Relation of Toxicity in Corn Seeds Treated with Zinc and Salicylic Acid

The beneficial effect of corn seed treatment with zinc (Zn) is directly related to the source used. The excess of this micronutrient causes seedling stress and reduces growth. Thus, assuming that the use of exogenous phytohormones can minimize such effects, we evaluated different doses and sources of Zn for the treatment of maize seeds with or without salicylic acid. The experiment took place in the laboratory, and two factorial experiments, 2 × 4 + 1, were performed in a randomized design. The seeds were treated with either ZnO or ZnSO₄ at doses of 0.5, 1, 2, and 3 g.kg^?1 seed with four replications, differing only by the addition of 4.14 mg L^?1 salicylic acid. Treating seeds with Zn and salicylic acid did not affect germination. ZnO led to a greater increase in dry mass in corn seedlings as compared with zinc sulfate, especially at higher doses (2 and 3 g kg^?1 seed). Seed treatment with sulfate reduces root and shoot length, and salicylic acid did not attenuate this toxic effect. Dry mass is not affected when oxide is used. Salicylic acid reduces the accumulation of zinc in the treatment of corn seeds, regardless of the source used.     

Occurrence and Distribution of Perfluorooctane Sulfonate and Perfluorooctanoic Acid in the Rivers of Tokyo

Comprehensive survey of major rivers in the Tokyo metropolitan area was conducted for clarifying the emission sources of perfluorooctane sulfonate (PFOS) in Tokyo. PFOS was found at all sampling sites at concentrations ranging from 0.5 to 58 ng L^?1; in addition to this, it was also indicated that unknown PFOS emission sources are present in the midstream of the Tama River basin. The relationship between PFOS and perfluorooctanoic acid (PFOA) was constant at a ratio of 10:3 (PFOS/PFOA) throughout the Tama River basin. The sum of daily load amounts of PFOS from Tokyo’s major rivers to Tokyo Bay reached 215 g day^?1. This value corresponds to 12.8 μg day^?1 per person using the sum of wastewater treatment district populations. In contrast, an estimation of PFOS contribution of domestic wastewater was also attempted, and the contribution was 1.6 μg day^?1 per person. We took samples up trunk sewers in the Tama River and finally found at the highest PFOS concentration (58,000 ng L^?1) from one of the wastewater of the electronic parts manufacturing facilities.     

生物措施缓解酸性土壤铝毒害研究进展

酸性土壤在世界上广泛存在,Al毒是酸性土壤限制作物生长和产量的主要限制因子之一.本文概述了酸性土壤Al毒害问题以及作物的耐Al机制,总结了遗传改良植物的耐Al性、向土壤或植物根际接种外生菌根真菌和其他耐Al微生物以缓解酸性土壤Al毒害的研究进展.以上措施在酸性土壤中的生态系统恢复具有应用前景.     

Modeling the Requirements of Agricultural Limestone in Acid Sulfate Soils of Brazil and Colombia

The aim of this study was to model the determination of the amount of agricultural limestone necessary to correct acidification in acid sulfate soils (ASS). This study used 14 equations and the chemical variables of the soils including pH, soil organic matter (SOM), potential acidity (H+ Al), sum of bases (BS), potential acidity (T), base saturation (V) and exchangeable Al with KCl. The results indicated that in the studied, the lowest requirements for doses of limestone (DL) were described by the equations DL = 2.906((H+ Al) (45-V)/100)°⁸⁰, DL = 0.08 + 1.22Al_KCl, DL = 0.6T – BS, and DL = 1.5Al_KCl, with mean values of 29.5, 30.5, 31.5 and 37.4 t ha^?1. In addition, the models with the best correlation for determining the limestone requirements to obtain 80% of the maximum production of sorghum (dry matter) were DL = ?1.43 + 0.9237 (SOM (6-pH)) and DL = ?0.022 + 2.7425 ((H+ Al) (45-V)/100).     

