Isotope Applications in Environmental Investigations

This book brings together a broad range of analytical and investigative isotope techniques relevant to the environmental consultancy and regulatory communities with topics including hydrology, geochemistry, and source discrimination and demonstration of transformation/degradation of major contaminant groups including petroleum hydrocarbons, chlorinated solvents and other organic constituents of concern, and metals and other inorganic constituents of concern. It is intended to be a practical guide to bridge the gap between academic studies and practical application.

Table of Contents:
Table of Contents. Chapter I Introduction This introductory chapter providesdefinitions, nomenclature, analytical techniques, and standardequations for stable and radioisotopes. Introduction Stable isotopes Definitions Nomenclature Analytical techniques Abundances Table of abundances for commonly used elements Fractionation Rayleigh model Mixing equations Conservative tracers Concentration-dependent mixing Radioisotopes Definitions Nomenclature Analytical techniques Half-life Table of half-lives of commonly utilized isotopes Age dating . . Chapter II Hydrology This chapter presents basic isotopetechniques applied in hydrology studies including oxygen andhydrogen isotopic composition of precipitation, surface waterhydrology including two- and three-component hydrograph separation,and groundwater hydrology including recharge processes, age dating,and estimating flow paths and flow rates. Isotope techniquespresented will be relevant to typical investigative practices forenvironmental investigations. Precipitation Oceanic evaporation Altitude and latitude effect d18O and dD meteoric water line Evaporation deviation from meteoric water line Surface water Hydrograph separation One tracer two sources Two tracers three sources Groundwater Recharge Age dating Tritium and tritium-helium T-3He Sulfur 35S Carbon 14C Chlorine 36Cl Other tracers Si, Ar, and Kr Sulfur hexafluoride CFCs Flow paths and flow rates Introduced tracers Noble gases Sulfur hexafluoride Inorganic salts Groundwater Surface water interactions 222Rn and radium Sediment Age Dating 210Pb 137Cs . . Chapter III Geochemistry This chapter presents typicalisotope techniques that can be used for evaluating geochemicalprocesses in surface water and groundwater. Isotopes can providevaluable information regarding oxidation and reduction processes.In turn, these important geochemical processes can dramaticallyaffect the fate and transport of contaminants in the environment. Asolid understanding of site geochemistry is important for designingappropriate remedial approaches. In addition, when present atsufficiently high concentrations, typical geochemical indicatorparameters, such as nitrate, sulfate, and methane can be consideredcontaminants in and of themselves. Therefore, this chapter willalso present isotope methods for discriminating sources of nitrate,sulfate, and methane in surface water and groundwater. General geochemistry (short intro contaminantdegradation perspective) Oxidation-reduction processes ORP Nitrate reduction d15N and d18O for evaluating nitrate reduction and sources ofnitrate Sulfate reduction d34S and d18O for evaluating sulfate reduction and sources ofsulfate Methanogenesis dD and d13C for evaluating methanogenesis and sources ofmethane . . Chapter IV Petroleum Hydrocarbons This chapter presentstypical isotope applications for identifying sources of petroleumhydrocarbons in the environment and for demonstrating degradationand discriminating degradation pathways. This chapter will alsoprovide a brief introduction of other standard petroleumhydrocarbon fingerprinting techniques. Petroleum hydrocarbon fingerprinting techniques Chromatograms for identifying fuel types PAH fingerprinting Isotope fingerprints using dD and d13C Bulk Compound-specific isotope analysis Typical ranges of dD and d13C values Source discrimination Demonstrating degradation Aerobic and anaerobic degradation of petroleumhydrocarbons Typical isotopic shifts during contaminant degradationprocesses Petroleum hydrocarbons Select additives including MtBE, TBA, and1,2-dichloroethane Identifying degradation pathways Methane and other light hydrocarbons MtBE Incorporating isotope monitoring for evaluating efficacy ofactive remediation Incorporating isotope monitoring in Monitored NaturalAttenuation remedies Importance of including assessment of potential sources as wellas potential degradation when using isotopes for either sourcediscrimination or demonstrating degradation, i.e., processes arecoupled isotopically... Chapter V Chlorinated Solvents and Other Organic Constituents This chapter presents typical isotope applications foridentifying sources of chlorinated solvents in the environment andfor demonstrating degradation of chlorinated solvents. This chapterwill also provide a brief introduction of other standardchlorinated solvent fingerprinting techniques. Chlorinated solvent fingerprinting techniques Ratio analyses Other techniques Isotopic analyses Bulk isotope analyses d37Cl Compound-specific isotope analyses dD and d13C(progress of d37Cl?) Typical isotopic composition of parent (manufactured)compounds Demonstrating degradation Aerobic and anaerobic degradation of chlorinated solvents Degradation reaction pathways Chlorinated ethenes: PCE a TCE a DCE a VC Chlorinated ethanes: PCA a TCA a DCA a CA andTCA a DCE a VC Typical isotopic shifts during contaminant degradationprocesses Incorporating isotope monitoring for evaluating efficacy ofactive remediation Incorporating isotope monitoring in Monitored NaturalAttenuation remedies Other organic constituents 1,4-dioxane PCBs Importance of including assessment of potential sources as wellas potential degradation when using isotopes for either sourcediscrimination or demonstrating degradation, i.e., processes arecoupled isotopically... Chapter VI Inorganic Constituents This chapter presentstypical isotope applications for identifying sources andtransformations of environmentally-relevant inorganic constituentsin the environment. A short description of the relevance of each ofthe elements and compounds to environmental investigations will beprovided. Metals Boron Discriminate sources of boron Chromium Discriminate sources of chromium Demonstrate reduction of chromate Copper Discriminate sources of copper Zinc Discriminate sources of zinc Mercury Discriminate sources of mercury Evaluate microbial cycling Lead Discriminate sources of lead Uranium Discriminate sources of uranium Demonstrate microbial reduction of oxidized uraniumspecies Other inorganic constituents Perchlorate Discriminate sources of perchlorate d17O, d18O, and d37Cl Distinguish between natural and anthropogenic perchlorate Demonstrate degradation . Chapter VII Methods for Field Sampling This chapterpresents techniques for sample collection and preservationincluding mass and/or volume of sample required, container types,preservation and shipping requirements, and practical hold timesfor analysis as well typical laboratory turn-around times for datareporting. Oftentimes, samples for isotope analyses can becollected during routine environmental investigations, then heldfor analysis pending results from more standard laboratory analysistechniques. . References. Index

About the Author :
Julie K. Sueker, Ph.D., P.H., P.E. Contact Information: ARCADIS US, Inc. 14142 Denver West Parkway, Suite 350 Golden, CO 80401