Pollution characteristics and risk assessment of organophosphate esters in aquaculture farms and natural water bodies adjacent to the Huanghe River delta

To date,little attention has been paid to the effects of organophosphate esters(OPEs)pollution on aquacultural environment and aquatic product safety.Huanghe(Yellow)River delta area is one of the largest aquaculture centers in China,where ecological security protection is crucial in the national strategy of China.To explore the pollution characteristics,bioaccumulation,and health risks of OPEs in aquaculture farms in the Huanghe River delta and natural water bodies in the adjacent seas,five species of organisms from different farm types nearby the Huanghe River delta,and the corresponding culture water and sediments were sampled in this study.The total concentrations of Σ_(13)OPEs in water,sediments,and organisms were 51.53-272.18 ng/L,52.63-63.17 ng/g dry weight(dw),and 46.82-108.90 ng/g dw,respectively.Among the five types of culture ponds,the water samples from the swimming crab and hairy crab culture ponds exhibited higher OPEs,the concentration of OPEs in the sediments from the few ponds was relatively balanced,and the OPEs in the organism from the holothurian ponds was higher.Tris(1,3-dichloro-2-isopropyl pho sphate)(TDCP)was the main contaminant in water samples and tripropyl phosphate(TPrP)in sediments and organisms.However,trisphenyl phosphate(TPhP)showed the strongest bioaccumulation ability,followed by 2-ethylhexyl diphenyl phosphate(EHDPP)and TPrP.The bioaccumulation capacities of the five species were as follows:prawn>holothurian>hairy crab>swimming crab>carp.These five types of organisms,as main seafood in human consumption,were at low risk of negative impacts of pollution.However,the risk from the mixture of organophosphate flame retardants(OPFRs)still requires more attention due to the increasing consumption and production in the world.

Biochemical indicators and the Peradeniya Organophosphate Poisoning scale in prediction and prognosis of organophosphorus poisoning:An observational prospective study

Objective:To study the value of some biochemical indicators and Peradeniya Organophosphate Poisoning scale in prediction and prognosis of organophosphorus poisoning.Methods:This was a hospital-based prospective,observational study.Various biochemical tests viz.complete blood count,random blood sugar,liver and renal function tests,creatine phosphokinase,and electrolytes were performed.Patients were assessed based on the Peradeniya Organophosphate Poisoning scale.All the patients were followed till the end point like recovery/death.Results:Out of the 100 patients,72%were males and 28%were females.The majority of the patients were farmers and 21 to 30 years of age.Suicidal was the most common manner(92,92%).Based on the Peradeniya Organophosphate Poisoning scale,47%were mild,34%moderate,and 19%severe.Serum creatinine,creatine phosphokinase,serum glutamic-oxaloacetic transaminase,serum glutamic pyruvic transaminase,and alkaline phosphatase levels showed a significant correlation with severity.Conclusions:Some biochemical indicators such as creatine phosphokinase,alkaline phosphatase can be used as prognostic markers of organophosphorus poisoning.The Peradeniya Organophosphate Poisoning scale can be used for assessing severity of the poisoning.

TRPA1 channel mediates organophosphate-induced delayed neuropathy

OBJECTIVE We want to investigate the mechanism of organophosphate-induced delayed neuropathy(OPIDN) and find appropriate therapeutic medicine.OPIDN,often leads to paresthesias,ataxia and paralysis,occurs in the late-stage of acute poisoning or after repeated exposures to organophosphate(OP) insecticides or nerve agents,and may contribute to the Gulf War Syndrome.METHODS FDSS Ca2^(+)-influx assays,single-cell calcium imaging and patch-clamp electrophysiology were the major testing techniques.Transfected HEK293 cells and dorsal root ganglion(DRG) neurons were used to evaluate the effects of compounds.Wild type and trpa1 knockout mice and adult hyline brown hens were used to evaluate the neuropathological damages caused by the OPs.Transmission electron microscopy imaging was used to observe the nerve injuries ultrastructurally.High-throughput screen for TRPA1 inhibitors was accomplished by Ion Works Barracuda(IWB) automated electrophysiology assay.RESULTS TRPA1(Transient receptor potential cation channel,member A1) channel mediates OPIDN.A variety of OPs,exemplified by malathion,activates TRPA1 but not other neuronal TRP channels.Malathion increases the intracellular calcium levels and upregulates the excitability of mouse DRG neurons in vitro.Mice with repeated exposures to malathion also develop local tissue nerve injuries and pain-related behaviors,which resembles the early symptoms of OPIDN.Both the neuropathological changes and the nocifensive behaviors can be attenuated by treatment of TRPA1 antagonist HC030031 or abolished by knockout of Trpa1 gene.In the classic hens OPIDN model,malathion causes nerve injuries and ataxia to a similar level as the positive inducer tri-ortho-cresyl phosphate(TOCP),which also activates TRPA1 channel.Treatment with HC030031 reduces the damages caused by malathion or TOCP.Duloxetine and Ketotifen,two commercially available drugs exhibiting TRPA1 inhibitory activity,show neuroprotective effects against OPIDN and might be used in emergency situations.CONCLUSION TRPA1 is the major mediator of OPIDN and targeting TRPA1 is an effective way for the treatment of OPIDN.

