Developmental Toxicity in Mice Following Paternal Exposure to Di-N-Butyl-Phthalate (DBP)

Objective The aim of the present study was to investigate the effects of paternal Di‐N‐butyl‐phthalate （DBP） exposure pre‐ and postnatally on F1 generation offspring,and prenatally on F2 generation offspring.Methods Male mice were exposed to either 500 mg/kg or 2 000 mg/kg of DBP for 8 weeks,and mated with non‐exposed females.Three‐quarters of the females were sacrificed a day prior to parturition,and examined for the number of living and dead implantations,and incidence of gross malformations.Pups from the remaining females were assessed for developmental markers,growth parameters,as well as sperm quantity and quality.Results There were no changes in the fertility of parents and in intrauterine development of the offspring.Pups of DBP‐exposed males demonstrated growth‐retardation.Following paternal exposure to 500 mg/kg bw of DBP,there were almost twice the number of males than females born in the F1 generation.F1 generation females had a 2.5‐day delay in vaginal opening.Paternal exposure to 2 000 mg/kg bw of DBP increased the incidence of sperm head malformations in F1 generation males;however,there were no changes in the fertility and viability of foetuses in the F2 generation.Conclusion Paternal DBP exposure may disturb the sex ratio of the offspring,delay female sexual maturation,and deteriorate the sperm quality of F1 generation males.

Prenatal amoxicillin exposure induces developmental toxicity in fetal mice and its characteristics

Amoxicillin,a widely used antibiotic in human and veterinary pharmaceuticals,is now considered as an“emerging contaminant”because it exists widespreadly in the environment and brings a series of adverse outcomes.Currently,systematic studies about the developmental toxicity of amoxicillin are still lacking.We explored the potential effects of amoxicillin exposure on pregnancy outcomes,maternal/fetal serum phenotypes,and fetal multiple organ development in mice,at different doses(75,150,300 mg/(kg·day))during late-pregnancy,or at a dose of 300 mg/(kg·day)during different stages(mid-/latepregnancy)and courses(single-/multi-course).Results showed that prenatal amoxicillin exposure(PAmE)had no significant infuence on the body weights of dams,but it could inhibit the physical development and reduce the survival rate of fetuses,especially during the midpregnancy.Meanwhile,PAmE altered multiple maternal/fetal serum phenotypes,especially in fetuses.Fetal multi-organ function results showed that PAmE inhibited testicular/adrenal steroid synthesis,long bone/cartilage and hippocampal development,and enhanced ovarian steroid synthesis and hepatic glycogenesis/lipogenesis,and the order of severity might be gonad(testis,ovary)>liver>others.Further analysis found that PAmE-induced multiorgan developmental and functional alterations had differences in stages,courses and fetal gender,and the most obvious changes might be in high-dose,late-pregnancy and multicourse,but there was no typical rule of a dose-response relationship.In conclusion,this study confirmed that PAmE could cause abnormal development and multi-organ function alterations,which deepens our understanding of the risk of PAmE and provides an experimental basis for further exploration of the long-term harm.

Developmental toxicity assessment of neonicotinoids and organophosphate esters with a human embryonic stem cell-and metabolism-based fast-screening model

In recent years,neonicotinoids(NEOs)and organophosphate esters(OPEs)have been widely used as substitutes for traditional pesticides and brominated fame-retardants,respectively.Previous studies have shown that those compounds can be frequently detected in environmental and human samples,are able to penetrate the placental barrier,and are toxic to animals.Thus,it is reasonable to speculate that NEOs and OPEs may have potential adverse effects in humans,especially during development.We employed a human embryonic stem cell differentiation-and liver S9 fraction metabolism-based fast screening model to assess the potential embryonic toxicity of those two types of chemicals.We show that four NEO and five OPE prototypes targeted mostly ectoderm specification,as neural ectoderm and neural crest genes were down-regulated,and surface ectoderm and placode markers up-regulated.Human liver S9 fraction's treatment could generally reduce the effects of the chemicals,except in a few specific instances,indicating the liver may detoxify NEOs and OPEs.Our findings suggest that NEOs and OPEs interfere with human early embryonic development.