三江源区高寒草甸湿地植被退化与土壤有机碳损失

人为活动影响下陆地生态系统退化对于土壤碳库损失的影响规模是当前全球变化研究的热点。在青海省三江源区选择了8个高寒草甸典型样区,划分4种不同退化程度样地（原生植被、轻度退化、重度退化、极度退化）,收割法采集地上部植物生物量,10cm等深度采集表土土壤样品,分析了地上生物量、可食牧草生物量以及土壤有机碳含量变化。结果表明,随着退化程度的加剧,地上生物量和饲草生物量均表现强烈下降的趋势,但后者的下降幅度更大,在极度退化下损失达99％。研究区内高寒湿地土壤的表土有机碳含量出现极大的变异性,随退化程度的加剧而呈显著下降。与原生植被下相比,轻度退化、重度退化和极度退化下0-30cm土壤有机碳含量分别平均降低了25％、44％和52％。这种损失固然与地上部生物量下降有关,有机碳分层系数显示土壤侵蚀也是重要因素。估计退化下土壤有机碳平均下降36tC·hm^-2,累积退化下表土有机碳损失可能在200TgC以上,保护高寒草甸生态系统,对于三江源区土壤的畜牧业可持续发展和我国陆地生态系统碳库具有极重要的意义。     

Flow and pH Modelling to Study the Effects of Liming in Regulated, Acid Salmon Rivers

In the regulated river Ekso, Western Norway, liming of the headwater has been introduced as a mitigating action to improve the water quality for Atlantic salmon (Salmo salar L.). Supply of lime from a dosing plant situated 5 km above the salmon producing part of the river, aims to raise pH from 5,0 to 6,5 during the smolt period for Atlantic salmon, and to 6,2 for the rest of the year. Hydrological modelling based on the relationship between CaCO₃ and pH is applied for the evaluation of the liming strategy, based on monitoring data from the spring 2000. The water quality demand was satisfied 80% of the time in the upper part of the salmon area, and 40% of the time in the lower part, influenced by power plant discharge. Flood forecasting and overdosing of lime ahead of floods will reduce the effects of acidified and unlimed tributaries. An additional lime doser is recommended to supply the power plant discharge.     

The origin of Vertisols and their relationship to Acid Sulfate Soils in the Senegal valley

In the Senegal valley, it is commonly considered that the Acid Sulfate Soils of the delta are fossil soils overlain by more recent sediments, and that the Vertisols, which abruptly overlie a thick sandy horizon, result from a change in the sedimentation mode of the river. However, we show that both soils belong to the same pedological system extending from the delta to the limit of the last marine transgression. This conclusion is based on (1) the study of soil profiles intermediate between Acid Sulfate Soils and Vertisols along a 100-m sequence in the delta, (2) the mineralogy of the clay fraction (<2 μm) in a 200-km transect along the river, and (3) the similarity of the sand size distribution across the textural discontinuity between the horizons. The following processes are involved in the pedological transformations: (1) development of acidity by oxidation of pyrite, (2) neutralization of acidity initially by the carbonate in shell beds, and later by the hydrolysis of easily weatherable silicate clays. The slightly alkaline river water precipitates kaolinite and later smectite at the contact between the strongly acidic and slightly alkaline environments. This results in the formation of a superficial vertic clay horizon surmounting a sandy horizon. Therefore, we emphasize that the soil morphology results from development and control of acidity and not from changes in past climates.     

