Di-(2-ethylhexyl) Phthalate Concentrations Research Articles

Di(2-ethylhexyl)phthalate exposure impairs insulin receptor and glucose transporter 4 gene expression in L6 myotubes

Di(2-ethyl hexyl)-phthalate (DEHP) is an endocrine disrupter and is the most abundantly used phthalate derivative, which is suspected to be an inevitable environmental exposure contributing to the increasing incidence of type-2 diabetes in humans. Therefore, the present study was designed to address the dose-dependent effects of DEHP on insulin signaling molecules in L6 myotubes. L6 myotubes were exposed to different concentrations (25, 50, and 100 μM) of DEHP for 24 h. At the end of exposure, cells were utilized for assessing various parameters. Insulin receptor and glucose transporter4 (GLUT4) gene expression, insulin receptor protein concentration, glucose uptake and oxidation, and enzymatic and nonenzymatic antioxidants were significantly reduced, but glutamine fructose-6-phosphate amidotransferase, nitric oxide, lipid peroxidation, and reactive oxygen species levels were elevated in a dose-dependent manner in L6 myotubes exposed to DEHP. The present study in turn shows the direct adverse effect of DEHP on the expression of insulin receptor and GLUT4 gene, glucose uptake, and oxidation in L6 myotubes suggesting that DEHP exposure may have a negative influence on insulin signaling.

Can CO2 Fertilization Enhance Phytoremediation of Organic Soil Contamination?

Low efficiency is a key problem confronting the development and application of phytoremediation technology. Based on political pressure to reduce CO2 emissions in China and the fact that CO2 is necessary for plant photosynthesis, the effects of captured CO2 fertilization on phytoremediation of soil di-(2-ethylhexyl) phthalate (DEHP) pollution by C3 plant (mung bean, Vigna radiata L.) and C4 plant (maize, Zea mays L.) were investigated. Results showed that DEHP pollution negatively affected the growth and rhizosphere environments of both plants. After CO2 fertilization, both plants had more biomass (aboveground, belowground, and total dry weight), higher alkaline phosphatase activity, and more microbes with DEHP tolerance in their rhizospheres. Superoxide dismutase activity in leaves of both plants decreased significantly. Microbial community composition in both rhizospheres changed. CO2 fertilization also increased plant uptake of DEHP, particularly in the roots, and decreased residual DEHP concentrations in the rhizospheres. These effects were more evident in the C3 than in the C4 plant. This study indicated that CO2 fertilization can enhance the phytoremediation process of polluted soil through promoting plant growth, improving the rhizosphere environment, and increasing plant uptake of DEHP, particular in a C3 plant. CO2 fertilization could be considered as a measure to enhance phytoremediation.

Indoor Residential Fate Model of Phthalate Plasticizers

Phthalates are ubiquitous pollutants in indoor environments and have emerged as a serious public concern due to their adverse effects on humans. Using emissions of di-2-ethylhexyl phthalate (DEHP) from vinyl flooring as an illustrative example, we developed a three-compartment model to predict the fate and transport of phthalates in a residential home. The model considered eight environmental media (i.e. air, particulate matter with six size fractions, vinyl flooring, carpet, furniture, settled dust, wall and ceiling). Particle movement (deposition and resuspension), dust removal (vacuuming), indoor cooking, and adsorption/absorption on indoor surfaces are also included. The predicted airborne DEHP concentrations at steady state are within the range of 0.1 ?g/m3 to 0.2 ?g/m3. After vinyl flooring (the primary source) is removed, it takes 2 years for indoor airborne DEHP level to reduce to below 0.01 ?g/m3, and the time doubles when carpet presents. Field measurements in a test house are conducted to validate the model, and the model predictions are of the same order of magnitude as measured data. Finally, the exposures to DEHP as well as several other phthalates via inhalation, dermal absorption from gas and deposited particles, and non-dietary ingestion of dust are evaluated. The daily exposure levels shows that several effective removal strategies might be necessary to lower the exposure level.

Urinary phthalates and increased insulin resistance in adolescents.

