomodulatory and toxicological outcomes, thus giving rise to different types of diseases. This finding may provide novel insights into evaluating the toxicity of environmental pollutants on the immune system.

Combined toxicity of triclosan, 2,4-dichlorophenol and 2,4,6-trichlorophenol to zebrafish (Danio rerio)

Triclosan (TCS), 2,4,6-trichlorophenol (2,4,6-TCP) and 2,4-dichlorophenol (2,4-DCP) are the most prevalent chlorinated phenolic pollutants in aquatic environments. Our results showed LC₅₀ and EC₅₀ values of 0.51, 1.11, 2.45mg/L, and 0.36, 0.74, 1.53mg/L for TCS, 2,4,6-TCP and 2,4-DCP, respectively, to 120hpf zebrafish. The highest TCSD (the mixture of TCS, 2,4,6-TCP and 2,4-DCP) toxicity was observed at a TCS:2,4,6-TCP:2,4-DCP concentration ratio of 1:2:4. LC₅₀ and EC₅₀ values of TCSD mixtures for 120-hpf zebrafish were 2.28 and 1.16mg/L, respectively. Two toxicity assessment methods (Toxic Unit and Mixture Toxicity Index) indicated that TCSD interactions produced partly additive toxicity. TCSD exposure decreased zebrafish hatching rate and led to a series of malformations. Following alkaline phosphatase staining, a large area of vascular ablation was observed with almost complete disappearance of vascular branches and a smaller coverage range. Prominent reddening of the yolk sac and visceral mass after oil red O staining implied that TCSD exposure severely affected fat metabolism. Following acridine orange staining, cell death occurred in eyes while high TCSD concentrations (0.84mg/L) induced cardiovascular circulation dysfunction. Alcian blue staining increased the α angle between Meckel's cartilages and β angle between two ceratobranchial. Basihyal and palatoquadrate became shorter and developmental abnormality or defects occurred in the fifth ceratobranchial. Overall, these results provide a theoretical basis for systematically evaluating the combined toxicity of the prevalent chlorinated phenolic pollutants in real-world aquatic environments.

Effect of bromide on the transformation and genotoxicity of octyl-dimethyl-p-aminobenzoic acid during chlorination

Octyl-dimethyl-p-aminobenzoic acid (ODPABA), one of the most commonly used organic UV filters, can undergo considerable transformation in water when entering into the disinfection process. The impacts of bromide on degradation kinetics, formation and speciation of transformation products, regulated disinfection by-products (DBPs) as well as genotoxicity changes during ODPABA chlorination were investigated in this study. Results indicated that the reaction of ODPABA with chlorine followed pseudo-first-order and second-order kinetics. Adding bromide noticeably enhanced the degradation rate of ODPABA, but reduced the impact of chlorine dose. Four halogenated transformation products (Cl-ODPABA, Br-ODPABA, Cl-Br-ODPABA and Br₂-ODPABA) were detected by LC-MS/MS. Mono-halogenated products were stable during 24-h chlorination, while di-halogenated products constantly increased. The total yields of trihalomethanes (THMs) and haloacetic acids (HAAs) were both low, but predominated by bromine substitution at high levels of bromide. In addition, SOS/umu tests showed that genotoxicity was generated after ODPABA chlorination, which was increased at least 1.5 times in the presence of bromine. Whereas, no significant genotoxicity variation was observed following bromide concentration change.

Disulfide isomerase-like protein AtPDIL1-2 is a good candidate for trichlorophenol phytodetoxification

Trichlorophenol (TCP) is a widely used and persistent environmentally toxic compound that poses a carcinogenic risk to humans. Phytoremediation is a proficient cleanup technology for organic pollutants. In this study, we found that the disulfide isomerase-like protein AtPDIL1-2 in plants is a good candidate for enhancing 2,4,6-TCP phytoremediation. The expression of AtPDIL1-2 in Arabidopsis was induced by 2,4,6-TCP. The heterologously expressed AtPDIL1-2 in Escherichia coli exhibited both oxidase and isomerase activities as protein disulfide isomerase and improved bacteria tolerance to 2,4,6-TCP. Further research revealed that transgenic tobacco overexpressing AtPDIL1-2 was more tolerant to high concentrations of 2,4,6-TCP and removed the toxic compound at far greater rates than the control plants. To elucidate the mechanism of action of AtPDIL1-2, we investigated the chemical interaction of AtPDIL1-2 with 2,4,6-TCP for the first time. HPLC analysis implied that AtPDIL1-2 exerts a TCP-binding activity. A suitable configuration of AtPDIL1-2-TCP binding was obtained by molecular docking studies using the AutoDock program. It predicted that the TCP binding site is located in the b-b' domain of AtPDIL1-2 and that His254 of the protein is critical for the binding interaction. These findings imply that AtPDIL1-2 can be used for TCP detoxification by the way of overexpression in plants.

