Histopathological changes and antioxidant response in brain and kidney of common carp exposed to atrazine and chlorpyrifos

We investigated oxidative stress response and histopathological changes in the brain and kidney of the common carp after a 40-d exposure to CPF and ATR, alone or in combination, and a 20-d recovery. Superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) activities and malondialdehyde (MDA) content were measured using standard assays. Our results indicated that exposure to ATR, CPF or a combination of the two for 40 d induced significant changes in antioxidant enzyme (SOD, CAT and GSH-Px) activities and MDA content in the brain and kidney of the common carp. Pathological changes included tissue damage that was more severe with increased of exposure dose. To our knowledge, this is the first report to study oxidative stress and histopathological effects caused by subchronic exposure to ATR, CPF and ATR/CPF combination on common carp. The information presented in this study may be helpful to understanding the mechanisms of ATR-, CPF- and ATR/CPF combination-induced oxidative stress in fish.     

河南省2014-2020年PM2.5浓度时空分布特征及气象成因分析

利用2014—2020年河南省18个地级城市空气质量监测资料和气象数据,运用空间自相关分析、ArcGIS制图及相关性分析等方法,从时空分布特征上揭示河南省PM_2.5污染特征,并分析其气象成因。结果表明：河南省2014—2020年PM_2.5年均浓度为40～100μg/m³,总体呈递减趋势。PM_2.5浓度季节分布特征为冬季>秋季=春季>夏季。河南省2019年和2020年PM_2.5污染空间分布存在显著自相关,污染程度严重的地区主要是中部和东北部地区。冷热点分析发现,热点城市为濮阳、安阳、济源、郑州、新乡、焦作、鹤壁,冷点城市为信阳、驻马店、周口。PM_2.5在年尺度上与气压、气温、相对湿度、风向、风速、能见度显著相关,其中,与气温相关性最高,相关系数为-0.424。当相对湿度处于90%以下时,PM_2.5浓度与相对湿度呈正相关;而在相对湿度超过90%之后,PM_2.5浓度下降至70μg/m³...     

Acidification of lead/zinc mine tailings and its effect on heavy metal mobility

The acid-forming potential of lead/zinc (Pb/Zn) mine tailings at Lechang City of Guangdong Province was studied using both net acid generation (NAG) and acid-base accounting (ABA) methods. The pyritic and total sulfur contents of the tailings were 12.6% and 18.7%, respectively. The mean acid neutralization capacity (ANC) was 63.5 kg H2SO4/t while three oxidized tailings samples had an ANC less than zero. The NAG and net acid production potential (NAPP) values were 220 and 326 kg H2SO4/t, and both the NAG and NAPP results indicated that the tailings had a high acid-forming potential. NAG was more accurate than NAPP in predicting acid-forming potential of the tailings due to uncompleted oxidization of pyritic sulfur. Analysis of samples from two profile tests indicated that acidification mainly occurred at the surface (0-20 cm) and had little effects at deep layer of the tailings. Total concentrations of Pb, Zn, Cu, and Cd were increased greatly with depth at the acidified tailings profile, while heavy metal concentrations at different depths of nonacidified tailings profile were similar. The results indicated that depletion of heavy metals at the acidified surface was due to acidification. The diethylenetetramine pentaacetic acid (DTPA)-extractable Pb, Zn, Cu, and Cd concentrations of acidified tailings surface (0-20 cm) were significantly higher than those of nonacidified tailings, which further revealed that acidification enhanced the mobility of heavy metals in the tailings.     

建设生态农业促进无公害农产品生产

本文从生态环境的概念入手分析了人和生态环境的关系、生态农业建设的作用、无公害农产品生产与生态农业建设的关系，指出了无公害农产品生产中存在的问题，提出了加快建设生态农业、生产无公害农产品、提升江苏农业竞争力的建议。     

