Partial solubility parameters of chlorobenzene and chlorophenol compounds at equilibrium distribution in two immiscible phases

Partial solubility parameters of chlorobenzene and chlorophenol compounds at equilibrium distribution in two immiscible phases such as soil-water system were studied. An integral distribution equilibrium equation is derived from the concept of partial solubility parameters and Flory-Hungins equation. Twelve chlorobenzenes and nineteen chlorophenols were employed in this study and their partial solubility parameters including dispersion( (δ_d),and polar van der Waals (δ_p), as well as their electron acceptor and donor solubility parameters (δ_a and δ_b) were calculated.Hildebrand's solubility parameter(δ) of the compounds was also obtained by using boiling point and formula.HPLC was performed by octadecyl-bonded phase as the stationary phase with methanol or acetonitrile as the mobile phase to determine the capacity factor k′ of all compounds for the calculation of δ_a and δ_b.     

Estimating temperature dependence of solubility and octanol-water partition coefficient for organic compounds using RP-HPLC.

Temperature dependence data for physical-chemical properties is increasingly required for modelling the fate of chemicals in the environment. Solubility and octanol-water partition coefficient (Kow) are among the most important parameters. A simple and fast method is presented to determine solubility and Kow of organic chemicals at different temperatures (5 degrees C, 15 degrees C, 25 degrees C, 35 degrees C) utilising a variable temperature RP-HPLC column. Correlations between capacity factors (k') and solubility and Kow were determined for some halogenated and methylated benzenes and showed that this approach could be used to predict acceptable results. New values for solubility and Kow as function of temperature for several compounds are presented.     

Impacts of microbial redox conditions on the phase distribution of pyrene in soil-water systems

Variations in the soil/sediment organic matter (SOM)-hydrophobic organic contaminant (HOC) bindings upon microbially mediated redox conditions were examined. While the extractability of pyrene associated with soil declined after its biodegradation began during aerobic incubation, its variations were almost constant (±3.0-4.4%) during anoxic/anaerobic incubations. The dissolved organic matter released from the soil incubated under highly reduced conditions became more humified and aromatic, had a higher average molecular weight, and was more polydispersed compared to that obtained from oxic incubation, similar to the SOM alterations in the early stage of diagenesis (humification). The concentrations of pyrene in the aqueous phase increased significantly during the soil incubations under highly reduced conditions due to its favorable interaction with the altered DOM. Our results suggest that the microbially mediated redox conditions have significant impacts on SOM and should be considered for the transport, fate, bioavailability, and exposure risk of HOCs in the geo-environments.     

Correlations between meteorological data and water-soluble sulphur compounds in fine aerosols

Water soluble components (NH₄⁺, H⁺, SO₄²⁻, NO₃⁻ and Cl⁻) in fractionated aerosols (< 2 μm), total S and soot in unfractionated aerosols and SO₂ concentrations have been correlated with meteorological data at the Swedish west coast during 82 days spread over the periods January–June 1973 and February–April 1974. The aerosol content of metal ions (Al, K, Ca, Fe, Ni, Zn, Pb, V, Cu and Mn) was also included for part of the period. Different kinds of correlation calculations were performed, and the dependence between SO₄²⁻ and other parameters were investigated. As expected, SO₄²⁻ shows high and significant correlations with NH₄⁺ and H⁺ and other ions. However, the metals Mn, Fe or Cu, often claimed to have catalytical effect on the oxidation of sulphur dioxide to sulphate, did not show any conclusive correlation with the sulphate concentration in the fine aerosols. Among the meteorological parameters, significant positive correlation to SO₄²⁻ was found for absolute humidity and south-west wind trajectory directions, significant negative correlation for rainfall (wash-out), while no correlation was found for weather (i.e. sun-shine → cloudiness). These results indicate that the sulphate sampled at the Swedish west coast is mainly formed by heterogenous reactions, i.e. uncatalysed or catalysed oxidation in liquid droplets or in the liquid film on particle surfaces.     