Studies on the Purification and Characterization of Soybean Esterase,and Its Sensitivity to Organophosphate and Carbamate Pesticides

Soybean esterase, a cholinesterase-like enzyme, was purified by differential centrifugation firstly, then, ammonium sulfate precipitation, dialysis, and finally, DEAE-cellulose-32 ion-exchange chromatography after extracting it from soybean seeds with phosphate buffer （0.3 mol L^-1, pH 7.0）. The extract recovery rate of the purified enzyme was 8.18% and purification fold was 91.58. The soybean esterase appeared as two bands on the denaturing SDS-PAGE with molecular weights of 24 and 37.2 kDa, respectively, which proved that it is a dimer protein consisting of two subunits. The result of nondenaturing PAGE revealed that the soybean esterase is a single band with cholinesterase-like activity using α- naphthyl acetate as the substrate and fast blue B salt as coloring agent. The esterase showed very high sensitivity to 18 kinds of organophosphate pesticides and 6 kinds of carbamate pesticides with the lowest detective limits of 0.03125- 0.0625 and 0.03125-0.25 mg kg^-1, respectively, and can meet the demands of MRL specified by the most countries.

CHEMICAL INCORPORATING INSECTICIDES 1.SYNTHESIS OF NEWPYRETHROIDS WITH ORGANOPHOSPHATE AS POTENTIAL INSECTICIDES

Abstract: Several potential insecticides were synthesized by incorporating chrysanthemic acid and O,O-dialkyl phosphorodithioate through a pyrrolongdine-2,5-dione group. Their structures were determined by elementary analysis, NMR, IR and MS.

Studies of n-Octanol/water Partition Coefficients (lgK_(ow)) for Organophosphate Compounds by Density Functional Theory

Optimized calculation of 35 dialkyl phenyl phosphate compounds （OPs） was carded out at the B3LYP/6-31G^＊ level in Gaussian 98 program. Based on the theoretical linear solvation energy relationship （TLSER） model, the obtained parameters were taken as theoretical descriptors to establish the novel QSPR model for predicting n-octanol/water partition coefficients （lgKow） of OPs. The new model achieved in this work contains three variables, i.e., molecular volume （Vm）, dipole moment of the molecules （μ） and enthalpy （H^0）. For this model, R^2 = 0.9167 and SD = 0.31 at large t values. In addition, the variation inflation factors （VIF） of variables are all close to 1.0, suggesting high accuracy of the predicting model. And the results of cross-validation test （q^2 = 0.8993） and method validation also showed the model of this study exhibited optimum stability and better predictive power than that from semi-empirical method. The model achieved can be used to predict IgKow of congeneric compounds.

A highly sensitive bio-barcode immunoassay for multi-residue detection of organophosphate pesticides based on fluorescence antiquenching

Balancing the risks and benefits of organophosphate pesticides(OPs)on human and environmental health relies partly on their accurate measurement.A highly sensitive fluorescence anti-quenching multi-residue bio-barcode immunoassay was developed to detect OPs(triazophos,parathion,and chlorpyrifos)in apples,turnips,cabbages,and rice.Gold nanoparticles were functionalized with monoclonal antibodies against the tested OPs.DNA oligonucleotides were complementarily hybridized with an RNA fluorescent label for signal amplification.The detection signals were generated by DNA-RNA hybridization and ribonuclease H dissociation of the fluorophore.The resulting fluorescence signal enables multiplexed quantification of triazophos,parathion,and chlorpyrifos residues over the concentration range of 0.01-25,0.01-50,and 0.1-50 ng/mL with limits of detection of 0.014,0.011,and 0.126 ng/mL,respectively.The mean recovery ranged between 80.3% and 110.8% with relative standard deviations of 7.3%-17.6%,which correlate well with results obtained by liquid chromatography-tandem mass spectrometry(LC-MS/MS).The proposed bio-barcode immunoassay is stable,reproducible and reliable,and is able to detect low residual levels of multi-residue OPs in agricultural products.

