Suchergebnisse

Som et resultat af menneskelige aktiviteter er lægemidler og biocider allestedsnærværende i miljøet på sporstofniveau. Store mængder af disse stoffer, også kendt som miljøfremmede stoffer (på Engelsk XTCs: Xenobiotic Trace Chemicals), frigives dagligt fra: (i) husholdninger og sundhedsfaciliteter, som følge af indtagelse og bortskaffelse; (ii) dyrehold og tilsvarende faciliteter, som følge af dyrs indtagelse; og (iii) industrianlæg. En betydelig del af disse udledninger når frem til kommunale renseanlæg, hvor de miljøfremmede stoffer kun delvist bliver fjernet. I sidste ende udledes de miljøfremmede stoffer således til miljøet, f.eks. til ferskvandsområder der fungerer som recipienter for renseanlæg, hvor de udgør en trussel for levende organismer. Renseanlæg er blevet identificeret som en vigtig punktkilde for udledning af miljøfremmede stoffer til miljøet. På grund af det høje antal af markedsførte og forbrugt kemikalier, og de usikkerheder forbundet til prøveudtagning og analysemetoder, er der dog stadig store udfordringer forbundet med kvantificering af i hvor høj grad miljøfremmede stoffer bliver fjernet i forbindelse spildevandsrensning. Udvikling af robuste modelleringsværktøjer til at forudsige miljøfremmede stoffers skæbne i renseanlæg kan hjælpe med at overvinde denne udfordring. Men dybtgående forståelse af de mekanismer og processer, der styrer miljøfremmede stoffers fjernelse under spildevandsrensning, er stadig nødvendig. Målet med nærværende ph.d.-projekt var at udfylde huller i vores viden omkring modellering af miljøfremmed stoffers skæbne i renseanlæg og efterfølgende. Vi ville gerne forbedre forståelsen af miljøfremmede stoffers skæbne og dermed forbedre modellernes forudsigelsesevne: (i) ved processkalaen, med fokus på sorption og biologisk nedbrydning af miljøfremmede stoffer i biologiske renseanlæg; (ii) i fuldskala renseanlæg, hvor vi ville vurdere effekten af gendannelse og driften af renseanlægget på fjernelsesgraden; og (iii) i integrerede renseanlæg-landbrugssystemer. Forskellige modelleringsværktøjer, velegnede til hvert specifikt formål i undersøgelser, blev udviklet, udvidet eller anvendt innovativt. Følgende velkendte modeller blev anvendt: Activated Sludge Modelling framework for Xenobiotics (ASM-X); den generiske renseanlægsmodel SimpleTreat Activity; og den dynamiske jord-plante model til forudsigelse af kemikaliers skæbne i landbrugssystemer. Vi kombinerede eksperimentelle og modelbaserede observationer til at vurdere sorption af ioniserbare miljøfremmede stoffer til aktiveret slam og nedbrydning af miljøfremmede stoffer i "moving bed"-biofilmreaktorer (MBBRs). De fleste miljøfremmede stoffer er ioniserbare, og kan således være til stede i neutral og / eller ioniseret form i spildevand. Vi viste, at pH-betingelser, og i mindre grad, dosering af jernsalt til kemisk phosphorfjernelse, med sikkerhed påvirker faststof-væskepartitioneringen af det zwitterioniske antibiotikum ciprofloxacin i aktivt slam. Elektrostatiske interaktioner og kompleksdannelse er således dominerende sorptionsmekanismer. Vi observerede non-lineær sorption (n=0.62–1.33) under forskellige pH-, redox- og jernsalt doseringsforhold. Vi foreslog derfor en udvidelse til traditionelle sorptionsmodeller for ciprofloxacin og andre zwitterioniske miljøfremmede stoffer, som beskriver ionisering som funktion af pH og ændret sorptionspotentiale for ioniserede stoffer. Miljøfremmede stoffer findes typisk i spildevand i koncetrationsniveauer mellem ng L-1 og ug L-1, hvilket medfører at de ikke kan bruges som substrater for vækst. Vi vurderede effekten af primære metaboliske processer i MBBRs på fjernelse af miljøfremmede stoffer. Undersøgelsen blev udført ved at sammenligne kinetikken i pre-denitrificerende MBBRs kørt i enkelttrins- og tretrinskonfigurationer. Sidstnævnte konfiguration produceret en langvarig udsættelse af biofilmen for faldende belastning med COD, hvilket påvirkede kinetikken af heterotrof denitrifikation og nedbrydning af miljøfremmede stoffer. Vi fandt at nedbrydningskonstanten for en række miljøfremmede stoffer var afhængig af denitrifikationspotentialet i biofilmen, hvilket indikerer, at nedbrydning af miljøfremmede stoffer var en co-metabolisk proces. Der er beskrevet en række faktorer der påvirker fjernelsen af miljøfremmede stoffer i fuldskala renseanlæg. Relevant effekt kan tilskrives (i) faststoffers opholdstid i den biologiske rensningsproces; og (ii) dannelse af miljøfremmede stoffer via f.eks. delvis nedbrydning af menneskelige metabolitter. Mange miljøfremmede stoffer udskilles af mennesker i form af metabolitter, som efterfølgende kan omdannes til moderstoffet igen. I dette projekt vurderede vi effekten af gendannelse og faststofsopholdstid på sulfamethoxazols skæbne i fuldskala renseanlæg. Vi brugte en metode baseret på sammenligning af ASM-X