Presence of fluoroquinolones and sulfonamides in urban sewage sludge and their degradation as a result of composting

The concentrations of some widely used pharmaceuticals, namely fluoroquinolones (ciprofloxacin C17H18FN3O3, norfloxacin C16H18FN3O3 and ofloxacin C18H20FN3O4) and sulfonamides (sulfadimethoxine C12H14N4O4S and sulfamethoxazole C10H11N3O3S) were determined in urban sewage sludge utilized for making compost. The levels of degradation of these pharmaceuticals resulting from sludge treatment were assessed. The concentrations of the studied pharmaceuticals sufficiently varied both in sewage sludge and in compost and due to this phenomenon the possible danger resulting from the presence of pharmaceuticals in sewage sludge, used for composting, can not be ignored. The concentrations of the studied pharmaceuticals were lower in compost, if compared to the relevant concentrations in sewage sludge. The highest pharmaceutical concentration in sewage sludge - 426 mu g/kg - was detected in the case of ciprofloxacin. The highest concentrations present in compost were 22 mu g/kg of norfloxacin and 20 mu g/kg of ciprofloxacin. Results show that before using the sewage sludge for making compost or before using the compost a fertilizer for food plants, they should be carefully tested against the content of commonly used pharmaceuticals.