木屑和花生壳吸附去除水溶液中Cr3+的试验研究

以废弃物木屑和花生壳作为吸附剂,进行了吸附去除水中Cr3 的试验.研究了溶液pH值、初始Cr3 浓度以及温度等因素对这2种吸附剂去除Cr3 作用的影响,对吸附曲线作了线性拟合,确定了相应的平衡吸附率,在Cr3 初始浓度为1、5、10和20 mg/L时,木屑对Cr3 的平衡吸附率为81%、68%、56%和40%,花生壳依次为77%、63%、53%和42%,并探讨了这2种吸附剂对溶液中Cr3 的吸附机理.     

羧甲基壳聚糖-膨润土复合吸附剂对Cu^2＋、Ni^2＋、Cr^3＋的吸附

用羧甲基壳聚糖和膨润土制备复合吸附剂，研究了复合吸附剂在不同参数下对Cu^2＋、Ni^2＋和Cr^3＋吸附的影响。结果表明，复合吸附剂对Ni^2＋的吸附可以很快达到吸附平衡，而对Cu^2＋和Cr^3＋的吸附分别在30min和180min时达到平衡；且pH值对吸附容量的影响很显著。通过计算不同温度下的热力学参数△G、△H和△S，3种金属的△G〈0，证实这3种金属吸附都是自发过程。Cu^2＋、Ni^2＋和Cr^3＋的吸附等温线较符合Langmuir型；反应动力学都更符合准二级吸附速率方程。     

香蕉皮吸附废水中铜、锌的研究

用香蕉皮作为吸附剂，对含有Cu^2＋、Zn^2＋的重金属废水进行了吸附研究。分别考察了pH值、溶液初始浓度、吸附剂量、吸附剂粒径以及吸附时间等因素对吸附的影响。结果表明，香蕉皮对Cu^2＋、Zn^2＋有较好的吸附效果。溶液的pH值在5左右，吸附时间为7h，香蕉皮对Cu^2＋、Zn^2＋的吸附率可达95％以上。     

交联菌丝体吸附剂的制备及其对Cr^3＋的吸附特性

深入研究了交联菌丝体吸附剂的制备工艺及其对Cr^3＋的吸附特性。交联菌丝体吸附剂制备工艺简单，但在制备过程中，活化剂NaOH和交联剂的用量对吸附特性影响较大。与纯菌丝体吸附剂相比，交联菌丝体吸附剂表观吸附容量提高48％，达到49．83mg／g（pH=2．53，水溶液中的Cr^3＋浓度为600mg／L），同时其机械强度明显增强。交联菌丝体吸附剂对Cr^3＋的吸附特点是将沉淀法与吸附法相结合，将沉淀与吸附两过程合二为一，从而简化了处理工艺，降低了处理成本。     

花生壳、大豆壳和柚子皮对Cr3+、Cu2+和Ni2+的吸附研究

采用农林废弃物花生壳、大豆壳、柚子皮对重金属离子Cr3+、Cu2+和Ni2+进行吸附研究,探讨反应时间、吸附剂用量、pH、重金属离子初始浓度以及温度对吸附的影响.结果表明:柚子皮对Cr3+、Cu2+、Ni2+的吸附效果优于花生壳和大豆壳,其在20℃、pH 5.00、10.0 mg/kg条件下,反应360 min,Cr3+、Cu2+、Ni2+的吸附率分别可达83.20％、84.50％、59.10％;花生壳、大豆壳和柚子皮对Ni2+的吸附率远低于Cr3+和Cu2+；花生壳、大豆壳和柚子皮对Cr3+、Cu2+、Ni2+的吸附动力学可以用准二级动力学方程描述；吸附率随初始重金属离子浓度增加而降低,其吸附等温线可以用Langmuir方程描述；在一定范围内,吸附率随吸附剂用量增加而增加；溶液初始pH在2～5时,吸附率随pH增大而增加；Cu2、Ni2+的吸附量随温度的上升而逐渐减少,但Cr3+的吸附量随着温度的上升而略增加.     