Screening of Total Organophosphate Pesticides in Agricultural Products with a Cellular Biosensor

Organophosphates belong to the most important pesticides used in agricultural practice worldwide. Although their analytical determinations are quite feasible with various conventional methods, there is a lack of efficient screening methods, which will facilitate the rapid, high-throughput detection of organophosphates in different food commodities. This study presents the construction of a rapid and sensitive cellular biosensor test based on the measurement of changes of the cell membrane potential of immobilized cells, according to the working principle of the Bioelectric Recognition Assay (BERA). Two different cell types were used, derived either by animal (neuroblastoma) or plant cells (tobacco protoplasts). The sensor was applied for the detection of a mixture of two organophosphate pesticides, diazinon and chlorpyrifos in two different substrates (tomato, orange). The pesticides in the samples inhibited the activity of cell membrane-bound acetylcholinesterase (AChE), thus causing a measurable membrane depolarization in the presence of achetylcholine (Ach). Based on the observed patterns of response, we demonstrate that the sensor can be used for the qualitative and, in some concentrations, quantitative detection of organophosphates in different substrates with satisfactory reproducibility and sensitivity, with a limit of detection at least equal to the official Limit of Detection (LOQ). The assay is rapid with a total duration of 3 min at a competitive cost. The sensitivity of the biosensor can be further increased either by incorporating more AChE-bearing cells per test reaction unit or by using cells engineered with more potent AChE isoforms. Standardization of cultured cell parameters, such as age of the cells and subculture history prior to cell immobilization, combined with use of planar electrodes, can further increase the reproducibility of the novel test.

Enzyme Biosensor for Detection of Organophosphate Pesticide Residues Base on <i>Screen Printed Carbon Electrode</i>(SPCE)-Bovine Serum Albumin (BSA)

The maximum level of organophosphate pesticide residues in rice is 0.1 mg/kg and 0.5 mg/kg in vegetables. The control of pesticide residues in agricultural products required a method of analysis quickly and accurately. The research developed a biosensor for the detection of organophosphate pesticide residues in agricultural products. The research studied immobilized organophosphate hydrolase (OPH) mass and characterization of biosensor. The solution conductivity measurement in the conductivity cell consists of a 1 × 5 mm2 pair of electrodes screen printed carbon electrode (SPCE). The instrument is a converted local conductometer. From the results of study concluded that the optimum performance of the biosensor was obtained from the 105 μg OPH, at pH 8.5 with a response time of 45 seconds. In that condition the sensitivity of biosensor is 28.04 μS/ppm and 0.18 ppm detection limit and the maximum concentration of pesticide which can be measured is 1 ppm. Biosensors have been applied to measure pesticide residues in some vegetable samples.

CHEMICAL INCORPORATING PESTICIDES 2．SYNTHESIS OF NEW SUCCINIMIDO ORGANOPHOSPHATES AS POTENTIAL PESTICIDES

A series of succinimido-organophosphate analogueswas synthesized with maleic anhydride as starting material viamaleimide and its analogues as intermediates and characterized by IR,1HNMR and elementary analysis.

Organophosphate pesticides and new-onset diabetes mellitus:From molecular mechanisms to a possible therapeutic perspective

Organophosphate is a commonly used pesticide in the agricultural sector.The main action of organophosphate focuses on acetylcholinesterase inhibition,and it therefore contributes to acute cholinergic crisis,intermediate syndrome and delayed neurotoxicity.From sporadic case series to epidemiologic studies,organophosphate has been linked to hyperglycemia and the occurrence of newonset diabetes mellitus.Organophosphate-mediated direct damage to pancreatic beta cells,insulin resistance related to systemic inflammation and excessive hepatic gluconeogenesis and polymorphisms of the enzyme governing organophosphate elimination are all possible contributors to the development of newonset diabetes mellitus.To date,a preventive strategy for organophosphatemediated new-onset diabetes mellitus is still lacking.However,lowering reactive oxygen species levels may be a practical method to reduce the risk of developing hyperglycemia.

