Utvärdering av ett laktest för jordar kontaminerade med ... - Sysav

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Förord Detta examensarbete är gjort inom Miljövetenskapsprogrammet vid Lunds Universitet under HT-2006. Arbetet har utförts i samarbete mellan Statens Geotekniska Institut (SGI), som varit uppdragsgivare, Institutionen för Analytisk kemi vid Lunds Universitet och Kemiska Institutionen vid Umeå Universitet. Examensarbetet har ingått som en del av SGI:s forskningsprojekt ”Organiska lakningar” som syftar till utveckling av metoder för bestämning av lakning av organiska föreningar. Jag vill tacka alla som har medverkat till detta examensarbete; framförallt Anja Enell för engagerad handledning, Ylva Persson för analyser, rådfrågning och diskussioner, Jan Åke Jönsson för handledning, David Bendz för rådgivning och Eva Narbrink för stor hjälp på labbet. Jag vill även tacka annan personal på SGI som varit till god hjälp och stöd. Tack också till familj och vänner som varit med på resans gång. Malmö maj 2007 Kristian Hemström 2
Abstract In order to reach the Swedish environmental objective 'A Non-Toxic Environment' there is a need to make inventories of, and decontaminate, polluted sites. Approximately 80 000 contaminated sites have been identified in Sweden and 16 500 of these are estimated to pose a large or very large risk to human health or to the environment. Decontamination of polluted sites is often accompanied by large costs. Therefore it is of great importance that priority is given to the right areas and that resources are used in an efficient way. Risk assessments of sites polluted with organic compounds are often based on estimations of the soil solute concentration from measured total contents of the contaminants in the area. However, this method has proven to be inadequate. There is therefore a need for reliable experimental methods describing the equilibrium distribution of organic contaminants between soil particles and solute in order to make more realistic estimates of the soil solute concentration, and thus the potential for transport and leaching, of the contaminants in question. The purpose of this study has been to evaluate the stability and the repeatability of an experimental method for estimating the leaching potential of soils contaminated with nonvolatile organic compounds. The method is a column leaching test with recirculation aiming to determine the equilibrium between solid and liquid phase, and thus the maximal soil solute concentration in the investigated soil. The method has previously been validated for determination of leaching potential of soils contaminated with polyaromatic hydrocarbons (PAHs). In this study one soil contaminated with PAHs and another contaminated with chlorophenols (CPs), chlorinated diphenyl ethers (PCDEs), polychlorinated dibenzofurans (PCDFs) and polychlorinated dibenzo-p-dioxins (PCDDs) were used. The results showed that the method is satisfactory in respect of repeatability for determination of leaching potentials of PAHs and CPs. The repeatability of the method decreased with increased hydrophobicity of the investigated compounds and was considered unsatisfactory for PCDEs, PCDFs and PCDDs. The influence of colloidal transport on the leaching of the chlorinated compounds was investigated and the results showed that the CPs predominantly were transported in dissolved form. Only 1-3% of the leached CPs were transported bound to particles. 66-94% of the PCDEs, 77-93% of the PCDFs and 82-99% of the PCDDs were transported bound to particles. The poor repeatability of the PCDEs, PCDFs and PCDDs is thought to be caused by contaminant heterogeneity in the soil and on the colloids set in motion. The method was robust to a 50% increase in flow, from 20 to 30 ml h -1 . No differences in physical and chemical parameters, flow regimes, leached concentrations or colloid facilitated transport appeared to be caused by the change in flow. Evaluation of the contact time showed that the recommended recirculation time of 7 days was not sufficient for obtaining chemical equilibrium in the system. When increasing the contact time to 22 days the leached concentrations increased for all PAHs except Naphthalene. The low-chlorinated CPs appear to reach equilibrium after 7 days, whereas the leached concentrations of the highchlorinated CPs, above all TeCP, increased with increased contact time. When comparing experimentally determined leaching with leaching estimated from the total content of the contaminants in the soil, large differences were observed. The estimated leaching was much higher than experimentally determined for the most hydrophilic compounds and much lower for the most hydrophobic. The large differences exemplify the need of a reliable method that can be used in risk assessments for determination of leaching potential from soils contaminated with organic compounds. The investigated column leaching test has the potential to meet this need for PAHs and CPs. 3
Page 1: Examensarbete 20 p HT 2006 Utvärde
Page 5 and 6: 1. Inledning I Sverige har riksdage
Page 7 and 8: och av dessa har US Environmental P
Page 9 and 10: komplexa och miljökonsekvenserna s
Page 11 and 12: 1.3.3.2. Kolloider och DOC Som näm
Page 13 and 14: där transporten sker under icke-id
Page 15 and 16: mättade förhållanden genom att v
Page 17 and 18: dispersions-ekvationen. Utifrån de
Page 19 and 20: Tabell 3: Totalkoncentrationer av P
Page 21 and 22: Tabell 4: Repeterbarheten (standard
Page 23 and 24: espektive 0,005% av den totalt utla
Page 25 and 26: Tabell 7: Totalkoncentrationen av P
Page 27 and 28: Cw för PCDF:erna visas även i fig
Page 29 and 30: Det var inte någon skillnad mellan
Page 31 and 32: Koncentration (mg L -1 ) Koncentrat
Page 33 and 34: C/C0 C/C0 C/C0 1 0,5 Luleå 1a 0 0
Page 35 and 36: Cw (mg L -1 ) Cw (ng L -1 ) 90 80 7
Page 37 and 38: 4.2. Metodens repeterbarhet med avs
Page 39 and 40: PCDE:er var något lägre, men fort
Page 41 and 42: kemikaliska parametrar mellan de ol
Page 43 and 44: jämviktskoncentrationen. Gamst et
Page 45 and 46: och de som är adsorberade till gla
Page 47 and 48: tolkningen av resultaten försvåra
Page 49 and 50: Fingler S., Drevenkar V., Fröbe Z.
Page 51 and 52: Nilsson C-A., Renberg L., 1974, Fur

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