Variation in the response of the invasive species Potamopyrgus antipodarum (Smith) to natural (cyanobacterial toxin) and anthropogenic (herbicide atrazine) stressors

In the context of increasing freshwater pollution, the impact on life-traits (survival, growth and fecundity) and locomotion of Potamopyrgus antipodarum of a 5-week field-concentration exposure to the cyanobacterial toxin microcystin-LR and the triazine herbicide, atrazine was studied. Whatever the age of exposed snails (juveniles, subadults, adults), microcystin-LR induced a decrease in survival, growth and fecundity but had no effect on locomotion. Atrazine induced a decrease in locomotory activity but had no significant effect on the life-traits. These results are discussed in terms of consequences to field populations.     

Simultaneous conversion of CHClF(2) and CH(3)Br to CH(2)CF(2)

Gas phase reaction of CHClF(2) with CH(3)Br in an alumina tube reactor at 773-1123 K as a function of various input ratios of CH(3)Br to CHClF(2) is presented. The major products detected include C(2)F(4), CH(2)CF(2), and CH(4). Minor products include CH(3)Cl, CHF(3), C(2)H(4), C(2)H(2), CH(2)CF-CF(3), and C(2)H(3)F. The reaction produces a high yield of CH(2)CF(2) (53% based on CHClF(2) feed) at 1123 K and an input molar ratio of CH(3)Br to CHClF(2) of 1.8, suggesting that the reaction potentially can be developed as a process to convert two ozone depleting substances (CHClF(2) and CH(3)Br) to a highly valuable chemical, CH(2)CF(2). The reaction of CHClF(2) with CH(3)Cl and CH(3)I was also investigated under similar reaction conditions, to assist in understanding the reaction chemistry involved in the reaction of CHClF(2) with CH(3)Br.     

Acceleration of the Fe(III)EDTA(-) reduction rate in BioDeNO(x) reactors by dosing electron mediating compounds

BioDeNO(x), a novel technique to remove NO(x) from industrial flue gases, is based on absorption of gaseous nitric oxide into an aqueous Fe(II)EDTA(2-) solution, followed by the biological reduction of Fe(II)EDTA(2-) complexed NO to N(2). Besides NO reduction, high rate biological Fe(III)EDTA(-) reduction is a crucial factor for a succesful application of the BioDeNO(x) technology, as it determines the Fe(II)EDTA(2-) concentration in the scrubber liquor and thus the efficiency of NO removal from the gas phase. This paper investigates the mechanism and kinetics of biological Fe(III)EDTA(-) reduction by unadapted anaerobic methanogenic sludge and BioDeNO(x) reactor mixed liquor. The influence of different electron donors, electron mediating compounds and CaSO(3) on the Fe(III)EDTA(-) reduction rate was determined in batch experiments (21mM Fe(III)EDTA(-), 55 degrees C, pH 7.2+/-0.2). The Fe(III)EDTA(-) reduction rate depended on the type of electron donor, the highest rate (13.9mMh(-1)) was observed with glucose, followed by ethanol, acetate and hydrogen. Fe(III)EDTA(-) reduction occurred at a relatively slow (4.1mMh(-1)) rate with methanol as the electron donor. Small amounts (0.5mM) of sulfide, cysteine or elemental sulfur accelerated the Fe(III)EDTA(-) reduction. The amount of iron reduced significantly exceeded the amount that can be formed by the chemical reaction of sulfide with Fe(III)EDTA(-), suggesting that the Fe(III)EDTA(-) reduction was accelerated via an auto-catalytic process with an unidentified electron mediating compound, presumably polysulfides, formed out of the sulfur additives. Using ethanol as electron donor, the specific Fe(III)EDTA(-) reduction rate was linearly related to the amount of sulfide supplied. CaSO(3) (0.5-100mM) inhibited Fe(III)EDTA(-) reduction, probably because SO(3)(2-) scavenged the electron mediating compound.     

