Molecular composition of recycled organic wastes,as determined by solid-state 13C NMR and elemental analyses

Using solid state ¹³C NMR data and elemental composition in a molecular mixing model, we estimated the molecular components of the organic matter in 16 recycled organic (RO) wastes representative of the major materials generated in the Sydney basin area. Close correspondence was found between the measured NMR signal intensities and those predicted by the model for all RO wastes except for poultry manure char. Molecular nature of the organic matter differed widely between the RO wastes. As a proportion of organic C, carbohydrate C ranged from 0.07 to 0.63, protein C from <0.01 to 0.66, lignin C from <0.01 to 0.31, aliphatic C from 0.09 to 0.73, carbonyl C from 0.02 to 0.23, and char C from 0 to 0.45. This method is considered preferable to techniques involving imprecise extraction methods for RO wastes. Molecular composition data has great potential as a predictor of RO waste soil carbon and nutrient outcomes.     

Benthic Fluxes and Pore Water Profiles in the Tigullio Gulf

Diffusive fluxes of elements (NO^-₂, NO^-₃, NH⁺₄, SiO₂, PO^3-₄, Cl^-, SO^2-₄, Fe, Mn) have been measured by applying the Fick's first law in two stations of the Tigullio Gulf: the first one characterized by sandy sediments rich in vegetal detritus and the second one, located to within the tourist harbour, characterized by a silty-clay sediments.

Benthic fluxes were measured only in the second station by means of benthic chamber experiments. Although the significant presence of dissolved oxygen in the surface sediments, and the evidence of processes usually occurring in oxidised sediments such as nitrification, both stations also presented characteristics of anoxic sediments such as high oxygen consumption rate and high pore water concentrations of ion, manganese and N-ammonia and reactive orthophosphate.

In both stations, sediments seemed to represent a potential source for most of the chemical species studied, although fluxes were not confirmed for ion, manganese and reactive orthophosphate in benthic chamber experiments.

Diffusive fluxes presented a general agreement for both stations, with higher fluxes of N-nitrate and N-nitrite at the first station were oxidative processes of N-ammonia in the upper layer of the sediments seemed to be more active. the comparison between diffusive and benthic fluxes showed a possible contribution of bioturbation.     

Carbon Pool Dynamics in the Lower Fraser Basin from 1827 to 1990

/ To understand the total impact of humans on the carbon cycle, themodeling and quantifying of the transfer of carbon from terrestrial pools tothe atmosphere is becoming more critical. Using previously published data,this research sought to assess the change in carbon pools caused by humans inthe Lower Fraser Basin (LFB) in British Columbia, Canada, since 1827 anddefine the long-term, regional contribution of carbon to the atmosphere. Theresults indicate that there has been a transfer of 270 Mt of carbon frombiomass pools in the LFB to other pools, primarily the atmosphere. The majorlosses of biomass carbon have been from logged forests (42%), wetlands(14%), and soils (43%). Approximately 48% of the forestbiomass, almost 20% of the carbon of the LFB, lies within old-growthforest, which covers only 19% of the study area. Landfills are nowbecoming a major sink of carbon, containing 5% of the biomass carbonin the LFB, while biomass carbon in buildings, urban vegetation, mammals, andagriculture is negligible. Approximately 26% of logged forest biomasswould still be in a terrestrial biomass pool, leaving 238 Mt of carbon thathas been released to the atmosphere. On an area basis, this is 29 times theaverage global emissions of carbon, providing an indication of the pastcontributions of developed countries such as Canada to global warming andpossible contributions from further clearing of rainforest in both tropicaland temperate regions.KEY WORDS: Carbon pools; Global warming; Carbon release to atmosphere;Greenhouse effect     

ADSORPTION IN MULTICOMPONENT SOLUTION BY ACTIVATED CARBON

It was found that the total adsorptive capacity of activated carbon was enhanced by using a multicomponent solution with glucose, peptone and phenylphosphonic acid. A maximum use of the carbon adsorptive capacity is possible if the carbon is used for tertiary treatment followed by treating a stronger waste.     

A stochastic-advective transport model for NAPL dissolution and degradation in non-uniform flows in porous media

Remediation schemes for contaminated sites are often evaluated to assess their potential for source zone reduction of mass, or treatment of the contaminant between the source and a control plane (CP) to achieve regulatory limits. In this study, we utilize a stochastic stream tube model to explain the behavior of breakthrough curves (BTCs) across a CP. At the local scale, mass dissolution at the source is combined with an advection model with first-order decay for the dissolved plume. Field-scale averaging is then employed to account for spatial variation in mass within the source zone, and variation in the velocity field. Under the assumption of instantaneous mass transfer from the source to the moving liquid, semi-analytical expressions for the BTC and temporal moments are developed, followed by derivation of expressions for effective velocity, dispersion, and degradation coefficients using the method of moments. It is found that degradation strongly influences the behavior of moments and the effective parameters. While increased heterogeneity in the velocity field results in increased dispersion, degradation causes the center of mass of the plume to shift to earlier times, and reduces the dispersion of the BTC by lowering the concentrations in the tail. Modified definitions of effective parameters are presented for degrading solutes to account for the normalization constant (zeroth moment) that keeps changing with time or distance to the CP. It is shown that anomalous dispersion can result for high degradation rates combined with wide variation in velocity fluctuations. Implications of model results on estimating cleanup times and fulfillment of regulatory limits are discussed. Relating mass removal at the source to flux reductions past a control plane is confounded by many factors. Increased heterogeneity in velocity fields causes mass fluxes past a control plane to persist, however, aggressive remediation between the source and CP can reduce these fluxes.     