铁还原和硫酸盐还原对红壤中二苯砷酸释放与硫化的影响

二苯砷酸（diphenylarsinic acid,DPAA）是含砷化学武器在环境中的主要降解产物之一,研究铁还原和硫酸盐还原对土壤中DPAA释放与硫化的影响对于深入认识DPAA的环境地球化学行为至关重要。考察了在淹水和添加不同浓度乳酸钠（C）和硫酸钠（S）培养时花生地和林地红壤中DPAA的释放与硫化情况,并分析铁还原和硫酸盐还原的影响。结果显示：（1）对花生地而言,与不添加硫酸钠和乳酸钠（S-C-）以及仅添加硫酸钠（426 μg?g-1,以S计,S+C-）的处理相比,同时添加硫酸钠和乳酸钠（1 300 μg?g-1（以C计,下同）,S+C+;2 170 μg?g-1,S+C++）的处理中DPAA释放明显增强,这与乳酸钠促进了铁还原（>45%）从而有利于DPAA的释放有关;（2）在花生地的S+C+处理中硫酸盐还原最为显著（13周时溶解态硫化物浓度为11.28 mg?L-1）,DPAA的去除率（59.6%）最高且主要发生硫化,而在S+C++处理中铁还原程度的增加和硫酸盐还原程度的降低不利于DPAA的硫化;（3）与花生地不同,无论是否添加乳酸钠和硫酸盐,林地中未见DPAA的释放与硫化现象,这与其铁还原程度较低（<25%）和硫酸盐未发生还原（未检测到溶解态硫化物）有关;（4）与林地相比,花生地中梭菌属、芽孢杆菌属和脱硫芽孢杆菌属的丰度明显增加,这很可能分别促进了铁还原和硫酸盐还原,最终对DPAA释放和硫化产生了更显著的影响。总体而言,与铁还原促进DPAA的释放和进一步的硫化相比,硫酸盐的还原程度以及溶液相中硫化物的浓度很可能是控制淹水红壤中DPAA硫化的一个更重要的因素。研究结果将为深入认识DPAA的环境行为和发展DPAA污染红壤的生物刺激修复技术提供理论基础。     

Influence of the Soil Solution Composition on Retention and Release of Sulfate in Acid Forest Soils

The potential for sulfate retention is an important soil feature for buffering of atmospheric acid deposition. We studied the effects of increasing additions of different neutral salts and acids on mobilization and retention of SO₄ ²- in acid forest soils. Soils containing up to 11 mmol SO₄ ²- kg^-1 were equilibrated with H₂O, NaCl, MgCl₂, and HCl. Release of SO₄ ²- was highest with H₂O and NaCl additions and lowest when HCl was used. Increasing the ionic strength of the added solutions caused decreasing SO₄ ²- concentrations in equilibrium solution. Decreasing pH in equilibrium solution was found to be the reason for the decrease in release. Even when the pH was < 4, the SO₄ ²- release decreased. We assume that this finding resulted from the fact that in the soils studied the SO₄ ²- sorption was controlled by the high contents of Fe oxides/hydroxides. Experiments with Na₂SO₄, MgSO₄, and H₂SO₄ demonstrated that the B horizons already containing high amounts of SO₄ ²- were still able to retain SO₄ ²-. Sulfate retention increased in the order Na₂SO₄ < MgSO₄ < H₂SO₄, which corresponds to increasing H⁺ availability. The higher SO₄ ²- retention along with MgSO₄ compared to Na₂SO₄ may be caused by higher potential of Mg to mobilize soil acidity compared to Na.     

水稻和两种野生植物对酸性硫酸盐土耐性及矿质元素吸收

酸性硫酸盐土是发育于还原性硫化物成土母质的一种恶劣土壤类型,虽然其分布区气候条件十分有利于水稻生长,但由于土壤条件限制,水稻生产潜力难以发挥。为筛选出适应该土壤的水稻品种,在酸性硫酸盐土(pH 3.69)上种植了240个水稻品种,但是所有水稻品种均未获得经济产量,却发现两种野生植物在该土壤中生长茂盛。经形态和分子鉴定,两种野生植物为野荸荠(Eleocharis kuroguwai)和五棱飘拂草(Fimbristylis quinquangularis)。进一步分析了水稻和两种野生植物的根际和非根际土壤性质、根部和地上部矿质元素含量。结果表明,根际土壤pH、交换性铝和有效锰含量不能解释水稻和两种野生植物耐性差异,锰毒和缺氮亦不是酸性硫酸盐土限制植物生长的关键因子,而植物地上部矿质元素含量与植物耐性差异相关。铝毒、铁毒和较低的养分(磷、钾、钙、镁)吸收是酸性硫酸盐土中水稻生长不良的主要因子。相反,两种野生植物对铝毒和铁毒的耐性较强,对养分吸收能力较强,所以生长良好。     

Phosphorus Solubilizing Microorganisms in the Rhizosphere of Local Rice Varieties Grown without Fertilizer on Acid Sulfate Soils