胺化木质素对水中Cu（Ⅱ）、Cd（Ⅱ）的吸附

以胺化木质素作吸附剂对水中Cu2＋、Cd2＋的去除进行了研究，主要考察了吸附时间、溶液pH值、温度和金属离子初始浓度对吸附去除率的影响，并研究了其吸附等温线和动力学。结果表明，胺化木质素能有效去除水溶液中的Cu2＋、Cd2＋，且对Cd2＋的吸附能力大于Cu2＋吸附动力学符合准二级动力学方程，吸附等温线均可以很好地用Langmuir方程描述。     

膨润土对Pb^2＋、Cu^2＋、Cr^3＋的吸附动力学及等温线研究

研究所用膨润土的主要成分为SiO2和Al2O3，属于Ca基膨润土，BET表面积为50．83m^2／g。在恒温及恒定pH条件下，用静态吸附法研究了膨润土对Pb^2＋、Cu^2＋、Cr^3＋的吸附特性，结果表明其较好地符合Lagergren二级吸附速率方程，对这3种离子的吸附速率为Pb^2＋〉Cu^2＋〉Cr^3＋。利用3种等温线方程对吸附过程进行拟合，发现利用Langmuir吸附等温方程计算的值与膨润土吸附Pb^2＋、Cu^2＋、Cr^3＋试验数据最为吻合。膨润土对3种金属离子的平衡吸附量为Cr^3＋〉Cu^2＋〉Pb^2＋。     

改性玉米秸秆炭和花生壳炭对溶液中Cd~(2+)的吸附

对玉米秸秆和花生壳炭化制备的生物炭,运用高锰酸钾进行改性,研究其对Cd~(2+)的吸附效果。通过批次吸附实验,考察了两种改性生物炭对Cd~(2+)吸附的初始浓度、pH值、接触时间等因素的影响。结果表明,在pH为6.0,Cd~(2+)浓度为100 mg·L~(-1),温度为20℃,吸附时间为12 h,吸附剂投加量为1.0 g·L~(-1)条件下,改性玉米秸秆炭和花生壳炭对Cd~(2+)的去除率分别为67.03%和46.10%,与未改性的生物炭相比,吸附率分别提高了3.8倍和6.2倍。改性玉米秸秆炭和花生壳炭对溶液中Cd~(2+)的吸附均符合Langmuir和Freundlich等温吸附模型,最大吸附量分别为68.97和55.55 mg·g-1。两种改性生物炭的吸附行为均符合准二级吸附动力学模型,说明其吸附以化学吸附为主。改性玉米秸秆炭和花生壳炭吸附Cd~(2+)后,可用NaOH溶液进行解吸,解吸4次后,对Cd~(2+)仍有较好的吸附效果,吸附量分别为31.40和24.10 mg·g~(-1)。这说明,高锰酸钾改性玉米秸秆炭和花生壳炭是一种吸附性能高且能够重复利用的去除溶液中Cd~(2+)的吸附材料。     

非活体生物质对水中活性艳红X-3B的吸附研究

研究了4种非活体生物质(米酒糟、花生壳、柚子皮、稻草秸秆)对模拟废水中活性艳红X-3B的吸附条件及吸附机理。结果表明,活性艳红X-3B初始浓度为100 mg/L、pH为1.0~2.0、吸附剂浓度为10 mg/L时,4种吸附剂对活性艳红X-3B的吸附率可达到80%。吸附在60 min左右达平衡后最大吸附量的顺序为:米酒糟(58.8 mg/g)花生壳(28.0mg/g)柚子皮(23.6 mg/g)稻草秸秆(19.5 mg/g)。在达最大吸附率时,米酒糟的用量可减少一半、pH范围可宽为1.0~6.0,且吸附量是另三者的2倍以上。综合比较,米酒糟具有较强的吸附废水中活性艳红X-3B的能力,可作为废水中活性染料的吸附剂使用。而花生壳、柚子皮和稻草秸秆的吸附能力相对较弱,不是理想的吸附材料。数学模型模拟表明,米酒糟和柚子皮的吸附过程更符合Freundlich方程,而花生壳和稻草秸秆更符合Langmuir方程;动力学研究表明4种吸附剂的吸附拟合更符合拟二级动力学方程。     