Developmental toxicity and programming alterations of multiple organs in offspring induced by medication during pregnancy

Medication during pregnancy is widespread,but there are few reports on its fetal safety.Recent studies suggest that medication during pregnancy can affect fetal morphological and functional development through multiple pathways,multiple organs,and multiple targets.Its mechanisms involve direct ways such as oxidative stress,epigenetic modification,and metabolic activation,and it may also be indirectly caused by placental dysfunction.Further studies have found that medication during pregnancy may also indirectly lead to multi-organ developmental programming,functional homeostasis changes,and susceptibility to related diseases in offspring by inducing fetal intrauterine exposure to too high or too low levels of maternal-derived glucocorticoids.The organ developmental toxicity and programming alterations caused by medication during pregnancy may also have gender differences and multi-generational genetic effects mediated by abnormal epigenetic modification.Combined with the latest research results of our laboratory,this paper reviews the latest research progress on the developmental toxicity and functional programming alterations of multiple organs in offspring induced by medication during pregnancy,which can provide a theoretical and experimental basis for rational medication during pregnancy and effective prevention and treatment of drug-related multiple fetal-originated diseases.

Developmental toxicity of TCBPA on the nervous and cardiovascular systems of zebrafish (Danio rerio): A combination of transcriptomic and metabolomics

Tetrachlorobisphenol A(TCBPA),a widely used halogenated flame retardant,is frequently detected in environmental compartments and human samples.However,unknown developmental toxicity and mechanisms limit the entire understanding of its effects.In this study,zebrafish(Danio rerio)embryos were exposed to various concentrations of TCBPA while a combination of transcriptomics,behavioral and biochemical analyzes as well as metabolomics were applied to decipher its toxic effects and the potential mechanisms.We found that TCBPA could interfere with nervous and cardiovascular development through focal adhesion and extracellular matrix-receptor(ECM-receptor)interaction pathways through transcriptomic analysis.Behavioral and biochemical analysis results indicated abnormal swimming behavior of zebrafish larvae.Morphological observations revealed that TCBPA could cause the loss of head blood vessels.Metabolomic analysis showed that arginine-related metabolic pathways were one of the main pathways leading to TCBPA developmental toxicity.Our study demonstrated that by using omics,TCBPA was shown to have neurological and cardiovascular developmental toxicity and the underlying mechanisms were uncovered and major pathways identified.

Mepanipyrim induces visual developmental toxicity and vision-guided behavioral alteration in zebrafish larvae

Mepanipyrim,an anilinopyrimidine fungicide,has been extensively used to prevent fungal diseases in fruit culture.Currently,research on mepanipyrim-induced toxicity in organisms is still very scarce,especially visual developmental toxicity.Here,zebrafish larvae were employed to investigate mepanipyrim-induced visual developmental toxicity.Intense light andmonochromatic light stimuli-evoked escape experiments were used to investigate vision-guided behaviors.Meanwhile,transcriptomic sequencing and real-time quantitative PCR assays were applied to assess the potential mechanisms of mepanipyrim-induced visual developmental toxicity and vision-guided behavioral alteration.Our results showed that mepanipyrim exposure could induce retinal impairment and vision-guided behavioral alteration in larval zebrafish.In addition,the grk1b gene of the phototransduction signaling pathway was found to be a potential aryl hydrocarbon receptor(AhR)-regulated gene.Mepanipyrim-induced visual developmental toxicity was potentially related to the AhR signaling pathway.Furthermore,mepanipyrim-induced behavioral alteration was guided by the visual function,and the effects of mepanipyrim on long and middle wavelength light-sensitive opsins may be the main cause of vision-guided behavioral alteration.Our results provide insights into understanding the relationship between visual development and vision-guided behaviors induced by mepanipyrim exposure.

