title: pH-dependent ecological risk assessment of pentachlorophenol in Taihu Lake and Liaohe River.
abstract: Pentachlorophenol (PCP) has been reported toxic to aquatic organisms, and it frequently occurs at relatively high concentrations in most Chinese waters due to the re-emergence of schistosomiasis since 2003. Several studies about Water Quality Criteria (WQC) for PCP had been performed to protect the aquatic ecosystem, but in most of these studies the toxicity data were not properly analyzed (e.g. screening and processing methods). Moreover, little study was carried out on the ecological risk assessment (ERA) based on environmental factors. In this study, through collecting published native toxicity data of PCP along with relationships between toxicity and pH, pH-dependent WQC was established using a standardized scientific statistical method in China. The Criterion Maximum Concentration (CMC) and Criterion Continuous Concentration (CCC) were expressed as a function of pH. These were (1) CMC = exp(1.361×pH-8.034) and (2) CCC = exp(1.361×pH-10.434). At pH 7.8, the derived CMC and CCC were 13.21 and 1.20μg/L, respectively. In addition, four tiers of the ERA were conducted based on pH for different waterbodies at different seasons. In tiered 1, 2, 3 and 4 ERA, PCP exposure concentrations were standardized to that at pH 7.8. Results showed that all levels of ERA method in the tiered framework were consistent with each other, and the risks of PCP in Liaohe river of wet season, Taihu lake and Liaohe river of dry season increased successively. The Hazard quotient (HQ) method indicated that small fluctuations in pH would lead to misleading hazard results. PCP concentrations of 8.66μg/L at pH 7.37 in one site posed more risk than PCP of 9.57μg/L at pH 7.93 in another site. The joint probability suggested that ecological risks may exist 11.84% in the dry season and 1.51% in the wet season in Liaohe River, and 4.98% in Taihu Lake, respectively while 5% thresholds (HC5) were set up to protect aquatic organisms. We hope this work could provide more information to manage and control PCP pollution in Taihe Lake and Liaohe River.
authors.affiliation: College of Water Science, Beijing Normal University, Beijing 100875, China; State Key Laboratory of Environmental Criteria and Risk Assessment, State Environmental Protection Key Laboratory of Ecological Effect and Risk Assessment of Chemicals, Chinese Research Academy of Environmental Sciences, Beijing 100012, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Zheng
authors.affiliation: State Key Laboratory of Environmental Criteria and Risk Assessment, State Environmental Protection Key Laboratory of Ecological Effect and Risk Assessment of Chemicals, Chinese Research Academy of Environmental Sciences, Beijing 100012, China. Electronic address: liuzt@craes.org.cn.
authors.forename: Zhengtao
authors.initials: Z
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Environmental Criteria and Risk Assessment, State Environmental Protection Key Laboratory of Ecological Effect and Risk Assessment of Chemicals, Chinese Research Academy of Environmental Sciences, Beijing 100012, China. Electronic address: zgyan@craes.org.cn.
authors.forename: Zhenguang
authors.initials: Z
authors.lastname: Yan
authors.affiliation: State Key Laboratory of Environmental Criteria and Risk Assessment, State Environmental Protection Key Laboratory of Ecological Effect and Risk Assessment of Chemicals, Chinese Research Academy of Environmental Sciences, Beijing 100012, China.
authors.forename: Yahui
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: School of Food and Environment, Dalian University of Technology, Panjin 124221, China.
authors.forename: Xianliang
authors.initials: X
authors.lastname: Yi
authors.affiliation: State Key Laboratory of Environmental Criteria and Risk Assessment, State Environmental Protection Key Laboratory of Ecological Effect and Risk Assessment of Chemicals, Chinese Research Academy of Environmental Sciences, Beijing 100012, China.
authors.forename: Juan
authors.initials: J
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Environmental Criteria and Risk Assessment, State Environmental Protection Key Laboratory of Ecological Effect and Risk Assessment of Chemicals, Chinese Research Academy of Environmental Sciences, Beijing 100012, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Zheng
authors.affiliation: State Key Laboratory of Environmental Criteria and Risk Assessment, State Environmental Protection Key Laboratory of Ecological Effect and Risk Assessment of Chemicals, Chinese Research Academy of Environmental Sciences, Beijing 100012, China.
authors.forename: Junli
authors.initials: J
authors.lastname: Zhou
authors.affiliation: College of Environmental Science and Engineering, Guilin University of Technology, Guilin 541004, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhu
mesh_terms: D002681:China; D004463:Ecology; D017753:Ecosystem; D004784:Environmental Monitoring / Q000379:methods; D006863:Hydrogen-Ion Concentration; D060106:Lakes / Q000737:chemistry*; D010416:Pentachlorophenol / Q000032:analysis* / Q000633:toxicity; D018570:Risk Assessment / Q000379:methods; D045483:Rivers / Q000737:chemistry*; D012621:Seasons; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000633:toxicity; D060753:Water Quality / Q000592:standards*
chemical_list: D014874:Water Pollutants, Chemical; D010416:Pentachlorophenol
keywords: Ecological risk assessment; Joint probability; Pentachlorophenol; Standardization; Water quality criteria; pH