核桃壳粉对水溶液中Pb2＋的吸附

实验通过间歇吸附方式研究了核桃壳粉对水溶液中Pb^2＋的吸附特性，探讨了核桃壳粉粒径及用量、溶液pH、Pb^2＋初始浓度等参数对吸附的影响，并讨论了吸附过程的热力学和动力学特征。结果表明，核桃壳粉对Pb^2＋吸附的最佳pH为5．0，去除率随吸附剂粒径的减小、用量的增加、Pb^2＋初始浓度的减小而增加。优化实验条件下，0～0．3mm15g／L的吸附剂在298K时，对pH=5的50mL50mg／LPb^2＋溶液的去除率达96．98％。核桃壳粉对Pb^2＋的吸附等温线符合Sips模型，在283、293和303K的最大吸附量分别为18．25、18．27和20．94mg／g。吸附过程是放热的、混乱度减小的自发过程，且符合准二级动力学模型。吸附速率常数随温度升高而减小，在293和303K时分别在90和120min基本达到平衡。结合FTIR和SEM手段发现核桃壳对Pb^2＋的吸附以物理吸附为主，同时包括离子交换、螯合等化学吸附以及颗粒内扩散步骤，是一个复杂的过程。     

Radionuclides and trace elements in fish collected upstream and downstream of Los Alamos national laboratory and the doses to humans from the consumption of muscle and bone

Abstract

The purpose of this study was to determine radionuclide and trace element concentrations in bottom‐feeding fish (catfish, carp, and suckers) collected from the confluences of some of the major canyons that cross Los Alamos National Laboratory (LANL) lands with the Rio Grande (RG) and the potential radiological doses from the ingestion of these fish. Samples of muscle and bone (and viscera in some cases) were analyzed for ³H, ⁹⁰Sr, ¹³⁷Cs, ^totU, ²³⁸Pu, ^239,240Pu, and ²⁴¹Am and Ag, As, Ba, Be, Cr, Cd, Cu, Hg, Ni, Pb, Sb, Se, and Tl. Most radionuclides, with the exception of ⁹⁰Sr, in the muscle plus bone portions of fish collected from LANL canyons/RG were not significantly (p<0.05) higher from fish collected upstream (San Ildefonso/background) of LANL. Strontium‐90 in fish muscle plus bone tissue significantly (p<0.05) increases in concentration starting from Los Alamos Canyon, the most upstream confluence (fish contained 3.4E‐02 pCi g^‐1 [126E‐02 Bq kg^‐1]), to Frijoles Canyon, the most downstream confluence (fish contained 14E‐02 pCi g^‐1 [518E‐02 Bq kg^‐1]). The differences in ⁹⁰Sr concentrations in fish collected downstream and upstream (background) of LANL, however, were very small. Based on the average concentrations (±2SD) of radionuclides in fish tissue from the four LANL confluences, the committed effective dose equivalent from the ingestion of 46 lb (21 kg) (maximum ingestion rate per person per year) of fish muscle plus bone, after the subtraction of background, was 0.1 ± 0.1 mrem y^‐1 (1.0 ± 1.0 μSv y^‐1), and was far below the International Commission on Radiological Protection (all pathway) permissible dose limit of 100 mrem y^‐1 (1000 μSv y^‐1). Of the trace elements that were found above the limits of detection (Ba, Cu, and Hg) in fish muscle collected from the confluences of canyons that cross LANL and the RG, none were in significantly higher (p<0.05) concentrations than in muscle of fish collected from background locations.     

Radionuclides in deer and elk from Los Alamos national laboratory and the doses to humans from the ingestion of muscle and bone