Acute Developmental Toxicity of Panax notoginseng in Zebrafish Larvae

Objective:To evaluate toxicity of raw extract of Panax notoginseng(rPN)and decocted extract of PN(dPN)by a toxicological assay using zebrafish larvae,and explore the mechanism by RNA sequencing assay.Methods:Zebrafish larvae was used to evaluate acute toxicity of PN in two forms:rPN and dPN.Three doses(0.5,1.5,and 5.0μg/mL)of dPN were used to treat zebrafishes for evaluating the developmental toxicity.Behavior abnormalities,body weight,body length and number of vertebral roots were used as specific phenotypic endpoints.RNA sequencing(RNA-seq)assay was applied to clarify the mechanism of acute toxicity,followed by real time PCR(qPCR)for verification.High performance liquid chromatography analysis was performed to determine the chemoprofile of this herb.Results:The acute toxicity result showed that rPN exerted higher acute toxicity than d PN in inducing death of larval zebrafishes(P<0.01).After daily oral intake for 21 days,d PN at doses of 0.5,1.5 and 5.0μg/m L decreased the body weight,body length,and vertebral number of larval zebrafishes,indicating developmental toxicity of dPN.No other adverse outcome was observed during the experimental period.RNA-seq data revealed 38 genes differentially expressed in dPN-treated zebrafishes,of which carboxypeptidase A1(cpa1)and opioid growth factor receptor-like 2(ogfrl2)were identified as functional genes in regulating body development of zebrafishes.qPCR data showed that dPN significantly down-regulated the mRNA expressions of cpa1 and ogfrl2(both P<0.01),verifying cpa1 and ogfrl2 as target genes for dPN.Conclusion:This report uncovers the developmental toxicity of dPN,suggesting potential risk of its clinical application in children.

Comparison of developmental toxicity of different surface modified CdSe/ZnS QDs in zebrafish embryos

Quantum dots(QDs)are new types of nanomaterials.Few studies have focused on the effect of different surface modified QDs on embryonic development.Herein,we compared the in vivo toxicity of Cd Se/Zn S QDs with carboxyl(-COOH)and amino(-NH 2)modification using zebrafish embryos.After exposure,the two Cd Se/Zn S QDs decreased the survival rate,hatching rate,and embryo movement of zebrafish.Moreover,we found QDs attached to the embryo membrane before hatching and the eyes,yolk and heart after hatching.The attached amount of carboxyl QDs was more.Consistently,the Cd content in embryos and larvae was higher in carboxyl QD-treatment.We further observed that the two QDs caused zebrafish pericardial edema and cardiac dysfunction.In line with it,both carboxyl and amino QDs upregulated the transcription levels of cardiac development-related genes,and the levels were higher in carboxyl QD-treated groups.Furthermore,the chelator of Cd^2+diethylene triamine pentacetate acid could partially rescued the developmental toxicity caused by the two types of QDs suggesting that both the nature of QDs and the release of Cd^2+contribute to the developmental toxicity.In conclusion,the two Cd Se/ZnS QDs have developmental toxicity and affect the cardiac development,and the carboxyl QDs is more toxic possibly due to the higher affinity and more release to embryos and larvae.Our study provides new knowledge that the surface functional modification of QDs is critical on the development on aquatic species,which is beneficial to develop and applicate QDs more safely and environmentfriendly.

