实测/预测辽河铬(Ⅵ)水生生物基准与风险评估

该研究对辽河流域重金属铬(Ⅵ)的水生生物毒性数据进行搜集与筛选,推导辽河流域铬(Ⅵ)的水生生物基准值,并对辽河流域25个采样点位采集水样,测定铬(Ⅵ)的环境暴露浓度,最后对辽河流域水生生物铬(Ⅵ)暴露的潜在风险进行评估.此外,采用美国环境保护署(US EPA)物种种间关系估算模型(ICE)对辽河流域物种毒性值进行预测,并对基于预测毒性值的水生生物基准进行推导.结果表明,辽河流域基于实测毒性数据的水生生物急性基准值(CMC)为17.73μg·L-1,慢性基准值(CCC)为12.15μg·L-1;ICE模型预测的辽河流域生物毒性值推导的CMC值为13.97μg·L-1,实测CMC值与预测值比较接近,表明ICE模型可应用于水生生物基准值的预测.铬(Ⅵ)的水质分析结果表明25个采样点位水体铬(Ⅵ)浓度较低,均达到GB 3838-2002地表水质标准中铬(Ⅵ)的Ⅰ类或Ⅱ类标准,水质状况良好;然而,在对水生生物的潜在风险方面,通过生态风险评估得出7月辽河流域25个点位中环境暴露值超过慢性基准CCC值的有7个,12月超过慢性基准CCC值的有6个,表明辽河流域个别点位铬(Ⅵ)暴露可能会对水生生物产生不可接受的风险.     

Biodegradation of phenol and m-cresol by mutated Candida tropicalis

The phenol and m-cresol biodegradations were studied using the mutant strain CTM 2 obtained by the He-Ne laser irradiation on wild-type Candida tropicalis. The results showed that C. tropicalis exhibited the increased capacity of phenolic compounds degradation after laser irradiation. It could degrade 2600 mg/L phenol and 300 mg/L m-cresol by 5% inoculum concentration, respectively. In the dual-substrate biodegradation system, 0–500 mg/L phenol could accelerate m-cresol biodegradation, and 300 mg/L m-cresol could be completely utilized within 46 hr at the presence of 350 mg/L phenol. Besides, the maximum biodegradation of m-cresol could reach 350 mg/L with 80 mg/L phenol within 61 hr. Obviously, phenol, as a growth substrate, could promote CTM 2 to degrade m-cresol, and was always preferentially utilized as carbon source. Comparatively, low-concentration m-cresol could result in a great inhibition on phenol degradation. In addition, the kinetic behaviors of cell growth and substrate biodegradation were described by kinetic model proposed in our laboratory.     

基于组内-组间主成分分析的土地利用与团聚体有机碳关系的研究

通过对喀斯特山区典型土地利用方式下(灌丛、水田、菜园、玉米地和退耕地)土壤有机碳、团聚体有机碳在不同土壤层次下(0~10、10~20、20~30 cm)含量的系统研究,结合组内-组间主成分分析方法,探讨了喀斯特山区土地利用与团聚体有机碳分布的关系.结果表明:不同土地利用方式下土壤团聚体组成均以大粒径团聚体为主,并且 > 2 mm粒径团聚体对土壤总有机碳的贡献率可高达70%以上.随土壤层次的增加,土壤有机碳和团聚体有机碳含量降低明显,变幅范围分别为15.1~38.0 和15.4~40.3 g· kg^-1,表现以水田含量最高,菜园和灌丛相对居中,而以退耕3 a 草丛最低.组内-组间主成分分析结果显示,不同土地利用方式下土壤有机碳和团聚体有机碳的累积效应按水田、菜园、灌丛、退耕15 a 草丛、玉米地和退耕3 a 草丛依次下降,表明水田可作为喀斯特山区土壤有机碳固定的优势农业类型.与玉米地相比,退耕3 a 草丛有机碳储量降低了15.8%,而退耕15 a 草丛土壤有机碳储量有所提高,但恢复速率相对缓慢,以每年0.35 Mg· hm^-2的速度增加.     

Intersexual plasticity in aspects of the biology of the mudskipper Periophthalmus barbarus (Gobhdae) in the mangrove swamps of IMO Estuary, Nigeria

Between April 1992 and March 1993,intersexual plasticity in aspects of the biology of the mudskipper,Periophthalmus barbarus was studied.Sec was differentiated on the basis of the genital papillae,it was broader in females than males.Sexually active females were slightly heavier than similarly-sized males.Sex ratio was strongly female-biased.Length-weight relationship of the sexes was isometric.There was no significant difference in the feeding intensity of both sexes;uniformity was also apparent in diet breadth.There was no named sex-based difference in hepatosometic index but condition index was higher in males than females.the uniformity in intersexual plasticity of P.barbarus is consequent upon homogeneity of the mangrove ecosystem,which can only be altered anthropogenically.     