High-Performance Liquid Chromatograph (HPLC) Equipped with a Neurophysiological Detector (NPD) as a Tool for Studying Olfactory System Intoxication by the Organophosphate (OP) Pesticide Diazinon and the Influence of OP Pesticides on Reproduction

A neurophysiological detector (NPD) is a hybridization of olfactory system neurons of the fish crucian carp, Carassius carassius L., with a computerized electronic device connected to a high-performance liquid chromatograph (HPLC). This system makes it possible to measure neurophysiological activities in the olfactory system of C. carassius L. after exposure of this fish to alarm pheromones. The construction of the system was presented for the first time at the 3rd International Symposium on Separation in Bio Sciences SBS 2003 in I. Brondz, et al., The Fish Olfactory System Used as an In-Line HPLC Neurophysiologic Detector NPD, 3rd Int. Symposium on Separation in Bio Sciences SBS 2003: A 100 Years of Chromatography, 13-18 May, Moscow, Russia, 2003, Abstract O- 27, p. 95. A complete paper was published in I. Brondz, et al., Neurophysiologic Detector (NPD)—A Selective and Sensitive Tool in High-Performance Liquid Chromatography, Chromatography B: Biomedical Sciences and Applications, Vol. 800, No. 1-2, 2004, pp. 41-47, and the hybridization of living cells with an electronic device has been discussed (I. Brondz, et al., International Scientific-Technical Conference Sensors Electronics and Microsystems Technology (SEMST-1), 1-5 June, (Odessa), Ukraine, 2004, Plenum Lecture, Abstract p. 17;I. Brondz, et al., The European Chemoreception Research Organization ECRO 2004 Congress, 12-15 September, (Dijon), France, 2004, Abstract P-3;and I. Brondz, et al., Biosensors as Electronic Compounds for Detector in the High-Performance Liquid Chromatography (HPLC), Electronic Components and Systems, Vol. 3, No. 103, 2006, pp. 25-27). In the present study, an HPLC equipped with an NPD was used to assess the influence of organophosphate (OP) pesticides on olfactory sensory nerves and the modification of nerve signals from the olfactory organ. The results show that exposure of the olfactory system to OP pesticides can lead to disruption of normal reflexes and to significant suppression of individual sexual activity and, as a result, to the suppression of a population.

Effect of Deliberate Ingestion of Organophosphate Pesticide on Distortion Product Oto-Acoustic Emissions (DPOAE)

Background: Oto-Acoustic Emissions (OAE) are low intensity sounds produced by the cochlea in response to an acoustic stimulus. Deliberate self-poisoning has become an increasingly common response to emotional distress in young adults (NHS, 1998). Organophosphate (OP) compounds are most commonly involved in 76% of pesticide poisoning especially in the developing countries like India. Several pesticides are neurotoxin which could potentially affect hearing and, animal studies showed that OP treatment leads to change in hearing threshold, outer and inner hair cell loss but human studies on the same are very few. Aim: The present study was aimed at exploring the cochlear changes after self-poisoning with OP pesticides by measuring the Distortion Product Oto-Acoustic Emissions (DPOAE). Method: 114 subjects were participated in the study, with an age range of 18-30 years having pure tone audiometric thresholds within the normal limits and no history of middle ear pathology. They were further divided into two groups, I and II which includes self-poisoned and healthy subjects respectively. Results: The “pass” and “fail” criteria of DPOAE measures in group I were 30% and 70% respectively whereas in group II, it was found 91% and 9% respectively. Discussion: There was a significant failure in DPOAE in Group I (subjects who were self-poisoned) compared to group II (healthy subjects). The two important pathologies behind OP toxicity are the generation of Reactive Oxygen Species and the depletion of NADPH which is necessary for normal function. Conclusion: The results of the present study highlight that;the minute cochlear changes caused due to pesticide poisoning can be effectively measured through DPOAE. Further it can suggest in other clinical targets like Ototoxicity, Noise-induced hearing loss, Meniere’s disease etc., which has an effect on cochlear hair cells can be monitored through DPOAE.