modelforudsigelser med værdier fra litteraturen. Vores undersøgelse viste, at effekten af gendannelse under sekundær spildevandsrensning er bestemt af: (i) størrelsen af renseanlæggets opland, idet høj grad af gendannelse i kloaksystemet kan forventes i store oplande; og (ii) typen af opland (med eller uden hospital). Dette peger på anvendelsen af en integreret tilgang til miljøfremmede stoffers skæbne-vurdering i spildevandsssystemer (kloaksystemer og rensningsanlæg). Endvidere forudså vi og fandt forbedret fjernelse af sulfamethoxazol i renseanlæg der kører med faststofsopholdstider på mere end 16 dage. Ved faststofsopholdstider over denne værdi kan der forventes forbedrede nedbrydningskinetikker på grund af vækst i langsomtvoksende organismer (f.eks. specialiserede nedbrydere) eller på grund af blandede substratudnyttelsesstrategier. Miljøfremmede stoffer bliver som regel kun delvist nedbrudt i renseanlæg, og er derfor tilstede i udledninger fra renseanlæg og i spildevandsslammet. Udbringning af slam på marker og brug af renset spildevand eller ferskvand der modtager renset spildevand til kunstvanding af marker medfører i sidste ende optagelse af miljøfremmede stoffer i fødevareafgrøder. I dette projekt udviklede og afprøvede vi et generisk simuleringsværktøj til at forudsige miljøfremmede stoffers skæbne fra forbrug til optagelse i vinterhvede via nedbrydning i renseanlæg i en række geografiske scenarier i EU. Værktøjet kombinerede SimpleTreat Activity-modellen og den dynamiske jord-plante model, med særligt fokus på at forudsige skæbnen af ioniserbare stoffer. Ionisering har, som vist i vores første studie, store konsekvenser på faststof-væske partitioneringen, og på fordelingen ind i kornets væv. Vi udvalgte tre miljøfremmede stoffer som anvendes i store mængder, nemlig biocidet triclosan, det vanddrivende middel furosemid og antibiotikummet ciprofloxacin. Vi valgte tre reelle geografiske scenarier for områder i Den Europæiske Union og brugte gennemsnitlige forbrugsdata eller udledningsværdier fra forskellige EU-lande. Vi fandt at furosemid blev meget svagt nedbrudt i spildevandsrensning og blev signifikant akkumuleret i hvede. Optagelse af furosemid var større når udledning til jord-plante-systemet opstod via kunstvanding med ferskvand, i forhold til udbringning af slam. Set i lyset af de få eksperimentelle data indikerer vores modelberegninger et behov for uddybende undersøgelser af miljøfremmede stoffers skæbne i landbrugssystemer. Ophobning i fødevareafgrøder kan resultere i indirekte eksponering af mennesker for miljøfremmede stoffer via kosten; denne eksponering kan estimeres ved hjælp modelsimuleringer. Det præsenterede simuleringsværktøj kan således anvendes til pre-screening og prioritering af kemikalier samt til at undersøge betydningen af miljøfremmede stoffers emmisionsveje (f.eks. udbringning af gødning irrigation med behandlet spildevand) i forbindelse med akkumulering i fødevareafgrøder. ; As a result of widespread human activities, pharmaceuticals and biocides are ubiquitously present at trace levels in the environment. Large amounts of these substances, also identified as xenobiotic trace chemicals (XTCs), are released daily from: (i) households and healthcare facilities, following human consumption and disposal; (ii) husbandry and other analogous facilities, following veterinary consumption; and (iii) industrial facilities. A significant fraction of these emissions reaches municipal wastewater treatment plants (WWTPs), where XTCs undergo incomplete removal partly due to WWTP design limitations. These chemicals are thus eventually released to the environment, e.g. in freshwater bodies receiving WWTP effluents, representing a threat to living organisms. WWTPs have been generally identified as a major point source of XTC emissions to the environment. Nevertheless, due to the high number of marketed and consumed chemicals, and to the uncertainties associated to sampling and analytical methodologies, quantifying the elimination of XTCs during wastewater treatment still remains a challenge. Developing robust modelling tools to predict the fate of XTCs in WWTPs can help overcoming this challenge. However, in-depth understanding of mechanisms and processes, determining XTCs removal during wastewater treatment, is still required. This PhD thesis aimed at filling knowledge gaps in the field of XTC fate modelling during and beyond wastewater treatment. We aimed at improving the comprehension of XTC fate, and thus the predictive capabilities of fate models: (i) at process scale, with a focus on sorption and biological transformation of XTCs in biological treatment systems; (ii) in full-scale WWTPs, assessing the impact of retransformation and WWTP operation on XTC elimination; and (iii) in integrated WWTP-agricultural systems. Different modelling tools, suiting the specific purposes