Suspended particulate mercury associated with tidal fluxes in a lagoon environment impacted by cinnabar mining activity (northern Adriatic Sea)

The Isonzo River has been demonstrated to be a continuing point source of mercury(Hg)in the Gulf of Trieste although the Idrija mine was last active in 1996. The present study aims to investigate the role of the suspended particulate matter(SPM) associated with tidal fluxes to disperse particulate Hg(PHg) into the Grado coastal lagoon system. PHg concentrations(avg. 3.11 ± 2.62 μg/g, d.w.), notwithstanding the ebb or flood tides, were significantly higher than the local sediment background(0.13 μg/g). The relative affinity of Hg for the particulate phase in surface waters was confirmed by higher average distribution coefficient(Kd) values(5.6–6.7). PHg contents showed the highest values in ebb tide conditions, thus suggesting their origin from the erosion of tidal flats and saltmarshes of the lagoon. When compared to river discharge, high PHg surface concentrations in flood tide are related to rainfall events occurring within the river basin. Results can be used to make an indicative assessment of the amount of Hg bound to SPM which is transported in and out of the lagoon basin following the action of tidal fluxes. A simple estimation provides a negative budget for the Grado lagoon sub-basin which loses between 0.14 and 1.16 kg of PHg during a tidal semi-cycle. This conclusion is in agreement with the evidence of morphological deterioration which has emerged from recent studies on the lagoon environment, and which testifies to a current sedimentary loss from the lagoon into the northern Adriatic Sea.     

唐岛湾网箱养殖区沉积物-水界面溶解无机氮的扩散通量

2004-08～2005-05分4个航次对唐岛湾网箱养殖区的10个站的沉积物间隙水和上覆水中的溶解无机氮营养盐（NH⁺₄-Ｎ、NO^-₃-Ｎ、NO^-₂-Ｎ）进行了现场调查, 并使用Fick第一定理对该海区沉积物-水界面溶解无机氮的扩散通量进行了估算.结果表明,网箱养殖区的上覆水和沉积物间隙水中溶解无机氮均以NO^-₃-Ｎ为主,分别占溶解无机氮总量的73.34%和61.45%;上覆水中溶解无机氮（DIN）和NO^-₃-Ｎ含量的季节变化趋势一致,在2004-10达到峰值,NH⁺₄-Ｎ的季节变化稍有不同;间隙水中溶解无机氮（DIN）和NO^-₃-Ｎ、NH⁺₄-Ｎ的变化趋势一致,表现为从5月份到8月份含量逐渐增加,到10月份达到最大,然后到次年2月份又减少;上覆水和间隙水中NO^-₂-Ｎ的含量随养殖进程表现为一个逐步积累的过程.NH⁺₄-Ｎ、NO^-₃-Ｎ和NO^-₂-Ｎ在沉积物-海水界面上的扩散通量分别为5.46、-5.04、8.71 μmol/（m²·d）,NO^-₂-Ｎ的扩散释放对唐岛湾网箱养殖区的水环境质量影响较大.     

不同施氮处理下旱作农田土壤CH_4、N_2O气体排放特征研究

依托甘肃农业大学布设在定西市李家堡镇的长期施氮定位实验,对不同施氮农田CH4和N2O气体通量,采用静态箱-气相色谱法进行小麦生育期的连续观测,并对影响通量变化的环境因子同期观测.结果表明:5个施氮处理下(0、52.5、105、157.5、210 kg·hm-2),旱作农田土壤在小麦全生育期内表现为CH4累积通量的汇和N2O累积通量的源;且不施氮处理时,CH4累积吸收通量最大;施氮量为210 kg·hm-2时,土壤CH4的累积吸收通量所受抑制最大,即土壤CH4累积吸收通量随施氮量升高而降低.相反,不施氮处理时,土壤N2O的累积排放通量最小,施氮量为210 kg·hm-2时,土壤N2O的累积排放通量最大,土壤N2O累积排放通量随施氮量的增加而增大.综合分析,施氮量增大会抑制全生育期旱作春小麦田土壤CH4吸收通量,提高土壤N2O的排放通量.因此,合理控制施氮量有利于生育期旱作农田土壤减排.CH4平均吸收通量随土壤温度的升高而降低,随土壤水分的升高而升高;相反,N2O平均排放通量随土壤温度的升高而升高,随土壤水分的升高而降低.5~10 cm层次的土壤温度与CH4平均吸收通量呈极显著线性负相关,与N2O平均排放通量呈显著正相关.5~10 cm层次的土壤水分与CH4平均吸收通量呈极显著线性正相关,与N2O平均排放通量呈显著负相关.     

铁路企业开发碳资产项目分析

在概述国际和国内碳交易市场发展现状的基础上,从企业获取碳资产途径及开展碳交易基础方面分析企业碳资产开发.探讨铁路企业开展碳资产项目的必要性和可行性,认为国内统一碳市场发展为铁路开发碳资产创造条件、铁路系统具有巨大的碳资产开发潜力、铁路系统相关碳资产开发方法学已较为成熟、改革为铁路碳资产开发提供助力、技术革新为铁路碳资产...     

低浓度二氧化碳检测管的研制

应用活性氧铝—百里香酚酞吸附ＣＯ２线性比长法研制出低浓度ＣＯ２检测管。测定范围０．０５～０．９０％;灵敏度为０．０５％;检测管变色长度与ＣＯ２浓度的相关系数γ＝０．９９８１,精密度与准确度符合国家标准８３ＧＢ７２２０～７２８０。其可靠性与经典的何氏气体分析器比较,结果基本一致。低浓度的ＳＯ２、Ｈ２Ｓ和ＮＨ３对测定无明显干扰,现场监测应用效果可靠,值得推广应用。