四平市二龙湖底泥磷释放研究

采用室内实验模拟法对四平市二龙湖富营养化限制因子磷的底泥释放速率及释放量进行了研究,并研究在各种环境因子（温度、pH、DO和扰动因素）影响下底泥磷的释放规律.结果表明,（1）二龙湖年平均底泥释磷量为208.78kg,最大释磷率为0.889 μg/g（T=20℃,pH=8,DO为4.68 mg/L）;（2）自然和人为的扰动因素会促进底泥的磷释放;（3）pH在弱酸至中性范围内底泥释磷量最小,酸性和碱性条件都有利于磷的释放;（4）随着温度的升高底泥释磷量增大;（5）厌氧条件比好氧条件更有利于磷的释放.     

四平市二龙湖底泥磷释放研究

采用室内实验模拟法对四平市二龙湖富营养化限制因子磷的底泥释放速率及释放量进行了研究,并研究在种环境因子(温度、pH、DO和扰动因素)影响下底泥磷的释放规律。结果表明,(1)二龙湖年平均底泥释磷量为208·78g,最大释磷率为0·889μg/g(T=20℃,pH=8,DO为4·68mg/L);(2)自然和人为的扰动因素会促进底泥的磷释放;(3)H在弱酸至中性范围内底泥释磷量最小,酸性和碱性条件都有利于磷的释放;(4)随着温度的升高底泥释磷量增大;(5)厌条件比好氧条件更有利于磷的释放。     

湖泊底泥磷释放及磷形态变化

为研究底泥中内源性磷释放对城市景观水体富营养化的影响,以西安市曲江南湖为对象,采用底泥磷形态标准测试方法(SMT)分析了磷的赋存形态,通过模拟实验探究了在不同环境条件(温度、pH和溶解氧)下磷形态变化的特征。结果表明:温度升高促进内源磷的释放,在夏季加剧水体富营养化程度;碱性条件有利于磷的释放,增大补给水源可减少底泥释磷量;厌氧环境下底泥释磷量是好氧时的3.96倍;Al-P和Ca-P较稳定,在酸性条件下会加速其溶解;NH+4-P、Fe-P和OrgP受溶解氧、pH和温度影响较大,其吸附与释放能力有明显的差异。     

上覆水环境条件对底泥氮磷释放的影响研究

研究了不同温度、pH、DO环境条件下底泥对上覆水总氮、总磷释放强度的影响。结果表明:(1)随着温度升高,总氮、总磷释放强度增加;中性(pH=7)不利于底泥总氮、总磷的释放,强碱性(pH=10)条件下总氮、总磷释放强度最大;底泥中总氮、总磷的释放强度总体随DO浓度的升高而降低。(2)底泥中总氮平均释放强度与温度(R2为0.998)的关系符合二次曲线,与pH(R2为0.976)和DO(R2为1.000)的关系都符合三次曲线;总磷平均释放强度与温度(R2为0.999)、pH(R2为0.999)和DO(R2为1.000)的关系均符合三次曲线。(3)极差分析发现,环境条件对底泥总氮释放影响的大小表现为温度DOpH,对底泥总磷释放影响的大小表现为pH温度DO。     

阳宗海沉积物中磷的稳定性

絮凝剂(Fe Cl3)治理阳宗海砷污染的过程中,水体中的磷被大量沉积进入底泥,弄清其是否会在环境条件变化后发生反溶形成二次污染对湖泊富营养化防治具有重要意义。通过模拟实验模拟泥-水界面p H变化、物理扰动和微生物活动的变化,旨在分析这些环境因子变化对沉积物中磷溶出的影响。结果表明,阳宗海水体在目前这种磷浓度下,底泥的磷会随时间的增加而溶出再次造成水体磷污染,当暴露在清洁水条件下时磷的释放率会增加;这种由于絮凝剂吸附沉淀到湖底的磷,在上覆水p H增加0.5时底泥磷解吸附释放速率增加;每年秋季湖泊上下层水的交换活动会造成水体磷浓度的季节性升高,形成不可忽视的磷内源。而夏季水温分层导致湖泊底部厌氧,使厌氧微生物活性增强,这将进一步促进底泥中磷的释放。     

底泥释磷及其对西湖富营养化的影响

杭州西湖底泥由上部藻骸腐泥和下部泥炭层构成,含有丰富的碳和氮,含磷属中等水平。通过实验室模拟和现场模拟两种方法,测定了西湖底泥的释磷量和释磷速率,获得了pH、DO、温度及上复水组成等因子与释磷通量的相关关系。室内模拟底泥最大释磷量为0.368μg/g;夏季现场模拟底泥平均释磷速率为1.02mg/m~2·d,估算西湖底泥释磷量达1.346t/y,相当于年平均外部入湖磷负荷的36.4％。底泥释磷对西湖富营养化有着不客忽视的影响。     