Abstract

This paper summarizes radionuclide concentrations (³H, ⁹⁰Sr, ¹³⁷Cs, ²³⁸Pu, ^239,240Pu, ²⁴¹Am, and ^totU) in muscle and bone tissue of mule deer (Odocoileus hemionus) and Rocky Mountain elk (Cervus elaphus) collected from Los Alamos National Laboratory (LANL), Los Alamos, New Mexico, lands from 1991 through 1998. Also, the committed effective dose equivalent (CEDE) and the risk of excess cancer fatalities (RECF) to people who ingest muscle and bone from deer and elk collected from LANL lands were estimated. Most radionuclide concentrations in muscle and bone from individual deer (n = 11) and elk (n = 22) collected from LANL lands were either at less than detectable quantities (where the analytical result was smaller than two counting uncertainties) and/or within upper (95%) level background (BG) concentrations. As a group, most radionuclides in muscle and bone of deer and elk from LANL lands were not significantly higher (p<0.10) than in similar tissues from deer (n = 3) and elk (n = 7) collected from BG locations. Also, elk that had been radio collared and tracked for two years and spent an average time of 50% on LANL lands were not significantly different in most radionuclides from road kill elk that have been collected as part of the environmental surveillance program. Overall, the upper (95%) level net CEDEs (the CEDE plus two sigma for each radioisotope minus background) at the most conservative ingestion rate (50 lbs of muscle and 13 lbs of bone) were as follows: deer muscle = 0.22 mrem y^‐1 (2.2 μSv y^‐1), deer bone = 3.8 mrem y^‐1 (38 μSv y^‐1), elk muscle = 0.12 mrem y^‐1 (1.2 μSv y^‐1), and elk bone = 1.7 mrem y^‐1 (17 μSv y^‐1). All CEDEs were far below the International Commission on Radiological Protection guideline of 100 mrem y^‐1 (1000 μSv y^‐1), and the highest muscle plus bone net CEDE corresponded to a RECF of 2E‐06, which is far below the Environmental Protection Agency upper level guideline of 1E‐04.     

Leaching of seven pesticides currently used in cotton crop in Mato Grosso State—Brazil

This study aimed to evaluate the leaching of pesticides and the applicability of the Attenuation Factor (AF) Model to predict their leaching. The leaching of carbofuran, carbendazim, diuron, metolachlor, α and β endosulfan and chlorpyrifos was studied in an Oxisol using a field experiment lysimeter located in Dom Aquino – Mato Grosso. The samples of percolated water were collected by rain event and analyzed. Chemical and physical soil attributes were determined before pesticide application to the plots. The results showed that carbofuran was the pesticide that presented a higher leaching rate in the studied soil, so was the one representing the highest contamination potential. From the total carbofuran applied in the soil surface, around 6 % leached below 50 cm. The other pesticides showed lower mobility in the studied soil. The calculated values to AF were 7.06E-12 (carbendazim), 5.08E-03 (carbofuran), 3.12E-17 (diuron), 6.66E-345 (α-endosulfan), 1.47E-162 (β-endosulfan), 1.50E-06 (metolachlor), 3.51E-155 (chlorpyrifos). AF Model was useful to classify the pesticides' potential for contamination; however, that model underestimated pesticide leaching.     

Endosulfan in China 2—emissions and residues

Background, aim, and scope  Endosulfan is one of the organochlorine pesticides (OCPs) and also a candidate to be included in a group of new persistent organic pollutants (UNEP 2007). The first national endosulfan usage inventories in China with 1/4° longitude by 1/6° latitude resolution has been reported in an accompanying paper. In the second part of the paper, we compiled the gridded historical emissions and soil residues of endosulfan in China from the usage inventories. Based on the residue/emission data, gridded concentrations of endosulfan in Chinese soil and air have been calculated. These inventories will provide valuable data for the further study of endosulfan. Methods  Emission and residue of endosulfan were calculated from endosulfan usage by using a simplified gridded pesticide emission and residue model—SGPERM, which is an integrated modeling system combining mathematical model, database management system, and geographic information system. By using the emission and residue inventories, annual air and soil concentrations of endosulfan in each cell were determined. Results and discussion  Historical gridded emission and residue inventories of α- and β-endosulfan in agricultural soil in China with 1/4° longitude by 1/6° latitude resolution have been created. Total emissions were around 10,800 t, with α-endosulfan at 7,400 t and β-endosulfan at 3,400 t from 1994 to 2004. The highest residues were 140 t for α-endosulfan and 390 t for β-endosulfan, and the lowest residues were 0.7 t for α-endosulfan and 170 t for β-endosulfan in 2004 in Chinese agricultural soil where endosulfan was applied. Based on the emission and residue inventories, concentrations of α- and β-endosulfan in Chinese air and agricultural surface soil were also calculated for each grid cell. We have estimated annual averaged air concentrations and the annual minimum and maximum soil concentrations across China. The real concentrations will be different from season to season. Although our model does not consider the transport of the insecticide in the atmosphere, which could be very important in some areas during some special time, the estimated concentrations of endosulfan in Chinese air and soil derived from the endosulfan emission and residue inventories are in general consistent with the published monitoring data. Conclusions  To our knowledge, this work is the first inventory of this kind for endosulfan published on a national scale. Concentrations of the chemical in Chinese air and agricultural surface soil were calculated for each grid cell. Results show that the estimated concentrations of endosulfan in Chinese air and soil agree reasonably well with the monitoring data in general. Recommendations and perspectives  The gridded endosulfan emission/residue inventories and also the air and soil concentration inventories created in this study will be updated upon availability of new information, including usage and monitoring data. The establishment of these inventories for the OCP is important for both scientific communities and policy makers.     

