The reuse of municipal biosolids as fertilizers presents a number of potential physical, chemical, biological and radiological hazards that have the potential to harm humans and wildlife. Endocrine disrupting chemicals (EDCs) are substances that may interfere with the body's endocrine system and produce adverse developmental, reproductive, neurological, and immune effects. They enter municipal sewage systems through the use and disposal of pharmaceuticals, runoffs, and the use of detergents. Wastewater treatment plants, designed to remove conventional pollutants such as suspended solids and biodegradable organic compounds may not remove low concentrations of synthetic pollutants, such as pharmaceuticals. The result is contaminated biosolids that are applied (without regulation) to agricultural fields.
Development of an analytical method, as well as use of the method for preliminary investigation for determination of EDCs in biosolids was achieved through successive extraction, analysis, and optimization of standards of selected EDCs. The developed method principally consisted of using Accelerated Solvent Extraction (ASE) and Gas Chromatography coupled with Mass Spectrometry (GC-MS) technique. During the method development, several conditions and parameters were applied for better optimization and recoveries.
The Varian 450 GC - 220 MS were used for this research. The column used on the GC was Factor Four TM® capillary column (VF 5ms, 30m, 0.2mm, 0.25µm). Injector temperature was set to 250°C, flow rate was 1.0mL/min, and detector temperature and voltage were 50°C and 510V respectively. A temperature program was set for the column with a total run time of 44.25mins. Electron ionization (using filaments) was used as the ion source on the MS. Ions were analyzed with the ion trap mass analyzer and detected on the electron multiplier.
A two temperature program was set for the ASE at 40°C and 100°C. Pressure was set constant at 1600psi; 5min heating time, 10min static time, and 60s purge time for both methods. However, the rinse volumes were 60% and 100% of the cell volume for 40°C and 100°C respectively for the temperature programs. Methylene chloride was used for the extraction since it yielded the best recovery with an average recovery of 82.65%. The highest recovery of 109.9% was recorded for Triclosan while the lowest recovery of 70.2% was recorded for Chlordane.
Through the development of this novel analytical method, technical grade nonylphenol was detected in biosolids from the Southern Illinois University Edwardsville wastewater treatment plant. The average concentration detected was 0.984ppm. The source of this compound could be from detergents and personal care products (such as hair shampoos) used in the university community.
|Advisor:||Johnson, Kevin A., Shabangi, Masangu|
|Commitee:||Dixon, Robert, Lin, Zhi-Qing|
|School:||Southern Illinois University at Edwardsville|
|School Location:||United States -- Illinois|
|Source:||MAI 52/02M(E), Masters Abstracts International|
|Subjects:||Toxicology, Surgery, Analytical chemistry|
|Keywords:||Accelerated solvent extraction, Biosolid, Endocrine disrupting chemicals, Gas chromatography, Hormones|
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