Di-2-ethylhexylphthalate (DEHP) is an environmental chemical commonly found in processed foods. Phthalate exposures, in particular to DEHP, have been associated with insulin resistance in adults, but have not been studied in adolescents. Using cross-sectional data from 766 fasting 12- to 19-year-olds in the 2003-2008 NHANES, we examined associations of phthalate metabolites with continuous and categorical measures of homeostatic model assessment of insulin resistance (HOMA-IR). Controlling for demographic and behavioral factors, diet, continuous age, BMI category, and urinary creatinine, for each log (roughly threefold) increase in DEHP metabolites, a 0.27 increase (95% confidence interval 0.14-0.40; P < .001) in HOMA-IR was identified. Compared with the first tertile of DEHP metabolite in the study population (14.5% insulin resistant), the third tertile had 21.6% prevalence (95% confidence interval 17.2%-26.0%; P = .02). Associations persisted despite controlling for bisphenol A, another endocrine-disrupting chemical commonly found in foods, and HOMA-IR and insulin resistance were not significantly associated with metabolites of lower molecular weight phthalates commonly found in cosmetics and other personal care products. Urinary DEHP concentrations were associated with increased insulin resistance in this cross-sectional study of adolescents. This study cannot rule out the possibility that insulin-resistant children ingest food with higher phthalate content, or that insulin-resistant children excrete more DEHP.

Preliminary toxicological assessment of phthalate esters from drinking water consumed in Portugal

This paper reports, for the first time, the concentrations of selected phthalates in drinking water consumed in Portugal. The use of bottled water in Portugal has increased in recent years. The main material for bottles is polyethylene terephthalate (PET). Its plasticizer components can contaminate water by leaching, and several scientific studies have evidenced potential health risks of phthalates to humans of all ages. With water being one of the most essential elements to human health and because it is consumed by ingestion, the evaluation of drinking water quality, with respect to phthalate contents, is important. This study tested seven commercial brands of bottled water consumed in Portugal, six PET and one glass (the most consumed) bottled water. Furthermore, tap water from Lisbon and three small neighbor cities was analyzed. Phthalates (di-n-butyl phthalate ester (DnBP), bis(2-ethylhexyl) phthalate ester (DEHP), and di-i-butyl phthalate ester (DIBP)) in water samples were quantified (PET and glass) by means of direct immersion solid-phase microextraction and ionic liquid gas chromatography associated with flame ionization detection or mass spectrometry due to their high boiling points and water solubility. The method utilized in this study showed a linear range for target phthalates between 0.02 and 6.5μgL(-1), good precision and low limits of detection that were between 0.01 and 0.06μgL(-1), and quantitation between 0.04 and 0.19μgL(-1). Only three phthalates were detected in Portuguese drinking waters: dibutyl (DnBP), diisobutyl (DIBP), and di(ethylhexyl) phthalate (DEHP). Concentrations ranged between 0.06 and 6.5μgL(-1) for DnBP, between 0.02 and 0.16μgL(-1) for DEHP, and between 0.1 and 1.89μgL(-1) for DIBP. The concentration of DEHP was found to be up to five times higher in PET than in glass bottled water. Surprisingly, all the three phthalates were detected in glass bottled water with the amount of DnBP being higher (6.5μgL(-1)) than in PET bottled water. These concentrations do not represent direct risk to human health. Regarding potable tap water, only DIBP and DEHP were detected. Two of the cities showed concentration of all three phthalates in their water below the limits of detection of the method. All the samples showed phthalate concentrations below 6μgL(-1), the maximum admissible concentration in water established by the US Environmental Protection Agency. The concentrations measured in Portuguese bottled waters do not represent any risk for adult's health.

Short- and long-term temporal changes in soil concentrations of selected endocrine disrupting compounds (EDCs) following single or multiple applications of sewage sludge to pastures

Temporal changes in soil burdens of selected endocrine disrupting compounds were determined following application to pasture of either sewage sludge or inorganic fertilizer. Soil polycyclic aromatic hydrocarbon and polychlorinated biphenyl concentrations were not altered. Changes in concentrations of diethylhexyl phthalate (DEHP) and PBDEs 47 and 99 differed with season but concentrations remained elevated for more than three weeks after application, when grazing animals are normally excluded from pasture. It is concluded that single applications of sewage sludge can increase soil concentrations of some, but not all classes of EDCs, possibly to concentrations sufficient to exert biological effects when different chemicals act in combination, but patterns of change depend on season and soil temperature. Analysis of soil from pasture subjected to repeated sludge applications, over 13 years, provided preliminary evidence of greater increases in soil burdens of all of the EDC groups measured, including all of the PBDE congeners measured.