Impact of spiked concentrations of Cd,Pb, As and Zn in growth medium on elemental uptake of Nasturtium officinale (Watercress)

This study is aimed at investigating the impact of water quality on the uptake and distribution of three non-essential and toxic elements, namely, As, Cd and Pb in the watercress plant to assess for metal toxicity. The plant was hydroponically cultivated under greenhouse conditions, with the growth medium being spiked with varying concentrations of As, Cd and Pb. Plants that were harvested weekly for elemental analysis showed physiological and morphological symptoms of toxicity on exposure to high concentrations of Cd and Pb. Plants exposed to high concentrations of As did not survive and the threshold for As uptake in watercress was established at 5 ppm. Translocation factors were low in all cases as the toxic elements accumulated more in the roots of the plant than the edible leaves. The impact of Zn on the uptake of toxic elements was also evaluated and Zn was found to have an antagonistic effect on uptake of both Cd and Pb with no notable effect on uptake of As. The findings indicate that phytotoxicity or death of the watercress plant would prevent it from being a route of human exposure to high concentrations of As, Cd and Pb in the environment.     

Butyltin compounds in sediment and fish from the Polish Coast of the Baltic Sea

Concentrations of mono- (MBT), di- (DBT), and tri-(TBT) butyltin compounds were measured in eggs, liver, and muscle of nine species of fish from four regions of the Baltic Sea - the Firth of Vistula, the Gulf of Gdańsk, Puck Bay, and the mouth of the Vistula River. The overall concentration ranges among all the fish sampled from the four sites were: < 7 to 79 ng/g for MBT, 6 to 1100 ng/g for DBT, 7 to 3600 ng/g for TBT, and 16 to 4800 ng/g for total BTs, on a wet wt basis. The highest concentration of total BTs was found in herring liver from the Firth of Vistula (4800 ng/g, wet wt) and in roach muscle from Puck Bay (3300 ng/g, wet wt), while the least concentration was found in burbot eggs and liver from the Vistula River (39 and 32 ng/g, wet wt, respectively). TBT was the major form of BTs present in most samples analyzed. Sediment samples collected from shipyards in the Gulf of Gdańsk contained butyltin concentrations ranging from 1.2 to 46 μg/g (dry wt) for MBT, 2.0 to 42 μg/g for DBT, and 2.6 to 40 μg/g for TBT. As with the fish, the majority of the BTs in sediment were present as TBT, which suggested recent exposure of the aquatic environment of the region to TBT.     

Malathion-induced sublethal toxicity on the hematology of cricket frog (Fejervarya limnocharis)

The effect of malathion [diethyl(dimethoxythiophosphorylthio)succinate] at sublethal concentration (0.006 ppm) on hematological parameters of the cricket frog (Fejervarya limnocharis) was studied for 24 hrs to 240 hrs of exposure and remarkable hematological alterations were observed. The study on hematological parameters revealed a highly significant decrease (P < 0.01) in the total erythrocytes count in malathion-exposed animals from 24 hours to 96 hrs of exposure as compared to control. Significant decreases (P < 0.01) of hemoglobin and packed cell volume were also observed from 48 hrs to 240 hrs. A significant increase (P < 0.01) in leucocytes count was noted throughout the exposure period. Elevated numbers of lymphocytes and eosinophils as found in the present study revealed lymphocytosis as well as eosinophilia, suggesting that this was a result of direct stimulation of the immunological defense due to the presence of a toxic substance or may be associated with tissue damage. The cytomorphological and cytopathological study of erythrocytes and leucocytes in malathion-exposed frogs at 0.006 ppm concentration revealed various cytotoxic effects at different exposure times. It was noted that the size and the shape of the erythrocytes were subjected to variation in different blood disorders.     

