Bioaccumulation of glyphosate and its formulation Roundup Ultra in Lumbriculus variegatus and its effects on biotransformation and antioxidant enzymes

The bioaccumulation potential of glyphosate and the formulation Roundup Ultra, as well as possible effects on biotransformation and antioxidant enzymes in Lumbriculus variegatus were compared by four days exposure to concentrations between 0.05 and 5 mg L⁻¹ pure glyphosate and its formulation. Bioaccumulation was determined using ¹⁴C labeled glyphosate. The bioaccumulation factor (BCF) varied between 1.4 and 5.9 for the different concentrations, and was higher than estimated from log P_ow. Glyphosate and its surfactant POEA caused elevation of biotransformation enzyme soluble glutathione S-transferase at non-toxic concentrations. Membrane bound glutathione S-transferase activity was significantly elevated in Roundup Ultra exposed worms, compared to treatment with equal glyphosate concentrations, but did not significantly differ from the control. Antioxidant enzyme superoxide dismutase was significantly increased by glyphosate but in particular by Roundup Ultra exposure indicating oxidative stress. The results show that the formulation Roundup Ultra is of more ecotoxicological relevance than the glyphosate itself.     

Bioaccumulation of PAHs from creosote-contaminated sediment in a laboratory-exposed freshwater oligochaete, Lumbriculus variegatus

The oligochaete, Lumbriculus variegatus, was used for a bioaccumulation assay in the creosote-contaminated sediment of Lake J?ms?nvesi in a 28-day experiment. The PAH concentrations of the whole body tissue of worms, sediments and water samples were determinated by GC-MS. Chemical analyses showed that benzo(k)fluoranthene, anthracene and fluorene were the main PAH compounds present in the tissue of oligochaetes, just as in the sediment. The biota-sediment accumulation factors (BSAFs) of the individual PAHs varied from 1.2 to 5.7. It is concluded that oligochaetes have a marked ability to accumulate and retain PAHs from creosote-contaminated sediment.     

Bioaccumulation of 14C-17alpha-ethinylestradiol by the aquatic oligochaete Lumbriculus variegatus in spiked artificial sediment

A bioaccumulation study was performed with the endobenthic freshwater oligochaete Lumbriculus variegatus MULLER exposed to the radiolabelled synthetic steroid 17alpha-ethinylestradiol (14C-EE2) in a spiked artificial sediment. Concentration of total radioactivity increased constantly and almost linearly during 35 days of exposure. The accumulation factor normalised to worm lipid content and sediment TOC (AFlipid/OC) was 75 at the end of the uptake period, but a steady state was not reached. Uptake kinetics were calculated fitting the measured AFs to a kinetic rate equation for constant uptake from sediment using iterative non-linear regression analysis. After 10 days of elimination in contaminant-free sediment 50% of the accumulated total radioactivity was excreted by the worms. Extracts from L. variegatus sampled at the end of the uptake phase were analysed by thin layer chromatography (TLC). The results showed that 6% of the total radioactivity incorporated by the worms was 14C-EE2. After treatment of extracts with beta-glucuronidase the amount of 14C-EE2 increased to 84%. These results suggest that L. variegatus has the potency to accumulate high amounts of conjugated EE2. Hence, a transfer of EE2 to benthivores and subsequent secondary poisoning of predators might be possible.     

The effects of particle size, organic matter content, crop residues and dissolved organic matter on the sorption kinetics of atrazine and isoproturon by clay soil

Reliable predictions of the fate and behaviour of pesticides in soils is dependent on the use of accurate ‘equilibrium’ sorption constants and/or rate coefficients. However, the sensitivity of these parameters to changes in the physicochemical characteristics of soil solids and interstitial solutions remains poorly understood. Here, we investigate the effects of soil organic matter content, particle size distribution, dissolved organic matter and the presence of crop residues (wheat straw and ash) on the sorption of the herbicides atrazine and isoproturon by a clay soil. Sorption K_d's derived from batch ‘equilibrium’ studies for both atrazine and isoproturon by <2 mm clay soil were approximately 3.5 L/kg. The similarity of K_oc's for isoproturon sorption by the <2 mm clay soil and <2 mm clay soil oxidised with hydrogen peroxide suggested that the sorption of this herbicide was strongly influenced by soil organic matter. By contrast, K_oc's for atrazine sorption by oxidised soil were three times greater than those for <2 mm soil, indicating that the soil mineral components might have affected sorption of this herbicide. No significant differences between the sorption of either herbicide by <2 mm clay soil and (i) <250 μm clay soil, (ii) clay soil mixed with wheat straw or ash at ratios similar to those observed under field conditions, (iii) <2 mm clay soil in the presence of dissolved organic matter as opposed to organic free water, were observed.     