T-2 toxin induces developmental toxicity and apoptosis in zebrafish embryos

T-2 toxin is one of the most important trichothecene mycotoxins occurring in various agriculture products. The developmental toxicity of T-2 toxin and the exact mechanism of action at early life stages are not understood precisely. Zebrafish embryos were exposed to different concentrations of the toxin at 4-6 hours post fertilization （hpf） stage of development, and were observed for different developmental toxic effects at 24, 48, 72, and 144 hpf. Exposure to 0.20 Ixmol/L or higher concentrations of T-2 toxin significantly increased the mortality and malformation rate such as tail deformities, cardiovascular defects and behavioral changes in early developmental stages of zebrafish. T-2 toxin exposure resulted in significant increases in reactive oxygen species （ROS） production and cell apoptosis, mainly in the tall areas, as revealed by Acridine Orange staining at 24 hpf. In addition, T-2 toxin-induced severe tail deformities could be attenuated by co-exposure to reduced glutathione （GSH）. T-2 toxin and GSH co-exposure induced a significant decrease of ROS production in the embryos. The overall results demonstrate that T-2 toxin is able to produce oxidative stress and induce apoptosis, which are involved in the developmental toxicity of T-2 toxin in zebrafish embryos.

Developmental Toxicity and Potential Teratogenicity of Compound Danshen Tablet, Angong Niuhuang Pill, and Lidan Paishi Tablet in Zebrafish Embryos

Objective Herbal medicines containing toxic herbs or minerals such as Compound Danshen Tablet （CDT）, Angong Niuhuang Pill （ANP）, and Lidan Paishi Tablet （LPT） are avoided or used with caution for pregnant women because of potential teratogenicity. To understand their mechanism, they were chosen as model subjects for the research. Methods Zebrafish embryos were used to evaluate their potential teratogenic risk in vitro. Results All of them showed teratogenic and lethal effects in zebrafish embryos, with the ECs0 values at 351,793, and 220 μg/mL, and LC50 values at 41 7, 596, and 380 μg/mL, respectively. CDT and LPT, displaying week potential teratogenicity as their teratogenicity indexes were greater than 1, induced tail malformation and cardiac edema mainly in zebrafish embryos, respectively. Conclusion The results provide the significant guidance of clinical safety of medication.

Toxicity of Graphene Quantum Dots in Zebrafish Embryo

Objective To evaluate the bio-safety of graphene quantum dots （GQDs）, we studied its effects on the embryonic development of zebrafish. Methods In vivo, biodistribution and the developmental toxicity of GQDs were investigated in embryonic zebrafish at exposure concentrations ranging from 12.5-200μg/mL for 4-96 h post-fertilization （hpf）. The mortality, hatch rate, malformation, heart rate, GQDs uptake, spontaneous movement, and larval behavior were examined. Results The fluorescence of GQDs was mainly localized in the intestines and heart. As the exposure concentration increased, the hatch and heart rate decreased, accompanied by an increase in mortality. Exposure to a high level of GQDs （200μg/mL） resulted in various embryonic malformations including pericardial edema, vitelline cyst, bent spine, and bent tail. The spontaneous movement significantly decreased after exposure to GQDs at concentrations of 50, 100, and 200μg/mL. The larval behavior testing （visible light test） showed that the total swimming distance and speed decreased dose-dependently. Embryos exposed to 12.5 μg/mL showed hyperactivity while exposure to higher concentrations （25, 50, 100, and 200μg/mL） caused remarkable hypoactivity in the light-dark test. Conclusion Low concentrations of GODs were relatively non-toxic. However, GQDs disrupt the progression of embryonic development at concentrations exceeding 50 μg/mL.

