16种除草剂对家蚕的毒性评价研究(Toxicity Evaluation of Sixteen Herbicides to Bombyx mori)

采用食下毒叶法在室内测定了二甲戊乐灵、异丙甲草胺、草甘膦铵盐等16种除草剂对家蚕的急性毒性,并根据其毒性范围进行分极,评价了其对环境的安全性.结果表明,10%啶嘧磺隆可湿性粉剂96hLC50为5.58mg·kg-(1桑叶),属于高毒;50%草甘膦可溶粉剂和80%莠灭净可湿性粉剂96hLC50分别为68.17mg·kg-(1桑叶)和111.75mg·kg-1(桑叶),属于中毒;其它13种药剂的LC50>200mg·kg-(1桑叶),属于低毒.     

集约化蔬菜地土壤磷素累积特征及流失风险

以南京市郊集约化蔬菜长期种植基地为对象,采集蔬菜种植年限分别为3~5、15~20、25~30 a的土壤,测定土壤全磷(TP)、速效磷(Olsen-P)、水溶性磷(CaCl2-P)、生物有效磷(NaOH-P)的含量,并对0—20 cm土层磷素吸附特性进行分析,通过研究土壤磷吸附饱和度(DPS)、最大缓冲容量(MBC)来对土壤磷素流失风险进行评估。结果表明,在0—20 cm土层,除NaOH-P外,其余各形态磷(TP、Olsen-P、CaCl2-P)都随种植年限延长呈增加趋势。不同种植年限土壤TP、Olsen-P、CaCl2-P、NaOH-P主要积累在0—20 cm土层,且随着土层深度的增加土壤磷的累积量逐渐降低。DPS随种植年限延长而升高,种植年限25~30 a的菜地0—5 cm土层DPS超过土壤磷素流失环境敏感指标临界值(25%),其MBC也最低,表明随着蔬菜种植年限的延长土壤磷素流失风险加剧,且流失风险主要体现在0—5 cm土层。     

Leachability of elements from sub-bituminous coal fly ash from India

Environmental concerns regarding the potential contamination of soil, surface and ground water due to the presence of soluble metal species in the ash pond leachate is of great importance. Serial batch leaching was carried out simulating the rainwater condition of the study area to understand the behaviour of elements during leaching. The leachates were analysed for the elements Al, Ca, K, Mg, Na, P, S, Si, As, Ba, Fe, Mn, Mo, Ti, V, Pb, Zn, Co, Cr, Cu, Ni and Cd by inductively coupled plasma optical emission spectrometer (ICP-OES). It was found that Cd, Co, Cr and Ni did not leach from the ash while Cu and Pb concentrations were insignificant in the leachate regardless of liquid to solid (L/S) ratio. Most of the elements showed maximum concentrations at lower L/S ratio and then decreased with increasing L/S. The total cumulative concentrations of As, Mn and Mo were found to be higher than the World Health Organization (WHO) recommended values for drinking water while the concentrations of Fe, Mn and As exceeded the maximum allowable concentrations prescribed by the United States Environmental Protection Agency (USEPA). The pre and the post leached ash samples were analysed for morphology, specific surface area and mineralogical changes. Analysis of post-leached fly ash indicated changes in the specific surface area and morphology but no change in mineralogy.     

Determinants of nitrous oxide emission from agricultural drainage waters

Emissions of the powerful greenhouse gas nitrous oxide (N₂O) from agricultural drainage waters are poorly quantified and its determinants are not fully understood. Nitrous oxide formation in agricultural soils is known to increase in response to N fertiliser application, but the response of N₂O in field drainage waters is unknown. This investigation combined an intensive study of the direct flux of N₂O from the surface of a fertilised barley field with measurement of dissolved N₂O and nitrate (NO₃) concentrations in the same fields drainage waters. Dissolved N₂O in drainage waters showed a clear response to field N fertilisation, following an identical pattern to direct N₂O flux from the field surface. The range in N₂O concentrations between individual field drains sampled on the same day was large, indicating considerable spatial variability exists at the farm scale. A consistent pattern of very rapid outgassing of the dissolved N₂O in open drainage ditches was accentuated at a weir, where increased turbulence led to a clear drop in dissolved N₂O concentration. This study underlines the need for carefully planned sampling campaigns wherever whole farm or catchment N₂O emission budgets are attempted. It adds weight to the argument for the downward revision of the IPCC emission factor (EF₅-g) for NO₃ in drainage waters.     

河台金矿形成机制的实验研究

本文对河台金矿测定了形成时的物理化学条件,T=200～280℃,P=573.3×10°Pa,fo_2=10~(-37)—10~(-39),成矿溶液具有Na~+>K~+>Ca~(2+),HCO_3~->Cl~_>F~->ΣS,CO_2>CH_4的特点,从早期到晚期,成矿溶液中的Au与Na~+、K~+、F~-、Cl~-等呈同步增长。在高压釜中不同温度压力下以不同浓度的NaHCO_3、HCl为介质对含金建造进行了淋滤试验;模拟了成矿时的温度压力条件,成功地用硫化物还原出溶液中的金,揭示出硫化物、溶液与还原金的定量关系,并阐述了成矿物质、成矿溶液的来源以及金在成矿溶液中的迁移形式和沉淀机制。     

Genetically engineered herbicide resistance,part two

Should we continue to support publicly funded research on genetically engineered herbicide resistant crops? In Part One, I discussed the difference between science and ethics, presented a brief history of weed control, and explained three moral principles undergirding my environmentalist perspective. I then argued that unqualified endorsement (E) of the research is unjustified, as is unqualified opposition (O). In Part Two, I argue against qualified endorsement (QE), and for qualified opposition (QO).     