Influence of suspended particles on indoor semi-volatile organic compounds emission

Semi-volatile organic compounds (SVOCs) have been attracting more and more attentions to many researchers in these years. Because SVOCs have a strong tendency for adsorption to suspended particles, we take the effect of suspended particles into account to study the transport mechanism of SVOCs in the air. We establish a mathematical model to describe the transport mechanism of SVOCs, and study the transport processes of both gas- and particle-phase di-2-ethylhexyl phthalate (DEHP) in Field and Laboratory Emission Cells (FLECs). The predictions by the proposed model not only fit well with the experimental data of previous studies, but also show that the gas-phase DEHP concentration increases rapidly in the first few seconds and increases slowly during the following 200 days due to different transport mechanisms in the two periods. Meanwhile, when the particle radiuses are of the order of micron and the air changes per hour (ACH) is large enough, the characteristic time for DEHP getting gas/particle equilibrium is much longer than the residence time of a particle in the flow field, and thus there is no significant influence of suspended particles on the total concentration of DEHP in the air. Oppositely, the influence of particles on DEHP emission will be enhanced for a cycling air flow system with a small ACH, where increasing ACH will reduce the concentrations of particle-phase SVOCs. Besides, if the particle radiuses are of the order of nanometer, decreasing the particle radiuses will shorter the characteristic time for DEHP getting gas/particle equilibrium, and finally increase the particle-phase concentration of DEHP.

Concentrations and geographic distribution of selected organic pollutants in Scottish surface soils

Concentrations of selected persistent organic pollutants (POPs) representing three chemical classes (polycyclic aromatic hydrocarbons (PAH), polybrominated diphenyl ethers (PBDE) and polychlorinated biphenyls (PCB) and the organic pollutant diethylhexyl phthalate (DEHP), were determined in surface soil samples (0–5 cm) collected at 20 km grid intersects throughout Scotland over a three-year period. Detectable amounts of all chemical classes and most individual congeners were present in all samples. There were no consistent effects of soil or vegetation type, soil carbon content, pH, altitude or distance from centres of population on concentrations which exhibited extreme variation, even in adjacent samples. It is concluded that soil POPs and DEHP concentrations and associated rates of animal and human exposure were highly variable, influenced by multiple, interacting factors, and not clearly related to local sources but possibly related to wet atmospheric deposition and the organic carbon content of the soil.

Effects of diethylphthalate and di-(2-ethyl)hexylphthalate on the physiology and ultrastructure of cucumber seedlings

Phthalic acid esters (PAEs) are one kind of persistent organic pollutants. This study was conducted to investigate the effects of diethylphthalate (DEP) and di(2-ethyl)hexylphthalate (DEHP) with different concentrations (0, 30, 50, 100, and 200mg L(-1)) on early seedling growth of Cucumis sativus L. Physiological, biochemical, and ultrastructure of seedling leaves were examined for 7-day exposure. The three antioxidant enzymes' activities was stimulated at low-DEP treatments and decreased under higher levels (>200mg L(-1)) compared to the controls. Furthermore, MDA and H2O2 gradually enhanced with the elevation of DEP and DEHP concentration. Significant impact on the chloroplast and mitochondrion was visible, possibly as a consequence of free radical generation. DEP induced bigger and more starch grains in chloroplasts than DEHP. This study concluded that the effects of DEP and DEHP on cucumber seedlings represented the adverse impacts of DEP and DEHP on the ecosystem and agricultural production. The environmental harm caused by DEP was severer than DEHP.