Relationships between colored dissolved organic matter and dissolved organic carbon in different coastal gradients of the Baltic Sea

Due to high terrestrial runoff, the Baltic Sea is rich in dissolved organic carbon (DOC), the light-absorbing fraction of which is referred to as colored dissolved organic matter (CDOM). Inputs of DOC and CDOM are predicted to increase with climate change, affecting coastal ecosystems. We found that the relationships between DOC, CDOM, salinity, and Secchi depth all differed between the two coastal areas studied; the W Gulf of Bothnia with high terrestrial input and the NW Baltic Proper with relatively little terrestrial input. The CDOM:DOC ratio was higher in the Gulf of Bothnia, where CDOM had a greater influence on the Secchi depth, which is used as an indicator of eutrophication and hence important for Baltic Sea management. Based on the results of this study, we recommend regular CDOM measurements in monitoring programmes, to increase the value of concurrent Secchi depth measurements.     

Fenton法降解垃圾渗滤液中的溶解性有机质

垃圾渗滤液是一种高浓度难降解废水,含有大量有毒物质和溶解性有机质（dissolved organic matter, DOM）,可生化性差。Fenton试剂（Fe2++H2O2）能产生活性极强的羟基自由基（·OH）,能快速氧化渗滤液中DOM和微量有机物质。本研究采用Fenton法处理垃圾渗滤液,结果表明,在优化的处理条件下,渗滤液COD和TOC去除率分别为65%和42%,其中混凝作用去除的COD和TOC分别为20%和21%。进一步通过紫外可见光谱扫描、SUVA254、E3/E4等指标评价,发现Fenton法可以有效降低渗滤液中的DOM含量,大分子有机物的含量明显减少,而分子量小的有机物含量相对增加,反应体系中溶解性有机物分子量随着反应的进行而降低,腐殖化程度降低。利用GC-MS定性出渗滤液原液中47种有机物,该类有机物在Fenton反应后上清液中未再检出,但5种物质（邻苯二甲酸二（2-乙基己）酯、植酮、角鲨烯、麥角甾烷醇和二氢胆固醇）在沉淀的铁泥中检出。研究发现不同pH值、H2O2和Fe2+浓度条件下,残留的COD与DOM、TOC和UV254存在显著的相关关系（R2> 0.9）。本研究结果为改进垃圾渗滤液处理工艺和探索DOM在Fenton过程中的降解行为提供科学依据。     

pH和溶解性有机质对磺胺甲恶唑光降解的影响

为了考察pH和溶解性有机质(DOM)对磺胺甲恶唑(SMX)自然光降解的影响,采用光化学反应器对SMX降解过程进行模拟实验,并利用傅里叶变换红外光谱(FT-IR)和三维荧光光谱(3DEEM)对腐殖酸进行表征。结果表明：SMX光解过程符合准一级反应动力学方程,在中等酸性条件下反应速率明显高于中性或碱性条件;添加不同浓度的Pahokee泥炭腐殖酸(PPHA)和Sigma-Aldrich腐殖酸(SigHA)时,均对SMX的光降解产生了不同程度的抑制作用;FT-IR检测发现,PPHA与SigHA均含有含氧官能团,具有一定的还原能力,3DEEM显示PPHA具有荧光特性,可能和SMX结合生成配合物。pH影响SMX的光解与物质本身的酸离解常数有关,对光子的竞争、淬灭作用和掩蔽效应可能是PPHA和SigHA对SMX光降解抑制作用的主要原因。     

Cosorption study of organic pollutants and dissolved organic matter in a soil

In this study we have evaluated the effects of dissolved organic matter (DOM) on sorption of imidacloprid, 3,4-dichloroaniline (3,4-DCA) and 4-bromoaniline (4-BA) on a typical calcareous soil (Luvic Xerosol) from south-eastern Spain. Two different types of DOM were used, that is to say, dissolved natural organic matter extracts from a commercial peat (DNOM) and a high-purity tannic acid (TA) solution. The experiments were carried out in a 0.01 M CaCl2 aqueous medium at 25 degrees C. The results indicated that the presence of both DNOM and TA, over a concentration range of 15-100 mg L(-1), produced an increase in the amount of 3,4-DCA and 4-BA sorbed and a decrease in the amount of imidacloprid retained on the soil studied. A modified distribution coefficient, K(doc), has been proposed as a safer parameter for soil sorption predictions of organic pollutants and it could be of help to model the fate of these in the environment.     