Performance of dithiocarbamate-type flocculant in treating simulated polymer flooding produced water

Produced water from polymer flooding is di cult to treat due to its high polymer concentration, high viscosity, and emulsified characteristics. The dithiocarbamate flocculant, DTC (T403), was prepared by the amine-terminated polyoxypropane-ether compound known as Je amine-T403. The product was characterized by IR spectra and elemental analysis. The DTC agent chelating with Fe2+ produced a network polymer matrix, which captured and removed oil droplets e ciently. Oil removal by the flocculent on simulated produced water with 0, 200, 500, 900 mg/L of partially hydrolyzed polyacrylamide (HPAM) was investigated for aspects of e ectiveness of DTC (T403) dosage and concentrations of HPAM and Fe2+ ions in the wastewater. Results showed that HPAM had a negative influence on oil removal e ciency when DTC (T403) dosage was lower than 20 mg/L. However, residual oil concentrations in tested samples with di erent concentrations of HPAM all decreased below 10 mg/L when DTC (T403) dosage reached 30 mg/L. The concentration of Fe2+ in the initial wastewater had a slight e ect on oil removal at the range of 2–12 mg/L. Results showed that Fe3+ could not be used in place of Fe2+ as Fe3+ could not react with DTC under flocculated conditions. The e ects of mineral salts ions were also investigated.     

氨基比林在氯化消毒前后对小球藻生长及生理特性的影响

为探讨典型的吡唑酮类药物——氨基比林(Aminopyrine,AMP)在氯化消毒前后对普通小球藻生长及生理特性的影响,设置了生长抑制试验和生理特性影响试验。在生长抑制试验中,设定药物暴露质量浓度为0.1~32.0 mg/L,共7个处理组,以不加药物组为对照组,再按照药物与氯气(C12)物质的量比为4:1、1:1、1:2、1:5分别向各处理组加入相应的NaClO溶液,并氮吹至余氯在检测限下,测定小球藻的生物量。结果表明:72 h内小球藻的生长抑制率先升高后降低,并随药物质量浓度升高而升高;氯化消毒处理后,抑制率随投氯量增加而上升。在生理特性影响试验中,设置药物质量浓度为2.0~32.0 mg/L,共5个处理组,其他处理同生长抑制试验,测定培养96 h后的抗氧化酶(超氧化物歧化酶SOD、过氧化氢酶CAT)活性和丙二醛(MDA)含量,结果表明:MDA含量随机体抗氧化酶活性降低而升高;氯化消毒处理后,1:5处理组的SOD和CAT活性均低于氯化消毒前,而MDA含量均高于氯化消毒前,表明该比例的氯化消毒对小球藻的抑制作用较其他各组更为显著。     

防晒剂对氨基苯甲酸在硝酸根溶液中的光解研究

以氙灯为模拟太阳光光源,研究了防晒剂分子对氨基苯甲酸（PABA）在硝酸根溶液中的光解,探讨了pH值、硝酸根离子的浓度和天然水体中广泛存在的腐殖质浓度对防晒剂PABA光解速率的影响.结果表明,PABA在硝酸根溶液中的光解反应符合一级动力学规律,PABA的光化学反应速率随硝酸根离子浓度的提高显著增大,其速率常数可由0.00...     

ECHA向候选物质清单中增加7种物质

<正>2013年12月16日ECHA向REACH候选物质清单中增加了7种高度关注物质(SVHC)。这些物质是:1)硫化镉,基于致癌性和关于其对人类肾脏和骨骼的影响的严重关注增加;2)3,3'-[[1,1'-联苯]-4,4'-二基双(偶氮)]二(4-氨基萘-1-磺酸)二钠(C.I.直接红28),基于其致癌性增加;     

溴酸钾氧化氨基黑10B催化光度法测定痕量亚硝酸根

研究了在磷酸介质中 ,痕量亚硝酸根对溴酸钾氧化氨基黑 1 0 B的催化褪色作用 ,建立了催化动力学光度法测定痕量亚硝酸根的新方法 ,并探讨了动力学反应条件 ,方法的线性范围为 0～ 1μg/1 0 ml,检出限为 4.88× 1 0 - 9g/ml,用于地面水及雨水中亚硝酸根的测定 ,结果满意。     

4-氨基安替比林比色法测定土壤中挥发酚含量探讨

用4—氨基安替比林比色法测定土壤中挥发酚，经过对不同性质的土壤样品进行分析及质控实验，结果证明操作简便，准确度及精密度均符合质量保证要求。