Rapid and sensitive determination of plasticizer diethylhexyl phthalate in drink by diffuse reflectance UV spectroscopy coupled with membrane filtration

A rapid, sensitive and selective method for the determination of illegal additive diethylhexyl phthalate (DEHP) in drink was proposed. The method was based on membrane filtration-enrichment and diffuse reflectance UV (DRUV) spectroscopy. The DEHP solution was passed through the membrane, and then quantified directly on the membrane surface by using an integrating sphere accessory of the UV spectrophotometer. Effects of pH value, sample volume and vacuum degree were investigated in order to optimize the sensitivity. The absorbance of the UV spectra was linearly related to the concentration of DEHP in the ranges of 0.03–0.7 mg/L and 1–5 mg/L, with the squared correlation coefficients (R2) being 0.9911 and 0.9928, respectively. Under the chosen optimal conditions, the limit of detection (LOD) was 0.0079 mg/L. The recoveries were between 99% and 105% when the real drinks were analyzed, and the relative standard deviation (RSD) ranged from 1.0% to 5.0%.

Endocrine disruption by di‐(2‐ethylhexyl)‐phthalate in Chinese rare minnow (Gobiocypris rarus)

Great concern has been raised over the potential impact of environmental contaminants on fish populations that inhabit the Three Gorge Reservoir. The present study investigated the endocrine-disrupting effects of di-(2-ethylhexyl)-phthalate (DEHP) on the Chinese rare minnow (Gobiocypris rarus), an endemic fish distributed in upstream waters in the Yangtze River. Adult rare minnow were exposed to environmentally relevant concentrations of DEHP (0 µg/L, 3.6 µg/L, 12.8 µg/L, 39.4 µg/L, and 117.6 µg/L) for a 21-d period. Then, concentrations of sex hormones in the plasma and relative transcription of various associated genes were measured in the hypothalamic-pituitary-gonadal (HPG) axis and liver of the fish. Exposure to DEHP resulted in greater circulating concentrations of testosterone (T) and lower concentrations of estradiol (E2), which were accompanied by upregulation of Cyp17 mRNA and downregulation of Cyp19a mRNA in the gonads of females. In males, increases of T and E2 levels were consistent with upregulation of Cyp17 and Cyp19a in the gonads. Furthermore, the T/E2 ratio was increased in females but reduced in males. A significant increase in the levels of hepatic vitellogenin (VTG) gene transcription was observed in both females and males. The present study showed that waterborne exposure to DEHP altered plasma sex hormone levels and modulated gene transcription profiles of associated genes in the HPG axis and liver, occurring mostly at higher concentrations (>39.4 µg/L), which suggests that environmental concentration of DEHP (5.4 µg/L) alone might not disturb the endocrine system of the rare minnow in the TGR.

Electrochemical impedance spectroscopy based MEMS sensors for phthalates detection in water and juices

Phthalate esters are ubiquitous environmental and food pollutants well known as endocrine disrupting compounds (EDCs). These developmental and reproductive toxicants pose a grave risk to the human health due to their unlimited use in consumer plastic industry. Detection of phthalates is strictly laboratory based time consuming and expensive process and requires expertise of highly qualified and skilled professionals. We present a real time, non-invasive, label free rapid detection technique to quantify phthalates' presence in deionized water and fruit juices. Electrochemical impedance spectroscopy (EIS) technique applied to a novel planar inter-digital (ID) capacitive sensor plays a vital role to explore the presence of phthalate esters in bulk fluid media. The ID sensor with multiple sensing gold electrodes was fabricated on silicon substrate using micro-electromechanical system (MEMS) device fabrication technology. A thin film of parylene C polymer was coated as a passivation layer to enhance the capacitive sensing capabilities of the sensor and to reduce the magnitude of Faradic current flowing through the sensor. Various concentrations, 0.002ppm through to 2ppm of di (2-ethylhexyl) phthalate (DEHP) in deionized water, were exposed to the sensing system by dip testing method. Impedance spectra obtained was analysed to determine sample conductance which led to consequent evaluation of its dielectric properties. Electro-chemical impedance spectrum analyser algorithm was employed to model the experimentally obtained impedance spectra. Curve fitting technique was applied to deduce constant phase element (CPE) equivalent circuit based on Randle's equivalent circuit model. The sensing system was tested to detect different concentrations of DEHP in orange juice as a real world application. The result analysis indicated that our rapid testing technique is able to detect the presence of DEHP in all test samples distinctively.