Terbuthylazine Contamination of the Aquifer North of Vicenza (North-East Italy) (5 pp)

- DOI: http://dx.doi/10.1065/espr2006.01.016 Background and Goal Agricultural practices can affect the quality of aquifers given that they are often located in cropped areas, so significant amounts of pesticides can be found in the water. In particular, triazine herbicides are always carefully checked by the official monitoring systems. The goal of this study was to find the mean concentration of terbuthylazine in an Italian aquifer and to set up a mass balance of this compound. Methods Terbuthylazine concentrations in the aquifer were measured in various check-wells during 1998–2004, and the value of censored data were estimated using a Gompertz inverse in order to evaluate the overall mean concentration. The total terbuthylazine load in the recharge area was calculated on the basis of surveys of cropped land and the main weed control techniques applied in the area. Data on aquifer water balance were obtained from previous studies. Results and Discussion The herbicide terbuthylazine applied in the recharge zone can be transported by surface water and enter the aquifer. Detected concentrations were always well below the EU drinking water limit and the fraction that can reach the groundwater under normal cropping practices is small, very likely less than 0.2%. Recommendations and Outlook The use and application rates of pesticides should be strictly regulated in recharge areas. Vegetated buffer strips can mitigate the impact of herbicides on surface water through reducing drift and early-spring runoff. Attention should also be paid to the fate of the main metabolites from soil biochemical processes.     

Chlorobenzenes and hexachlorocyclohexanes (HCHs) in the atmosphere of Bitterfeld and Leipzig (Germany)

Concentrations of tetrachlorobenzenes, pentachlorobenzene, hexachlorobenzene and alpha-, beta-, gamma- and delta-HCH in air and deposition were measured at three different contaminated sites in Greppin, Roitzsch (both near Bitterfeld) and Leipzig during five time intervals of 14 days in the summer months of 1998. The mean values of the chlorobenzene concentrations (gas phase and particle bound portions) over the whole sampling time were 0.11 ng/Nm3 (Leipzig), 0.17 ng/Nm3 (Roitzsch) and 0.37 ng/Nm3 (Greppin), the mean values of the HCH concentrations were 0.22 ng/Nm3 (Leipzig), 0.31 ng/Nm3 (Roitzsch) and 0.69 ng/Nm3 (Greppin). This increase of the concentration values from Leipzig over Roitzsch to Greppin indicates the influences of industrial waste sites in the Bitterfeld region on the atmospheric environment. The significantly higher values of hexachlorobenzene, alpha- and beta-HCH in Greppin are probably caused by emissions from the former chemical plant Bitterfeld-Wolfen and the landfill 'Antonie' near Greppin. Compared with literature data from other industrial impacted areas the measured air concentration and deposition values are relatively low.     

Atmospheric chemistry of HFE-7000 (CF(3)CF (2)CF (2)OCH (3)) and 2,2,3,3,4,4,4-heptafluoro-1-butanol (CF (3)CF (2)CF (2)CH (2)OH): kinetic rate coefficients and temperature dependence of reactions with chlorine atoms

