Techniques for the Analysis of Organic Micro-Contaminants and Their Application to Environmental Monitoring

Pirie, David John (1996) Techniques for the Analysis of Organic Micro-Contaminants and Their Application to Environmental Monitoring. PhD thesis, University of Glasgow.

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The rapid increase in the commercial use of organic chemicals since the mid twentieth century has led to a need for governments to monitor and regulate the levels of these chemicals introduced into the environment. This study was carried out to improve and expand the existing analytical methodology used in environmental organic contaminant monitoring, and to apply these methods to field investigations of two sites (Annick Water and Irvine Bay) where organic chemicals were suspected of having an adverse effect on the environment. Analytical organic contaminant monitoring methods were reviewed and the necessary component chemical and instrumental techniques required for the determination of both organochlorine and pyrethroid contaminants in an analytical method identified and investigated. A robust modular analytical method was developed, optimised and validated for river water, effluent, sediment and biota matrices. The optimised methods consisted of: 1. Duplicate liquid-liquid extractions of a 1 litre aqueous samples with 50mls of hexane, 2. Solid phase extractions of 1 litre aqueous samples using octadecyl bonded silica adsorbents, 3. Soxhlet extraction of solid matrices for 7 hours using MTBE as the extracting solvent, 4. Removal of coextracted sulphur using tert butyl ammonium sulphate or copper powder, 5. Cleanup of extracts using normal phase adsorption chromatography with either florisil, alumina or silver nitrate impregnated alumina as the adsorbent, 6. Separation of analyte classes using silica gel adsorption chromatography, 7. Separation and detection of the analytes by gas chromatography using a 60m medium polarity capillary column and electron capture detection. The suitability of the methods to field investigations and regulatory use was demonstrated by determining the fate and effects of a range of organic contaminants released by the textile and wool processing industry on a freshwater (Annick Water) and a marine (Irvine Bay) ecosystem. Permethrin, isomers of HCH, dieldrin, DDT and metabolites of DDT were detected in the effluent from Stewarton STW which discharges into the Annick Water. Permethrin and isomers of HCH were the compounds detected most frequently and at the highest concentrations. The concentrations of permethrin detected were likely to cause a breach of the freshwater environmental quality standard in the Annick Water immediately downstream of the STW. Permethrin, dieldrin, HCH isomers, DDT, metabolites of DDT and PCBs were detected in sediments from the Annick Water. Comparison of the concentrations of contaminants detected in the sediments with published sediment contaminant concentrations, derived sediment quality standards, and published sediment toxicity data indicated that permethrin was the most significant contaminant detected in the sediments. Comparison with invertebrate biotic index scores for the Annick water and fish population studies of the Annick water, indicated that the sediments between the STW and Chapeltoun were acutely toxic to invertebrates. Invertebrate biotic index scores from the lower reaches of the Annick Water were lower than could be explained by comparison with published sediment toxicity data. Faster degradation of trans permethrin in the environment to form a more toxic mixture of permethrin isomers, synergistic activity with organophosphorus pesticides and the negative insecticidal temperature coefficient of permethrin were suggested as a possible explanations of these low biotic index scores. Permethrin was not detected in eels caught from the Annick water or the Glazert Burn, suggesting that eels can metabolise permethrin. Dieldrin was the major contaminant detected in eels downstream of the STW. The concentrations of dieldrin detected in these eels were so high as to suggest that regular human consumption of these eels presented a significant hazard to human health and the viability of wild populations of fish-eating birds and aquatic mammals. Similar organochlorine contaminants were detected in effluents from Irvine and Garnock Valley sewers and in sediment from Irvine Bay. Contaminants found in the Irvine Bay sea outfall effluents include permethrin, HCH isomers, dieldrin, DDT and metabolites of DDT. Permethrin and isomers of HCH were the compounds most frequently detected and at the highest concentrations. The concentration of permethrin detected in the effluent from the valley sewers in typical conditions were likely to cause a slight breach of the EQS at the edge of the mixing zone. In adverse conditions the concentrations of permethrin in the effluent from both valley sewers were likely to result in permethrin concentrations at the edge of the mixing zone approximately 5 and 10 times higher than those permitted by the EQS. Permethrin, dieldrin, HCH isomers, DDT, DDT metabolites and PCBs were detected in sediments from Irvine Bay. Permethrin and G HCH were the major contaminants detected. The spatial distribution of organic carbon normalised contaminants indicated that the valley sewers are the major sources of these contaminants within Irvine Bay.

Item Type: Thesis (PhD)
Qualification Level: Doctoral
Additional Information: Adviser: C D McPhail
Keywords: Organic chemistry, Analytical chemistry, Environmental health
Date of Award: 1996
Depositing User: Enlighten Team
Unique ID: glathesis:1996-75514
Copyright: Copyright of this thesis is held by the author.
Date Deposited: 19 Nov 2019 19:35
Last Modified: 19 Nov 2019 19:35

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