Uptake of Di(2-ethylhexyl) Phthalate (DEHP) by the Plant Benincasa hispida and Its Use for Lowering DEHP Content of Intercropped Vegetables

Uptake of di(2-ethylhexyl) phthalate (DEHP) by the plant Benincasa hispida and its use for topical phytoremediation were investigated by cultivation of plants in DEHP-contaminated environments. The results showed that major plant organs of B. hispida , including leaves, stems, and fruits, readily absorbed DEHP from the air. The amount of DEHP that accumulated in leaves, stems, and fruits was mainly dependent upon exposure time, and most DEHP accumulated in their inner tissues. A single plant of B. hispida with a gourd was able to absorb more than 700 mg of DEHP when it was exposed to DEHP-contaminated air for 6 week. B. hispida reduced air DEHP concentration by 65-76% as the air DEHP concentration ranged from 2351 to 3955 μg/m³ (high DEHP level) and 85-92% as the air DEHP concentration ranged from 35.1 to 65.3 μg/m³ (low DEHP level) in greenhouse experiments. When intercropping of B. hispida and Brassica chinensis or Brassica campestris , B. hispida reduced more than 87% of DEHP accumulation in the latter, which indicates that B. hispida has excellent use potential for lowering the DEHP content of intercropped vegetables.

Estimating the contribution of inhalation exposure to di-2-ethylhexyl phthalate (DEHP) for PVC production workers, using personal air sampling and urinary metabolite monitoring

Because of troubling reports of high urinary metabolite levels and adverse reproductive health effects in workers exposed to di(2-ethylhexyl)phthalate (DEHP) in occupational settings, concern about exposure to DEHP in occupational settings is increasing. However, the contributions of different routes of exposure to DEHP are unclear. We used personal air sampling and biomonitoring to determine the contribution of inhalation exposure to the body burden of DEHP in the workplace. Eighty-nine workers (high-exposure group: 66 raw-materials workers; low-exposure group: 23 administrative workers) were recruited from three polyvinyl chloride (PVC) factories. Urinary levels of mono(2-ethylhexyl) phthalate (MEHP), (mono(2-ethyl-5-oxohexyl) phthalate (MEOHP), and mono(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP) were measured in pre-shift and post-shift samples. The geometric means of airborne concentrations of DEHP were 5.3 μg/m3 (low-exposure group) and 32.7 μg/m3 (high-exposure group) (P<0.01). Correlation analysis showed a consistently significant association between airborne DEHP concentration and urinary DEHP metabolite levels in the high-exposure group. Calculating daily DEHP intake based on total urinary metabolite levels showed that the geometric means of total daily urinary metabolite levels of DEHP were 9.2 μg/kg/day (low-exposure group) and 15.5 μg/kg/day (high-exposure group) (P<0.01). A quartile analysis of all workers showed a significant trend toward an association between the individual contribution of inhalation exposure to DEHP and urinary DEHP metabolite levels, for which the mean inhalation contribution was 46.7% in the highest quartile. We conclude that inhalation-absorbed airborne DEHP significantly increased the total body burden of DEHP in these occupationally exposed workers.

Phthalate Concentrations and Dietary Exposure from Food Purchased in New York State

Background: Phthalates have been found in many personal care and industrial products, but have not previously been reported in food purchased in the United States. Phthalates are ubiquitous synthetic compounds and therefore difficult to measure in foods containing trace levels. Phthalates have been associated with endocrine disruption and developmental alteration.Objectives: Our goals were to report concentrations of phthalates in U.S. food for the first time, specifically, nine phthalates in 72 individual food samples purchased in Albany, New York, and to compare these findings with other countries and estimate dietary phthalate intake.Methods: A convenience sample of commonly consumed foods was purchased from New York supermarkets. Methods were developed to analyze these foods using gas chromatography–mass spectroscopy. Dietary intakes of phthalates were estimated as the product of the food consumption rate and concentration of phthalates in that food.Results: The range of detection frequency of individual phthalates varied from 6% for dicyclohexyl phthalate (DCHP) to 74% for di-2-ethylhexyl phthalate (DEHP). DEHP concentrations were the highest of the phthalates measured in all foods except beef [where di-n-octyl phthalate (DnOP) was the highest phthalate found], with pork having the highest estimated mean concentration of any food group (mean 300 ng/g; maximum, 1,158 ng/g). Estimated mean adult intakes ranged from 0.004 μg/kg/day for dimethyl phthalate (DMP) to 0.673 μg/kg/day for DEHP.Conclusions: Phthalates are widely present in U.S. foods. While estimated intakes for individual phthalates in this study were more than an order of magnitude lower than U.S. Environmental Protection Agency reference doses, cumulative exposure to phthalates is of concern and a more representative survey of U.S. foods is indicated.