底泥污染物释放动力学研究

采用模拟试验方式和新型微生物数量测定方法 ,研究了沼泽化湖泊底泥和受污染河流底泥在不同扰动状态下 ,底泥耗氧速率、氮和磷污染物释放动力学过程。结果表明 :( 1)底泥耗氧速率是同样条件下上覆水耗氧速率的 48倍 ,而在扰动状态下 ,底泥耗氧速率达到上覆水耗氧速率的 5 96— 93 6倍 ,扰动底泥显著增大其耗氧速率 ,底泥污染越严重 ,其耗氧速率越大 ,对水体产生的影响也越大。 ( 2 )扰动底泥可以显著增大底泥的氮磷释放速率 ,氮的释放受有机氮的氨化、氨氮的硝化、硝酸盐氮的反硝化以及氨氮被微生物吸收转化为有机氮等的影响 ;磷的释放过程受厌氧过程和底泥颗粒吸附的影响 ,耗氧速率高的底泥具有更大的氮磷释放潜力。 ( 3 )微生物数量在底泥污染物释放动力学中起着关键性作用 ,新型方法可以快速检测微生物总量。试验结果对于水环境的管理、受污染水体的修复 ,以及底泥的处理处置等都具有重要的指导意义     

淀山湖底泥氮、磷释放通量的研究

水体中氮、磷含量是影响藻类生长的重要因子,来源可分为外源性和内源性,而底泥氮、磷释放是内源性氮、磷的重要组成.为了解城市浅水型湖泊中底泥氮、磷释放过程及其规律,根据淀山湖底泥状况,在湖的进水口2个采样点、湖中心1个采样点、湖的出水口1个采样点分别采集底泥,通过在室内模拟不同的温度、扰动、pH共3个环境因子,考察其对底泥...     

底泥污染物释放动力学研究

采用模拟试验方式和新型微生物数量测定方法，研究了沼泽化湖泊底泥和受污染河流底泥在不同扰动状态下，底泥耗氧速率、氮和磷污染物释放动力学过程。结果表明：（1）底泥耗氧速率是同样条件下上覆水耗氧速率的48倍，而在扰动状态下，底泥氧速率达到上覆水耗氧速率的596－936倍，扰动底泥显著增大其耗氧速率，底泥污染越严重，其耗氧速率越大，对水体产生的影响也越大。（2）扰动底泥可以显著增大底泥的氮磷释放速率，氮的释放受到机氮的氨化、氨氮的硝化、硝酸盐氮的反硝化以及氨氮被微生物吸收转化为有机氮等的影响；磷的释放过程受厌氧过程和底泥颗粒吸附的影响，耗氧速率高的底泥具有更大的氨磷释放潜力。（3）微生物数量在底泥污染物释放动力学中起着关键性作用，亲型方法可以快速检测微生物总量。试验结果对于水环境的管理、受污染水体的修复，以及底泥的处理处置等都具有重要的指导意义。     

城市富营养化水体底泥净化磷效果

以城市富营养化水体底泥和上覆水为材料,研究了扰动状态下底泥对外源磷的净化效果。结果表明,扰动状态下,200 g湿底泥从上覆水中共吸收外源磷19.92 mg,而静止状态下,200 g湿底泥仅吸收了13.61 mg。然而,厌氧状态下,前者内源磷释放量仅占吸收磷量的43%,而后者则高达63.4%。说明底泥扰动不仅强化了底泥对外源磷的吸收,而且也强化了内源磷的固定能力。这与扰动状态下外源磷在不同形态磷间的数量分布有关。底泥扰动和静止状态下,难释放态磷(HCl-P、闭蓄态Fe/Al-P)的增加量分别占底泥吸收外源磷量的36%和21%。     

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.     

Patterns of volatile metabolites and nonvolatile trichothecenes produced by isolates of <Emphasis Type="Italic">Stachybotrys,Fusarium, Trichoderma,Trichothecium</Emphasis> and <Emphasis Type="Italic">Memnoniella</Emphasis>

We reported previously that trichodiene, a volatile trichothecene derivative, was produced by a Stachybotrys isolate, also known to produce highly cytotoxic, non-volatile, macrocyclic trichothecenes (satrotoxins). We investigated the relationship between the production of trichodiene and various non-volatile trichothecenes for several molds. Volatile metabolites were concentrated by adsorption on Tenax TA and analyzed by GC/MS, while non-volatile metabolites were separated by HPLC, derivatized and analyzed by GC/MS. Stachybotrys chartarum isolates producing macrocyclic trichothecenes secreted significantly larger amounts of trichodiene and other sesquiterpenes than isolates which only produced simple trichothecenes. The amounts of secreted trichodiene were relatively small in all cases. With the exception of Memnoniella, which excreted small amounts of sesquiterpenes, the other isolates produced varying amounts of sesquiterpenes, including trichodiene, as well as simple tricothecenes, no detectable trichodiene, but large amounts of griseofulvin derivatives. In Stachybotrys there is apparently a correlation between trichodiene and macrocyclic trichothecene production. In the remaining isolates, there was no simple relationship between trichodiene and non-volatile trichothecene synthesis. Trichodiene is produced in larger amounts by Stachybotrys isolates, which also produce satratoxins, but it will be difficult to utilize this metabolite to detect toxic isolates in buildings due to the relatively small amounts excreted.     

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.