某电镀厂污泥酸浸除杂提磷试验

探讨了武汉某工业园电镀厂污泥酸浸、除杂提磷的工艺及条件。当H2SO4（浓度为72％）用量为4mL/g污泥,在液固比为5：1,常温搅拌浸出时间为1h,用碱液调节浸出液pH为4后沉淀1h,过滤,磷的浸出率为86％,铁的沉淀率达到94．2％,除铁后的浸出液进一步用NH4HCO3净化,并制取磷铵产品,总养分（N＋P2O5）为52％。产品达到国家合格品的标准。     

贵州典型森林群落植被冠层的酸雨淋溶特征及缓冲作用

在贵州龙里地区开展酸雨模拟实验,并进行天然降雨连续监测,采集马尾松、灌丛冠层穿透雨,结果表明:①研究区降雨中主要阳离子浓度依次为NH4+Ca2+K+Na+Mg2+,降雨pH值大于6.0时,降雨中NH4+含量降低,Ca2+占优势;降雨中主要阴离子浓度依次为SO42-NO3-Cl-;冠层穿透雨与降雨相比,Na+、K+、Ca2+、Mg2+、Cl-、NO3-、SO42-和有机酸富集,特别是K+、Ca2+、SO42-和有机酸富集倍数最大.②森林冠层对酸雨的缓冲作用体现在酸雨中H+与树叶组织中的盐基阳离子发生交换反应,淋出K+、Mg2+、Ca2+等阳离子,减少了酸雨中H+含量.Na+相对惰性,在降雨和穿透雨中的含量变化不大;K+、Mg2+、Ca2+的淋出是冠层缓冲降雨酸度的主要原因,其中K+和Ca2+作用最突出,其次是Mg2+.③贵州典型森林群落植被冠层的缓冲作用随降雨pH值而变化.对pH值接近3.0的强酸性降雨,经过冠层形成的穿透雨pH值大于降雨,典型森林群落植被冠层对酸雨的缓冲作用依次为马尾松林针阔混交林灌丛;对4.0pH6.0的降雨,马尾松林冠层使降雨更加酸化,典型森林群落植被冠层对酸雨的缓冲作用依次为针阔混交林灌丛马尾松林;对pH值大于6.0的非酸性降雨,经过冠层后被酸化,穿透雨pH值小于降雨;穿透雨pH值基本在4.0～6.0范围内.     

垃圾焚烧飞灰中重金属的浸出规律

测定了垃圾焚烧飞灰中Zn、Pb、Cu、Cr、Ni的浸出率与pH值的关系,并利用MINTEQA2模型进行了浸出规律模拟。结果表明:Pb、Cu、Zn、Cr、Ni的模拟浸出值与实测浸出值基本吻合,模拟浸出值可反映实际浸出情况;pH2时,Zn、Cu、Pb的浸出率较大,8pH12时浸出率接近0;Zn、Pb的浸出率分别在pH7、pH2时达到最大值,最大值分别约为75%及72%,pH值12时随pH值的增加,其浸出率逐渐增强;Cr在pH4时浸出率较大,最大浸出率达43%,4pH12时浸出率接近零,pH12时其浸出率再次增加;Ni的浸出率在pH2时随pH值的增加而降低,2pH13时其浸出率接近零。     

多环芳烃在土壤剖面中迁移行为的土柱淋滤模拟研究

京津地区典型土壤剖面分析表明,土壤中PAHs含量和组成均随深度增大而呈现明显的变化.为了揭示PAHs在土壤剖面中的迁移特征与控制因素,开展了室内土柱模拟实验,考察了PAHs的迁移特点及影响因素,特别是土壤有机质含量的影响.采用3种土壤质地和TOC不同的土样装填土柱,以去离子水作为淋滤液对预先加入土柱表层的污染物(包括不同环数PAHs、d-Flu)进行淋滤,当达到淋滤量后分析土柱中PAHs含量及组成.结果表明,不同实验条件下,淋滤后土壤剖面不同层次土壤中PAHs含量均高于原土样中的,且PAHs主要富集在土柱表层,随深度增加其含量明显降低,但不同土柱中降幅不同;不同环数PAHs分布特征存在差异.与原土柱相比,除d-Flu和Flu等低环数芳烃的含量在剖面不同深度均有明显增大外,部分高环数PAHs相对含量在土柱的不同深度也明显增加,说明高环数PAHs也具有一定的迁移能力,但相对于3环PAHs,高环数PAHs在土壤中迁移能力较低.此外,土壤剖面PAHs的富集程度明显受土壤中TOC影响,PAHs总量或单体PAH含量在土柱中迁移的深度随着TOC含量降低而增加.