SPATIAL ECONOMICS OF TARGETING MANURE POLICY1

ABSTRACT: Increasing specialization separates animal production from cropland, complicating manure management. To assist policy targeting efforts, we highlight areas where on-farm use of manure may be problematic. Matching confined animal production with land, on the farm- rather than at the county-level, gives our analysis an advantage over previous studies in avoiding aggregation problems. With manure-based water quality problems, data aggregated to the county level may fail to convey the heterogeneity of animal production across regions and animal types. Aggregation bias blurs the distinction between areas with specialized animal production and those that merely have numerous animals. We estimate bias from using county aggregates, show its distribution spatially and by animal sector, and link it to concentration. Ongoing vertical integration in agriculture likely alters in-county variability in facility scale and scope, and may influence decisions about which data we should gather and use.     

土壤作物系统镉污染及其防治研究

选择我国北方主要粮食作物冬小麦和夏谷进行盆栽试验，研究了土壤镉污染对作物生长发育和产量的影响及泥炭、羊粪两种不同类型的有机肥缓减土壤镉污染危害的作用；分析了镉在两种作物不同器官中的迁移效率和累积规律；认为施加有机肥是缓减土壤镉污染危害的有效措施，且施羊粪的效果比施泥炭好。     

Characterization and role of carbonic anhydrase in the calcification process of the azooxanthellate coral <Emphasis Type="Italic">Tubastrea aurea</Emphasis>

In zooxanthellate corals, the photosynthetic fixation of carbon dioxide and the precipitation of CaCO₃ are intimately linked both spatially and temporally making it difficult to study carbon transport mechanisms involved in each pathway. When studying Tubastrea aurea, a coral devoid of zooxanthellae, we can focus on carbon transport mechanisms involved only in the calcification process. We performed this study to characterize T. aurea carbonic anhydrase and to determine its role in the calcification process. We have shown that inhibition of tissular carbonic anhydrase activity affects the calcification rate. We have measured the activity of this enzyme both in the tissues and in the organix matrix extracted from the skeleton. Our results indicate that organic matrix proteins, which are synthesized by the calcifying tissues, are not only structural proteins, but they also play a crucial catalytic role by eliminating the kinetic barrier to interconversion of inorganic carbon at the calcification site. By immunochemistry we have demonstrated the presence of a protein both in the tissues and in the organic matrix, which shares common features with prokaryotic carbonic anhydrases.     

菜田养分资源综合管理与可持续发展

过量施肥通常导致集约化菜田土壤质量劣化、养分利用效率低及环境风险增加。合理的养分资源管理需要考虑蔬菜的养分吸收规律、土壤养分的迁移和转化及环境养分供应的特点。由于土壤氮素具有较强的移动性,氮素养分资源管理可通过根层氮素实时监控来实现;而磷和钾养分水平在土壤中相对比较稳定,可采取衡量监控技术决定养分的需要量。菜田有机肥的投入总量及其氮磷养分的释放特点也是养分资源管理中的重要内容。有机肥施用于新菜田应考虑“以氮定量”的原则,而施用于土壤有效磷过量累积的老菜田,应采取“以磷定量”原则,来控制有机肥中的磷素投入;根据不同有机肥的氮磷释放特点的差异,可搭配施用不同比例和类型有机肥,以满足作物主要生育期的养分需求,减少环境污染的风险。     

Bioavailability of hydrophobic organic contaminants and quality of organic carbon

U.S. laws require that contaminant bioaccumulation potential be evaluated before dredged material can be recycled. Simple fugacity models, e.g. organic contaminant aqueous partition coefficient (K _oc)-derived theoretical bioaccumulation potential, are commonly used to estimate the partitioning of hydrophobic organic contaminants between sediment organic matter and organism lipid. K _oc-derived models, with or without the addition of a soot carbon term, did not accurately or consistently predict total polycyclic aromatic hydrocarbons (PAHs) and polychlorobiphenyls partitioning of eight sediments from ongoing dredging operations onto C₁₈-coated filter paper. These models also failed to predict the partitioning of individual PAHs from these eight sediments. These data underscore the trade-offs between the ease of using simple models and the uncertainty of predicted partitioning values.     

