Screening for acute ocular toxicity of commercialized products of cartap,an insecticide,and correlation to blood concentrations in rabbits

Cartap is an insecticide known to produce contraction and damage to mouse and rabbit diaphragms, and plays a pivotal role in respiratory paralysis and mortality in rabbits. The aim of this study was conducted to screen for the toxic properties and blood concentrations of commercialized cartap products in New Zealand White (NZW) rabbits. Five granular formulations (GRs) with different concentrations (4, 6, 6.5, 6.66 or 10%) and seven water-soluble powders (SPs, 50%) of commercialized cartap products were chosen to study toxicity following ocular instillation. Furthermore, ocular instillation (5, 12.5, 25 or 50 mg kg^?1) and oral administration (25 mg kg^?1) of the technical material (TC) cartap was also performed to compare blood concentration changes in rabbits. There was no death or eye irritation with all GR products; however, soluble powder (SP) products produced severe toxicity and mortality in rabbits. The blood concentration of TC cartap in rabbits started to increase from 2 min and reached peak levels at 7–9 min after ocular instillation in a dose-related pattern. For comparison of the blood distribution of cartap via different administration routes, oral exposure exhibited a higher absorption of cartap than ocular instillation. It was suggested that the commercialized GR products of cartap were safe but 50% SP products were highly toxic to rabbits following ocular exposure. This study provides valuable data to screen for potential acute toxicity of cartap to farmers and animals in the field.     

气相色谱／质谱测定电子垃圾拆解区土壤中四溴双酚A的方法

本研究建立气相色谱/质谱来测定电子垃圾拆解区土壤中四溴双酚 A（TBBPA）的方法。该化合物通过超声波辅助萃取,溶剂选择V（丙酮）﹕V（正己烷）=1﹕1或乙酸乙酯;净化柱选择酸化的氟罗里硅土和无水硫酸钠混合物或CleanertC18-SPE进行净化;净化液浓缩后经衍生反应,衍生试剂选用N,O-双（三甲基硅烷基）三氟乙酰胺（BSTFA）和含1%的三甲基氯硅烷（TMCS）。该方法测定电子垃圾拆解区土壤中TBBPA的检出限为（S/N=3）0.1μg·kg^-1加标回收率平均值为92.7%（n=5）,重现性RSD为2.52%（n=5）;线性范围是20～400μg·kg^-1相关系数0.999。该方法用于调查电子垃圾拆解区土壤中四溴双酚A,范围值为5.17～218.00μg·kg^-1其周围农田土壤中四溴双酚A,范围值为0.312～4.170μg·kg^-1     

Crediting uncertain ecosystem services in a market

The margin of safety (MOS) approach is an increasingly prevalent tool for ensuring the integrity of market-based programs for providing ecosystem services. Over-crediting is reduced by setting aside mean estimates of uncertain services in favor of a more conservative estimate. Like many environmental policy problems, ecosystem service markets involve the aggregation of uncertainty over multiple scales, e.g. from landowners to market intermediaries to the overall market. We examine how the MOS instrument affects, and is affected by, an ecosystem services market. We show that the common bottom-up approach of imposing risk preferences at a local, disaggregated level—held over from earlier development in the context of toxics and command and control-style health risk regulation—leads to several unintended consequences. Furthermore, discounting landowner services can actually increase their profits, conditional on the elasticity of credit demand. We illustrate theoretical insights with an empirical application to greenhouse gas offset crediting in agriculture.     

