Occurrence and distribution of short-chain chlorinated paraffins (SCCPs) in sediments from mariculture bays in northern China

Abstract

Short-chain chlorinated paraffins (SCCPs) are emerging organic pollutants, yet their occurrence characteristics and ecological risks in sedimentary environments of coastal aquaculture zones remain insufficiently characterized. This study provides the first systematic assessment of SCCPs contamination levels, spatial distribution, homolog patterns, and potential ecological risks in surface sediments from four representative mariculture bays in northern China. SCCPs were detected in all surface sediment samples across 41 stations, indicating their widespread presence in coastal mariculture sediments. ΣSCCP concentrations ranged from 6.02 to 70.79 ng/g (dry weight, dw) across the four bays, reflecting moderate to low pollution levels. Although concentrations varied among bays, higher values occurred mainly in coastal industrial zones, estuaries, ports, and other areas affected by human activity. Carbon homolog analysis (C₁₀–C₁₃) showed that sediments from Haizhou Bay, Jiaozhou Bay, and Sishili Bay were dominated by C₁₃ homologs (28.1%–50.2%), whereas sediments from Laizhou Bay were dominated by C₁₁ and C₁₂ components. When classified by chlorine number, Cl_5–7 SCCPs were the most abundant homologs (75.1%–80.3%) in all bays, reflecting strong associations with local industrial discharges and shipping activities. Although the ecological risk of SCCPs in the sediments is relatively low, their bioaccumulation potential and possible synergistic effects with other pollutants warrant continued attention to their environmental fate and their effects on benthic fishery organisms.