Effects of a fire-retardant chemical to fathead minnows in experimental streams

BACKGROUND: Each year millions of liters of fire-retardant chemicals are applied to wildfires across the nation. Recent laboratory studies with long-term fire-retardant chemicals indicate a significant photoenhanced toxicity of products containing sodium ferrocyanide corrosion inhibitors. Our objective of this study was to determine the toxicity of fire-retardant chemicals to fathead minnows during exposure in experimental outdoor streams. METHODS: Stream tests were conducted to determine the potential toxicity of a pulse of exposure as might occur when fire retardant chemical is rinsed from the watershed by rainfall. Two artificial 55-meter experimental streams were dosed with different concentrations of Fire-Trol GTS-R, or uncontaminated for a control. Replicate groups of fathead minnows were added to screened containers (10 fish per container) and exposed to retardant chemicals in the recirculating flow of the stream for up to 6 hours. RESULTS AND DISCUSSION: Under field conditions toxicity of GTS-R only occurred in the presence of sunlight. When GTS-R was tested on sunny days, 100% mortality occurred. However, when tested during heavily overcast conditions, no mortality occurred. CONCLUSIONS: Lethal concentrations of cyanide were measured when GTS-R with YPS exposures were conducted under sunny conditions, but not under cloudy conditions, indicating that a minimum UV level is necessary to induce toxicity as well as the release of cyanide from YPS. The toxicity observed with GTS-R was likely associated with lethal concentrations of cyanide. Rainwater runoff following applications of this fire-retardant at the recommended rate could result in lethal concentrations in small ponds and streams receiving limited water flow under sunny conditions. RECOMMENDATIONS AND OUTLOOK: In addition to avoiding application to aquatic habitats, it is important to consider characteristics of the treated site including soil binding affinity and erosive properties.     

磁性海藻酸铁介孔碳微球的合成及对水体中砷的去除

本研究以海藻酸钠作为基体前驱材料,利用离子交联法合成了海藻酸铁微球,然后进一步运用真空冷冻和高温裂解法制备了表面附着纳米铁氧化物的磁性海藻酸铁介孔碳微球(MAMC).同时,采用热场发射扫描电镜显微镜、X射线光电子能谱、热重分析仪、磁学测量系统、BET比表面孔径分析仪等对MAMC进行表征,并研究了MAMC对As(Ⅲ)和As(Ⅴ)的吸附性能,重点考察投加量、pH、时间、初始污染物浓度对吸附性能的影响,并对吸附过程进行了动力学拟合和等温吸附方程拟合,最后对材料进行了再生实验.结果表明,MAMC对As(Ⅲ)和As(Ⅴ)均表现出良好的吸附性能,对As(Ⅲ)的吸附能力优于As(Ⅴ);当pH值为5~7时,MAMC对两种价态As的吸附效率最优;材料的吸附量随着时间的增加而增加.动力学拟合结果表明,MAMC的吸附过程较好地满足准二级动力学方程,等温吸附曲线较好地满足于Langmuir方程.此外,使用0.1 mol·L~(-1)的Na OH对材料的再生和脱附效果较好,能够实现材料的二次利用.本研究结果对处理含砷废水提供了重要的理论依据.     

烟气脱硫石膏对滨海盐渍土的改良效果

为研究烟气脱硫石膏对滨海盐渍土的改良效果,选取上海南汇东滩的滩涂盐渍土为研究对象,开展了两年的烟气脱硫石膏修复试验,研究不同施用量（0、15、30、45和60 t/hm2）烟气脱硫石膏对滨海盐渍土化学性质的改良效果和对绿化乔木生长特性的影响,以及烟气脱硫石膏作为滨海盐渍土改良剂的重金属安全性.结果表明:施加适量烟气脱硫石膏显著降低了滨海盐渍土的pH和ESP（碱化度）,增加了对植物生长有利的Ca2+和SO₄2-含量,减少盐渍土中对植物生长有害的Na+和Cl-含量,降低了土壤速效磷和速效钾含量,增加了植物的株高和胸径.与对照处理相比,烟气脱硫石膏处理的土壤pH和ESP分别降低了5.7%~14.4%和16.7%~59.4%;土壤水溶性Na+和Cl-的含量降低了25.8%~64.4%和16.7%~59.5%,而土壤水溶性Ca2+和SO₄2-含量分别增加了4.08~31.30倍和9.83~23.33倍.施用烟气脱硫石膏2 a后,土壤速效氮与对照处理相比无显著差异,但土壤速效磷和速效钾含量分别较对照处理下降了35.6%~41.1%和21.9%~48.5%.烟气脱硫石膏施用量为60 t/hm2时,银杏和紫薇的株高分别增长了25.1%和34.7%,胸径分别增加了64.5%和35.2%.施用烟气脱硫石膏不会造成土壤重金属污染,不同处理下的土壤重金属含量均小于GB 15618—1995《土壤环境质量标准》二级标准.研究显示,烟气脱硫石膏应用于滨海盐渍土的改良,可以有效改善土壤质量和生态环境,为滨海城市贡献绿色耕地或绿化用地.      