of our investigations, were developed, extended and/or innovatively applied. Fate models used as reference in this thesis include: the Activated Sludge Modelling framework for Xenobiotics (ASM-X); the generic WWTP model SimpleTreat Activity; and the dynamic soil-plant model for fate prediction in agricultural systems. Experimental and model-based observations were combined to assess sorption of ionizable XTCs onto activated sludge and XTC biotransformation in moving bed biofilm reactors (MBBRs). Most XTCs are in fact multispecies chemicals, being present in neutral and/or ionized form in wastewater. We demonstrated that pH conditions and, to a lesser extent, iron salt dosing for chemical phosphorus removal can significantly affect solid-liquid partitioning of the zwitterionic antibiotic ciprofloxacin onto activated sludge. Electrostatic interactions and complexation are thus dominating sorption mechanisms. Under a range of pH, redox and iron salt dosing conditions, non-linear sorption (n=0.62–1.33) was observed. Extensions to traditional partitioning models were accordingly proposed for ciprofloxacin and other zwitterionic XTCs, accounting for: (i) high non-linearity of XTC sorption; or (ii) ionization with changing pH and different sorption potential of ionized species. Furthermore, XTCs are typically present in ng L-1 to µg L-1 concentrations in wastewater, being referred to as non-growth substrates, and their biological degradation can be associated with microbial growth processes. In this PhD thesis, we assessed the influence of primary metabolic processes on XTC biotransformation in MBBR biofilm. Our investigation was performed by comparing biotransformation kinetics in pre-denitrifying MBBRs operated in single-stage and three-stage configurations. The latter configuration produced a prolonged biofilm exposure to organic electron donor (COD) loading and complexity tiered by segregated and integrated biofilm reactors, which significantly influenced kinetics of heterotrophic denitrification and XTC biotransformation. Biotransformation rate constants for a number of non-recalcitrant XTCs were found correlated to the denitrification potential of MBBR biofilm, suggesting that XTC degradation occurred via microbial co-metabolism. In addition, enhanced biotransformation kinetics was shown for a number of XTCs (sulfamethoxazole, erythromycin, atenolol) as compared to previous findings for conventional activated sludge. A number of factors have been described to influence the elimination of XTCs in full-scale WWTPs. Specifically, relevant impact was attributed to (i) solid residence time (SRT), at which biological treatment is operated; and (ii) the formation of XTCs due to, e.g., deconjugation of human metabolites. Many XTCs are in fact excreted by humans in the form of conjugates, which can undergo biotic retransformation to parent chemicals. In this PhD thesis, we specifically assessed the influence of retransformation processes and SRT on the fate of sulfamethoxazole in full-scale WWTPs. A methodology based on the comparison of ASM-X predictions and literature data was used. We demonstrated that the impact of retransformation during secondary wastewater treatment is determined by: (i) the size of WWTP catchments, with major in-sewer retransformation expected in large catchments; (ii) the type of catchment (hospital or urban catchment). This evidence accordingly suggests an integrated approach to XTC fate assessment in wastewater systems (sewer networks and WWTPs). Furthermore, improved elimination of sulfamethoxazole was found and predicted in WWTPs operated at SRT greater than 16 d. Beyond this critical SRT, enhanced biotransformation kinetics may occur due to the enrichment of slow-growing organisms (e.g., specialist degraders) or mixed substrate utilization strategies. This finding supported our experimental evidence of enhanced sulfamethoxazole biotransformation kinetics in denitrifying MBBRs. As a result of incomplete biodegradation in WWTPs, XTCs persist in effluents and sewage sludge. Reuse of municipal biosolids and treated wastewater or use of freshwater for agricultural purposes eventually leads to XTC uptake into food crops. In this PhD thesis, we developed and tested a generic simulation tool to predict the fate of XTCs from consumption, through wastewater treatment and eventually to the uptake by winter wheat for a number of geographical scenarios in the European Union. The tool combined was specifically addressed for fate prediction of ionizable XTCs (the biocide triclosan, the diuretic furosemide and the antibiotic ciprofloxacin). Furosemide was found rather persistent to wastewater treatment (removal efficiency ≤ 40%) and to further undergo significant accumulation in wheat. Uptake of furosemide was predicted to increase (+20% of emissions to soil) when emissions to the soil-plant system occurred via freshwater irrigation, as compared to soil amendment with biosolids. Due to the scarce availability of experimental data, our model predictions indicate the need of deepening investigations of XTC fate in agricultural systems. Accumulation in food crops may result in indirect human exposure to XTCs via dietary intake, which can be eventually estimated using model predictions. The presented simulation tool can thus be used for pre-screening and priority setting of chemicals, and to explore the impact of additional XTC emission pathways (e.g., manure application, irrigation with reclaimed WWTP effluent) in terms of food crop accumulation.

