The occurrence of non-steroidal anti-inflammatory drugs (NSAIDs) in Malaysian urban domestic wastewater

Abstract

The water stream has been reported to contain non-steroidal anti-inflammatory drugs (NSAIDs), released from households and premises through discharge from Sewage Treatment Plant (STP). This research identifies commonly consumed NSAIDs namely ibuprofen (IBU), diclofenac (DIC), ketoprofen (KET) and naproxen (NAP) in the influent wastewater from two urban catchments (i.e. 2 STPs). We expand our focus to assess the efficiency of monomer (C18) and dimer (HLB) types of sorbents in the solid phase extraction method followed by gas chromatography mass spectrometry (GCMS) analysis and optimize model prediction of NSAIDs in the influent wastewater using I-Optimal design. The ecological risk assessment of the NSAIDs was evaluated. The HLB produced reliable analysis for all NSAIDs under study (STP1: 6.7 × 10^-3 mg L^-1 to 2.21 × 10^-1 mg L^-1, STP2: 1.40 × 10^-4 mg L^-1 to 9.72 × 10^-2 mg L^-1). The C18 however, selective to NAP. Based on the Pearson proximity matrices, the DIC_HLB can be a good indicator for IBU_HLB (0.565), NAP_C18 (0.721), NAP_HLB (0.566), and KET_HLB (0.747). The optimized model prediction for KET and NAP based on DIC are successfully validated. The risk quotients (RQ) values of NSAIDs were classified as high (RQ > 1), medium (RQ, 0.1-1) and low (RQ, 0.01-0.1) risks. The optimized models are beneficial for major NSAIDs (KET and NAP) monitoring in the influent wastewater of urban domestic area. An upgrade on the existing wastewater treatment infrastructure is recommended to counteract current water security situation.

Keywords: Ecological risk assessment; Emerging contaminants (ECs); Gas chromatography mass spectrometry (GCMS); Non-steroidal anti-inflammatory drugs (NSAIDs); Sewage treatment plant (STP); Solid phase extraction (SPE).