Background, aim, and scope  The adverse environmental impacts of chlorinated hydrocarbons on the Earth’s ozone layer have focused attention on the effort to replace these compounds by nonchlorinated substitutes with environmental acceptability. Hydrofluoroethers (HFEs) and fluorinated alcohols are currently being introduced in many applications for this purpose. Nevertheless, the presence of a great number of C–F bonds drives to atmospheric long-lived compounds with infrared absorption features. Thus, it is necessary to improve our knowledge about lifetimes and global warming potentials (GWP) for these compounds in order to get a complete evaluation of their environmental impact. Tropospheric degradation is expected to be initiated mainly by OH reactions in the gas phase. Nevertheless, Cl atoms reaction may also be important since rate constants are generally larger than those of OH. In the present work, we report the results obtained in the study of the reactions of Cl radicals with HFE-7000 (CF₃CF₂CF₂OCH₃) (1) and its isomer CF₃CF₂CF₂CH₂OH (2). Materials and methods  Kinetic rate coefficients with Cl atoms have been measured using the discharge flow tube–mass spectrometric technique at 1 Torr of total pressure. The reactions of these chlorofluorocarbons (CFCs) substitutes have been studied under pseudo-first-order kinetic conditions in excess of the fluorinated compounds over Cl atoms. The temperature ranges were 266–333 and 298–353 K for reactions of HFE-7000 and CF₃CF₂CF₂CH₂OH, respectively. Results  The measured room temperature rate constants were k(Cl+CF₃CF₂CF₂OCH₃) = (1.24 ± 0.28) × 10⁻¹³ cm³ molecule⁻¹ s⁻¹and k(Cl+CF₃CF₂CF₂CH₂OH) = (8.35 ± 1.63) × 10⁻¹³ cm³ molecule⁻¹ s⁻¹ (errors are 2σ + 10% to cover systematic errors). The Arrhenius expression for reaction 1 was k ₁(266–333 K) = (6.1 ± 3.8) × 10⁻¹³exp[−(445 ± 186)/T] cm³ molecule⁻¹ s⁻¹ and k ₂(298–353 K) = (1.9 ± 0.7) × 10⁻¹²exp[−(244 ± 125)/T] cm³ molecule⁻¹ s⁻¹ (errors are 2σ). The reactions are reported to proceed through the abstraction of an H atom to form HCl and the corresponding halo-alkyl radical. At 298 K and 1 Torr, yields on HCl of 0.95 ± 0.38 and 0.97 ± 0.16 (errors are 2σ) were obtained for CF₃CF₂CF₂OCH₃ and CF₃CF₂CF₂CH₂OH, respectively. Discussion  The obtained kinetic rate constants are related to the previous data in the literature, showing a good agreement taking into account the error limits. Comparing the obtained results at room temperature, k ₁ and k ₂, HFE-7000 is significantly less reactive than its isomer C₃F₇CH₂OH. A similar behavior has been reported for the reactions of other fluorinated alcohols and their isomeric fluorinated ethers with Cl atoms. Literature data, together with the results reported in this work, show that, for both fluorinated ethers and alcohols, the kinetic rate constant may be considered as not dependent on the number of –CF₂– in the perfluorinated chain. This result may be useful since it is possible to obtain the required physicochemical properties for a given application by changing the number of –CF₂– without changes in the atmospheric reactivity. Furthermore, lifetimes estimations for these CFCs substitutes are calculated and discussed. The average estimated Cl lifetimes are 256 and 38 years for HFE-7000 and C₃H₇CH₂OH, respectively. Conclusions  The studied CFCs’ substitutes are relatively short-lived and OH reaction constitutes their main reactive sink. The average contribution of Cl reactions to global lifetime is about 2% in both cases. Nevertheless, under local conditions as in the marine boundary layer, τ _Cl values as low as 2.5 and 0.4 years for HFE-7000 and C₃H₇CH₂OH, respectively, are expected, showing that the contribution of Cl to the atmospheric degradation of these CFCs substitutes under such conditions may constitute a relevant sink. In the case of CF₃CF₂CF₂OCH₃, significant activation energy has been measured, thus the use of kinetic rate coefficient only at room temperature would result in underestimations of lifetimes and GWPs. Recommendations and perspectives  The results obtained in this work may be helpful within the database used in the modeling studies of coastal areas. The knowledge of the atmospheric behavior and the structure–reactivity relationship discussed in this work may also contribute to the development of new environmentally acceptable chemicals. New volatile materials susceptible of emission to the troposphere should be subject to the study of their reactions with OH and Cl in the range of temperature of the troposphere. The knowledge of the temperature dependence of the kinetic rate constants, as it is now reported for the case of reactions 1 and 2, will allow more accurate lifetimes and related magnitudes like GWPs. Nevertheless, a better knowledge of the vertical Cl tropospheric distribution is still required.     

Biomagnification of polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) studied in pike (Esox lucius), perch (Perca fluviatilis) and roach (Rutilus rutilus) from the Baltic Sea

Pike, perch and roach from rural waters of the Baltic Sea were investigated for possible biomagnification of polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs). For this we used data on delta15N, weight and sex of the fish. We were able to separate body size effects from trophic position effects on biomagnification. Both these parameters lead to biomagnification of PCBs and PBDEs. All investigated PCBs (tri- to deca-CBs) biomagnify and the biomagnification potential is positively correlated with hydrophobicity up to log Kow 8.18. Tri- to hepta-BDEs also biomagnify but showed a maximum biomagnification for the penta-BDEs (log Kow 6.46-6.97). The biomagnification of hexa- to hepta-PBDEs was negatively correlated with degree of bromination, likely due to large molecular size or high molecular weight (644-959 Da). Octa-, nona- and deca-BDEs did not biomagnify but were found in two (octa-BDE) and three (nona- and deca-BDEs) of the species, respectively. Increased size of pike is correlated with increased lipid weight based PCB and PBDE concentrations in males but not in females and mean PCB and PBDE concentrations in males are generally higher than in females. For the least hydrophobic PCBs, no sex difference is observed, probably as a consequence of faster clearance of these substances over the gills, making the spawning clearance of PCBs and PBDEs of lesser relative importance.     