Phosphoinositide and phospholipid phosphorylation and hydrolysis pathways<br/>—Organophosphate and organochlorine pesticides effects<br>

Phospholipid and phosphoinositide phosphorylation pathways have been shown to be of crucial importance on producing lipid mediators. The earlier findings reported on lipid molecules playing roles in different metabolic pathways used to assign them the exclusive role of second messenger generators. Several researchers have recently described how direct interaction of phospholipids and phosphoinositides with molecules or organelles, without the need for producing second messenger molecules, is responsible for their mechanism of action. Organophosphate and organochlorine pesticide toxicity mechanisms have been extensively studied in relation to their well known effects on cholinesterase activities and on the alterations of electric activity in the nervous system of different organisms respectively. There is little but consistent evidence that some compounds, including in both groups of pesticides, are also able to interact with phospholipid and phosphoinositide phosphorylation pathways in several organisms and tissues. The present review consists of an actualization of basic research on phospholipid and phosphoinositide phosphorylation and hydrolysis pathways, as well as a description of some reported evidences for the effects of the above mentioned pesticides on them.

Organophosphate Pesticides in Coastal Lagoon of the Gulf of Mexico

The worldwide use of semi-persistent organophosphate pesticides has become increasingly frequent and notorious. Their presence is registered in both continental and coastal waters;the latter ones are known for their subtly balanced environmental richness, difficult to recover once lost. These xenobiotics compounds reach the coastal zone through rivers that have crossed human settlements, as well as through peripheral run-off water used to exterminate agricultural pests. In Mexico, a developing country, the use of pesticides for several decades has not been adequately regulated, which is why various coastal ecosystems are the accumulation areas of these agrochemicals used in the continent. In the Gulf of Mexico, one of the coastal systems of high fishing importance for many years is the lagoon of Alvarado and receives the discharges of two great rivers, Blanco, Limón and Papaloapan, which travel more than 200 km from its source to the sea, crossing large extensions of farmland where there are also livestock activities and the use of these pesticides. For this reason, the objective of this work was to determine the presence of organophosphate pesticides in the Alvarado lagoon at the Gulf of Mexico as a potential aspect of high impact contamination. Five pesticides have been identified in the lagoon sediments, of which the most important and highest concentrations are Dimethoate and Chlorpyrifos, with 75.65 - 79.0 ng/g and 0.17 - 0.23 ng/g respectively, both internationally classified as moderately toxic. These concentrations were comparable to levels in other world regions with intense agricultural activity and vector control like the Mediterranean Sea and the lagoon of Alvarado was evidenced as a hot spot for the accumulation of these organophosphates with the high risk for the benthic organisms and for the human health when consuming these fishery products.

Isolation and molecular characterization of a novel <i>pseudomonas putida</i>strain capable of degrading organophosphate and aromatic compounds

A bacterial strain designated in this study as POXN01 was found to be capable of degrading the synthetic organophosphorus pesticides paraoxon and methyl parathion. The strain was initially isolated through enrichment technique from rice field soil near Harlingen, Texas. Phylogenetic analysis based on 16S rRNA, gyrB and rpoD gene alignments identified the POXN01 isolate as a new strain of Pseudomonas putida, which is closely related to the recently discovered nicotine-degrading strain Pseudomonas putida S16. While being unable to metabolize nicotine, the POXN01 isolate was observed to actively proliferate using monocyclic aromatic hydrocarbons, in particular toluene, as nutrients. Search for the genetic determinants of paraoxon catabolism revealed the presence of organophosphorus-degrading gene, opd, identical to the one from Sphingobium fuliginis (former Flavobacterium sp. ATCC 27551). Assimilation of aromatic compounds likely relies on phc ARKLMNOPQ gene cluster for phenol, benzene and toluene catabolism, and on benRABCDKGEF cluster for benzoate catabolism. The observed versatility of POXN01 strain in degradation of xenobiotics makes it useful for the multi-purpose bioremediation of contaminated sites in both agricultural and industrial environmental settings.

Pollutants, Snails, Oxidative-Stress, Organophosphates, Metals

Aquatic reservoirs remain the ultimate sink of chemical pollutants emanating from anthropogenic activities such as agriculture, mining and industry. Freshwater biota undoubtedly is at risk from the adverse effects of these water pollutants and there is therefore, a need to monitor effects of these chemical pollutants in order to safeguard the health of aquatic biota. We investigated the oxidative stress effects of chlorpyrifos and lead on the freshwater snail Helisoma duryi to assess the potential of using this enzyme system as a biondicator of exposure to environmental pollutants. Groups of snails were exposed to 5 ppb lead acetate and 25 ppb chlorpyrifos for 7 days after which half of the snails were sacrificed and the other half were allowed to recover in clean water and sacrificed after another 7 days. Post mitochondrial fractions were used to measure the activities of the following antioxidant enzymes: superoxide dismutase, catalase, glutathione peroxidase, glutathione S-transferase and diphosphotriphosphodiaphorase. Both pollutants enhanced the activities of all the antioxidant enzymes suggesting a defensive mechanism by the snail to combat the oxidative stress due to the organophosphate chlopryrifos and metal pollutant lead. There was a significant recovery of the antioxidant defense system of the snails allowed to recover in clean water shown by the reduced alteration of the antioxidant enzyme activities of the snails allowed to recover for 7 days. This suggests the need to minimize exposure of aquatic biota to chemical pollutants and remediate the polluted water reservoirs in order to safeguard the health of aquatic life.