Forensic science transforms criminal investigations by resolving previously unsolvable cases and bringing an increased sense of justice to communities. This application of scientific disciplines to legal questions aids investigators in solving crimes. While many sciences can be utilized—such as physics (pattern evidence), chemistry (toxicology), or biology (cause of death), to name a few—two aspects of scientific advancement have played an outsized role in responding to crime. Trace evidence analysis—specifically, deoxyribonucleic acid (DNA) analysis—is an essential component to an effective and accurate criminal justice system. DNA evidence has emerged as a powerful tool to identify perpetrators of unspeakable crimes and to exonerate innocent individuals accused of similarly heinous actions. However, a different method of examining traditional trace evidence has quietly grown somewhat unnoticed. The emergence of so-called "touch-DNA" evidence and chemical analysis of skin traces represents powerful, novel uses of trace evidence that have significant implications for personal privacy. Furthermore, these abilities are developing within an outdated DNA jurisprudence that is wholly inadequate to protect individual privacy and facilitate the legitimate government interest in accurately investigating crime. Just as beeper and antiquated cellphone jurisprudence was an inadequate framework for the issues arising from smartphones or GPS tracking, DNA jurisprudence has failed to keep pace with modern uses of DNA. This article addresses touch DNA, chemical analysis of skin traces, and their implications for crime scene investigation, arguing that changes in how trace evidence is analyzed require alterations in the law's approach to its use. Discussing the history of traditional DNA analysis, the article also examines the emergence of touch DNA and related technologies and how they differ from traditional DNA analysis. It analyzes new risks of these new technologies, specifically to suspects and victims of crime. Finally, it proposes a legal framework to address these privacy threats - drawing a distinction between the collection of DNA and cellular materials for identification purposes and a subsequent examination of these materials for other information about the source. The framework adopted by the Supreme Court for cell phone examination in Riley v. California, required a more specific level of suspicion to examine the contents of a cell phone than to obtain it incident to arrest. This article advocates utilizing this framework in the collection and examination of the even more personal information contained within DNA and cellular evidence. Specifically, it distinguishes between collecting the evidence and routinely testing it for identity and the more invasive examination of the evidence for additional personal information about the source. Before searching this deeply into this evidence for any information beyond identification, the government must establish a higher level of suspicion and obtain a warrant.

The presence of trace organic chemicals (TOrCs) in municipal biosolids in the U.S. has received considerable attention by the public and scientific community over the last several years. Of particular concern is whether the presence of TOrCs in biosolids results in significant risks to public health and the environment upon land application of the biosolids. While the U.S. Environmental Protection Agency has evaluated the risks associated with dioxins present in biosolids-amended soils, to date, no other TOrCs, particularly those of emerging concern, have been subjected to complete risk assessments with respect to the land application of municipal biosolids. This study identified the scientific data gaps that should be filled if appropriate risk assessments are to be conducted. The focus of this effort was to compile data from published peer-reviewed literature that addresses the occurrence, mobility, persistence, bioaccumulation, toxicity, and microbial impacts of biosolids-borne TOrCs in soils. In addition, an evaluation of the current modeling approaches employed to evaluate the risks of biosolids-borne TOrCs was conducted