Occurrence and Ecological Impact of Chemical Mixtures in a Semiclosed Sea by Suspect Screening Analysis

Abstract

Stress from mixtures of synthetic chemicals is among the key issues that have significant adverse impacts on the marine ecosystems. A robust screening workflow integrating toxicological-based ranking schemes is still deficient for comprehensive investigation on the main constituents in chemical mixtures that contribute to the ecological risks. In this study, the presence and compositions of a collection of priority pollutants were monitored by suspect screening analysis of seawater and estuarine water samples from the semiclosed Bohai Sea. In total, 108 organic pollutants in nine use categories were identified. Pesticides, intermediates, plastic additives, and per-and polyfluoroalkyl substances were the extensively detected chemical groups. Varied distribution patterns of the pollutants were illustrated intuitively in distinctive sampling areas by hierarchical cluster analysis, which were mainly influenced by run-off inputs, ocean currents, and chemical use history. Ecological risks of chemicals with quantified residue levels were first assessed by the toxicity-weighted concentration ranking scheme, and pentachlorophenol was found as the main contributor in the investigating areas. By optimization of multiple alternative variables (e.g., instrumental response and detection frequency), extended ranking of all the identified pollutants was plausible under the toxicological priority index framework. Similarity in toxicological endpoints of the prioritized pollutants could further been screened by ToxAlerts. Aromatic amine was highlighted as the most frequently detected structural alert (SA) for genotoxic carcinogenicity and mutagenicity. These findings fully demonstrate rationality of the ranking schemes integrated into the suspect screening analysis for profiling contamination characteristics, assessing ecological risk potentials, and prioritizing SAs.

Identification and Prioritization of Environmental Organic Pollutants: From an Analytical and Toxicological Perspective

“…A group of 610 compounds were found to have both the P and B properties, which are mainly analogues of the highly halogenated compounds, alkyl-substituted and condensed aromatics, and siloxane substances . Similarly, by suspect screening analysis on environmental occurrence and residue levels of 5202 priority pollutants in seawater samples from the semiclosed Bohai sea, aromatic amine was noticed as the most frequently detected structural toxicophore for the genotoxic carcinogenicity and mutagenicity end points in view of toxicological-based ranking schemes . On the contrary, the phrase “top-down” is a common description of the approach that starts with a general idea to which details are added later .…”

“…77 Similarly, by suspect screening analysis on environmental occurrence and residue levels of 5202 priority pollutants in seawater samples from the semiclosed Bohai sea, aromatic amine was noticed as the most frequently detected structural toxicophore for the genotoxic carcinogenicity and mutagenicity end points in view of toxicological-based ranking schemes. 108 On the contrary, the phrase "top-down" is a common description of the approach that starts with a general idea to which details are added later. 107 This concept is more consistent with analytical workflow of the EDA methodology that the main contributing component of a measured toxicological response is assumed as the primary and explicit target; nevertheless, the subsequent identification processes might involve multiple interactive and repetitive experimental procedures (e.g., biological test, component fractionation, chemical characterization, and effect confirmation) depending on results of the previous steps.…”

“…It features a formalized and rational integration of information from different domains (e.g., data from exposure status, chemical properties, in vitro assays, and biological pathways), and thus, more robust conclusions are expected to be obtained than any data source used alone . In particular, the accurately quantified concentration was illustrated to be a replaceable variable in case studies. , With reasonable selection and evaluation procedures, alternative variables in mass spectrometry data such as detection frequency and instrument response can be used to characterize the ecological risks of all detected chemicals beyond the scope of commercially available standards. It will significantly increase the likelihood of identifying causative pollutants corresponding to an adverse effect in complex samples. TEF i = AC 50 false( normalmin false) AC 50 false( normali false) TEQ i = TEF i × C i TEQ i % = TEQ i TEQ total EAR i = Exposure false( environmental concentration , μ normalM false) Activity ( activity concentration at cutoff , μ M ) …”

“…359 In particular, the accurately quantified concentration was illustrated to be a replaceable variable in case studies. 108,360 With reasonable selection and evaluation procedures, alternative variables in mass spectrometry data such as detection frequency and instrument response can be used to characterize the ecological risks of all detected chemicals beyond the scope of commercially available standards. It will significantly increase the likelihood of identifying causative pollutants corresponding to an adverse effect in complex samples.…”

An Integrated Workflow Assisted by In Silico Predictions To Expand the List of Priority Polycyclic Aromatic Compounds

“…10,14 In particular, the carcinogenicity of certain congeners and their long-distance transport and bioaccumulation warrant consideration. 47 The frequency of occurrence as an important indicator of exposure, 29 and the ease of analysis are also required to be integrated in the workflow. Therefore, a ToxPi scoring approach 26…”