城市垃圾问题及处理对策

中国的城市垃圾问题已经成为比较严重的环境问题之一,目前的垃圾处理存在很多问题.以全过程控制思想为基础,在可持续发展和"三化"原则的指导下,运用环境管理的经济、法律、行政等方法,提出解决城市垃圾问题的城市垃圾管理对策和技术对策,提出了城市生活垃圾多元化综合处理的设想,以求建立适合中国国情的城市垃圾管理体系和垃圾产业化体系.     

基于RuO2-IrO2/Ti和Fe0电极的电氧化-电絮凝处理含Tl废水

基于RuO₂-IrO₂/Ti形稳电极和Fe⁰牺牲电极实现电氧化-电絮凝(EO-EC)一体化处理含Tl (I)废水,并与单一的电絮凝(EC)进行比较,探讨了EO-EC处理含Tl废水的机理.结果表明,相较于单一EC,EO-EC (1:1)组合技术适应于宽pH (4-10)以及电流密度范围(5-20mA/cm²)下含Tl废水高效处理,且不易发生钝化;活性氯以及氧化还原电位在Tl (I)间接氧化Tl (III)过程中扮演重要角色,沉淀分析表明生成的Tl (OH)_3(s)与絮体Fe (OH)_3(am)共沉淀,纤铁矿位点可吸附残留Tl (I).EO-EC一体化技术可满足实际含Tl废水达标处理(<2µg/L)且具有经济可行性.     

泥石流灾情综合评估模式

泥石流灾情综合评估模式是在灾情绝对评估的基础上建立的。首先，建立了泥石流灾情评估的步骤框图；然后依据已有的泥石流灾情评估指标体系对各项指标进行量化分析处理，将得了各灾情评估指标公值分布及其量纲换算法，确定了反映直接损失的灾情绝对评估指标和相对评估指标（直接经济损失占灾区国民收入的比例），并对绝对和相对评估结果的等级进行了划分；最后，建立了绝对评估和相对评估结果对比的灾情综合评估模式。经过实例应用验证，评估结果能较好地反映灾情。     

Tube-building by a marine meiobenthic harpacticoid copepod

Pseudostenhelia wellsi Coull and Fleeger is a meiobenthic harpacticoid copepod inhabiting muddy, estuarine sediments. All individuals observed, and all ages including nauplii, build and inhabit elongate, mucous tubes which may extend to a depth of 3.9 mm into the sediment. Many of the narrow tubes, 0.27 mm in diameter, have a tube-cap extending 0.32 mm above the sediment-water interface. The tubes are a matrix of fine silt, sand and detritus cemented with a mucopolysaccharide, as shown by the Periodic Acid Schiff stain, apparently secreted from glands in the ventrolateral margin of the cephalothorax. Upon addition to sterile, homogeneous sediment, P. wellsi quickly (within 1 to 2 h) transform the upper 0.4 cm to a cohesive conglomerate of tubes, silt-clay particles and mucous filaments.     

Are meiofaunal species cosmopolitan? Morphological and molecular analysis of Xenotrichula intermedia (Gastrotricha: Chaetonotida)

Many meiofaunal species are reported to be cosmopolitan, but due to uncertainties of identification, the affiliation of specimens from geographically distant areas to the same species-taxon is problematic. In this study, we examined morphological and molecular variation in samples of Xenotrichula intermedia Remane (Gastrotricha: Chaetonotida) from the Mediterranean Sea, the northwestern Atlantic and the northern Gulf of Mexico. Univariate analysis of 16 morphological traits was unable to detect differences among populations, except for the length of the pharynx, which was significantly shorter in the Gulf of Mexico specimens. Canonical discriminant analysis separated the Gulf of Mexico specimens from the other two populations, with pharynx length contributing about half of the total discrimination. Molecular analysis based on restriction-fragment length polymorphisms (RFLPs) in a 710-base pair polymerase chain-reaction (PCR) produet representing roughly half of the mitochondrial cytochrome oxidase I (COI) gene detected four haplotypes: one each from the Mediterranean and the Gulf of Mexico populations and two coexisting within the Atlantic population. The estimated nucleotide-sequence divergence calculated for each pairwise combination of haplotypes (based on the proportion of shared fragments) ranged from 5.3 to 11.5%. The high genetic divergence and the inability to clearly separate populations based on morphology suggest that individuals characterized by different haplotypes are genetically isolated sibling species.     