广州市天河区2016年雨季挥发性有机物污染特征及来源解析

采用"GCMS/FID"在线分析方法,对广州市区2016年7月大气VOCs的污染特征及来源进行了研究,共检出了73种VOCs组分.结果表明,观测期间总VOCs的小时平均浓度为（118.83±79.40）μg·m^-3,最高值为492.42 μg·m^-3,最低值为10.54 μg·m^-3.07：00左右TVOC浓度出现高峰,说明早高峰的机动车污染对该站点的VOCs具有较大贡献;14：00左右浓度最低,与光化学损耗相关;21：00~24：00间VOCs浓度又出现高值,可能和污染源排放或边界层压缩有关.运用PMF模型解析出VOCs的5个主要来源分别是：交通污染源、溶剂使用污染、加油站污染、植物排放和餐厨废气,其贡献分别为29.79%、26.61%、24.86%、9.91%、8.84%;白天交通废气源贡献最大,而中午植物排放的贡献也明显增大;夜间溶剂污染源和加油站污染源占比上升,为该时段VOCs的主要来源.     

汽油机排气颗粒粒径分布特征试验研究

对汽油机排气中颗粒的数浓度和粒径分布特征进行了测试.在测试工况下,汽油机排气中的颗粒呈包含核模态粒子(10 nm＜DP＜50 nm)和积聚模态粒子(50 nm＜DP＜487 nm)的双峰分布,排气颗粒的总数和总质量浓度分别为4.2×105-7.9×106个·cm-3和0.02-0.27 mg·m-3.汽油机在开环控制状态下(车速不低于90 km·h-1时)的颗粒数量排放明显高于闭环控制状态(车速不高于70 km·h-1),总颗粒质量浓度随车速的增大显著增加.随车速增大,积聚模态粒子的平均粒径先减小后增大,核模态粒子的几何平均粒径先增大后减小,低车速时,有大量10-20 nm的核模态粒子生成.柴油机和汽油机排气颗粒中核模态粒子通常占有大的数量百分比,为75%-95%,而其质量百分比仅为5%-25%.汽油机的总颗粒、核模态粒子和积聚模态粒子的数量和质量排放均远低于柴油机.     

螃蟹活动对闽江河口互花米草沼泽湿地土壤温室气体排放通量的影响

于2015年1月（冬季）、4月（春季）、6月（夏季）和9月（秋季）,以闽江河口互花米草沼泽湿地为研究区,采用静态箱与气相色谱结合的方法,研究螃蟹对湿地土壤CO₂、CH₄和N₂O排放通量及综合增温潜势的影响。研究表明：温室气体排放季节变化较为显著,CO₂、CH₄排放通量最大值均出现在夏季,N₂O排放通量最大值出现在秋季,CO₂、CH₄和N₂O排放通量最小值均出现在春季。与无螃蟹组相比,高潮滩和中潮滩螃蟹组CO₂、CH₄和N₂O排放通量均值都增大,其中高潮滩螃蟹组CO₂、CH₄和N₂O排放通量依次增大了46.36%、66.67%和69.66%,中潮滩螃蟹组CO₂、CH₄和N₂O排放通量依次增大了53.57%、142.97%、73.08%。相关性分析结果表明：土壤CO₂排放通量与土壤温度显著正相关（n=96,p＜0.05）,CH₄和N₂O排放通量与土壤温度显著正相关（n=96,p＜0.01）;N₂O排放通量与土壤pH显著正相关（n=96,p＜0.01）,与土壤含水量显著正相关（n=96,p＜0.05）。综上所述,螃蟹活动对闽江河口互花米草沼泽湿地土壤的干扰促进了温室气体的排放,为有效调节湿地碳、氮固持作用和湿地生态系统科学管理提供了参考。     

