Organic Contaminants in Canadian Municipal Sewage Sludge. Part I. Toxic or Endocrine-Disrupting Phenolic Compounds

Abstract

Abstract The occurrence of toxic or endocrine-disrupting chemicals such as nonylphenol ethoxylates (NPEO), 4-nonylphenol (NP), 4-tert-octylphenol (OP), bisphenol A (BPA), triclosan (TCS), pentachlorophenol (PCP), hexachlorophene (HCP), and tetrabromobisphenol A (TBBPA) in 35 sewage sludge samples collected from cities across Canada is documented. Samples were extracted by supercritical carbon dioxide and the phenols were converted into their acetyl derivatives using published methods. The ethoxylates were analyzed by HPLC with a fluorescence detector. The other extracts, after silica gel column cleanup, were analyzed by GC/MS in either the electron impact or negative-ion chemical ionization mode. With minor exceptions, the above-mentioned compounds were present in all samples. The levels of these contaminants varied widely in the samples. The more abundant chemicals were NP as well as its mono- and di-ethoxylates, with median concentrations of 232, 69.4, and 26.4 µg/g (dry weight), respectively. Triclosan, a common antibacterial agent, BPA, and HCP were also ubiquitous in the sludge samples, with median concentrations of 12.5, 0.45, and 0.37 µg/g, respectively. Also present, albeit at much lower concentrations, were PCP and TBBPA, with median concentrations of 27.7 and 12.4 ng/g, respectively. Except for the last two compounds, all the chemicals are components or additives in various formulations of household and industrial detergents and personal care products. The potential risk of these toxic chemicals reaching the aquatic environment as a result of land spreading of sewage sludge should be investigated.