Relation between forest vegetation, atmospheric deposition and site conditions at regional and European scales

Several monitoring programs have been set up to assess effects of atmospheric deposition on forest ecosystems. The aim of the present study was to evaluate effects on the understorey vegetation, based on the first round of a regional (the Netherlands) and a European forest monitoring program. A multivariate statistical analysis showed surprisingly similar results for both data sets; the vegetation appeared to be largely determined by the ‘traditional’ factors soil, climate, and tree species, but there was a small but statistically significant effect of atmospheric deposition. The effects of deposition include a slight shift towards nitrophytic species at high N deposition in the European network, and towards acidophytic species at high S-deposition in the Dutch network. The relatively small effect of atmospheric deposition is understandable in view of the very large natural variation in environmental conditions. Time series of both vegetation and environment are needed to assess deposition effects in detail.     

Influence of crop residues on trifluralin mineralization in a silty clay loam soil

Trifluralin is typically applied onto crop residues (trash, stubble) at the soil surface, or onto the bare soil surface after the incorporation of crop residues into the soil. The objective of this study was to quantify the effect of the type and amount of crop residues in soil on trifluralin mineralization in a Wellwood silty clay loam soil. Leaves and stubble of Potato (Solanum tuberosum) (P); Canola (Brassica napus) (C), Wheat (Triticum aestivum) (W), Oats (Avena sativa), (O), and Alfalfa (Medicago sativa) (A) were added to soil microcosms at rates of 2%, 4%, 8% and 16% of the total soil weight (25 g). The type and amount of crop residues in soil had little influence on the trifluralin first-order mineralization rate constant, which ranged from 3.57E-03 day^?1 in soil with 16% A to 2.89E-02 day^?1 in soil with 8% W. The cumulative trifluralin mineralization at 113 days ranged from 1.15% in soil with 16% P to 3.21% in soil with 4% C, again demonstrating that the observed differences across the treatments are not of agronomic or environmental importance.     

Concurrent nitrate and Fe(III) reduction during anaerobic biodegradation of phenols in a sandstone aquifer

The biodegradation of phenols (5, 60, 600 mg l⁻¹) under anaerobic conditions (nitrate enriched and unamended) was studied in laboratory microcosms with sandstone material and groundwater from within an anaerobic ammonium plume in an aquifer. The aqueous phase was sampled and analyzed for phenols and selected redox sensitive parameters on a regular basis. An experiment with sandstone material from specific depth intervals from a vertical profile across the ammonium plume was also conducted. The miniature microcosms used in this experiment were sacrificed for sampling for phenols and selected redox sensitive parameters at the end of the experiment. The sandstone material was characterized with respect to oxidation and reduction potential and Fe(II) and Fe(III) speciation prior to use for all microcosms and at the end of the experiments for selected microcosms.The redox conditions in the anaerobic microcosms were mixed nitrate and Fe(III) reducing. Nitrate and Fe(III) were apparently the dominant electron acceptors at high and low nitrate concentrations, respectively. When biomass growth is taken into account, nitrate and Fe(III) reduction constituted sufficient electron acceptor capacity for the mineralization of the phenols observed to be degraded even at an initial phenols concentration of 60 mg l⁻¹ (high) in an unamended microcosm, whereas nitrate reduction alone is unlikely to have provided sufficient electron acceptor capacity for the observed degradation of the phenols in the unamended microcosm.For microcosm systems, with solid aquifer materials, dissolution of organic substances from the solid material may occur. A quantitative determination of the speciation (mineral types and quantity) of electron acceptors associated with the solids, at levels relevant for degradation of specific organic compounds in aquifers, cannot always be obtained. Hence, complete mass balances of electron acceptor consumption for specific organic compounds degradation are difficult to confine. For aquifer materials with low initial Fe(II) content, Fe(II) determinations on solids and in aqueous phase samples may provide valuable information on Fe(III) reduction. However, in microcosms with natural sediments and where electron acceptors are associated with the sediments, complete mass-balances for substrates and electron acceptors are not likely to be obtained.