The Increase in Bismuth Consumption as Reflected in Sewage Sludge

Abstract

As the use of dangerous substances in consumer products increases, these substances may also be found in society’s end products, among them sewage sludge. Measuring concentrations in sewage sludge can be a way to reflect the consumption of a substance. By using substance flow analysis, the inflow, stock and outflow of the specific substance to, e.g. a city region, may be analysed. Bismuth is a heavy metal that is found in increasing levels in sewage sludge in Swedish wastewater treatment plants (WWTPs) and a similar increase cannot be excluded for WWTPs around the world. This study aims to examine possible sources that could explain the amounts measured in one Swedish WWTP. Household products such as cosmetics (24 %) and plastics (14 %) are found to be major sources of Bi measured in sewage sludge. The remaining unidentified amounts in this study (approximately 50 %) are most likely found in effluent waters from industries or sources outside the household. There is, however, no information on measurements of Bi released by industry available and there is no legislation in place that may encourage industry to conduct such measurements.