基于输出系数模型的北京地区农业面源污染负荷估算

农业生产活动产生的面源污染物是环境污染负荷的主要来源之一。利用输出系数模型对北京市农业面源污染负荷进行了估算。结果表明,2006年北京市农业面源污染物总氮和总磷负荷量分别是19 565.7×106和2 413.1×106 g/a。土地利用方式显著影响氮和磷负荷,不同污染源类型对污染负荷贡献的差异较大。不同污染源类型对总氮污染负荷贡献率的大小顺序为农村生活污水及废弃物＞耕地＞林地＞畜禽养殖＞园地＞牧草地,对总磷负荷贡献率的大小顺序为农村生活污水及废弃物＞畜禽养殖＞耕地＞林地＞园地＞牧草地。各区县总氮和总磷负荷量和负荷强度的差异较大,其中大兴、顺义、房山、密云和通州的总氮和总磷负荷量较大,而朝阳、丰台、通州、顺义和大兴的总氮和总磷负荷强度较大。农业面源污染物氮和磷分布状况和负荷强度的研究,为北京地区区域规划和农业结构调整提供了科学依据。     

农业面源污染防治的难点、问题及对策

实现农业绿色发展,提升农产品品质是破解新时代社会主要矛盾在农业领域表现的重要途径,其前提是对农业面源污染进行有效防治,以提升农业生产系统环境质量。本文在系统梳理农业面源污染领域研究文献的基础上,剖析了农业面源污染防治的难点及问题,一是化肥施用总量（折纯量）大与施用强度高并存;使用效率低与流失严重同在;二是农药使用量的增加以及包装物带来的面源污染呈现加重态势;三是农用薄膜造成的"白色污染"短期内难以从根本上解决;四是畜禽废弃物产生量大,污染严重;同时,兽用抗生素的环境影响不容忽视。在农业面源污染防治中,存在着防治对象具有多源性、防治主体多元性以及防治技术有效性不足、机制缺失等问题。为此,应以绿色发展理念为指导,提升全社会对农业面源污染防治重要性的认识;强化农业面源污染防治行动计划的实施监督,并注重实施效果的监测与评价;实施多维创新,保障农业生产系统的健康,以更好地推进农业面源污染防治。     

红枫湖流域非点源污染控制区划

非点源污染发生的广域性、分散性、随机性等特征使得对其进行效管控难度较大。以非点源污染关键源区识别为基础,对流域进行分区管控是实现非点源污染控制的有效途径。基于源头削减和过程管控协同管理的思路,将GIS技术、ArcSWAT模型、非参数检验和因子分析技术相结合,以农耕养殖程度较高的贵州红枫湖上游羊昌河流域为研究区,通过对流域近5 a非点源污染负荷特征进行模拟,识别影响非点源污染流失的关键因素,在此基础进行污染控制区划。结果表明：1）总氮和总磷负荷高风险区主要集中于地势较高且农业耕作活动频繁区域,刘官乡、黄腊乡、旧州镇及白云镇是非点源污染控制的重点乡镇;2）采用多因素方差分析7种不同因素对流域非点源污染负荷的影响程度表明,施肥量是影响总氮、总磷输出的最主要的因子,坡长、坡度及土地利用方式是次重要因子。针对羊昌河流域长期传统耕作以及化肥过量施用的现实特征来看,土壤有机磷的含量也会对总磷的输出产生一定的影响;3）羊昌河流域可划分为3个污染控制区,第1类：生态农业综合整治区（以近河道耕种区为主,面积254.4 km2）;第2类：污染治理区（农村生活及畜禽养殖区为主,面积405.74 km2）;第3类：生态修复区（高坡度强降雨区为主,面积464.47 km2）。研究结果可有效提升羊昌河流域非点源污染治理的效率,为水源地环境保护提供参考。     

河北省污水灌溉农业环境污染经济损失评估

以河北省为例 ,采用市场价值法、人力资本法和工程费用法对污水灌溉所造成的农田土壤、地下水和作物污染及其对人群健康的影响进行经济损失评估 ,研究结果表明 2 0 0 0年河北省污水灌溉造成的环境污染总经济损失为 7.37亿元 ,占农业生产总值的 0 .87% ,其中以人群健康损失所占比重最大 ,占污染总经济损失的 95 .3% ,地下水和作物污染经济损失相对较小 ,故污水灌溉的潜在负面影响 ,尤其是对污灌区人群健康的影响应引起高度重视。     

水土保持措施防治非点源污染的作用机制

 进入土壤或水体中的非点源污染物一般可分为化肥、农药和重金属3大类。这3大类污染物在土壤或水体中通过植物吸收、土壤胶体吸附、微生物降解、径流淋失与挥发等途径进行迁移转化。系统阐述水土保持生物措施、工程措施和农业技术措施3大措施对化肥、农药和重金属3大污染物的各种迁移转化途径所具有的促进与抑制作用,可为合理配置水土保持措施,有效防治非点源污染提供重要的理论依据。     