Population dynamics of three estuarine meiobenthic harpacticoids (Copepoda) in South Carolina

To elucidate the population dynamics of abundant meiofauna, a 15-month field study of 3 species of harpacticoid copepods was conducted in a South Carolina (USA) estuary. Per capita birth and death rates and average brood size (number of eggs per adult female) were lowest for Enhydrosoma propinguum (Brady), Microarthridion littorale (Poppe), and Stenhelia (Delavalia) bifidia (Coull) from November–February, indicating that food or density-independent factors such as temperature regulated winter densities. Reproduction for all species began in February, with the first appearance of copepodites approximately 1 month later. From March–October, M. littorale displayed high per capita birth and death rates (>0.6 individual^-1 day^-1), and high average brood size (8 to 9 eggs per adult female). As this species is epibenthic, and thus susceptible to grazing by detritivores, these data suggest that M. littorale was limited by predation. S. (Delavalia) bifidia displayed a sharp increase in density, birth rate and average brood size in July, but birth and death rates (0.3 individual^-1 day^-1) were always lower than those of M. littorale and average brood size gradually decreased from July–December. As this species burrows and is less susceptible to grazing predation, these data are consistent with the hypothesis that S. (Delavalia) bifidia became food-limited as population growth approached its carrying capacity. Although E. propinguum was the most abundant species, quantification of birth potential was not accomplished due to an underestimate of the number of ovigerous females. Therefore, little can be concluded about the mechanism of the summer density regulation of E. propinguum.Contribution No. 274 from the Belle W. Baruch Institute for Marine Biology and Coastal Research, University of South Carolina.     

Ontogenetic feeding shifts in the meiobenthic harpacticoid copepod Nitocra lacustris

¹⁴C-radiolabelling experiments indicate that adult stages of the salt-marsh harpacticoid copepod Nitocra lacustris (Schmankevitsch) receive a large part of their nutrition through the ingestion and assimilation of certain diatoms. An abundance of empty diatom frustules occurs in the gutpellet contents of field-collected individuals. Naupliar stages do not ingest diatoms in the laboratory, and nauplii from the field do not contain frustules in their gut pellets. Ingestion of diatoms in the laboratory first occurs during the second or third copepodite stage. ³H-radiolabel expeiments and grazing experiments using bacterium-sized beads adhering to the diatoms indicated that both adults and nauplii ingest bacteria adhering to the outer mucus coating of the diatoms (and probably ingest the diatom mucus itself). Adults ingest bacteria (and probably mucus exopolymer) coincidently while ingesting diatoms. The nauplii ingest these components by scraping the outer surface of the diatoms. SEM observations indicate that diatoms are not punctured by the nauplii during feeding. While diatom mucus and associated bacteria play an (as yet unquantified) role in the nutrition of the adults, these components may comprise the bulk of food resources for naupliar stages.     

海外耕地保护的社会化扶持对策及其启示

由于耕地为公众提供了大量的、具有强烈外部性的非生产性功能,很多国家都把耕地保护作为一个公共目标,并通过社会化扶持手段来得到实施.中国作为一个人多地少,人均耕地占有量低的国家,耕地保护任务更加突出,虽然"切实保护耕地"成为我国的一个基本国策,提出要执行"世界上最严格的耕地保护",并制定了耕地总量动态平衡、土地用途管制等一系列耕地保护政策,但耕地保护整体效果却不窖乐观,其中一个原因就是没有形成全社会共同保护耕地的氛围.本文对当今世界耕地保护社会化扶持的政策依据及实践手段进行综合与分析,并结合我国耕地保护的形势,提出了我国耕地保护社会化扶持的一系列对策措施,包括加快耕地产权制度建设,明确耕地保护的责任主体;重视耕地的非生产功能,提高全社会的耕地保护意识;采用综合优惠措施,激励农户的耕地保护行为;完善城镇发展规划,严格控制城镇对耕地的侵占;延长农产晶产业链,增加农业产业的经济收入.     

Quantitative estimates of the meiofauna from the deep sea off North Carolina,USA

In 1974 the authors collected, sorted and enumerated meiofauna from 400, 800 and 4000 m off North Carolina, USA. Samples were replicated respectively with 4 boxcores and 21 subsamples, 2 boxcores and 7 subsamples and 2 boxcores and 8 subsamples. Total meiofaunal numbers were highest in fine silt sediment at 800 m ( =891.9 10 cm_–2) and lowest in very fine silt at 4000 m ( =73.5 10 cm_–2). Fine sand at 400 m yielded a mean of 442.4 10 cm^–2. At all depths, most fauna were located in the upper 3 cm of sediment ( depth distribution=2.2 cm), and typically only nematodes and foraminiferans were found below 4 cm. Total community abundances significantly differed with depth; however, there were no differences among replicate boxcores at particular depths. Since most (85.7%) of the variance was associated with subsamples from a boxcore, it appears that meiofauna densities are homomeneous within large areas at particular depths, and that patchiness is a smallscale phenomenon at the level of the 10 cm² subsampler. Comparisons of sorting efficiencies of live and preserved samples indicated that to accurately enumerate formainiferans, samples must first be fixed and stained, while turbellarians and oligochaetes must be sorted live.Contribution No. 151 from the Belle W. Baruch Institute for Marine Biology and Coastal Research. This research was supported by the Oceanography Section, National Science Foundation, NSF Grant GA-42792, and GC-00005 to Duke University for R.V. Eastward operations.