Cadmium and lead in tissues of Mallards (Anas platyrhynchos) and Wood Ducks (Aix sponsa) using the Illinois River (USA)

Cadmium and lead concentrations were determined in the tissues of Mallards and Wood Ducks collected from two waterfowl management areas along the Illinois River, USA, during the autumn and late winter of 1997-1998. Lead concentrations in livers of Mallards were lower than previously reported, and, along with those in a small sample of Wood Duck livers, were within background levels (<2.0 microg/g wet weight). Mean concentrations of cadmium in the kidneys of Wood Ducks utilizing the Illinois River were four times greater than in after-hatch-year Mallards, and 14 times greater than in hatch-year Mallards. Concentrations of cadmium in the kidneys of Wood Ducks were comparable with those of specimens dosed with cadmium or inhabiting contaminated areas in previous studies. Wood Ducks utilizing wetlands associated with the Illinois River, and presumably other portions of the lower Great Lakes region, may be chronically exposed to cadmium.     

PCDDs in the water/sediment-seagrass-dugong (Dugong dugon) food chain on the Great Barrier Reef (Australia)

Polychlorinated dibenzo-p-dioxin (PCDD) and dibenzofuran (PCDF) concentrations were measured in sediment and seagrass from five locations in or adjacent to the Great Barrier Reef Marine Park. A full spectrum of Cl5-8DDs were present in all samples and, in particular, elevated levels of Cl8DD were found. PCDFs could not be quantified in any samples. The PCDD concentrations ranged over two orders of magnitude between sites, and there was a good correlation between sediment and seagrass levels. There were large quantities of sediment present on the seagrass (20-62% on a dry wt. basis), and it was concluded that this was a primary source of the PCDDs in the seagrass samples. The PCDD levels in the seagrass samples were compared with the levels in the tissue of three dugongs stranded in the same region. The relative accumulation of the 2,3,7,8-substituted PCDD congeners in the dugongs decreased by over two orders of magnitude with increasing degree of chlorination. This was attributed to the reduced absorption of the higher chlorinated congeners in the digestive tract, a behaviour that has been observed in other mammals such as domestic cows.     

Sulphur-containing metabolites of the fungicides pentachloronitrobenzene (PCNB) and hexachlorobenzene (HCB) I. Syntheses

Syntheses of sulphur-containing metabolites of the fungicides pentachloronitrobenzene and hexachlorobenzene are described.     

Removal of mercury(II) from aqueous solutions using the leaves of the Rambai tree (Baccaurea motleyana)

This study was undertaken to evaluate the biosorption potential of a natural, low-cost biosorbent, Rambai leaves (Baccaurea motleyana), to remove trace amounts of Hg(II) from aqueous solutions. It was found that the amount of Hg(II) biosorption by Rambai leaves increased with initial metal ion concentration, contact time, and solution pH but decreased as the amount of biosorbent increased. The maximum biosorption capacity was 121.95 mg/g for an initial concentration range of 5 to 120 ppb. Overall, kinetic studies showed that the Hg(II) biosorption process followed pseudo-second-order kinetics based on pseudo-first-order and intraparticle diffusion models. Isotherm data revealed that the biosorption process followed both Freundlich and Langmuir isotherms. The value of separation factor, R(L), from the Langmuir equation and rate of biosorption, n, from the Freundlich model also indicated favorable adsorption.     

