Compound-Specific Isotope Analysis (CSIA) Application for Source Apportionment and Natural Attenuation Assessment of Chlorinated Benzenes

Compound-specific isotope analysis

The isotopic composition, e.g. 14C/12C, 13C/12C, 2H/1H, 15N/14N and 18O/16O, of matter elements is heterogeneous. It is ruled by physical, chemical and biological mechanisms. Isotopes thus be enable to follow the fate of mineral and organic compounds during biogeochemical transformations. The determination of the isotopic composition of organic substances occurring at trace level into very comp...

diagnostic and developmental potentials of dynamic assessment for writing skill

این پایان نامه بدنبال بررسی کاربرد ارزیابی مستمر در یک محیط یادگیری زبان دوم از طریق طرح چهار سوال تحقیق زیر بود: (1) درک توانایی های فراگیران زمانیکه که از طریق برآورد عملکرد مستقل آنها امکان پذیر نباشد اما در طول جلسات ارزیابی مستمر مشخص شوند; (2) امکان تقویت توانایی های فراگیران از طریق ارزیابی مستمر; (3) سودمندی ارزیابی مستمر در هدایت آموزش فردی به سمتی که به منطقه ی تقریبی رشد افراد حساس ا...

Use of stable isotope analyses to assess natural attenuation of chlorinated ethenes in groundwater

Chlorinated ethenes are among the most frequently detected groundwater contaminants in industrially developed countries. Although their degradation pathways have been understood, assessing the progress of natural attenuation of chlorinated ethenes still remains a challenge. Chlorinated ethenes undergo sequential reductive dechlorination under anoxic conditions; hence, the presence of less chlor...

Determination of Compound-Specific Carbon Isotope Ratios of Chlorinated Methanes, Ethanes, and Ethenes in Aqueous Samples

Compound-specific carbon isotope ratio analysis is a promising tool to assess the origin and fate of organic contaminants in groundwater. The aim of this study was to develop and evaluate a reliable, fast method to determine carbon isotope ratios of chlorinated methanes, ethanes, and ethenes in aqueous samples. Direct solid-phase microextraction (dSPME) and headspace solid-phase microextraction...

Natural and Enhanced Attenuation of Chlorinated Solvents Using RT3D