An In Situ Toxicity Identification and Evaluation Device

in situ TIE;trace organic;CEC PPCPs;fractionation;Natural Resources and Environment

Steigmeyer, AugustDrevnick, Paul ;

University of Michigan

关键词: in situ TIE;    trace organic;    CEC PPCPs;    fractionation;    Natural Resources and Environment;   

Others  :  https://deepblue.lib.umich.edu/bitstream/handle/2027.42/113180/Steigmeyer_thesis_2015.pdf?sequence=1&isAllowed=y

瑞士|英语

来源: The Illinois Digital Environment for Access to Learning and Scholarship

【 摘 要 】

Thousands of unregulated contaminants are broadly distributed in our natural waters and haveeither gone undetected until recently, or are now being detected in greater concentrations. Contaminants ofEmerging Concern (CECs) are trace chemicals that may pose serious ecological and human health risks.The exact sources and prevalence of these compounds are largely unknown and difficult to assess. Someknown CECs are components of pharmaceuticals, anti-biotics, and other personal care products, which areubiquitous and commonly discharged, untreated, from wastewater management facilities. It is usually notfiscally or technologically feasible to filter, extract, or degrade all these chemicals, so individual targetingof specific compounds is the most viable treatment option. Finding a causal link between observed toxicityand a specific compound or group of compounds is difficult when thousands exist in wastewater effluent,with significant variations in spatial and temporal concentrations. Toxicity Identification and Evaluation(TIE) is an EPA-developed experimental approach to take a complicated matrix with established toxicityand partition the components to identify the exact compound(s) responsible. Though TIE methods havebeen applied to wastewater effluent before, most tests are conducted in a laboratory environment, in whichcontamination and other artifacts can significantly affect the accuracy of final results. This research aimedto develop a device capable of autonomous in situ TIE experiments, providing unparalleled accuracy in theidentification of toxicity sources. Deployed directly in the aquatic environment of concern, the device cancontinuously collect the source water, fractionate its complex chemical mixture with sorbent resins, andconduct bioassay exposures. The first field version deployed in environments with observed biologicalimpairment successfully targeted specific compounds for extraction, reducing their concentration by 100%in some treatments. Through a series of selective CEC extractions, the possible source(s) of toxicity in acomplex solution become clearer. After addressing mechanical issues with the first model, a second iTIEsystem was designed and tested in a series of laboratory fractionation tests, which demonstrated its abilityto reliably conduct autonomous TIE experiments. These lab results also demonstrated that genetic methodscould be used in conjunction with the iTIE system to identify sub-lethal toxicity, which can be difficult toassess amidst an intricate web of natural and anthropogenic variables. The in situ TIE System can begin tofractionate and isolate confounding variables in a complex system, and help identify indistinct biologicalthreats in the environment.