Characterizing Gas-Particle Interactions of Phthalate Plasticizer Emitted from Vinyl Flooring

Phthalates are widely used as plasticizers, and improved ability to predict emissions of phthalates is of interest because of concern about their health effects. An experimental chamber was used to measure emissions of di-2-ethylhexyl-phthalate (DEHP) from vinyl flooring, with ammonium sulfate particles introduced to examine their influence on the emission rate and to measure the partitioning of DEHP onto airborne particles. When particles were introduced to the chamber at concentrations of 100 to 245 μg/m(3), the total (gas + particle) DEHP concentrations increased by a factor of 3 to 8; under these conditions, emissions were significantly enhanced compared to the condition without particles. The measured DEHP partition coefficient to ammonium sulfate particles with a median diameter of 45 ± 5 nm was 0.032 ± 0.003 m(3)/μg (95% confidence interval). The DEHP-particle sorption equilibration time was demonstrated to be less than 1 min. Both the partition coefficient and equilibration time agree well with predictions from the literature. This study represents the first known measurements of the particle-gas partition coefficient for DEHP. Furthermore, the results demonstrate that the emission rate of DEHP is substantially enhanced in the presence of particles. The particles rapidly sorb DEHP from the gas phase, allowing more to be emitted from the source, and also appear to enhance the convective mass-transfer coefficient itself. Airborne particles can influence SVOC fate and transport in the indoor environment, and these mechanisms must be considered in evaluating exposure and human health.

Occurrence of phthalate esters in sediments in Qiantang River, China and inference with urbanization and river flow regime

Phthalate esters (PAEs), a group of emerging organic contaminants, have become a serious issue arousing much attention for their ubiquitous presence and hazardous impact on the environment. This study provides the first data on distribution of PAEs in the sediments in the Qiantang River, Zhejiang Province, China, and the inference with urbanization and river flow regime. PAEs were detected in all 23 sediment samples analyzed, and the total concentrations of their 16 congeners in sediments ranged from 0.59 to 6.74μg/g dry weight (dw), with the geometric mean value of 2.03μg/g dw. Of the 16 PAE congeners, di-n-butyl phthalate (DnBP), diisobutyl phthalate (DiBP), and di(2-ethylhexyl) phthalate (DEHP) were present in all sediment samples. The PAEs concentrations in urban regions were higher than those in rural regions because of higher discharge of PAEs from plastic materials in urbanized areas. Concentrations of PAEs were positively correlated with sediment organic matter (fOM) and negatively correlated with logistic value of annual average flow volume at sample sites. River flow regime modified by man-made dams significantly affected the distribution of PAEs. Analysis of congener composition of PAEs indicated that the DEHP was predominant congener in the Qiantang River. The normalized concentration of DEHP exceeded recommended environmental risk limit (ERL).