不同居民燃煤炉具大气污染物排放差异性及减排分析

为探究不同类型炉具的大气污染物排放差异,本研究选择5种常见的新式居民燃煤炉具(方型煤炉具、折流换热炉具、炕暖炊一体化炉具、气化正烧及气化反烧炉具)在实验室内进行模拟燃烧和大气污染物排放水平监测,定量评估不同炉具的环境效果,识别污染排放水平差异的影响因素及原因,从而提出炉具研发设计等污染减排的改进建议.结果表明:(1)不同炉具大气污染物排放差异较大,炕暖炊一体的炉具污染排放强度最大, 3种大气污染物(SO₂、 NO_x和颗粒物)的排放强度为2.9 kg·t^-1,是平均值的1.6倍;应用方型煤技术的炉具大气污染物排放强度最低,是平均值的65%.(2)不同炉具在不同燃烧阶段其气态污染物排放也呈现出明显的差异和特征.旺火阶段方型煤炉具NO_x排放浓度为0.49mg·m^-3,相较于其他类型炉具降低了45%～72%;气化反烧炉具的SO₂排放浓度为1.38mg·m^-3,相较于其他类型炉具最高降低了28%.(3)影响炉具大气污染物排放因素包括应用技术及燃...     

Thermal stabilization of chromium slag by sewage sludge: Effects of sludge quantity and temperature

To investigate the feasibility of detoxifying chromium slag by sewage sludge,synthetic chromium slag containing 3% of Cr(VI) was mixed with sewage sludge followed by thermal treatment in nitrogen gas for stabilizing chromium.The effects of slag to sludge ratio(0.5,1 and 2) and temperature(200,300,500,700 and 900°C) on treatment efficiency were investigated.During the mixing process before thermal treatment,59.8%-99.7% of Cr(VI) was reduced,but Cr could be easily leached from the reduction product.Increasing heating temperature and decreasing slag to sludge ratio strengthened the reduction and stabilization of Cr(VI).When the slag to sludge ratio was 0.5 and thermal treatment temperature was 300°C,the total leached Cr and Cr(VI) declined to 0.55 mg/L and 0.17 mg/L respectively,and 45.5% of Cr in the thermally treated residue existed as residual fraction.A two-stage mechanism was proposed for the reduction and stabilization of Cr.     

基于OMI数据的东南沿海大气臭氧浓度时空分布特征研究

基于臭氧监测仪(OMI)卫星反演数据,对2005—2018年东南沿海5省区域大气臭氧柱浓度数据进行提取及分析,探讨其时空分布格局及影响因素.结果表明:①在时间变化上,14年间,该区域大气臭氧柱浓度整体呈先上升后下降的趋势,2005—2013年臭氧柱浓度持续升高,最高值为324.52 DU,高值区不断向南部区域扩大;2013—2018年臭氧柱浓度呈下降趋势,最低值为228.27 DU,但在2017、2018年略有上升.②在空间分布上,臭氧柱浓度自北向南逐渐降低,高值区集中分布在江苏及浙江省北部;低值区集中于福建省南部及广东省大部分地区.③在季节变化上,大体呈现出春夏季高于秋冬季,高值区在春夏季交替出现,秋季略高于冬季,但差异不明显.④稳定性分析表明:研究区臭氧柱浓度整体呈现中部分散、南北部集聚、差异较显著的分布格局.⑤自然因素中,风向、气温均呈现显著正相关,江淮地区的梅雨季节(降水)及华南地区的台风和暴雨也起到显著作用.⑥人文因素中,臭氧柱浓度与地区生产总值、各产业生产总值及机动车保有量均表现出正相关,其中,臭氧柱浓度与第二产业的相关度最高.另外,臭氧柱浓度与NO_x排放量表现出显著相关性.VOC_s对臭氧柱浓度的影响中,工业源是主控因素,交通源和居民源次之,电厂源对臭氧柱浓度的影响最弱.这进一步说明臭氧浓度的变化受到了诸多因素的综合影响,但气温、NO_x及VOC_s的排放是臭氧浓度变化的主导因素.     

基于TDLAS的火灾气体探测系统研制

将TDLAS(Tunable Diode Laser Absorption Spectroscopy)技术应用于极早期火灾气体产物的检测.对于火灾早期特征气体CO和CO2气体探测,选择中心波长为1582nm和1607nm的近红外吸收谱线,设计了一个基于TDLAS的火灾气体探测系统.对于CO和CO2气体,最低检测灵敏度分别达到2.3×10-6和22×10-6体积比浓度.该系统信号响应线性度高,长期运行稳定.