改良剂对铜矿尾矿砂与菜园土混合土壤性质及黑麦草生长的影响

用蒙脱石、稻草、鸡粪作为改良剂 ,研究不同改良剂对铜矿尾矿砂与菜园土混合土壤pH、有效态重金属含量、脲酶和磷酸酶活性以及混合土壤上种植的黑麦草生长的影响。结果表明 :添加蒙脱石对不同生长期黑麦草的生长量没有显著影响 ;使用稻草和鸡粪处理尽管在开始阶段不利于黑麦草 (第 1茬和第 2茬 )的生长 ,但随时间延长 ,黑麦草的生物量 (第 3茬和第 4茬 )明显增加 ,表现出很好的后效。黑麦草的根重与鸡粪的添加量关系显著 ,施用稻草的纯尾矿砂处理组 (处理 2 2 )根重最大 ,而且蚯蚓只能在使用适量稻草的处理条件下才能在混合土壤中生长。土壤酶的分析发现 ,磷酸酶的活性除了在蚯蚓能够生长的处理组表现出较高外 ,其它处理之间无明显差异 ,但脲酶的活性则随着稻草和鸡粪施用量的增加而显著提高。各处理之间土壤的 pH值变化不大。添加稻草减少了土壤中有效态重金属的含量 ,而使用鸡粪处理明显增加了土壤中包括铜、铅和锌等有效态重金属的含量 ,说明在施用含有重金属的畜禽粪便时务必小心谨慎 ,以防二次污染。     

Organic pollutants in riparian wetlands of the Lippe river (Germany)

Organic-geochemical investigations were performed on layers of a dated sediment core taken from a riparian wetland of the Lippe river, Germany. The samples were collected from two distinct depth intervals representing sedimentation periods of 1944–1952 and 1972–1984, respectively. Comprehensive screening analyses by gas chromatography-mass spectrometry (GC-MS) revealed a complex mixture of anthropogenic contaminants. Here, we report the quantitative distribution of selected persistent lipophilic organic substances characterizing municipal as well as industrial emissions. Considering both geochemical and geochronological data, we deduced time-dependent information about industrial production and domestic effluents for the region investigated. In addition, usage and subsequent emission of characteristic pollutants into the riverine system were interpreted for both time periods monitored.     

牛粪发酵过程中抗生素耐药基因及相关菌群组成变化规律

随着规模化奶牛养殖迅速发展,牛粪带来的环境污染问题日益严重。实验探究牛粪及其堆肥过程中养分变化、抗生素耐药基因消减情况以及细菌群落演替规律,探讨细菌菌群与养分、抗生素耐药基因之间的相关性。采集牛粪及其堆肥过程样品,测定样品中养分、检测抗生素耐药基因相对丰度,采用16S r RNA高通量测序技术研究牛粪堆肥过程细菌群落变化。结果表明,从新鲜牛粪(组FM)到发酵牛粪(组C),样品中有机质含量下降,全氮和全磷含量有不同程度增加,全钾(TK)显著升高(P<0.05)。堆肥发酵后,抗生素耐药基因erm B、tet M、bla CTX-M和aac(6')-Ib-cr的相对丰度呈现不同程度的下降,而基因sul1相对丰度增加。高通量测序结果表明,在门水平,各组均以Firmicutes、Proteobacteria和Bacteroidetes这3个菌门为主,在属水平,各组具有不同的优势物种,其中发现Bacteroides、Paeniclostridium和Pseudomonas等7个潜在病原菌属的相对丰度在堆肥后有效降低。通过相关性分析发现,潜在病原菌属与基因tet M和sul1呈显著正相关(P<0.05),此外,大部分优势菌属与养分TK有显著相关性(P<0.05)。研究结果表明,牛粪经堆肥发酵后,病原菌相对丰度有效降低,抗生素耐药基因相对丰度的下降与细菌菌群结构变化存在相关关系。     

Monofunctionalized cyclodextrin polymers for the removal of organic pollutants from water

Water is an important resource for domestic, industrial, agricultural and recreational purposes. The quality of water is however significantly deteriorating due to the accumulation of organic pollutants in aqueous systems. Conventional water treatment technologies fail to remove these contaminants to desirable levels. Recent studies have revealed that cyclodextrin nanoporous polymers are capable of absorbing pollutants from water to parts per billion levels. We have demonstrated that functionalised cyclodextrin polymers have enhanced absorption capacities for some organic pollutants. Here we report the synthesis of several insoluble monosubstituted cyclodextrin polymers or “nanosponges”. We show that these polymers have improved abilities in the absorption of p-nitrophenol and pentachlorophenol from aqueous solutions.     

鼓泡塔中有机酸强化粗颗粒石灰石新型烟气脱硫

对传统石灰石湿法烟气脱硫进行了改进,提出了一种新型烟气脱硫方法,即在鼓泡塔中添加有机酸,采用大颗粒石灰石(210 μm)代替传统的细颗粒石灰石(5～20 μm)进行脱硫.实验在鼓泡搅拌吸收反应器中对比研究了新老两种脱硫工艺.结果表明,当210 μm石灰石浆液中醋酸摩尔浓度达10～30 mmol/L,其脱硫率和石灰石利用率分别为95%和93.5%,均达到甚至优于传统石灰石脱硫结果.实验研究了影响脱硫率的各种因素:添加醋酸浓度、入口SO2浓度、石灰石浆液浓度、气体停留时间以及温度等,并提出添加醋酸促进SO2吸收的机理.运用该新型烟气脱硫方法,可降低电厂的基础投资和运行费用,大大加强系统的稳定性和抗击烟气中SO2波动的能力.