Partitioning of chloroaromatic compounds between the aqueous phase and dissolved and particulate soil organic matter at chlorophenol contaminated sites

The retention and mobility of hydrophobic organic contaminants (HOCs) in soil is mainly determined by hydrophobic partitioning to dissolved and particulate organic matter (DOM and POM, respectively). The aqueous phase, DOM, and POM fractions were extracted and separated from soils at three sites contaminated with technical chlorophenol formulations. Concentrations of chlorophenols (CP), polychlorinated phenoxyphenols (PCPP), polychlorinated diphenyl ethers (PCDE) and polychlorinated dibenzo-p-dioxins and furans (PCDD/F) were determined. The partitioning to POM, in relation to DOM, increased in all three soils with increasing hydrophobicity in the order CP < PCPP ~ PCDE ~ PCDF < PCDD. Differences in partitioning to DOM (logK(DOC)) and POM (logK(POC)) could not be explained by differences in gross organic C chemistry. Black carbon did not contribute significantly to the sorption of PCDDs, whereas >70% wood fibre in one soil resulted in a decrease of logK(POC) of 0.5 units for CPs and PCDDs. We conclude that logK(OC) for both DOM and POM need to be explicitly determined when the retention and mobility of HOCs is described and modelled in soils.     

北京某染料厂污染地块土壤和地下水6种氯苯类化合物的分布特征及迁移转化分析

针对染料化工企业用地存在多种氯苯类化合物污染的问题,以北京某染料厂污染地块为研究对象,采集并测定土壤样品260个、地下水样品6个,研究了地块包气带和饱和带中6种氯苯类化合物的分布特征,分析了6种物质的来源与迁移过程。结果表明,6种氯苯类化合物主要分布在生产区及污水处理区等重污染区的包气带中,低氯苯类化合物遍布地下水中。推断四氯苯、五氯苯和六氯苯主要由生产原料(二氯苯和三氯苯)在高温等工艺条件下发生氯化反应转化而成,而氯苯是由深层厌氧环境中的CBs经微生物还原脱氯生成。氯苯自深层厌氧区迁移扩散,部分向上扩散进入包气带再挥发至空气中;其它5种污染物在重污染区进入包气带,主要受淋溶以及重力作用向下迁移,汇集于包气带的黏粉~粉黏层,其中的二氯苯和三氯苯穿透包气带进入地下水并扩散至整个厂区。本研究结果可为染料化工污染地块的调查及修复工程提供参考。     

Relative efficacy of intrinsic and extant parameters for modeling biodegradation of synthetic organic compounds in activated sludge: dynamic systems.

The utility of intrinsic and extant kinetic parameters for simulating the dynamic behavior of a biotreatment system coupled with a distributed, unstructured, balanced microbial growth model were evaluated against the observed response of test reactors to transient loads of synthetic organic compounds (SOCs). Biomass from a completely mixed activated-sludge (CMAS) system was tested in fed-batch reactors, while a sequencing batch reactor (SBR) was tested by measuring SOC concentrations during the fill and react period. Both the CMAS system and the SBR were acclimated to a feed containing biogenic substrates and several SOCs, and the transient loading tests were conducted with biogenic substrates along with one or more SOCs. Extant parameters more closely reflect the steady-state degradative capacity of activated-sludge biomass than intrinsic parameters and, hence, were expected to be better predictors of system performance. However, neither extant nor intrinsic parameters accurately predicted system response and neither parameter set was consistently superior to the other. Factors that may have contributed to the inability of the model to predict system response were identified and discussed. These factors included the role of abiotic processes in SOC removal, disparity in the bases used to evaluate parameter estimates (substrate mineralization) and reactor performance (substrate disappearance), inhibitory substrate interactions under the severe loading conditions of the SBR, changes in the physiological state of the biomass during the transient loading tests, and the presumed correlation between the competent biomass concentration and the influent SOC concentration.     