Local farmers who living in South Kalimantan (Banjarese farmers) apply almost none of phosphatic (P) fertilizers to grow local rice varieties. This practice has been adopted for many years. We have investigated the mechanisms involved in P availability for the crop. This study focuses on identifying microorganisms involved in solubilizing insoluble P. The study was conducted in Balandean District, South Kalimantan, Indonesia. The soil was classified as acid sulfate soil. Three out of 8 rice varieties grown were selected for net P balance in the soil-plant system and the microbial studies. We found that the P uptakes by the rice crop was much higher than the sum of P released from soil, water and soil microbial biomass P. It was also observed that these soils harboured bacteria and fungi that have the capability of dissolving aluminium phosphate (AIPO₄) and tricalcium phosphate [Ca₃(PO₄)₂].
Based on the area of clear zone on plates, it seem that there were variations of ability in dissolving Al-P or Ca-P. DNA sequence analysis shown that Burkholderia sp. was the common P solubilizing bacterium found in the rhizosphere of rice varieties Siam Unus, Siam Ubi and Siam Puntal. The presence of other bacteria was specific for each rice variety grown.     

Spatial Variation and Correlations of Mercury Levels in the Terrestrial and Aquatic Components of a Wetland Dominated Ecosystem: Kejimkujik Park,Nova Scotia,Canada

This study investigates the ranges and spatial variation ofmercury in various media in the wetland ecosystems ofKejimkujik Park, Nova Scotia. Mercury concentrations infive-year-old yellow perch (age based on regression analysesof existing data) ranged from 0.12–0.72 μgg^-1(wet weight basis) in 24 lakes. Mercury concentrations inred maple ranged from 5 to 41 ng g^-1 and levels inwhite pine ranged from 5 to 58 ng g^-1, dry weight.Concentrations of total mercury were found to besignificantly higher in epiphytic lichens (maximum of 660 ngg^-1) and in feather mosses (maximum of 395 ng g^-1)compared to vascular species. The soil Ah horizon exhibitsthe highest concentrations for both mercury and gold, withmaximum values of 466 and 42.8 ng g^-1 respectively;whereas the C-horizon appears to host the most Zn (maximum209.9 μg g^-1). Lake water pH and dissolved organic carbon (DOC) were thevariables most highly correlated with mercury in lake watersand yellow perch. No correlations were observed betweenmercury in terrestrial components and mercury in yellowperch; however, mercury in yellow perch was correlated withP in leaf tissues of both red maple and white pine. Theimportance of understanding linkages between terrestrial andaquatic ecosystems is emphasized through this study.     

Status of Zoobenthos and Fish Populations in Subarctic Rivers of the Northernmost Finland: Possible Effects of Acid Emissions from Russian Kola Peninsula

In 1990, a monitoring programme was initiated to survey the status of benthic invertebrate communities and fish populations over a wide range of subarctic rivers in northernmost Finnish Lapland (68°15′–70°N). A special emphasis was placed on detecting possible effects of acidification through sulfur emissions from Russian Kola Peninsula. Sampling in 13 rivers within four major river systems covered watercourses from small brooks to large 7th order rivers, and watersheds with different distances from the emission sources. The community structure of zoobenthos and the occurrence of acid-sensitive indicator species were assessed in 90 sampling sites. Sensitive fluvial fish species, including Atlantic salmon (Salmo salar), brown trout (Salmo trutta), European minnow (Phoxinus phoxinus) and burbot (Lota lota), were monitored by studying their occurrence, abundance and juvenile recruitment. No signs of acid-induced failure in juvenile recruitment were detected in salmonid populations. The occurrence of minnow and burbot covered all the systems studied. In parallell, the structure of benthic communities with relatively high species diversity and wide distribution of a highly acid-sensitive caddisfly indicated no effects of acidification.     