Expression and characterization of a codon-optimized butyrylcholinesterase for analysis of organophosphate insecticide residues

Organophosphate insecticide residues on vegetable, fruit, tea and even grains are primary cause of food poisoning. Organophosphate compounds can cause irreversible inhibition of the activity of acetylcholinesterase and butyrylcholinesterase（BChE, EC 3.1.1.8）, which are both candidates for rapid detection of organophosphate pesticides. To develop an easy-tohandle method for detecting organophosphate pesticides using BChE, BChE from human was optimized according to the codon usage bias of Pichia pastoris and successfully expressed in P. pastoris GS115. The codon-optimized cDNA shared 37.3% of the codon identity with the native one. However, the amino acid sequence was identical to that of the native human butyrylcholinesterase gene（h BCh E） as published. The ratio of guanine and cytosine in four kinds of bases（（G＋C） ratio） was simultaneously increased from 40 to 47%. The recombinant hBChE expression reached a total protein concentration of 292 mg m L^–1 with an activity of 14.7 U m L^–1, which was purified 3.2×10^3-fold via nickel affinity chromatography with a yield of 68% and a specific activity of 8.1 U mg^–1. Recombinant hBChE was optimally active at pH 7.4 and 50°C and exhibited high activity at a wide pH range（〉60% activity at pH 4.0 to 8.0）. Moreover, it had a good adaptability to high temperature（〉60% activity at both 50 and 60°C up to 60 min） and good stability at 70°C. The enzyme can be activated by Li^＋, Co^＋, Zn^2＋ and ethylene diamine tetraacetic acid（EDTA）, but inhibited by Mg^2＋, Mn^2＋, Fe^2＋, Ag^＋ and Ca^2＋. Na^＋ had little effect on its activity. The values of h BChE of the Michaelis constant（Km） and maximum reaction velocity（Vm） were 89.4 mmol L^–1 and 1 721 mmol min^–1 mg^–1, respectively. The bim olecular rate constants（K_i） of the hBChE to four pesticides were similar with that of electric eel AChE（EeAChE） and higher than that of horse BChE（HoBChE）. All vlues of the half maximal inhibitory concentration of a substance（IC50） for hBChE were lower than those for HoBChE, but most IC50 for hBChE were lower than those for EeAChE except dichlorvos. The applicability of the hBChE was further verified by successful detection of organophosphate insecticide residues in six kinds of vegetable samples. Thus, hBChE heterologously over-expressed by P. pastoris would provide a sufficient material for development of a rapid detection method of organophosphate on spot and produce the organophosphate detection kit.

Fate of organophosphate esters from the Northwestern Pacific to the Southern Ocean:Occurrence,distribution,and fugacity model simulation

Eleven organophosphate esters(OPEs)in the air and seawater were investigated from the northwestern Pacific Ocean to the Southern Ocean during the 2018 Chinese 34th Antarctic Scientific Expedition.The concentration of total OPEs ranged from 164.82 to 3501.79 pg/m~3in air and from 4.54 to 70.09 ng/L in seawater.Two halogenated OPEs,tri(chloropropyl)phosphate(TCPP)and tri(2-chloroethyl)phosphate(TCEP),were generally more abundant than the non-halogenated OPEs.A levelⅢfugacity model was developed to simulate the transfer and fate of seven OPEs in the air and seawater regions of the central Ross Sea.The model results indicate that OPEs are transferred from the air to the seawater in the central Ross Sea in summer,during which the Ross Sea acts as a final OPE sink.Dry and wet deposition dominated the processes involving OPE transfer to seawater.The OPE degradation process was also found to be more pervasive in the atmosphere than in the seawater region.These findings highlights the importance of long-range transport of OPEs and their air–seawater interface behavior in the Antarctic.

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.