Correlations between physicochemical properties of PAHs and their distribution in soil, moss and reindeer dung at Ny-Ålesund of the Arctic

Concentrations of 16 polycyclic aromatic hydrocarbons (PAHs) in soil, moss and reindeer dung collected at Ny-Ålesund of the Arctic were measured to investigate their accumulation trends and distribution in the three compartments. Compared with the other regions, the proportions of 2 + 3 ring PAHs to the total PAHs were higher, whereas the proportions of 5 + 6 ring PAHs were lower in the three compartments at Ny-Ålesund. Significant log/log-linear relationship was observed between the sub-cooled liquid vapor pressure and the soil/moss quotient (Q_SM). The relation was similar to the relationship between the gas/particle partition coefficient (K_P) and of PAHs, implying Q_SM would be a “mirror image” of K_P. Excellent log/log-linear relationships were observed between Q_SM and K_OA as well as between the moss/dung quotient (Q_MD) and K_OW. The results presented here indicate the physicochemical properties are suitable for characterizing the distribution of PAHs in soil, moss and reindeer dung.     

Concentration and distribution of dioxins and related compounds in human tissues

Polychlorinated dibenzo-p-dioxin, polychlorinated dibenzofuran and dioxin-like polychlorinated biphenyl concentrations in human blood, lung, liver, bile, pancreas, spleen, kidney and mesentery fat were determined to assess the concentrations and distribution of these chemicals in human tissues from 20 donors. The mean TEQ concentrations in blood, lung, liver, bile, spleen, pancreas, kidney and mesentery fat were 119, 178, 228, 50, 113, 163, 138 and 139 pg TEQ/g lipid, respectively. Parallel levels were seen in the blood, spleen, kidney and mesentery fat; in the lungs and pancreas, the levels were somewhat higher. Among the organ tissues samples, the highest concentration was observed in the liver and the lowest in the bile. Mean total-TEQ concentration of the liver was about 4.5 times higher than that of bile. Positive correlations were observed among the concentrations of dioxins in various tissues. However, the concentrations in bile were not correlated with any tissues. It is suggested that the distribution behavior of dioxin-like congeners in human tissues varies among tissues and the kinds of congeners ingested. To evaluate the relationship between the accumulation levels of dioxins and their pathophysiological significance or risk, data must be accumulated from a more extensive group of human samples.     

Screening of organophosphorus compounds and their distribution in various indoor environments

Twelve organophosphorus compounds (OPs), which are used for diverse purposes (e.g. as plasticizers and flame retardants), were analysed in settled house dust from 15 indoor environments and in wipe test samples from computer screens and covers. Seven of the substances analysed dominated Swedish imports of OPs in 1999, six of these are also listed as EU High Production Volume Chemicals. Eight of the substances were found in all samples. Tris(2-butoxyethyl)phosphate was the most abundant in most of the samples, with levels ranging from 0.014 to 5.3 g/kg followed by tris(2-chloroethyl)phosphate, tris(chloropropyl)phosphate and tris(1,3-dichloropropyl)phosphate. In wipe test samples from computers, triphenyl phosphate proved to be the main component of the OPs analysed (4.0 microg/m2). Potential sources of these compounds include, inter alia, floor polish, polyvinylchloride floor coverings, upholstery and plastic products. The distribution patterns of the OPs differed between the sites and generally reflected the building materials and consumer products used in their vicinity.     

电镀污泥钠钙化焙烧过程金属的矿相转化及平衡分布

电镀污泥钠化焙烧过程,由于Al、Cr和Zn的氧化物易与Fe2O3反应生成铁酸盐及其他复杂含铁盐类,导致灰渣水浸过程浸其出率较低。在添加剂CaO作用下,采用FactSage软件模拟污泥焙烧过程金属的矿相转化规律,找到提高Cr、Al和Zn浸出率的方法。研究结果表明,污泥钠化焙烧过程,添加剂CaO易与Fe2O3反应生成2CaO·Fe2O3,阻止Fe2O3与Cr、Al和Zn的氧化物反应生成铁酸盐及其他复杂盐类,一定程度上提高了Cr、Al和Zn的浸出率。但高温下,Al2O3也易与Cr、Al和Zn的氧化物反应生成难溶性铝酸盐,所以浸出率提高幅度不大。可采用稀碱先脱除污泥中的铝,铝的浸出率达95%以上,脱铝渣再拌苏打和CaO焙烧,灰渣水浸脱铬率达95%以上。通过分析可知,污泥在焙烧之前脱铝和在焙烧过程铁转化成2CaO·Fe2O3,阻止了难溶性铝酸盐、铁酸盐以及其他复杂盐类的生成,同时Cr和Al得到分离,且灰渣中铜、镍和锌以游离氧化物和极少部分结合氧化物形式存在,有利于后续金属的浸出和分离。     