A pollution index for agricultural soils

The main purpose of the present investigation was to develop a pollution index for agricultural soils. For this purpose, 58 soil samples were collected from agricultural lands in Hamedan Province (Iran). The elemental contents of As, Cd and Co in soil samples and agricultural crops were measured by atomic absorption spectroscopy. The spatial distribution of studied metals was prepared by Kriging method. It is concluded that agricultural activities have led to the higher concentrations of Co, Cd and As. Results of the chemical partitioning studies revealed that a considerable portions of As, Cd and Co in agricultural soils are derived from anthropogenic sources. We believe that pollution index should show values that are in accordance with chemical partitioning data. The newly developed pollution index showed slightly higher values when compared with the previously published indices such as geochemical index (I_geo) and pollution index (I_poll). The health risk index in the area of study was found to be lower than many other reported ones. Among the studied elements, Co has the highest transfer factor of 17.95 that could be attributed to its lower retention rate.     

Indicators and trade-offs of ecosystem services in agricultural soils along a landscape heterogeneity gradient

Soil functions can be classified as supporting (nutrient cycling) and provisioning (crop production) ecosystem services (ES). These services consist of multiple and dynamic functions and are typically assessed using indicators, e.g. microbial biomass as an indicator of supporting services. Agricultural intensification negatively affects indicators of soil functions and is therefore considered to deplete soil ES. It has been suggested that incorporating leys into crop rotations can enhance soil ES. We examined this by comparing indicators of supporting soil services – organic carbon, nitrogen, water holding capacity and available phosphorous (carbon storage and nutrient retention); net nitrogen mineralisation rate and microbial biomass (nutrient cycling and retention) – in barley fields, leys and permanent pastures along a landscape heterogeneity gradient (100, 500 and 1000 m radii). In addition, barley yields (provisioning service) were analysed against these indicators to identify trade-offs among soil services. Levels of most indicators did not differ between barley and ley fields and were consistently lower than in permanent pastures. Leys supported greater microbial biomass than barley fields. Landscape heterogeneity had no effect on the indicators or microbial community composition. However, landscape heterogeneity correlated negatively with yield and soil pH, suggesting that soils in heterogeneous landscapes are less fertile and therefore have lower yields. No trade-offs were found between increasing barley yield and the soil indicators. The results suggest that soil ES are determined at the field level, with little influence from the surrounding landscape, and that greater crop yields do not necessarily come at the expense of supporting soil services.     

村镇饮用水源地污染关键区识别

为直接识别村镇饮用水源地污染关键区,以遥感影像分类技术提取水源地土地利用类型,基于水源地各类非点源污染源源强系数,根据不同污染因子贡献率采用指数超标法计算各污染因子权值,确定各类污染源的污染影响程度和分析水源地各子流域污染浓度,以地表水环境指标值为界限值进行识别。以安基山水源地2011年污染状况为研究对象,选择农村居民区、农田、矿山为污染源,采用化学需氧量、氨氮、总氮和总磷作为主要污染因子,应用ArcGIS软件划分水源地为19个子流域,在各子流域内综合考虑各类污染源的影响程度,以地表Ⅲ类、Ⅳ类和Ⅴ类水的指标值为界限划分水源地污染等级区,划分结果为:子流域8、14、16和17为正常区,子流域9、10和13为一般污染关键区,子流域2为次污染关键区,子流域1、3、4、5、6、7、11、12、15、18和19为污染关键区。该研究可为村镇饮用水源地污染关键区识别提供新的方法。     

水源保护区农村公众生活污染支付意愿研究

采用环境保护意愿价值评估法(CVM),以北京市密云水库为例,考察了地表水饮用水源保护区农村公众改善生活环境愿望的强烈程度及环境偏好,从而为更有效地实施水源区环境保护和农村环境管理工作提供依据.调查表明,77.7%的农户愿意为改善村镇卫生环境、保护饮用水源支付一定的金额,农户的平均支付意愿是16.10元·户-1a·-1,环保态度和认知、受教育程度是影响该区域公众环保需求的首要因素,家庭收入也是影响支付意愿的显著因素.支付意愿的地域差异分析表明,地域因素中,生态村建设与支付意愿显著相关,但生态村农户支付意愿低于非生态村,距水库的距离与人均支付意愿间相关关系不显著.提高公众受教育程度及农户的家庭收入是增强水源地公众改善环境愿望和加强环境管理的首要措施.     

