农业化肥污染的政策成因及对策分析

化肥污染是农村面源污染的重要组成部分,如何解决该问题已经成为中国学者热议的话题。为了定量分析国家政策对化肥过量施用的影响,基于我国1998—2007年各省市的面板数据,借助STATA软件包和化肥施用效用模型假设,对其进行了回归分析。结果表明：一是随着经济发展水平的提升,农业化肥污染仍会不断加剧。二是多年来国家给予化肥企业＂优惠＋补贴＋限价＂的化肥行业发展政策是化肥过量施用的根本政策原因,当前国家惠农政策有助于降低化肥的需求量。三是当国家取消对化肥企业的补贴政策,继续当前的惠农政策时,则农民直补政策需以农民有利于环境的施肥方式为前提。四是若国家继续当前化肥行业发展政策和惠农政策,则视国家给予化肥企业的补贴确定一个直补额度,当对农民直补小于该额度时,则直补有利于农民减少对化肥的需求;但当直补超过这一额度时,农民则会增加对化肥的需求,因此后者需以农民施肥行为有利于环境为前提。     

Part IV: Fitness for Aquatic Systems Long-term Forecast: Key to groundwater protection

Groundwater resources are at risk from pollution, climate change and land-management practices. Long-term forecast is a tool to demonstrate future development and to support decisions on measures which can be implemented, controlled and eventually corrected. As the basis for preventive action, a forecast can be viewed as a key to groundwater protection. The soil zone plays a vital role in groundwater protection. Research on soil and groundwater trends, as affected by change of climate and/or land-management practices, is on the agenda. Integrated research is necessary to develop numerical soil-water system models reflecting all relevant transport processes at various scales. Even relatively simple problems like forecasting pollutant release from contaminated materials are difficult to resolve. Batch tests may be sufficient in low-risk cases. At higher risk when contaminated substrates are chosen for deposition on a large scale, a thorough characterization of the materials is necessary covering all aspects of stability and possible changes of the environment.     

Characteristics of mercury speciation in Minnesota rivers and streams

Patterns of mercury (Hg) speciation were examined in four Minnesota streams ranging from the main-stem Mississippi River to small tributaries in the basin. Filtered phase concentrations of methylmercury (MeHg), inorganic Hg (IHg), and dissolved organic carbon (DOC) were higher in all streams during a major summertime runoff event, and DOC was enriched with MeHg but not with IHg. Particulate-phase MeHg and IHg concentrations generally increased with total suspended solids (TSS) concentrations but the event data did not diverge greatly from the non-event data, suggesting that sources of suspended sediments in these streams did not vary significantly between event and non-event samplings. The dissolved fractions (filtered concentration/unfiltered concentration) of both MeHg and IHg increased with increasing DOC concentrations, but varied inversely with TSS concentrations. While MeHg typically constitutes only a minor portion of the total Hg (THg) in these streams, this contribution is not constant and can vary greatly over time in response to watershed inputs.     

Spatial trend and pollution assessment of total mercury and methylmercury pollution in the Pearl River Delta soil, South China

Total mercury (THg) and methylmercury (MeHg) were measured in large number of soil samples collected from areas with different types of land use, different depth in the Pearl River Delta (PRD) of South China. THg and MeHg concentrations ranged from 16.7 to 3320 ng g⁻¹ and 0.01 to 1.34 ng g⁻¹, respectively. THg levels are highest in the top 0-20 cm soil layer, and decrease from the surface to bottom layer soil. Spatial variation was observed with different types of land use. Urban parks had the highest concentrations and the other areas tended to decrease in the order of residential areas, industrial areas, vegetable fields, cereal fields, and woodlands. Temporal variation was also noted, and two relatively high THg contamination zones located in the northwestern part of the PRD have significantly expanded over the last two decades. Both THg and MeHg concentrations were correlated significantly with soil organic matter (OM), but not with soil pH. THg pollution status was evaluated using two assessment methods.     