Study of the Toxicity of 1-Bromo-3-Chloro-5,5-Dimethylhydantoin to Zebrafish

Objective 1-Bromo-3-chloro-5,5-dimethylhydantoin （BCDMH） is a solid oxidizing biocide for water disinfection.The objective of this study was to investigate the toxic effect of BCDMH on zebrafish.Methods The developmental toxicity of BCDMH on zebrafish embryos and the dose-effect relationship was determined.The effect of BCDMH exposure on histopathology and tissue antioxidant activity of adult zebrafish were observed over time.Results Exposure to 4 mg/L BCDMH post-fertilization was sufficient to induce a number of developmental malformations,such as edema,axial malformations,and reductions in heart rate and hatching rate.The no observable effects concentration of BCDMH on zebrafish embryo was 0.5 mg/L.After 96 h exposure,the 50% lethal concentration （95% confidence interval （CI）） of BCDMH on zebrafish embryo was 8.10 mg/L （6.15-11.16 mg/L）.The 50% inhibitory concentration （95% CI） of BCDMH on hatching rate was 7.37 mg/L （6.33-8.35 mg/L）.Histopathology showed two types of responses induced by BCDMH,defensive and compensatory.The extreme responses were marked hyperplasia of the gill epithelium with lamellar fusion and epidermal peeling.The histopathologic changes in the gills after 10 days exposure were accompanied by significantly higher catalase activity and lipid peroxidation.Conclusion These results have important implications for studies on the toxicity and use of BCDMH and its analogs.

Preliminary Validation of Tumor Cell Attachment Inhibition Assay for Developmental Toxicants With Mouse S180 Cells

This study was designed to explore the possibility of using ascitic mouse sarcoma cell line (S180) to validate the mouse tumor cell attachment assay for developmental toxicants, and to test the inhibitory effects of various developmental toxicants. The results showed that 2 of 3 developmental toxicants under consideration, sodium pentobarbital and ethanol, significantly inhibited S180cells attachment to Concanavalin A-coaed surfaces. Inhibition was dependent on concentration, and the IC50 (the concentration tha reduced attachment by 50% ), of these 2 chemicals was 1.2×10-3mol/L and 1 .0 mol/L, respectively. Anoher developmental toxiant, hydmiortisone, did not show inhibitory activity. Two non-developmental toxicants, sodium chloride and glycine were also tested and these did not decrease attachment rates. The main results reported here were generally sindlar to those obtained with ascitic mouse ovdrian tumor cells as a model. Therefore, this study added further evidence to the conclusion that cell specificity does not lindt attachment inhibition to Con A-coated surfaces, so S180 cell may serve as an altemative cell model, especially when other cell lines are unavailable. Furthermore, after optimal validation, it can be suggested that an S180 cell attachment assay may be a candidate for a series of assays to detect developmental toxicants.

Toxic effect of acrylamide on the development of hippocampal neurons of weaning rats

Although numerous studies have examined the neurotoxicity of acrylamide in adult animals,the effects on neuronal development in the embryonic and lactational periods are largely unknown.Thus,we examined the toxicity of acrylamide on neuronal development in the hippocampus of fetal rats during pregnancy.Sprague-Dawley rats were mated with male rats at a 1：1 ratio.Rats were administered 0,5,10 or 20 mg/kg acrylamide intragastrically from embryonic days 6–21.The gait scores were examined in pregnant rats in each group to analyze maternal toxicity.Eight weaning rats from each group were also euthanized on postnatal day 21 for follow-up studies.Nissl staining was used to observe histological change in the hippocampus.Immunohistochemistry was conducted to observe the condition of neurites,including dendrites and axons.Western blot assay was used to measure the expression levels of the specific nerve axon membrane protein,growth associated protein 43,and the presynaptic vesicle membrane specific protein,synaptophysin.The gait scores of gravid rats significantly increased,suggesting that acrylamide induced maternal motor dysfunction.The number of neurons,as well as expression of growth associated protein 43 and synaptophysin,was reduced with increasing acrylamide dose in postnatal day 21 weaning rats.These data suggest that acrylamide exerts dose-dependent toxic effects on the growth and development of hippocampal neurons of weaning rats.

