Occurrence and distribution of organophosphate flame retardants/plasticizers in wastewater treatment plant sludges from the Pearl River Delta, China

Abstract

Organophosphate esters (OPs) are widely used as flame retardants or plasticizers and are ubiquitously distributed in the environment. In the present study, the occurrence and distribution of 7 widely used OPs were analyzed in sludge samples collected from 19 municipal wastewater treatment plants in the Pearl River Delta, South China. All analytes were detected in these samples, and the total concentration of OPs ranged from 96.7 mg/kg to 1312.9 mg/kg dry weight, with a mean value of 420.1 mg/kg dry weight. In most sludge samples OPs exhibited a similar distribution pattern, for example, tris(2-butoxyethyl) phosphate (TBEP) and triphenyl phosphate (TPhP) were identified as the dominant compounds. However, the results also indicated significantly higher levels of OPs in specific sludges, such as tri-n-butyl phosphate (804.9 mg/kg), TBEP (783.7 mg/kg), TPhP (656.7 mg/kg), and tritolyl phosphate (265.0 mg/kg), which implied different discharge sources in the studied areas.

Occurrence and distribution of organophosphate triesters and diesters in sludge from sewage treatment plants of Beijing, China

“…The concentrations of TnBP (1.2-285.9 μg/kg) and TiBP (b LOD-473.7 μg/kg) in our study were similar to those detected in STPs in Norway (TnBP: 69-270; TiBP: 52-81 μg/kg) (Green et al, 2008), but much lower than those detected in sludge from Swedish STPs (TnBP: 39-850; TiBP: 27-2700 μg/kg) (Marklund et al, 2005a) and from STPs in the south of China (TnBP: 7.1-804.9 μg/kg) (Zeng et al, 2014). The concentrations of TPhP (4.4-66.8 μg/kg) and EHDPP (b LOD-139 μg/kg) in this study were also much lower than those detected in previous studies in Sweden (Marklund et al, 2005a), Norway (Green et al, 2008) and south of China (Zeng et al, 2014).…”

“…The level of TCrP in sludge from STPs in Beijing was higher than that detected in STPs in the south of China (LOQ-265.0 μg/kg) (Zeng et al, 2014). While the TBEP concentration in our study was lower than that detected in Swedish STPs (b 5.1-1900 μg/kg) (Marklund et al, 2005a) and in STPs in the south of China (25.1-783.7 μg/kg) (Zeng et al, 2014).…”

“…The concentrations of TPhP (4.4-66.8 μg/kg) and EHDPP (b LOD-139 μg/kg) in this study were also much lower than those detected in previous studies in Sweden (Marklund et al, 2005a), Norway (Green et al, 2008) and south of China (Zeng et al, 2014).…”

“…Similar level of TCEP has been reported in sewage sludge from Swedish STPs (6.6-110 μg/kg) (Marklund et al, 2005a), whereas the levels of TCPP and TDCP in our study were much lower than those in STPs from Sweden (TCPP: 61-1900; TDCP: 3.3-260; μg/kg) (Marklund et al, 2005a), Germany (TCPP: 1000-20,000 μg/kg) (Bester, 2005), Norway (TCPP: 650-944; TDCP: 110-330 μg/kg) (Green et al, 2008) and Spain (TCPP: 600-2900; TDCP: 92.0-600 μg/kg) Wei et al, 2015). However, concentrations of chlorinated OP triesters in this study were slightly higher than those found in STPs in the south of China (Zeng et al, 2014).…”

“…Up to now, several OP triesters, including TCPP, TCEP, TBEP and TnBP, have been determined at μg/L levels in influents and effluents of STPs (Paxeus, 1996;Meyer and Bester, 2004;Bester, 2005;Marklund et al, 2005a;Martinez-Carballo et al, 2007). However, only limited studies have demonstrated the levels of OP triesters in sewage sludge (Bester, 2005;Marklund et al, 2005a;Zeng et al, 2014).…”