邹城东滩矿区复垦土壤微生物量碳与#br# 基础呼吸的特征

探究复垦土壤微生物量碳与基础呼吸的特征及其演变归因,有助于监测复垦土壤质量演变,并为提高复垦土壤质量提供科学依据。利用“空间代替时间”的方法研究了邹城东滩矿区复垦土壤微生物量碳（MBC）与基础呼吸（SBR）随复垦年垦的变化及其与土壤环境因子的关系。结果表明：复垦土壤MBC和微生物熵（qSMBC）随复垦年限呈增加趋势;复垦土壤SBR均显著高于对照,土壤代谢熵（qCO2）随复垦年限趋于降低,复垦后土壤微生物量逐渐恢复,同时土壤微生物对碳源利用效率逐渐提高,说明土壤环境逐渐有利于土壤微生物的生长。土壤MBC与碱解氮、总氮和有机碳呈极显著正相关（p＜0.01）,反映土壤养分缺乏是复垦后土壤微生物生长的主要限制因素。土壤代谢熵（qCO2）与土壤碱解氮、速效磷和MBC均呈极显著负相关（p＜0.01）与pH呈显著正相关（p＜0.05）,说明氮磷等元素的缺乏以及较高的土壤pH环境是限制微生物生长的重要因素。这些对全面监测复垦后土壤质量的演变,并指导今后的复垦工作具有重要理论与实践意义。 关键词： 采煤塌陷区;土壤微生物量碳;土壤微生物熵;基础呼吸     

北京大气颗粒物中有机碳和元素碳的浓度水平和季节变化

分析了北京市两个采样点十三陵站(清洁对照点)和天坛站(居民生活区)的110个大气颗粒物样品有机碳和元素碳的测定数据,结果表明两站点具有明显的季节变化特征.一号站OC质量浓度年均值为22.0μg/m3,EC为3.6μg/m3,五号站OC质量浓度年均值为41.5μg/m3,EC为7.8μg/m3.OC百分含量秋季高,反映出活跃的大气化学反应和严峻的污染形势,春季低表现了风沙气候的影响.城区的EC百分含量冬季增高则是燃煤贡献所致.对1998年1月份和9、10月份的数据进行了实例分析.结果表明稳定的天气条件和北京特殊的地貌容易导致空气污染事件.有机物污染是1998年北京秋季空气污染的一个特征.     

交通干线铅污染对两侧土壤和蔬菜的影响

为了调查交通干线上汽车尾气的铅污染对两侧土壤和蔬菜的影响,淮阴市环境监测中心站于１９９７年至１９９８年在宁连一级公路（淮阴段）选择３个区域,横穿公路布设３个剖面,每个剖面设置１０个监测点,对大气、土壤和蔬菜中铅含量进行监测。结果表明,大气中铅含量与土壤表层、蔬菜叶片中铅含量正相关,与深层土壤中铅含量相关不明显。指出交通干线两侧应减少蔬菜的种植,加大树木和花卉的种植,同时大力提倡无铅化汽油的使用,友     

Performance evaluation of a water mist system in semiconductor wet bench fires

Wet benches are typically utilized in semiconductor facilities for wafer and parts cleaning. Heaters and some flammable liquids, such as acetone and isopropyl alcohol (IPA), are employed during the cleaning process. Wet bench fires have caused serious losses in the semiconductor industry. To assess the fire protection performance, several field tests were performed using a water mist system installed in the wet bench. In this study, acetone pan fuel was used as fire source. The test parameters were operational pressure, pan size, nozzle location, cylinder obstruction and degree of door closure. An appropriate design for operating pressure and the location of water mist nozzles extinguished wet bench fires effectively in the early fire stages. The nozzles are suggested to be fixed above or on the each side of the pan, ensuring that mist can completely cover a pan surface with sufficient momentum. With this suggested design, fires can be extinguished in the pan and do not spread over the wet bench.     

苏南太湖地区水资源价值补偿对物价水平的影响研究

对水资源进行价值补偿是解决我国现阶段水资源短缺和水污染问题的重要手段之一,解决好水资源价值补偿问题是实现资源,环境、社会可持续发展的前提。实施水资源价值补偿政策可能导致的物价水平上升是关系到人民群众生活稳定的重要问题。在实施水资源价值补偿政策之前,对实施这一政策可能引起的物价上涨幅度进行定量分析是十分必要的。本文运用投入产出模型计算苏南太胡地区水资源价值按一定比例（分别为１％、２％、３％、４％、５