外源有机酸对蚯蚓Zn积累的影响及毒性研究

为研究外源有机酸是否会增加土壤动物蚯蚓对重金属的吸收,从而加剧重金属对土壤生态系统的危害,采用溶液法,以锌为目标污染物,研究添加有机酸(乙酸、草酸、柠檬酸和EDTA)后,重金属对蚯蚓的毒害效应。结果表明,有机酸能有效缓解Zn对蚯蚓的毒性,缓解强弱顺序为EDTA柠檬酸草酸乙酸,主要表现为蚯蚓死亡率降低。暴露在Zn浓度为5,10,15 mg/L的溶液中时,死亡率分别为20%,55%,83.75%,随着有机酸浓度增加,蚯蚓死亡率下降越显著;抗氧化酶(SOD、CAT)和丙二醛(MDA)含量下降,不同的有机酸对蚯蚓SOD、CAT活性的影响不一,MDA含量则有明显的下降趋势,甚至接近于对照水平。这主要是由于有机酸抑制了蚯蚓对Zn的富集,有机酸的络合作用改变了Zn的亚细胞分布,E(胞残渣)组分的比例下降,而H(热稳定组分)组分上升,从而降低了重金属所引起的毒害。因此,有机酸在控制重金属的生物可利用性方面具有重要作用。     

Heavy Metals in Freshly Deposited Stream Sediments of Rivers Associated with Urbanisation of the Ganga Plain,India

Freshly deposited stream sediments from six urban centres of the Ganga Plain were collected and analysed for heavy metals to obtain a general scenery of sediment quality. The concentrations of heavy metals varied within a wide range for Cr (115–817), Mn (440–1 750), Fe (28 700–61 100), Co (11.7–29.0), Ni (35–538), Cu (33–1 204), Zn (90–1 974), Pb (14–856) and Cd (0.14–114.8) in mg kg^-1. Metal enrichment factors for the stream sediments were <1.5 for Mn, Fe and Co; 1.5–4.1 for Cr, Ni, Cu, Zn and Pb; and 34 for Cd. The anthropogenic source in metals concentrations contributes to 59% Cr, 49% Cu, 52% Zn, 51% Pb and 77% Cd. High positive correlation between concentrations of Cr/Ni, Cr/Cu, Cr/Zn, Ni/Zn, Ni/Cu, Cu/Zn, Cu/Cd, Cu/Pb, Fe/Co, Mn/Co, Zn/Cd, Zn/Pb and Cd/Pb indicate either their common urban origin or their common sink in the stream sediments. The binding capacity of selected metals to sediment carbon and sulphur decreases in order of Zn > Cu > Cr > Ni and Cu > Zn > Cr > Ni, respectively. Stream sediments from Lucknow, Kanpur, Delhi and Agra urban centres have been classified by the proposed Sediment Pollution Index as highly polluted to dangerous sediments. Heavy metal analysis in the <20-μm-fraction of stream sediments appears to be an adequate method for the environmental assessment of urbanisation activities on alluvial rivers. The present study reveals that urban centres act as sources of Cr, Ni, Cu, Zn, Pb and Cd and cause metallic sediment pollution in rivers of the Ganga Plain.     

菌糠搭载硫酸铝对盐碱地稻田养分状况的影响研究

基于盐碱地稻作改良,菌糠、Al_2(SO_4)_3各具优势。以大安市盐碱地稻田为供试对象,共设置菌糠搭载Al_2(SO_4)_3、菌糠、Al_2(SO_4)_3改良剂、单施化肥和池梗地对照五个处理,分别从水稻栽植前及当季生产结束后对盐碱地养分状况进行对比分析。结果表明:与对照相比,基于灌水泡田,四个改良处理均能够迅速提升盐碱地稻田有机质、有效磷的含量,Al_2(SO_4)_3、菌糠及单一化肥施入短期内即可促进稻田全磷、全钾含量的提升,搭载Al_2(SO_4)_3的菌糠尽管对两者影响不大,但能缓解碱解氮的流失;历经水稻生育期,菌糠及其配施Al_2(SO_4)_3以及单一化肥施入的三个处理均能有效促进盐碱地稻田有机质的矿化,反之,Al_2(SO_4)_3改良剂更利于有机质含量的累积;在此过程,各改良处理条件下的全磷含量均有所增加,但碱解氮含量均有消耗,其中,以菌糠搭载Al_2(SO_4)_3处理的效果更为明显;在水稻生产过后,与对照相比,单施化肥及菌糠施入能够对稻田全钾含量有所促进,而单施化肥及Al_2(SO_4)_3改良剂处理能够加速有效磷的消耗,与此同时,菌糠搭载Al_2(SO_4)_3、Al_2(SO_4)_3改良剂及单施化肥的三个处理更有利于速效钾含量的累积。     

