Seasonal Variation of Phthalate Esters in Urban River Sediments: A Case Study of Fengshan River System in Taiwan

Abstract

The Fengshan River system is one of the major rivers in Kaohsiung City, Taiwan. This study investigated the concentration of eight phthalate esters (PAEs) in sediments of the river and the impact of potential ecological risks during the dry and wet seasons. The potential risk assessment of sediment PAEs was evaluated by adopting the total risk quotient (TRQ) method. The total PAEs concentrations (∑PAEs) in the sediments of the Fengshan River system are between 490–40,190 ng/g dw, with an average of 8418 ± 11,812 ng/g dw. Diisononyl phthalate (38.1%), bis(2-ethylhexyl) phthalate (36.9%) and di-isodecyl phthalate (24.3%) accounted for more than 99.3% of ∑PAEs. The concentration of ∑PAEs in sediments at the river channel stations is higher during the wet season (616–15,281 ng/g dw) than that during the dry season (490–1535 ng/g dw). However, in the downstream and estuary stations, the wet season (3975–6768 ng/g dw) is lower than the dry season (20,216–40,190 ng/g dw). The PAEs in sediments of the Fengshan River may have low to moderate potential risks to aquatic organisms. The TQR of PAEs in sediments at the downstream and estuary (TQR = 0.13) is higher than that in the upstream (TQR = 0.04). In addition, during the wet season, rainfall transported a large amount of land-sourced PAEs to rivers, leading to increased PAEs concentration and potential ecological risks in the upper reaches of the river.

Spatiotemporal Variation and Ecological Risk Assessment of Heavy Metals in Industrialized Urban River Sediments: Fengshan River in Southern Taiwan as a Case Study

“…Fengshan River (including the Qianzhen River) is approximately 20 km, with a drainage area of ~53.85 km 2 . The primary pollutant sources in the Fengshan River drainage basin include 43% of industrial wastewater, 40% of domestic sewages, 15% of husbandry wastewater, and 2% agricultural wastewater [18]. Industrial wastewater can be regarded as the primary source of pollution in the river due to the distribution of many small factories along and within the river basin, such as metal finishing, basic metal manufacturing, electroplating, printed circuit board manufacturing, and leather processing, especially the pollution from leather processing and metal finishing factories in the upstream area [19].…”

“…where CF i and n are the contamination factor of each heavy metal obtained using the Equation ( 2) and the number of heavy metals studied, respectively. Based on the mCd value, the sediment heavy metal contamination level can be categorized into ultra-high degree (mCd > 32), extremely high degree (16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30)(31)(32), very high degree (8)(9)(10)(11)(12)(13)(14)(15)(16), high degree (4-8), moderate degree (2-4), low degree (1.5-2), and nil to very low degree of contamination (<1.5) [24].…”

“…The multivariate statistical analyses, including the Spearman correlation coefficient matrix and PCA/FA, were performed on the whole data set (13 variables) using IBM SPSS Statistics software version 20. The grain size composition (clay, silt, sand), organic matter (OM), total nitrogen (TN), and total phosphorus (TP) contents of the Fengshan River sediments in same study sites were obtained from our previous study [18].…”

“…The VF3 displays strong positive loadings on As only with 13.6% of the total variance, probably indicating the source of As was different from the other metals (Hg, Cr, Cu, Ni, Pb, and Zn). a Grain size, OM, TN, and TP data obtained from Lin et al [18]. Bold values indicate strong loadings (>0.7).…”

“…a Grain size, OM, TN, and TP data obtained from Lin et al[18]. ** significant at p < 0.01, expressed in bold; * significant at 0.01 < p < 0.05; n = 14.…”