澳大利亚农业系统中非点源污染的控制

The Australian farming sector is continuing to intensify, particularly within 300 km of the east and southern coastlines. In the future there will be fewer and larger farms, which will use more fertilizer, support more stock, grow more monoculture crops, and utilise more marginal soils. This is likely to increase the major environmental impacts of soil degradation, salt, nutrient and sediment contamination of waterways, and greenhouse gas emissions. Australian national water policy continues to focus on land, stream and groundwater salinity issues, although there is now a greater recognition of the importance of nitrogen and phosphorus losses from agriculture. The general philosophy of policy for dealing with nonpoint source pollution has been towards a voluntary rather than regulatory approach, with state and national governments supporting a range of programs to encourage sustainable agricultural practices. A catchment （watershed） based approach, through the use of integrated catchment management plans, is the primary way that non-point source pollution is addressed at the farm and local level. At an industry level, cotton, grains, meat, sugarcane and dairy amongst others, as well as the Australian fertilizer industry, have responded to non-point source issues by investing in research and development, and developing codes of practice aimed at abating these environmental impacts. Understanding the economic, social, political and cultural contexts of farming as well as the environmental impacts of agriculture are very important in determining the appropriateness of policy responses for Australian farming systems.     

基于AnnAGNPS模型的农业非点源污染模拟

以大沽河典型小流域为研究区,借助GIS和相关资料率定参数,完成模型数据库的建立。在此基础上,采用流域出口2001～2002年径流量、泥沙和总氮监测数据优化参数、校准和验证模型,分析AnnAGNPS模型在大沽河典型小流域应用的可行性。2000～2001年,地表径流的年均模拟偏差分别为12.7%和7%,丰水期的月模拟偏差都在±30%以内,日模拟值与实测值相关系数分别是0.98和0.91,模拟结果理想;年均泥沙输出模拟误差分别为19.1％和15%,月均泥沙估算的相关系数分别为0.78和0.73,模拟结果基本可接受;年均模拟误差为50%左右,月均估计及降雨场次模拟的相关系数分别低于0.7和0.6,总氮污染负荷估算有很大的不确定性。结果表明,如何提高模型的营养盐模拟精度将是未来AnnAGNPS模型在大沽河流域应用的前提与基础。研究成果对于AnnAGNPS模型在国内的应用和推广,具有很好的示范性,并为大沽河全流域分布式水文模型的构建奠定了基础。     

Use of geochemical fingerprints to trace sediment sources in an agricultural catchment of Argentina

Soil erosion and associated sediment redistribution are key environmental problems in Central Argentina. Specific land uses and management practices, such as intensive grazing and crop cultivation, are considered to be significantly driving and accelerating these processes. This research focuses on the identification of suitable soil tracers from hot spots of land degradation and sediment fate in an agricultural catchment of central Argentina with erodible loess soils. Using Energy Dispersive X-Ray Fluorescence (EDXRF), elemental concentrations were determined and later used as soil tracers for geochemical characterization. The best set of tracers were identified using two artificial mixtures composed of known proportions of soil sources collected from different lands having contrasting soil uses. Barium, calcium, iron, phosphorus, and titanium were identified for obtaining the best suitable reconstruction of source proportions in the laboratory-prepared artificial mixtures. Then, these elements, as well as the total organic carbon, were applied for pinpointing critical hot spots of erosion within the studied catchment. Feedlots were identified to be the main source of sediments, river banks and dirt roads together are the second most important source. This investigation provides key information for optimizing soil conservation strategies and selecting land management practices and land uses which do not generate great contribution of sediment, preventing pollution of the waterways of the region.     

Distribution of foraminifera near pollution sources in Chaleur Bay

Benthonic foraminifera samples were collected seasonally near several isolated sources of sewage and (or) industrial effluent in the Restigouche estuary. Distinct biotopes based on species diversity and population density are developed locally especially near Dalhousie peninsula and Belledune Point in response to the effects of effluent discharge. Averaged diversity indices calculated in known polluted describe an initially depressed curve that reflects the development of near-abiotic conditions close to the effluent source and, at some distance offshore, an anomalously high diversity which may be indicative of a zone near each outfall in which certain components of the effluent generate a temporary favorable artificial environment. TheElphidium incertumlclavatum group usually dominates the living fauna near sewage outfalls and appears to be able to invade and maintain itself on nearshore sediment substrates which have pH values in excess of 6.4.     