Aircraft measurements of the vertical distribution of sulfur dioxide and aerosol scattering coefficient in China

Information on the vertical distribution of air pollution is important for understanding its sources and processes and validating satellite retrievals and chemical transport models. This paper reports the results of the measurements of sulfur dioxide (SO₂) and aerosol scattering coefficient (B_sp) obtained from several aircraft campaigns during summer and autumn 2007 in the north-eastern (NE), north-western (NW), and central-eastern (CE) regions of China. Their vertical profiles over the three regions with contrasting emission characteristics and climates are compared. Very high concentrations/values of SO₂ and B_sp (with a value of up to 51 ppbv and 950 Mm^?1, respectively) were recorded in the lower planetary boundary layer in CE China, indicating high SO₂ emissions in the region. The SO₂ column concentrations determined from the in-situ measurements were compared with Ozone Monitoring Instrument (OMI) SO₂ retrievals. The results show that the OMI data could distinguish the varying levels of SO₂ pollution in the study regions, but appeared to have underestimated the SO₂ column in the highly polluted region of CE China.     

Evaluation of the procedures for the measurement of water solubility and n-octanol/water partition coefficient of chemicals results of a ring test in Japan

A ring test by 19 labolatories in Japan was carried out in 1984 for the evaluation of the experimental manuals for the measurements of water solubility and partition coefficient (n-octanol/water). The experimental data obtained by the procedures in the manuals were collected by Environmental Agency, Japan. In the measurement of water solubility, this manual applies a modified batch method (the glass beads technique), whereas the OECD Test Guidelines suggests the use of the column elution method for chemicals having water solubility lower than 10 mg/L. Anthracene and flouranthene were used as test chemicals for the measurement of water solubility, and γ -hexachlorocyclohexane (γ -HCH) and 1,2,3-trichlorobenzene were used for partition coefficient. Good agreements were observed at a practical basis between the OECD methods and our methods for the results of mesurements of water solubility and partition coefficient. We concluded that the present ring test showed an advantage of the use of the glass beads method which requires only simple apparatus in water solubility measurement, and the HPLC method is very useful to measure partition coefficient because of the simplicity of procedure and the wide range of measurement, especially at higher values of partition coefficient.     

Correlations between cadmium and mineral nutrients in absorption and accumulation in various genotypes of rice under cadmium stress

The absorption and accumulation of Cd2+, Fe3+, Zn2+, Mn2+, Cu2+ and Mg2+ in the roots and leaves of 20 rice cultivars (Oryza sativa L.) with different genotypes under cadmium (Cd) stress were investigated with pot experiments. The results showed that there existed significant differences among the rice cultivars in the contents of six mineral elements in both roots and leaves at both heading and ripening periods. The statistical analysis showed that, for their contents in roots, significant and positive correlations between Cd2+ and Fe3+, Cd2+ and Zn2+, Cd2+ and Mn2+, Cd2+ and Cu2+ existed, but no significant correlation between Cd2+ and Mg2+, at the two periods. In the leaves, Cd also showed significant and positive correlations with Fe3+, Zn2+ and Cu2+ at the both periods, but a significant and negative correlation with Mn2+ and no significant correlation with Mg2+ at heading, a significant and positive correlation with Mg2+ and no significant correlation with Mn2+ at ripening. These results suggested that there were cooperative absorption between Cd2+ and Fe3+, Mn2+, Cu2+, Mn2+ in rice plants. Genotypic differences in Cd uptake and translocation among the rice cultivars suggested that paddy field of some rice cultivars may be irrigated with partially treated sewage water.     