Investigation of the immune effects of Scutellaria baicalensis on blood leukocytes and selected organs of the chicken＇s lymphatic system

Background： The health of chickens and the welfare of poultry industry are central to the efforts of addressing global food security. Therefore, it is essential to study chicken immunology to maintain and improve its health and to find novel and sustainable solutions. This paper presents a study on investigation of the effect of Scutellaria baicalensis root（SBR） on the immune response of broiler chicken, especially on lymphocytes and heterophils reactivity, regarding their contribution to the development of immunity of the chickens.Methods： The 121-day-old Hubbard Hi-Y male broiler hybrids were randomly assigned to four treatment groups,three SBR supplemented groups（0.5, 1.0, and 1.5% of SBR） and one control group. Each treatment was replicated five times with six birds per replicate pen in a battery brooder. Blood was collected after 3-（rd） and 6-（th）wk of the experiment, and hemoglobin and hematocrit values were determined, as well as total leukocyte count and differential count were performed. Nitroblue tetrazolium test and phagocytosis assay as nonspecific immune parameters and humoral immune responses to the antigenic challenge by sheep red blood cells were performed.Moreover, the ability of peripheral blood lymphocytes to form radial segmentation（RS） of their nuclei was analyzed.Body weight and relative weight of spleen, liver, and bursa of Fabricius were recorded.Results： Results showed that mean heterophile/lymphocyte ratio increased in the SBR groups compared to the control group and the blood of the chickens showed lymphocytic depletion. The results also demonstrated that the relative weight of bursa of Fabricius and spleen in groups fed with SBR significantly decreased compared to the control group. This study also showed that the addition of SBR significantly inhibited the formation of RS of nuclei compared to some cytotoxic substances.Conclusion： We found that SBR supplementation should be carefully evaluated when given to poultry. The excess intake of SBR supplementation may cause immunologic inhibition and may negatively affect the development of immune organs. SBR has inhibited the formation of radial segmentation nuclei showing antimetastatic properties and also the phagocytosis of chicken heterophils.

Perfluorinated iodine alkanes promote the differentiation of mouse embryonic stem cells by regulating estrogen receptor signaling

Investigating the development toxicity of perfuorinated iodine alkanes(PFIs)is critical,given their estrogenic effects through binding with estrogen receptors(ERs).In the present study,two PFIs,including dodecafuoro-1,6-diiodohexane(PFHx DI)and tridecafuorohexyl iodide(PFHx I),with binding preference to ERαand ERβ,respectively,were selected to evaluate their effects on proliferation and differentiation of the mouse embryonic stem cells(m ESCs).The results revealed that,similar to E_(2),50μmol/L PFHx DI accelerated the cell proliferation of the m ESCs.The PFI stimulation at the exposure concentrations of 2–50μmol/L promoted the differentiation of the m ESCs as characterized by the upregulation of differentiation-related biomarkers(i.e.,Otx2 and Dnmt3β)and downregulation of pluripotency genes(i.e.,Oct4,Nanog,Sox2,Prdm14 and Rex1).Comparatively,PFHx DI exhibited higher induction effect on the differentiation of the m ESCs than did PFHx I.The tests on ER signaling indicated that both PFI compounds induced exposure concentration-dependent expressions of ER signaling-related biomarkers(i.e.,ERα,ERβand Caveolin-1)in the m ESCs,and the downstream ER responsive genes(i.e.,c-fos,c-myc and c-jun)well responded to PFHx I stimulation.The role of ER in PFI-induced effects on the m ESCs was further validated by the antagonistic experiments using an ER inhibitor(ICI).The findings demonstrated that PFIs triggered ER signaling,and perturbed the differentiation program of the m ESCs,causing the potential health risk during early stage of development.

Assessment of Bisphenol A(BPA) neurotoxicity in vitro with mouse embryonic stem cells

The adverse effects of environmental pollution on our well-being have been intensively studied with many in vitro and in vivo systems. In our group, we focus on stem cell toxicology due to the multitude of embryonic stem cell（ESC） properties which can be exerted in toxicity assays. In fact, ESCs can differentiate in culture to mimic embryonic development in vivo, or specifically to virtually any kind of somatic cells. Here, we used the toxicant Bisphenol A（BPA）, a chemical known as a hazard to infants and children, and showed that our stem cell toxicology system was able to efficiently recapitulate most of the toxic effects of BPA previously detected by in vitro system or animal tests. More precisely, we demonstrated that BPA affected the proper specification of germ layers during our in vitro mimicking of the embryonic development, as well as the establishment of neural ectoderm and neural progenitor cells.