1978-2017年中国农业污染物影子价格及污染成本测算

农业污染物影子价格及污染成本估算是制定农业污染减排政策的基础性工作。该研究以1978-2017年中国农业部门的省级面板数据为研究单元,利用二次型方向性距离函数和收益函数的对偶关系估算了农业污染物的影子价格,并测算了农业生产的污染成本。研究发现:1978-2017年,中国农业污染物总氮(TN)、总磷(TP)和化学需氧量(COD)的影子价格总体呈下降趋势,分别下降了26.8%、35.9%、59.7%,并大致经历了自由发展、改革推动、市场调控与政策激励4个阶段。由于受自然资源条件与社会经济条件的影响,农业污染物的影子价格存在明显的区域差异,表现为东北地区TN的影子价格最低,西南地区TN和TP的影子价格最高而COD的影子价格最低,华东地区TP的影子价格最低而COD的影子价格最高。中国农业生产年均污染成本为760.6亿元,占全国年均农业总产值的10.8%,尤其是宁夏、贵州、河北、山东的污染成本占各省年均农业总产值的比例高于14%,表明农业污染成本巨大。中国农业污染物影子价格的长期演变趋势及其污染成本分析表明,农业政策的制定应避免掉入"逐利政策"陷阱,并积极转变农业生产方式与探索农业管理新模式。     

徐州市北郊农业土壤重金属污染评价

研究评价徐州市北郊农业土壤重金属污染状况结果表明,该区农业土壤中Cu、Cd、Pb、Zn和Cr 5种重金属平均含量均高于土壤背景值,其农业土壤Cd、Cr为重污染,土壤Zn为污染警戒级(尚清洁水平),其他2种元素为安全级(清洁水平),其综合污染指数为Cr>Cd>Zn>Cu>Pb。     

小麦籽粒铅污染来源的同位素解析研究

以中国西北地区某工业区为研究区域,采集大气降尘、耕层土壤样品(0～20 cm),及对应农田位置的小麦籽粒样品,用电感耦合等离子质谱(ICP-MS)测定铅元素质量比及铅同位素比率值。运用普通块克里金法(Ordinary Kriging)预测大气铅沉降通量分布、耕层土壤和小麦籽粒铅质量比空间分布;结合二元混合模型计算各污染源对小麦籽粒铅质量比的贡献率。结果表明:1)耕层土壤铅质量比范围为21.8～40.0 mg/kg,平均值为27.1 mg/kg,高于当地土壤背景值(21.4 mg/kg),说明耕层土壤受到一定程度的污染。2)研究区域小麦籽粒铅质量比范围为0.269～0.768 mg/kg,平均值为0.430 mg/kg,超标率达100%。3)大气降尘和耕层土壤对小麦籽粒铅质量比的贡献率分别为90%～99%和1%～10%。通过研究耕层土壤和小麦铅污染的范围及程度,探讨小麦籽粒铅污染的来源,解析各污染源的相对贡献率,可为制定控制食品中重金属污染,保障食品安全措施提供依据。     

农业非点源污染预测模型研究进展

农业非点源污染是一种间歇发生、随机性、突发性、不确定性很强的复杂过程，因此, 模型化研究一直是非点源污染研究领域的一个核心内容。该文回顾了农业非点源污染预测模型的发展，简要阐述了国外农田尺度和流域规模尺度农业非点源污染模拟模型的功能和研究进展，对中国非点源污染预测、模型发展及存在问题进行了论述，提出从农业生产和水环境保护的角度去探讨污染物运移特征和定量预测模型，结合3S技术，并考虑非点源污染的不确定性将是今后非点源污染模型研究的主要内容之一。     

缓冲带截除农业面源强污染的效果

为了摸清草皮缓冲带对农田径流冲击负荷的耐受能力,通过工程尺度的现场试验,研究了高浓度污染负荷冲击对百慕大草皮缓冲带截除农业面源污染物能力的影响。结果表明:在高浓度污染负荷下,百慕大缓冲带能有效地截留农田径流中的悬浮固体(suspended solids,SS),SS浓度变化趋势与一般浓度污染负荷基本一致,前端下降速度较快,后端逐渐趋缓,2种污染负荷条件下末端出水SS质量浓度均在90mg/L以下,高浓度污染负荷冲击对农田径流SS的去除基本没有影响。缓冲带对高浓度氮磷污染负荷具有一定的净化效果,径流途径总氮(total nitrogen,TN)、氨态氮(ammonia nitrogen,NH4+-N)、总磷(total phosphorus,TP)的末端去除率为23%、16%和26%,分别为一般浓度污染负荷下末端去除率的59%、55%和70%;百慕大草皮缓冲带对渗流途径TN、TP具有一定的净化效果,2种浓度污染负荷下渗流水TN、TP浓度变化趋势基本一致,两者无显著差异(p>0.05),但TP去除速率较TN慢。该文为滨岸缓冲带的优化设计、维护管理及推广应用提供了依据。     

GIS技术在农业面源污染研究中的应用

地理信息系统(GIS)技术具有分析速度快、智能化、可视化和信息化的优点,利用 GIS技术研究农业面源污染问题已经成为近年来研究农业面源污染的一大趋势。本文阐述了基于 GIS在农业面源污染研究中的主要应用技术,包括农业面源数据处理与管理、时空分布与空间差异性、GIS信息系统开发、大数据可视化、模型模拟、污染风险评估及预警预测等,并提出了 GIS技术在农业面源污染控制和治理应用方面的发展趋势和研究方向。