汞的树木年轮化学研究进展

由于可以有效揭示重金属污染的时间变化序列,近年来,树木年轮被广泛应用于环境重金属污染的历史追溯。年轮化学技术也被应用于示踪某地区的汞污染历史,本文系统介绍了利用树木年轮化学对汞污染积累历史进行追溯研究的相关研究成果,包括样品采集与处理、含量测定及数据分析,并对木质汞来源进行了讨论,最后对汞年轮化学研究的未来发展进行了展望。     

基于卫星遥感数据和污染控制政策分析河南省2001—2018年SO2浓度变化特征

为研究河南省长时间序列的ρ（SO₂）变化特征,运用MERRA-2卫星遥感资料并结合《大气污染防治行动计划》的实施,对河南省2001—2018年ρ（SO₂）的时空分布特征进行分析.结果表明:①河南省2001—2018年ρ（SO₂）的空间分布呈东北高、西南低的特征,高值、低值区域分别位于焦作市-新乡市-郑州市北部一带和洛阳市-三门峡市-南阳市交界一带;秋季、冬季ρ（SO₂）高于春季、夏季,冬季ρ（SO₂）比春季、夏季高50%~70%.②2011年前,河南省年均ρ（SO₂）不断上升,北部较南部增速快,年均增速为3.5~4.0 μg/（m3·a）;2011年后,西北部大部分地区ρ（SO₂）呈下降趋势,焦作市-新乡市-安阳市一带下降最快.③2013年《大气污染防治行动计划》实施后,河南省北部ρ（SO₂）呈递减趋势,濮阳市及其周边下降最快,降速超过0.4 μg/（m3·a）;但中南部仍呈缓慢增长趋势,增速高达0.6 μg/（m3·a）.研究显示,主要污染物总量的减排和《大气污染防治行动计划》的实施促进了河南省ρ（SO₂）的下降,但不处于京津冀大气污染传输通道“2+26”城市的地区ρ（SO₂）下降速度较慢甚至略有增长,应进一步加大非传输通道城市大气污染防治力度.      

Role of NO and SO2 in mercury oxidation over a La2O3/Fe2O3 catalyst with high thermal stability

In this study, the thermal stability of a ferric oxide catalyst for mercury oxidation was found to be considerably promoted by doping with La₂O₃. The catalysts doped with La₂O₃ maintained a higher surface area when subjected to high-temperature calcination, with lower average pore size and a narrower pore size distribution. X-ray diffraction (XRD) results revealed that La₂O₃ doping hinders the growth of catalyst particles and crystallization of the material at high temperatures. Both NO and SO₂ inhibited Hg⁰ oxidation over the La₂O₃/Fe₂O₃ catalyst. Fourier transform infrared (FTIR) spectra revealed that SO₂ reacts with O₂ over the catalysts to form several species that are inert for mercury oxidation, such as SO₄^2?, HSO₄^?, or other related species; these inert species cover the catalyst surface and consequently decrease Hg⁰ oxidation capacity. In addition, NO or SO₂ competed with Hg⁰ for active sites on the La₂O₃/Fe₂O₃ catalyst and hindered the adsorption of mercury, thereby inhibiting subsequent Hg⁰ oxidation. Hg⁰ oxidation on the La₂O₃/Fe₂O₃ catalyst mainly followed the Eley–Rideal mechanism. Moreover, the inhibition effects of NO and SO₂ were at least partially reversible, and the catalytic activity was temporarily restored after eliminating NO or SO₂.     

企业实施清洁生产的障碍分析及政策建议框架

本文总结分析了企业实施清洁生产过程中遇到的问题障碍,提出了克服这些障碍,推进企业清洁生产的政策建议框架,在当前,来自思想观念、组织管理、经济、技术以及知识方法方面的障碍正直接影响着企业清洁生产的实施。对现行工业政策（包括技改政策）和环境政策进行调整、完善,制定清洁生产政策是促进我国清洁生产顺利健康开展的保证。     

蔬菜对大气汞和土壤吸收的研究

通过田间观测和盆栽试验研究了蔬菜富集汞的特性及土壤、大气对蔬菜汞的贡献。对田间 11种蔬菜的研究发现 ,蔬菜根和叶的含汞浓度高于茎和果 ;在自然条件下 ,蔬菜所吸收的汞 60 %以上分布于地上部的可食部分。盆栽试验结果表明 ,在气汞浓度为 5 7.6± 14.7ng· m- 3条件下 ,红萝卜、莴苣叶 (可食部分 )的含汞浓度超过了食品卫生标准 ;气汞、土壤汞对蔬菜汞的贡献率分别为 70 .4～ 90 .7%、9.3～ 2 9.6% ,气汞较土壤汞是蔬菜更为重要的汞源     

中国政府环境信息公开实施效果评价

环境信息公开是国际上公认的新一代环境治理手段,也是我国建设＂阳光政府＂的基本要求.在《环境信息公开办法》实施2 a后,针对31个省级、5个计划单列市和27个省会城市环境保护局落实环境信息公开的制度和行动进行调查分析,通过资料调查、实际公开申请和深入访谈,全面评估政府环境信息公开办法实施的有效性,以期为该办法的进一步完善...