2,4,6-Trichlorophenol Cytotoxicity Involves Oxidative Stress, Endoplasmic Reticulum Stress, and Apoptosis

This study aims to evaluate the cytotoxicity and potential mechanisms of 2,4,6-trichlorophenol (2,4,6-TCP) in mouse embryonic fibroblasts. Our results show that 2,4,6-TCP causes morphological changes and reduces cell viability. The overproduction of reactive oxygen species, the upregulation of nuclear factor-E2-related factor 2 (Nrf2) and heme oxygenase 1 (HMOX1) messenger RNA (mRNA) expressions, and the nuclear translocation of Nrf2 protein demonstrate that 2,4,6-TCP induces oxidative stress, and the Nrf2/HMOX1 pathway might be involved in 2,4,6-TCP-induced antioxidative response. Simultaneously, our data also demonstrate that 2,4,6-TCP upregulates the expressions of binding immunoglobulin protein, inositol-requiring enzyme/endonuclease 1α, and C/EBP homologous protein; stimulates α subunit of eukaryotic translation initiation factor 2 phosphorylation; and induces the splicing of Xbp1 mRNA, suggesting that endoplasmic reticulum (ER) stress is triggered. Moreover, 2,4,6-TCP alters the mitochondrial membrane potential and increases the apoptosis rate, the caspase 3 activity, and the Bax/Bcl-2 ratio, demonstrating that the mitochondrial pathway is involved in the 2,4,6-TCP-induced apoptosis. Thus, these results show that 2,4,6-TCP induces oxidative stress, ER stress, and apoptosis, which together contribute to its cytotoxicity in vitro.

Luminescent threat: toxicity of light stick attractors used in pelagic fishery

Light sticks (LS) are sources of chemiluminescence commonly used in pelagic fishery, where hundreds are discarded and reach the shores. Residents from fishing villages report an improper use of LS contents on the skin. Given the scarce information regarding LS toxicity, the effects of LS solutions in cell cultures were evaluated herein. Loss of viability, cell cycle changes and DNA fragmentation were observed in HepG2 cell line and skin fibroblasts. A non-cytotoxic LS concentration increased the occurrence of the mutagenic lesion 1,N(6)-εdAdo in HepG2 DNA by three-fold. Additionally, in vitro incubations of spent LS contents with DNA generated dGuo-LS adducts, whose structure elucidation revealed the presence of a reactive chlorinated product. In conclusion, the LS contents were found to be highly cyto- and genotoxic. Our data indicate an urgent need for LS waste management guidelines and for adequate information regarding toxic outcomes that may arise from human exposure.

Urinary concentrations of trichlorophenols in the Korean adult population: results of the National Human Biomonitoring Survey 2009

Trichlorophenols such as 2,4,5-trichlorophenol (2, 4,5-TCP) and 2,4,6-trichlorophenol (2,4,6-TCP) are organochlorine compounds to which the general public can be exposed via contaminated food, water, and air. This study assessed exposure to 2,4,5-TCP and 2,4,6-TCP in Koreans age 18-69 years based on the Korean National Human Biomonitoring Survey conducted in 2009. Using data from 1,865 representative Koreans, we found that the geometric mean urinary concentrations of 2,4,5-TCP and 2,4,6-TCP were 83.4 pg/mL [95 % confidence interval (CI)=78.6-88.6] and 0.39 ng/mL (95 % CI=0.35-0.42), respectively. The creatinine-adjusted geometric mean 2,4,5-TCP and 2,4, 6-TCP levels were 78.8 ng/g creatinine (95 % CI=73.8-84.1) and 0.36 μg/g creatinine (95 % CI=0.33-0.40), respectively. Of the Korean adult population, about 67.5 and 87.5 % had respective urine 2,4,5-TCP and 2,4,6-TCP concentrations >0.05 ng/mL (the limit of detection, LOD). Urine 2,4,5-TCP concentrations were significantly associated with age and place of residence, whereas urine 2,4,6-TCP concentrations were higher in rural residents. These findings suggest that most Koreans had detectable levels of 2,4,5-TCP and 2,4,6-TCP in their urine and that the body burden of 2,4,5-TCP and 2,4,6-TCP varied according to demographic and geographic factors.