Prediction of the retentions of polybrominated dibenzo-p-dioxins (PBDDs) by using the retentions of polychlorinated dibenzo-p-dioxins (PCDDs)

The retention equations In k' = A + B/T of 49 polychlorinated dibenzo-p-dioxins (PCDDs) and 4 polybrominated dibenzo-p-dioxins (PBDDs) in gas chromatography (GC) have been investigated to evaluate the properties of regression coefficients A and B. The quantitative relationships between A and B values of PCDDs and those of PBDDs are found. The regression equations derived have correlation coefficients greater than 0.997. The A, B values of any PBDD can be predicted by using the A, B values of the PCDD according to these relationships. Using these predicted A and B values, the retention times of all PBDDs can be predicted at any temperature program. It is very useful to identify the peak position of any PBDD because at present there are only a few standards of PBDDs available.     

椰纤维生物炭对Cd(Ⅱ)、As(Ⅲ)、Cr(Ⅲ)和Cr(Ⅵ)的吸附

为了研究不同裂解温度制备的椰衣生物炭对Cd(Ⅱ)、As(Ⅲ)、Cr(Ⅲ)和Cr(Ⅵ)的吸附性能差异及其机理,并为制备高效吸附生物炭提供依据,采用Langmuir和Freundlich模型拟合分析了300、500和700℃3个裂解温度下制备的椰衣生物炭对Cd(Ⅱ)、As(Ⅲ)、Cr(Ⅲ)和Cr(Ⅵ)的等温吸附曲线,使用元素分析仪、Boehm滴定法、扫描电子显微镜等研究了不同温度制备的生物炭的组成与理化性质。结果表明,Langmuir模型和Freundlich模型都能较好地拟合生物炭对这些重金属的吸附,提高生物炭的制备温度可增加其对Cd(Ⅱ)和Cr(Ⅲ)的最大吸附量,同时降低其对As(Ⅲ)和Cr(Ⅵ)的最大吸附量;制炭温度升高引起的生物炭C含量、灰分含量、p H、CEC的升高和生物炭表面积增大是导致其对Cd(Ⅱ)和Cr(Ⅲ)的最大吸附量增大的主要原因。而随着制炭温度的上升,O、H元素含量下降引起的碱性官能团的增加,和羟基和酚羟基官能团的减少是生物炭对As(Ⅲ)和Cr(Ⅵ)吸附量下降的主要因素。     

Genotoxicity of the organochlorine pesticides 1,1-dichloro-2,2- bis(p-chlorophenyl)ethylene (DDE) and hexachlorobenzene (HCB) in cultured human lymphocytes

The possible genotoxic potential of 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (DDE), which is a metabolite of dichlorobiphenyltrichloroetane (DDT), and hexachlorobenzene (HCB), which are organochlorine pesticides have been evaluated in vitro by using human lymphocytes as test system. Genetic damage was determined by scoring the frequency of micronuclei (MN) in primary lymphocyte cultures obtained from different donors. The results indicated that, under the experimental conditions used, the DDT metabolite DDE was able to induce significant increases in the frequency of micronucleated cells, which indicate a certain clastogenic and/or aneugenic potential. DDE was tested in the range of 10-80 mM, but the only concentration producing a significant genotoxic effect was 80 mM. On the other hand, HCB was unable to induce a significant increase in the MN frequency in the range of concentrations assayed, from 0.005 to 0.1mM. The selected concentrations of DDE and HCB were chosen according to their toxicity in cell blood cultures; higher concentrations reduced significantly cell proliferation and produced a low frequency of binucleated cells. In conclusion, the results indicate that a genotoxic risk is associated with the exposure to DDE at concentrations 80 mM and above.     

Effect of N-hydroxyethyl-ethylenediamine-triacetic acid (HEDTA) on Cr(VI) reduction by Fe(II)

The complexation of Fe(II) with organic ligand results in the decrease of redox potential, and enhances the reduction ability of Fe(II). An important example is the use of Fe(II)-organic complexes to accelerate Cr(VI) reduction. Dissolved O(2) and light can potentially affect Cr(VI) reduction; however, these two factors have not been adequately evaluated. A batch technique was used to investigate the Cr(VI) reduction as influenced by the light and dissolved O(2) using N-hydroxyethyl-ethylenediamine-triacetic acid (HEDTA) and Fe(II) solutions. The oxidation of Fe(II) by dissolved O(2) was rapid in the presence of HEDTA at low pH; nonetheless, the oxidation proceeded slowly when HEDTA was absent. Although Cr(VI) could be reduced by free Fe(II) at low pH, the reaction was considerably slower than that of systems involving HEDTA. The enhancement of Cr(VI) reduction by Fe(II) in the presence of high concentrations of HEDTA was achieved as a result of two processes. First, HEDTA acted as a ligand for expediting electron transfer between Fe(II) and Cr(VI). Secondly, HEDTA served as a reductant for Cr(VI) under illumination.     