Toxic effect of di(2-ethylhexyl)-phthalate on zebrafish heart development

Objective To determine the toxicity of the di(2-ethylhexyl)-phthalate(DEHP) on early development of zebrafish(danio rerio) embryos and to explore its mechanism during this procedure. Methods The fertilized embryos of zebrafish were divided into 6 groups: 4 groups of them were exposed to different concentrations of DEHP(1, 2, 4, 8 mg/L), while 2 other groups were treated with 79.2 mg/L methanol and 60 mg/L sodium chloride solution respectively as controls.To investigate the interaction between DEHP and early zebrafish embryonic development, the rate of hatching, malformation and lethality of embryos were studied from different DEHP-exposed and control groups.And to gain insight into the mechanisms underlying DEHP function in early zebrafish cardiac development, in situ hybridization for early cardiac molecular markers were performed. Results By carefully collecting and studying the results of DEHP-treated and control embryos, the rates of malformation of embryos and lethality of larvae were increased in a dose-dependent way, coupled with decreased hatching rate of embryos at 72 hpf.When the concentration of DEHP reached 8 mg/L, the hatching rate of embryo at 72 hpf was reduced to 62.22%, the malformation rate of embryo was increased to 27.30%, and the lethality rate of larvae at 120 hpf reached 40.00%.Expression of cardiac specific gene, indicated by using in situ hybridization, showed that heart position and heart tube looping of zebrafish embryos from DEHP-treated groups were strongly affected.Compared with control embryos, the expression of atrial myosin heavy chain(amhc), ventricular myosin heavy chain(vmhc) and cardiac myosin light chains(cmlc2) had been changed in the DEHP-treated groups at 24 hpf and 48 hpf. Conclusions DEHP could impact the development of zebrafish heart, and further lead to the malformation of zebrafish embryo and death of larvae.And the toxic effect of DEHP on zebrafish heart development may occur in the progress of heart tube looping. Key words: Zebrafish; Di(2-ethylhexyl)-phthalate; Heart development; Embryo toxicity

Effect of wetland reclamation and tillage conversion on accumulation and distribution of phthalate esters residues in soils

Accumulation and distribution of phthalate esters (PAEs) in the soils of natural and reclaimed wetlands for different cultivation purposes were investigated. The selected reclaimed soils have only been under cultivation since 1995, thus the behaviors of PAEs may precisely reveal their recent distribution patterns. Dimethyl phthalate (DMP), diethyl phthalate (DEP), di-n-butyl phthalate (DnBP) and di(2-ethylhexyl) phthalate (DEHP) were all detected in surface soil samples. The vertical distribution of PAEs differed between the natural wetlands and cultivated fields. The concentration of PAEs in wetland soil decreased from 0cm to 30cm, and then increased from 30cm to 40cm soil depth. However, the concentrations in 3 types of cultivated fields consistently increased from 0cm to 40cm soil depths. The total concentration of DMP, DEP, DnBP, and DEHP in the wetland surface soil was 109.2ng/g. The total concentrations in rice fields tended to be higher than that of the wetland soil although the difference was not statistically significant, most likely due to the short tillage history. The conversion of bean field to rice field has had a significant effect on accumulation of PAEs. The total concentrations of PAEs in the 1-year rice field were significantly higher than that in the bean field. This was partly due to differences in pesticide and fertilizer usage between rice and bean cultivations; slower biodegradation, abiotic degradation, and evaporation behavior resulting from water covering of rice field probably also contributed to the higher PAEs concentrations in the rice field.

Application of solar disinfection for treatment of contaminated public water supply in a developing country: field observations

A sustainable and low-cost point-of-use household drinking water solar disinfection (SODIS) technology was successfully applied to treat microbiologically contaminated water. Field experiments were conducted to determine the efficiency of SODIS and evaluate the potential benefits and limitations of SODIS under local climatic conditions in Karachi, Pakistan. In order to enhance the efficiency of SODIS, the application of physical interventions were also investigated. Twenty per cent of the total samples met drinking water guidelines under strong sunlight weather conditions, showing that SODIS is effective for complete disinfection under specific conditions. Physical interventions, including black-backed and reflecting rear surfaces in the batch reactors, enhanced SODIS performance. Microbial regrowth was also investigated and found to be more controlled in reactors with reflective and black-backed surfaces. The transfer of plasticizer di(2-ethylhexyl)phthalate (DEHP) released from the bottle material polyethylene terephthalate (PET) under SODIS conditions was also investigated. The maximum DEHP concentration in SODIS-treated water was 0.38 μg/L less than the value of 0.71 μg/L reported in a previous study and well below the WHO drinking-quality guideline value. Thus SODIS-treated water can successfully be used by the people living in squatter settlements of mega-cities, such as Karachi, with some limitations.