The effect of afforestation on mineralization of soil organic matter

The effect of afforestation on the activity of microbiological mineralization of soil organic matter has been studied in Siberia. The results show that this effect concerns mainly net nitrogen mineralization and net nitrification, while carbon mineralization (CO₂ formation) does not depend on the type of ecosystem. It is proposed to use the rates of net nitrogen mineralization and nitrification as the most sensitive indicators of changes in an ecosystem.     

重碳酸型地下水矿化度测定方法的探讨——以洛阳市浅层地下水为例

矿化度是地下水化学成份测定的重要指标，在环境监测中，用重量法测定矿化度是目前普遍采用的方法。其缺点主要为费时，繁琐，耗电。本文通过测定洛阳市地下水的电导率，分析对比电导率与矿化度的关联，并进一步用回归方程确定电导率与矿化度之间的数量关系，探索出用电导率法间接测定地下水矿化度，具有快速，经济，准确的优点。     

A respirometric method to measure mineralization of polymeric materials in a matured compost environment

A respirometric method was developed to measure the mineralization of polymeric materials in a matured compost environment. For the purpose of evaluating the method, results obtained for the mineralization of glucose and cellulose are presented. The matured compost, in addition to supplied nutrients, micronutrients, and an inoculum, serves as the matrix which supports the microbial activity. Recovery of the substrate carbon in the form of carbon dioxide from the glucose and cellulose added to test vessels was 68 and 70%, respectively. A statistical evaluation of the results obtained on substrate mineralization was carried out and showed acceptable reproducibility between replicate test vessels and test runs. The testing protocol developed has the following important characteristics: (1) the test reactors are maintained at 53 °C at a high solids loading (60% moisture), which has certain characteristics that are similar to a thermophilic compost environment; (2) the test matrix providing microbial activity is derived from readily available organic materials to facilitate reproducibility of the method in different laboratories; (3) the equipment required to perform this test is relatively inexpensive; and (4) the information obtained on polymer mineralization is vital to the study and development of biodegradable polymeric materials.Guest Editor: Dr. Graham Swift, Rohm & Haas.     

浅层地下水矿化度测定方法的探讨

矿化度是地下水化学成分测定的重要指标 ,在环境监测中 ,用重量法测定矿化度是目前普遍采用的方法。其缺点主要是费时、繁琐、耗电。本研究通过测定洛阳市地下水的电导率 ,分析对比电导率与矿化度的关联 ,并进一步用回归方程确定电导率与矿化度之间的数量关系 ,探索出用电导率法间接测定地下水矿化度 ,具有快速、经济、准确的优点     

铬渣作水泥矿化剂的经济及环境效应分析

铬渣的处理利用一直是铬盐行业和固体污染物处理的难点，本文介绍了用铬渣作水泥矿化剂处理铬渣这种新方法的原理，并进行了经济和环境效应分析，结果表明用铬渣作水泥矿化剂确实是一种很好的处理铬渣的方法。     

负载型纳米TiO2光催化剂的制备及其光催化活性

采用悬浮聚合法制备粉煤灰-聚苯乙烯微珠载体,通过矿化接枝技术将水热法制备的纳米TiO2负载在粉煤灰-聚苯乙烯微珠载体上,制成负载型纳米TiO2光催化剂。用x射线衍射仪、扫描电子显微镜对负载型纳米TiO2光催化剂进行了表征;通过光催化降解甲醛实验评价了负载型纳米TiO2光催化剂的活性。实验结果表明,纳米TiO2在载体上分散良好,平均粒径为36．4nm;该催化剂活性较高,明显优于粉体纳米TiO2光催化剂,重复使用10次左右,该催化剂的活性无明显下降。     

聚乙烯醇生化矿化度及自然降解的研究

通过对聚乙烯醇(PVA)生化矿化度、PVA在目然水域及土壤中的自净能力以及PVA降解过程中结构变化的研究,探讨PVA的可生化性及降解进程中物质的转化规律.PVA的生化矿化度高达50-70％,表明PVA在微生物作用下可以高度降解.由自净能力和结构变化过程的研究表明,PVA首先由大分子转变为小分子,经相应时间后向无机物转化,说明PVA在自然水域和土壤中有较好的自净作用。     