Investigations on the sorption of phenols to dissolved organic matter by a QSAR study

The sorption of various phenols to Aldrich-HA and BSA was investigated by solid phase microextraction (SPME). The Aldrich-HA sorption with log K(DOC)-values between 2 and 3 was determined, whereas the sorption to BSA with log K(DOC)-values between 2 and 6 was much stronger. To enable an estimation of sorption constants a QSAR model was investigated. The linear free energy relationship (LFER) model showed a good correlation between the sorption constants and the log K(OW)-values with correlation coefficients of R = 0.910 and R = 0.878 for Aldrich-HA and BSA, respectively.     

Effect of organic fertilizers derived dissolved organic matter on pesticide sorption and leaching

Incorporation of organic fertilizers/amendments has been, and continues to be, a popular strategy for golf course turfgrass management. Dissolved organic matter (DOM) derived from these organic materials may, however, facilitate organic chemical movement through soils. A batch equilibrium technique was used to evaluate the effects of organic fertilizer-derived DOM on sorption of three organic chemicals (2,4-D, naphthalene and chlorpyrifos) in USGA (United States Golf Association) sand, a mixed soil (70% USGA sand and 30% native soil) and a silt loam soil (Typic Fragiochrept). DOM was extracted from two commercial organic fertilizers. Column leaching experiments were also performed using USGA sand. Sorption experiments showed that sorption capacity was significantly reduced with increasing DOM concentration in solution for all three chemicals. Column experimental results were consistent with batch equilibrium data. These results suggest that organic fertilizer-derived DOM might lead to enhanced transport of applied chemicals in turf soils.     

Natural organic matter (NOM) in roof runoff and its impact on the Fe0 treatment system of dissolved metals

The present work investigates the impacts and mechanisms associated with natural organic matter (NOM) in the Fe0 treatment system of Cu2+ and Zn2+ under roof runoff conditions. The NOM in runoff waters was characterized using XAD-4/8 adsorption resins, copper complexation, acidic capacity and liquid chromatography with online carbon detection. Batch kinetic experiments and flow-through configurations were performed and the results of metal removal were elucidated taking into account the characteristics of NOM. Based on the findings, it is shown that NOM influences the removal of metals through several complex pathways. At an un-favored condition for adsorption of metals, i.e., on iron corrosion products, at pH相似文献   

Toxicokinetics,toxicity and lethal body residues of two chlorophenols in the oligochaete worm,Lumbriculus variegatus,in different sediments

Bioavailability, toxicokinetics and toxicity (LC(50)) of water- and sediment-associated 2,4,5-trichlorophenol (2,4,5-TCP) and pentachlorophenol (PCP) were measured in Lumbriculus variegatus Müller in a set of experiments. The critical body residue approach was applied by measuring also the lethal body residues (LBR(50)). Freshwater and three different sediments with various sediment organic carbon (SOC) concentrations were used as exposure media. SOC decreased the bioavailability of both chlorophenols, and the uptake rates decreased by 81% and 91% for 2,4,5-TCP and PCP, respectively, in the sediment with a SOC of 6.9% compared to those in sediment with a SOC of 0.5%. SOC appeared to be an important factor controlling the bioavailability as after the carbon normalisation the difference between the sediments was much smaller. The 96-h LC(50) values for instance for PCP were 145.3 microg/l in freshwater, and 6.8 and 8.1 microg/g dry weight in sediments with SOC concentrations of 0.5% and 2.4%, respectively. The LBR(50) values, were practically the same in freshwater and sediments: between 1.0 and 1.6 and from 0.4 to 0.9 micromol/g wet weight for 2,4,5-TCP and PCP, respectively, demonstrating the usefulness of this method for accurate, and more comparable, measurement of toxicity of chemicals with the same mode of toxic action in varying conditions. L. variegatus expressed a dose-response sediment avoidance behaviour but the PCP tissue concentrations were not affected by this behaviour.     