硫化钠对土壤汞、镉、铅的植物可利用性的调控

针对重庆市蔬菜重金属污染现状,通过盆栽试验,研究了硫化钠对污染土壤中Hg、Cd、Pb活性的影响及它们在植物体内的积累效应,筛选出控制叶菜类蔬菜中汞、镉、铅等重金属污染物进入蔬菜的经济有效、易于实施的化学添加剂用量,为蔬菜基地土壤重金属污染控制提供可靠的技术措施。分析结果表明,硫化钠能减少土壤中Hg、Cd的残留量,增加Hg、Cd的植物可利用性;降低土壤Pb的活性,减少Pb的植物可利用性。当硫化钠施用量为0.00351 thm-2时,植物体Pb质量分数下降了23.8%,同时使植物的生物量增加。     

菊酯类杀虫剂抗性棉铃虫para型钠离子通道基因的部分序列测定与突变

昆虫神经系统para型钠离子通道是菊酯类杀虫剂的主要靶标，对10多种昆虫的研究表明，钠离子通道基因发生点突变与昆虫对菊酯类杀虫剂的抗性密切相关．通过RT-PCR扩增的方法，我们获得了编码溴氰菊酯抗性和敏感品系棉铃虫钠离子通道域Ⅱ-Ⅳ的cDNA片段．核苷酸序列及推导的氨基酸序列分析结果表明，溴氰菊酯抗性品系棉铃虫钠离子通道基因不存在其它昆虫中报道的kdr和super-kdr抗性突变，但是我们发现了一个甲硫氨酸(M)到亮氨酸(L)的新突变，该突变位于域Ⅱ和Ⅲ之间．由于昆虫钠离子通道高度保守，因此，该突变很可能与棉铃虫对溴氰菊酯的抗性有关．另外，通过PCR扩增的方法，克隆了棉铃虫钠离子通道域Ⅱ-Ⅳ的基因片段，该片段全长7334bp，包含有13个外显子和12个内含子，与果蝇和烟蚜夜蛾相比，内含子在基因中的位置基本一致，进一步表明昆虫钠离子通道基因在进化过程中高度保守．图5表1参22     

高浓度褐藻酸钠生产废水处理工程设计

利用以EGSB反应器为主体的生物法与混凝工艺相结合处理高浓度褐藻酸钠生产废水，处理水质可达到国家污水综合排放二级标准。工程实践表明该工艺具有投资与占地面积少，运行效果稳定，可回收能源等优点。     

Exposure to metals (Ca,K, Mn) and road salt (NaCl) differentially affect development and survival in two model amphibians

ABSTRACT

Human activity has led to widespread chemical alteration of natural environments. Aquatic ecosystems are especially susceptible to chemical changes, including those caused by runoff and invasive species. Here, we examined the effects of water chemistry, specifically sodium chloride as well as three metals (Ca, K, and Mn) known to differ between native and invasive wetland plant species’ leaf tissues, on the development of two model amphibians: the native Northern leopard frog, Lithobates pipiens, and the non-native African clawed frog, Xenopus laevis. We exposed frog eggs to metal treatment solutions and measured time to hatching (TTH), and following hatching, we exposed tadpoles to a lethal concentration of sodium chloride and recorded time to death (TTD). We found that increasing metal concentrations generally resulted in acceleration of TTH for Xenopus tadpoles, but had no effect on leopard frogs. However, increasing metal concentrations (Ca, Mn) increased leopard frog tadpole susceptibility to NaCl (decreased TTD), while increasing metal concentrations (Ca, K) generally resulted in decreased Xenopus tadpole susceptibility to NaCl. Overall, our data suggest that invasive amphibians may be more tolerant to chemical changes than native amphibians, including those driven by the introduction of invasive plant species.     

亚硒酸钠对蚯蚓的毒性及蚓体富硒作用的研究

以100mgkg^-1,200mgkg^-1,300mg kg^-1等不同质量分数（w)的亚硒酸钠（NaSeO2)添加到蚯吲饵料中,研究了亚硒酸钠处理对蚯蚓生长发育及死亡的影响和蚯蚓的富硒作用,结果表明,3个w(NaSeO2)处理对蚯蚓生长发育和富硒量的影响都达到极显著水平,w(NaSeO2)越高,用其处理饲养的蚯蚓死亡率也较高,富硒量也较大,二者存在一定的正相关性,在200mg kg^-1的w(NaSeO2)处理下,当蚯蚓饲养到84d时,蚯蚓的富硒量可达到332．5mg kg^-1,同时死亡率高达90％。     

联碱废水资源化治理工艺的研究

提出预处理→二级蒸馏→吹脱治理联碱废水的新工艺 ,不仅使废水中的氨氮达到排放标准 ,而且能回收氨氮 ,具有一定的经济效益和社会效益。     

氟化钠与强致突变物联合诱致的高等植物细胞微核效应

氟化钠在与强致突变物的联合实验中均发生较强的颉颃(减毒)作用,例如非常显著地抑制由平阳霉素(染色体断裂剂)或秋水仙素(有丝分裂毒素)诱致的微核效应(F＇相似文献