Effects of ultrasonication on the DBP formation and toxicity during chlorination of saline wastewater effluents

Chlorine disinfection of saline wastewater effluents rich in bromide and iodide forms relatively toxic brominated and iodinated disinfection byproducts(DBPs). Ultrasonication is a relatively new water treatment technology, and it is less sensitive to suspended solids in wastewaters. In this study, we examined the effects of ultrasonication(in terms of reactor type and combination mode with chlorination) on the DBP formation and toxicity in chlorinated primary and secondary saline wastewater effluents. Compared with the chlorinated wastewater effluent samples without ultrasonication, ultrasonic horn pretreatment of the wastewater effluent samples reduced the total organic halogen(TOX) levels in chlorination by ~30%, but ultrasonic bath pretreatment of the wastewater samples did not significantly change the TOX levels in chlorination, which might be attributed to the higher energy utilization and decomposition extent of organic DBP precursors in the ultrasonic horn reactor. Moreover, the TOX levels in the chlorinated samples with ultrasonic horn pretreatment(USH–chlorination), simultaneous treatment(chlorination + USH) and subsequent treatment(chlorination–USH) were also significantly reduced, with the maximum TOX reductions occurring in the samples with ultrasonic horn pretreatment. A toxicity index was calculated by weighting and summing the levels of total organic chlorine, total organic bromine and total organic iodine in each treated sample. The calculated toxicity index values of the chlorinated wastewater effluent samples followed a descending rank order of “chlorination” > “chlorination + USH” > “chlorination–USH” > “USH–chlorination”, with the lowest toxicity occurring in the samples with ultrasonic horn pretreatment. Then, a developmental toxicity bioassay was conducted for each treated sample. The measured toxicity index values of the chlorinated wastewater samples followed the same descending rank order.

Studying developmental neurotoxic effects of bisphenol A(BPA) using embryonic stem cells

There is little to no toxicity information regarding thousands of chemicals to which people are exposed daily.In fact,of the84,000 chemicals listed in the United States Toxic Substances Control Act Inventory,there is limited information available on their effects on neural development（Betts,2010;US EPA,2015）.

Zebrafish embryo toxicity of 15 chlorinated, brominated, and iodinated disinfection by-products

Disinfection to protect human health occurs at drinking water and wastewater facilities through application of non-selective oxidants including chlorine. Oxidants also transform organic material and form disinfection by-products（DBPs）, many of which are halogenated and cyto-and genotoxic. Only a handful of assays have been used to compare DBP toxicity,and researchers are unsure which DBP（s） drive the increased cancer risk associated with drinking chlorinated water. The most extensive data set employs an in vitro model cell,Chinese hamster ovary cells. Traditionally, most DBP research focuses on the threat to human health, but the effects on aquatic species exposed to DBPs in wastewater effluents remain ill defined. We present the developmental toxicity for 15 DBPs and a chlorinated wastewater to a model aquatic vertebrate, zebrafish. Mono-halogenated DBPs followed the in vivo toxicity rank order： acetamides 〉 acetic acids 〉 acetonitriles ~ nitrosamines, which agrees well with previously published mammalian in vitro data. Di-and tri-halogenated acetonitriles were more toxic than their mono-halogenated analogues, and bromine-and iodine-substituted DBPs tended to be more toxic than chlorinated analogues. No zebrafish development effects were observed after exposure to undiluted or non-concentrated,chlorinated wastewater. We find zebrafish development to be a viable in vivo alternative or confirmatory assay to mammalian in vitro cell assays.