Effects of thiobencarb herbicide to an alga (Nannochloris oculata) and the cladoceran (Daphnia magna)

Chronic toxicity studies were conducted with an algae (Nannochloris oculata) and the cladoceran (Daphnia magna) to determine their relative sensitivities to the thiocarbamate herbicide thiobencarb (S-4-chlorobenzyl diethylthiocarbamate). Most of the algal populations were initially affected by exposure to the herbicide. Thiobencarb concentrations higher than 0.5 mg/L significantly reduced algal densities after 24-h exposure. The 24-h static EC50 in D. magna was 3.01 mg/L. The sublethal effects of 0.3, 0.37, 0.5, 0.75, and 1.5 mg/L of thiobencarb concentrations on the survival, reproduction, and growth of D. magna were monitored for 21 days. The parameters used to determined the effect of the herbicide on D. magna were mean total young per female; mean brood size; days to first brood; intrinsic rate of natural increase (r); growth; and survival. Reproduction was significantly reduced at thiobencarb concentrations of 0.30 mg/L and higher while survival was affected after exposure to 0.75 and 1.5 mg/L of the pesticide. The r value decreased with increasing concentrations of thiobencarb. Growth, as measured by body length, was depressed significantly after exposure to all herbicide concentrations tested.     

Abiotic reduction of antimony(V) by green rust (Fe(4)(II)Fe(2)(III)(OH)(12)SO(4).3H(2)O)

Green rust (Fe(4)(II)Fe(2)(III)(OH)(12)SO(4).3H(2)O) is an intermediate phase in the formation of iron (oxyhydr)oxides such as goethite, lepidocrocite, and magnetite. It is widely considered that green rust occurs in many soil and sediment systems. Green rust has been shown to reduce sorbed Se(VI), Cr(VI), and U(VI). In addition, it is also reported that green rust does not reduce As(V) to As(III). In this study, we have investigated for the first time the interaction between Sb(V) and green rust using XAFS and HPLC-ICP-MS. Most of the added Sb(V) was adsorbed on green rust, and Sb(III), a reduced form, was observed in both solid and liquid phases. Thus, it was shown that green rust has high affinity for Sb(V), and that Sb(V) was reduced to more toxic Sb(III) by green rust despite the high stability of the Sb(V) species even under reducing condition as reported in previous studies. Therefore, green rust can be one of the most important reducing agents for Sb(V), which can influence the Sb mobility in suboxic environments where green rust is formed.     

Peroxyacetyl nitrate (PAN) concentrations in the Antarctic troposphere measured during the photochemical experiment at Neumayer (PEAN'99)

Because investigations of PAN at higher southern latitudes are very scarce, we measured surface PAN concentrations for the first time in Antarctica. During the Photochemical Experiment at Neumayer (PEAN'99) campaign mean surface PAN mixing ratios of 13±7 pptv and maximum values of 48 pptv were found. When these PAN mixing ratios were compared to the sum of NO_x and inorganic nitrate they were found to be equal or higher. Low ambient air temperatures and low PAN concentrations caused a slow homogeneous PAN decomposition rate of approximately 5×10⁻² pptv h⁻¹. These slow decay rates were not sufficient to firmly establish the simultaneously observed NO_x concentrations. In addition, low concentration ratios of [HNO₃]/[NO_x] imply that the photochemical production of NO_x within the snow pack can influence surface NO_x mixing ratios in Antarctica. Alternate measurements of PAN mixing ratios at two different heights above the snow surface were performed to derive fluxes between the lower troposphere and the underlying snow pack using calculated friction velocities. Most of the concentration differences were below the precision of the measurements. Therefore, only an upper limit for the PAN flux of ±1×10¹³ molecules m⁻² s⁻¹ without a predominant direction can be estimated. However, PAN fluxes below this limit can still influence both the transfer of nitrogen compounds between atmosphere and ice, and the PAN budget in higher southern latitudes.