Degradation of ethylenethiourea pesticide metabolite from water by photocatalytic processes

In this study, photocatalytic (photo-Fenton and H₂O₂/UV) and dark Fenton processes were used to remove ethylenethiourea (ETU) from water. The experiments were conducted in a photo-reactor with an 80 W mercury vapor lamp. The mineralization of ETU was determined by total organic carbon analysis, and ETU degradation was qualitatively monitored by the reduction of UV absorbance at 232 nm. A higher mineralization efficiency was obtained by using the photo-peroxidation process (UV/H₂O₂). Approximately 77% of ETU was mineralized within 120 min of the reaction using [H₂O₂]₀ = 400 mg L^?1. The photo-Fenton process mineralized 70% of the ETU with [H₂O₂]₀ = 800 mg L^?1 and [Fe²⁺] = 400 mg L^?1, and there is evidence that hydrogen peroxide was the limiting reagent in the reaction because it was rapidly consumed. Moreover, increasing the concentration of H₂O₂ from 800 mg L^?1 to 1200 mg L^?1 did not enhance the degradation of ETU. Kinetics studies revealed that the pseudo-second-order model best fit the experimental conditions. The k values for the UV/H₂O₂ and photo-Fenton processes were determined to be 6.2 × 10^?4 mg L^?1 min^?1 and 7.7 × 10^?4 mg L^?1 min^?1, respectively. The mineralization of ETU in the absence of hydrogen peroxide has led to the conclusion that ETU transformation products are susceptible to photolysis by UV light. These are promising results for further research. The processes that were investigated can be used to remove pesticide metabolites from drinking water sources and wastewater in developing countries.     

The degradation of anilazine and dihydroxy‐anilazine at various soil depths of an orthic luvisol

Abstract

In conformity with Guideline 4.1 of the Federal German Biological Agency, degradation experiments with the fungicide active ingredient [benzene ring‐U‐¹⁴C]anilazine and its major metabolite [triazine ring‐U‐¹⁴C]dihydroxy‐anilazine were carried out in an orthic luvisol. Mineralization of the benzene ring carbon of anilazine amounted to less than 2 % in 110 days and that of the triazine ring carbon of dihydroxy‐anilazine to less than 8 %. Increasing the incubation temperature from 22 °C to 30 °C and adding organic substance influenced the mineralization slightly. In soils which received two or three applications in succeeding years with subsequent ageing in the open‐air lysimeter no stimulation of the mineralization was observed. Extractions after incubation showed that only 10.2 to 18.6 % of the ¹⁴C‐activity applied with anilazine was extractable with acetone/CaCl₂. The major proportion was bound in the fractions of the soil organic matter, namely 45.0 to 59.6 % of the radiocarbon applied was accounted for by the humin fraction, 12.0 to 27.4 % by the fulvic acids, and 9.4 to 15.0 % by the humic acids. In the case of dihydroxy‐anilazine, 28.9 to 89.7 % of the applied ¹⁴C‐activity was extractable with acetone/CaCl₂. Of tJhe radiocarbon bound in the soil, the greatest proportion, i.e. 18.5 to 35.5 % of the radiocarbon applied, was accounted for by the fulvic acids.     

Carbofuran degradation in soil profiles

Abstract

Two soils, Puyallup fine sandy loam from Puyallup, WA, and Ellzey fine sand from Hastings, FL, each with a prior history of carbofiiran exposure but with different pedological and climatological characteristics, were found to exhibit enhanced degradation toward carbofiiran in surface and subsurface soil layers. The treated Puyallup and Ellzey soils exhibited higher mineralization rates for both the carbonyl and the aromatic ring of carbofiiran when compared to untreated soils. Disappearance rates of [¹⁴C‐URL (uniformly ring labeled)] carbofiiran in the treated Ellzey soil was faster than in untreated soil, and also faster in surface soil than in subsurface soil. Initial degradation patterns in the treated Ellzey soil were also different from those in the untreated soil. The treated Ellzey soil degraded carbofuran mainly through biological hydrolysis, while untreated soil degraded carbofuran through both oxidative and hydrolytic processes.