Effects of azinphos-methyl exposure on enzymatic and non-enzymatic antioxidant defenses in Biomphalaria glabrata and Lumbriculus variegatus

Azinphos-methyl is an organophosphate insecticide used for pest control on a number of food crops in many parts of the world. The oligochaete Lumbriculus variegatus and pigmented and non-pigmented specimens of the gastropod Biomphalaria glabrata are freshwater invertebrates that have been recommended for contamination studies. Recently, it has been shown that L. variegatus worms exhibit a higher cholinesterase (ChE) activity and a greater sensitivity to in vivo ChE inhibition by azinphos-methyl than pigmented B. glabrata snails. The aims of the present study were (1) to investigate if, in addition to its anticholinesterase action, azinphos-methyl has also pro-oxidant activity in L. variegatus and B. glabrata, and (2) to examine if species that are highly susceptible to the neurotoxic effects of organophosphates also suffer a greater degree of oxidative stress. Therefore, total glutathione (t-GSH) levels and activities of cholinesterase (ChE), superoxide dismutase (SOD), catalase (CAT), glutathione S-transferase (GST), and glucose 6-phosphate dehydrogenase (G6PDH) were measured in the whole body soft tissue of organisms exposed for 48 and 96 h to a level of azinphos-methyl that produces 50% of inhibition on ChE. Results showed different patterns of antioxidant responses between the gastropods and the oligochaetes, and even between the two phenotypes of gastropods: (1) in exposed L. variegatus t-GSH levels increased and CAT and SOD activities decreased with respect to control organisms, (2) in pigmented gastropods, SOD decreased while CAT transiently diminished, and (3) in non-pigmented gastropods, SOD activity showed a biphasic response. GST and G6PDH were not altered by azinphos-methyl exposure. Of note, t-GSH levels were 4-fold times higher in L. variegatus than in both phenotypes of B. glabrata. This may suggest that GSH could play a more important role in antioxidant defense in L. variegatus than in B. glabrata.     

Partition coefficients of organochlorine pesticides on soil and on the dissolved organic matter in water

The partition coefficients of organochlorine pesticides (OCPs) between the organic matter of Taichung soil and water (K_oc) were evaluated with batch-type experiments. The partition coefficients of OCPs between Aldrich humic acid and water (K_doc) were estimated with solubility enhancement method as well. In this study, the K_ocs of aldrin, heptachlor, and p,p′-DDT are greater than their K_docs, and the relationship of dieldrin and heptachlor epoxide are opposite. The variations of partition coefficients are discussed. For predicting K_doc, a log-log regression relationship of K_doc and K_ow is determined.     

Soil mobility of sewage sludge-derived dissolved organic matter, copper, nickel and zinc

A soil (sandy loam) column leaching study aimed to determine the extent of mobility and co-mobility of Cu, Ni, Zn and dissolved organic matter (DOM) released from a surface-application (equivalent to 50 t ds ha(-1) of anaerobically-digested sewage sludge. Leaching of DOM through the soil column was found to be almost un-retarded. Decidedly similar behaviour was exhibited by Ni suggesting that it migrated as organic complexes. Whilst Cu was also found to be leached, significant retardation was evident. However, the importance of DOM in promoting the mobility of both Cu and Ni was evidenced by their lack of mobility when added to the soil column as inorganic forms. The presence of DOM did not prevent Zn from becoming completely adsorbed by the soil solid phase. In relation to WHO drinking water guidelines, only Ni concentrations showed potential environmental significance, due to the relatively poor retention of Ni by the sludge solid phase.     