Correlations between toxic Pb effects and production of Pb-induced thiol peptides in the microalga Stichococcus bacillaris

Comparing Pb toxicity to the green alga Stichococcus bacillaris and production of Pb-induced thiol peptides in 24-h exposed cells made it possible to show the level of these peptides to reflect Pb availability to algal cells. LC-ESI/MS analysis of these peptides confirmed that they are phytochelatins PC2-PC4 and their des-Gly derivatives. Studies were carried out at environmentally relevant pH values (5-8.5) and various concentrations of hardness cations (Ca, Mg) and orthophosphate: (0-0.1 mM), chloride (0-100 mM), citrate (0-1 mM), and humic acids (0-10 mg/l). It has been stated, on the basis of the level of Pb-induced thiol peptides, that Pb availability to algae changed significantly within the range of the pH values studied, and was limited in the presence of calcium and of some complexing ligands like orthophosphate, chloride and citrate; it did not decrease in the presence of magnesium or humic acid.     

Relationship of extinction coefficient, air pollution, and meteorological parameters in an urban area during 2007 to 2009

Light extinction, which is the extent of attenuation of light signal for every distance traveled by light in the absence of special weather conditions (e.g., fog and rain), can be expressed as the sum of scattering and absorption effects of aerosols. In this paper, diurnal and seasonal variations of the extinction coefficient are investigated for the urban areas of Tehran from 2007 to 2009. Cases of visibility impairment that were concurrent with reports of fog, mist, precipitation, or relative humidity above 90 % are filtered. The mean value and standard deviation of daily extinction are 0.49 and 0.39 km^?1, respectively. The average is much higher than that in many other large cities in the world, indicating the rather poor air quality over Tehran. The extinction coefficient shows obvious diurnal variations in each season, with a peak in the morning that is more pronounced in the wintertime. Also, there is a very slight increasing trend in the annual variations of atmospheric extinction coefficient, which suggests that air quality has regressed since 2007. The horizontal extinction coefficient decreased from January to July in each year and then increased between July and December, with the maximum value in the winter. Diurnal variation of extinction is often associated with small values for low relative humidity (RH), but increases significantly at higher RH. Annual correlation analysis shows that there is a positive correlation between the extinction coefficient and RH, CO, PM₁₀, SO₂, and NO₂ concentration, while negative correlation exists between the extinction and T, WS, and O₃, implying their unfavorable impact on extinction variation. The extinction budget was derived from multiple regression equations using the regression coefficients. On average, 44 % of the extinction is from suspended particles, 3 % is from air molecules, about 5 % is from NO₂ absorption, 0.35 % is from RH, and approximately 48 % is unaccounted for, which may represent errors in the data as well as contribution of other atmospheric constituents omitted from the analysis. Stronger regression equation is achieved in the summer, meaning that the extinction is more predictable in this season using pollutant concentrations.     

Correlations between water quality and frequencies of allozyme genotypes in spotfin shiner (Notropis spilopteris) populations

Genotype frequencies of glucose-6-phosphate isomerase (GPI) allozymes differed significantly among populations of the spotfin shiner Notropis spilopterus from sites with varying water quality. Frequencies of shiners with a GPI-2 BB genotype decreased significantly at sites with reduced water quality. Alternatively, the total frequencies of shiners with a genotype of GPI-2 AA and AB increased at sites with reduced water quality. Individuals with certain allozyme genotypes may be more sensitive to the toxic effects of polluted waters than those with other genotypes. The selection of individuals with sensitive genotypes may reduce genetic diversity in populations and thus increase the susceptibility of these populations to additional novel stresses. Because allele and genotype frequencies of GPI-2 were correlated with water quality, electrophoretic determination of genetic structure in fishes may be a useful tool for monitoring the health of aquatic populations.     