Long-term in situ Toxicity Bioassays of the Reconquista River (Argentina) Water with Cyprinus carpio as Sentinel Organism

Since the early 1970s, more than 25% of Japanese red pine forests have died or declined in Hiroshima Prefecture, Japan. Mass mortality phenomenon of pine trees has appeared throughout Japan, expanding northward from the Prefectures in southern Japan such as Nagasaki, Kogashima. The mortality was above 80% in Nagasaki, Kumamoto, Miyazaki and Tokyo. This study shows that the massive mortality of pines forest mainly occurred in south-facing slopes, where mortality was 90% in Gokurakujisann Mount, Hiroshima. The mortality was very low, < 3.7%, on north-facing slopes and mountain peaks. On west-facing slopes, the mortality was 20–40%. The foliar phenological development on south-facing slopes was 14 days earlier than that on north-facing slopes, 18 days earlier than that on mountain peaks. The mortality of pine trees in Gokurakujisann Mount increased with earlier phenological development and was significantly correlated (R = 0.98^**). The mortality of pine trees in each Prefecture increased from south to north with earlier phenological progress and was significantly correlated (R = 0.56^**). The outbreak of pine tree mortality was closely related to appearance of abnormally extreme lowest air temperature in February and March. The annual ring width in Gokurakujisann Mount was decreased from 1972 to 1984, concomitantly the abnormally extreme lowest air temperature in February and March. Based on these, it may be concluded that the combined effects of accelerated phenological progress and reduced frost hardiness caused by acid deposition, mainly nitrogen deposition, and extreme abnormally lowest air temperature in late winter and early spring in February and March are the original main factors of mortality of pine trees on a large scale.     

鲐鱼软骨糖胺聚糖的硫酸软骨素的结构及其与生长因子的相互作用

为了开发具有药用价值的硫酸软骨素(chondroitin sulfate,CS)的新资源,从鲐鱼(Pneumatophorus japonicus Houttuyn)软骨蛋白聚糖(proteoglycan,PG)制备了糖胺聚糖(glycosaminoglycan,GAG),用酶降解和阴离子交换HPLC法测定了GAG的CS的组成及其含量,用凝胶层析法测定了GAG的分子量,用表面等离子体谐振(surface plasmon resonance,SPR)法测定了其与多效生长因子(PTN)、中期因子(MK)和肝细胞生长因子(HGF)相互作用的动力学参数结合速率常数(ka)、解离速率常数(kd)和平衡解离常数(KD)。结果显示,鲐鱼软骨GAG含量约为651μg/mgPG或1.09μmol/mgPG(按照二糖单位计算),主要含CS(1.03μmol/mgPG,按照二糖单位计算),CS酶解产生的主要二糖单位是ΔDi-6S(38.8%)和ΔDi-4S(46.3%),有少量的ΔDi-0S(8.4%)和ΔDi-diSD(6.5%)。GAG(CS)的分子量为78kD。GAG(CS)与生长因子的相互作用的动力学参数ka((mol/L)-1.s-1)、kd(s-1)和KD(nmol/L)分别为(2.77±0.17)×105、(7.74±1.56)×10-5和(0.28±0.06)(MK),(1.05±0.22)×104、(4.16±0.80)×10-3和(417±131.3)(PTN),(7.04±0.94)×105、(7.84±2.82)×10-3和(11.1±3.80)(HGF)。该GAG同MK、HGF和PTN有高的或较高的亲和性,暗示鲐鱼软骨GAG的CS有可能通过调节生长因子的信号转导途径而对某些疾病发挥治疗作用,具有潜在进一步药用开发价值。     

主动作为 勇于担当 龙南县生态优美明珠县建设成绩斐然

江西省龙南县高度重视水土保持工作,20世纪80年代就创立了稀土矿山尾砂综合治理的"龙南模式"。在新的形势下,县委、县政府主动作为,勇于担当,出台了一系列水土保持工作的规范性文件,为水土保持监督执法铸造了一把"尚方宝剑"。同时,该县水土保持部门与时俱进,以水土保持科技示范园、生态示范园建设为抓手,突出特色,打造精品,为乡村振兴和美丽乡村建设贡献了水土保持智慧和力量,促进了龙南县生态明珠县建设。