Copper complexation by dissolved organic matter and uncertainty assessment of their stability constants

The interaction of Cu with dissolved organic matter (DOM, extracted from an organic forest floor) was investigated and the resulting data was evaluated in terms of their uncertainty. The speciation of Cu over ‘free’ Cu (as analysed by diffusive gradients in thin films (DGT)), dissolved Cu–DOM complexes and precipitated Cu–DOM was determined as a function of pH (3.5, 4.0 and 4.5) and Cu/C ratio. The dissolved organically bound fraction was highest at pH 4.5, but this fraction decreased with increasing Cu/C ratio, which was observed for all pH levels. In the range of Cu/C=7×10⁻⁵–2.3×10⁻² (mol/mol) the precipitated fraction was very small. The speciation of both Al and Fe was not affected by increasing Cu concentrations. From a continuous distribution model using the Scatchard approach, we calculated the optimal fit and corresponding upper and lower 95% uncertainty bounds of the overall stability constants (K_o) with the shuffled complex evolution Metropolis (SCEM) algorithm. Although the optimal equation fitted the data very well, the uncertainty of the, according to literature, most reliable approach to establish stability constants, was still large. Accordingly, the usually reported intrinsic stability constants exhibited large uncertainty ranging from logK_i=6.0–7.1 (optimal 6.7) for pH 3.5, logK_i=6.5–7.1 (optimal 6.8) for pH 4.0, and logK_i=6.4–7.2 (optimal 6.8) for pH 4.5 and showed only little effect of pH.     

Distribution of DDT and benzo[a]pyrene between water and dissolved organic matter in natural humic water

DDT and benzo[a]pyrene (BaP) were added both separately and as a mixture to filtered (0.22 μm) humic surface water samples. Following a contact time of 1 d, the fraction bound to dissolved organic matter and the freely dissolved part were separated by using reversed-phase octadecyl silica cartridges. The enriched solutes were analysed by gas chromatography-mass spectrometry in the selective ion monitoring (GC-MS/SIM) mode. Partition coefficients to dissolved organic matter, calculated on the basis of the recovery data, varied between 2.0 × 10⁴ and 6.6 × 10⁴ mL/g for BaP depending on the experimental conditions, whereas the corresponding values for DDT (0.6 × 10⁴ mL/g) showed no significant variation.     

Effect of dissolved organic matter and bacteria on contaminant transport in riverbank filtration

A mathematical model for the transport of hydrophobic organic contaminants in an aquifer under simplistic riverbank filtration conditions is developed. The model considers a situation where contaminants are present together with dissolved organic matter (DOM) and bacteria. The aquifer is conceptualized as a four-phase system: two mobile colloidal phases, an aqueous phase, and a stationary solid phase. An equilibrium approach is used to describe the interactions of contaminants with DOM, bacteria, and solid matrix. The model is composed of bacterial transport equation and contaminant transport equation. Numerical simulations are performed to examine the contaminant transport behavior in the presence of DOM and bacteria. The simulation results illustrate that contaminant transport is enhanced markedly in the presence of DOM and bacteria, and the impact of DOM on contaminant mobility is greater than that of bacteria under examined conditions. Sensitivity analysis demonstrates that the model is sensitive to changes of three lumped parameters: K+1 (total affinity of stationary solid phase to contaminants), K+2 (total affinity of DOM to contaminants), and K+3 (total affinity of bacteria to contaminants). In a situation where contaminants exist simultaneously with DOM and bacteria, contaminant transport is mainly affected by a ratio of K+1/K+2/K+3, which can vary with changes of equilibrium distribution coefficient of contaminants and/or colloidal concentrations. In riverbank filtration, the influence of DOM and bacteria on the transport behavior of contaminants should be accounted to accurately predict the contaminant mobility.     

臭氧对饮用水管网中溶解性有机物的影响

利用生物膜环状反应器模拟配水管网系统,将水厂砂滤池出水经过臭氧氧化后投加氯然后进入该模拟管网,另外把水厂砂滤池出水加氯后通入另一模拟管网作为对照实验。通过对两管网出水余氯、总铁、浊度、溶解性有机物(DOC)、以及消毒副产物三卤甲烷(THMs)、卤乙酸(HAAs)生成情况的测定,研究了饮用水臭氧处理对管网出水水质的影响。单因素方差分析结果表明,两管网出水的余氯、总铁、浊度以及THMs、HAAs含量相差不大,但DOC在臭氧氯管网中消耗较多。同时通过高效凝胶色谱(HPSEC), 红外光谱(FTIR)和三维荧光光谱(EEM)表征了不同管网进出水DOC变化,结果表明,臭氧氧化后的管网出水中溶解性有机物荧光光谱中三区富里酸和五区腐植酸荧光峰值(ФⅢ+Ⅴ,n)减小较多,管网出水消毒副产物稍有增加。