Phenolic compounds—Occurrence in water, sediment and sludge, and ecological risk evaluation
Sinayo Ndwabu, Mncedisi Malungana, Precious Mahlambi
Abstract
Abstract Ten phenolic compounds (PC) concentration levels were determined in river water, wastewater, sediments and sludge using solid phase extraction (SPE) microwave assisted extraction (MAE) and ultrasonic extraction (UE), and their ecological risk was evaluated. All the extraction methods showed good sensitivity with limit of detection and limit of quantification values at 0.01–2.00 and 0.02–6.07 µg L −1 for SPE, 0.05–1.20 and 0.17–3.17 µg kg −1 for MAE and 0.09–1.33 and 0.26–3.54 µg kg −1 for UE, correspondingly. Recovery ranges of 75.2–112% (SPE), 80.9–110% (MAE) and 79.3–119% (UE) were obtained. The PC concentrations in wastewater matrix were within the maximum allowable limit except for 2,4‐dichlorophenol at sampling point wdv4. In river water, at Camps Drift the highest concentrations compared to other sampling points was measured, however, all were within the acceptable limits. The risk quotient values exhibited high ecological risk in majority of the sites, with effects range median values indicating toxic effects to the surroundings likely to occur frequently. The probable carcinogenic risk potential was notably found to be high for adults with increment life cancer risk through dermal exposure (ILCR derm ) values of 5.34 × 10 −2 and 5.92 × 10 −2 compared to that for children at 1.26 × 10 −2 and 1.39 × 10 −2 for both sludge and sediment samples.