The evaluation of the equilibrium partitioning method using sensitivity distributions of species in water and soil

The equilibrium partitioning method (EqP-method) can be used to calculate soil quality standards (expressed in mg/kg) from aquatic quality standards (expressed in microg/l) using a partitioning coefficient. The validity of this application of the EqP-method was studied comparing aquatic with terrestrial toxicity data. The data set collected for deriving environmental quality standards in the Netherlands, was used for this study. For 10 organic substances (chlorpyrifos, atrazine, carbofuran, pentachlorophenol, chlordane, aldrin, trichlorobenzene, heptachlor, trichlorophenol and trichloroethene) and for 8 metals, sufficient data were available. The aquatic toxicity data were multiplied by the partitioning coefficient in order to obtain aquatic data expressed in mg/kg. For some compounds the terrestrial toxicity data were significantly higher than the aquatic data but for other compounds it was the other way around. These differences indicate that the EqP-method can give significant over-or underestimations, due to inaccurate partitioning coefficients or differences in species sensitivities. These over- or underestimations can have an impact on the setting of environmental quality standards which are based on the hazardous concentration 5% (HC5) values. The uncertainty in the calculation of HC5 values attributed to the use of the EqP-method, was quantified. The HC5 values derived using the EqP-method were in 5% of the cases more than 20 times higher than the corresponding HC5 values that were derived directly from soil toxicity tests. Despite of this uncertainty the use of the EqP-method can still be advocated for setting soil quality guidelines when only a very limited number of terrestrial toxicity data are available.     

Serum PCDD/F concentration distribution in residents living in the vicinity of an incinerator and its association with predicted ambient dioxin exposure

The aim of this study was to evaluate the serum polychlorinated dibenzo-p-dioxin (PCDD) and dibenzofuran (PCDF) concentration distribution in residents living in the vicinity of an incinerator and its association with annual ambient dioxin exposure predicted by an atmospheric dispersion model. A municipal waste incinerator in Northern Taiwan was chosen for this study. This incinerator had been in operation for 6 years at the time of this study. Using the incinerator site as the center, based on the simulated ambient annual average PCDD/F concentrations. Ninety-five volunteers, all live within a radius of 5 km from the incinerator for at least 5 years, who had no occupational exposure potential, were selected based on the population distribution in each district. The average serum PCDD/F concentration for these subjects living within four zones was about 14 pg I-TEQ/g lipid. The serum distribution levels of people of the four study zones, however, were not consistent with the predicted ambient levels. Results also suggest that ambient exposure might not be the most important contributor to serum concentrations when compared to other exposure sources, such as dietary intake.     

Factors affecting the distribution of hydrocarbon contaminants and hydrogeochemical parameters in a shallow sand aquifer

The distributions of hydrocarbon contaminants and hydrogeochemical parameters were investigated in a shallow sand aquifer highly contaminated with petroleum hydrocarbons leaked from solvent storage tanks. For these purposes, a variety of field investigations and studies were performed, which included installation of over 100 groundwater monitoring wells and piezometers at various depths, soil logging and analyses during well and piezometer installation, chemical analysis of groundwater, pump tests, and slug tests. Continuous water level monitoring at three selected wells using automatic data-logger and manual measuring at other wells were also conducted. Based on analyses of the various investigations and tests, a number of factors were identified to explain the distribution of the hydrocarbon contaminants and hydrogeochemical parameters. These factors include indigenous biodegradation, hydrostratigraphy, preliminary pump-and-treat remedy, recharge by rainfall, and subsequent water level fluctuation. The permeable sandy layer, in which the mean water table elevation is maintained, provided a dominant pathway for contaminant transport. The preliminary pump-and-treat action accelerated the movement of the hydrocarbon contaminants and affected the redox evolution pattern. Seasonal recharge by rain, together with indigenous biodegradation, played an important role in the natural attenuation of the petroleum hydrocarbons via mixing/dilution and biodegradation. The water level fluctuations redistributed the hydrocarbon contaminants by partitioning them into the soil and groundwater. The identified factors are not independent but closely inter-correlated.