ABSTRACT
Background As emerging environmental contaminants with ecological risks, flame retardants (FRs) exhibit obvious toxicity and persistence. In recent years, as FRs have been widely detected in indoor environments and human samples, the human health risks after FRs exposure are of great concern. Objective To systematically understand the topic evolution, research status, progress, and development trends on the toxicity and health effects of FRs on humans worldwide. Methods We retrieved the literature regarding toxicity of FRs and their effects on human health through the Web of Science database from 2000 to 2020, screened and processed the literature using Endnote software, and analyzed annual publications, important citations, and authors. CiteSpace and VOSviewer were employed to draw co-citation network, keyword co-occurrence network, and keyword clustering map for bibliometric visualization analysis. Results From 2000 to 2020, 472 international papers on toxic effects and human health impacts of FRs were published. In terms of publication years, FRs-related research was mainly divided into three stages: the infancy and exploration stage (2001—2006), when the research on the toxic effects of FRs was just starting; the growth stage (2007—2015), when the risk assessments of FRs on human health were conducted; and the acceleration stage (2016—), when the studies have shifted to the mechanism of FRs damage to human health. In this field, China published the largest number of published articles in the world (177 papers), but the intermediary centrality (reflecting academic influence) was only 0.19, far lower than that of European and American countries such as the Netherlands (0.78), Britain (0.51), and Germany (0.44). Among the top 10 research institutions in terms of the number of articles published, the Chinese Academy of Sciences topped the list with 49 articles. Van der Veen and other researchers had a strong influence on the research of the toxic effects of phosphorous FRs since their papers published in 2012 were cited 1319 times and in the most prominent node in the literature co-citation network. The high-frequency keywords in the literature on the human health effects of FRs were polybrominated diphenyl ethers (217 times), brominated FRs (166 times), toxicity (147 times), FRs (102 times), exposure, polychlorinated biphenyls, in vitro experiment, plasticizer, etc. Through keyword clustering and co-occurrence analyses, it was found that current research is systematically exploring the toxic mechanism of FRs from a perspective integrating pollution source-exposure route-final receptor of pollutants, and is evaluating the environmental health risks via different exposure routes. The visualized bibliometric analysis findings suggested that future studies understand the underlying mechanisms of various cell damage caused by FRs toxicity, identify the key factors of change and their relationships, aiming to provide a scientific basis for targeted prevention of health effects of FRs. Conclusion The research hotspots on the toxic effects of FRs and their effects on human health have changed over time, and the breadth and depth have been increasing. The toxic effects of brominated/phosphorus FRs have always been the mainstream direction in this field. Further studies will focus on the molecular mechanisms of human toxicity after FRs exposure.
ABSTRACT
Decabromodiphenylethane (DBDPE) has been widely used as an alternative flame retardant due to the restriction or phase-out of traditional polybrominated diphenyl ethers (PBDEs), and is of increasing concern regarding its ubiquity, persistence, and potential adverse effects. In the present study, the toxicological effects of DBDPE were evaluated using zebrafish as an in vivo model. Upon being exposed to DBDPE-polluted sediments for a short term, it was found that the mortality and malformation of zebrafish (including edema, bent notochord, and bent tail) were not affected even at the highest concentration tested (1000.0 µg/kg dry sediment). Regarding behavioral responses, it was found that zebrafish larvae of 48 hours post fertilization (hpf) in all groups escaped successfully with a touch to the dorsal fin. However, when exposed to the highest DBDPE concentration, the larvae of 120 hpf exhibited significantly smaller distances as compared to the control. Moreover, the results of the acetylcholinesterase (AChE) activity, the expression levels of two important nerve-related genes, and the cell apoptosis all indicated that DBDPE posed low neurotoxicity in embryo-larval zebrafish. The results in this study shed some light on the potential risks of DBDPE in the real environment and highlight the application of the sediment exposure route in the future.
Subject(s)
Animals , Abnormalities, Drug-Induced , Apoptosis , Behavior, Animal , Bromobenzenes , Toxicity , Geologic Sediments , Larva , Neurotoxicity Syndromes , Water Pollutants, Chemical , Toxicity , Zebrafish , EmbryologyABSTRACT
Background contamination is a major problem in the analysis of organophosphate esters (OPEs). In this study, the possible sources of OPEs pollution were screened and several different ways were applied to minimize the blank contamination. Under the strict quality control measures, the cleanup efficiency of different solid phase extraction (SPE) was investigated for OPEs in different environmental matrices. A method was developed for the detection of 7 OPEs in dust, soil and sediment samples by gas chromatograph coupled with mass spectrometry ( GC / MS). Target compounds were extracted by hexane:dichloromethane (1 : 1, V/ V) followed by aminopropyl silica gel SPE column cleanup for dust, and target compounds in soil and sediment were Soxhlet extracted and cleanuped by two-step SPE. The results showed that the aminopropyl silica gel SPE column displayed the best purification performance among the three employed columns. Instrumental detection limits among the 7 OPEs ranged from 2. 5 to 25. 8 μg / L, and the method limits of quantification (MLOQs) in dust and soil sample ranged from 1. 4 to 15. 7 ng / g and 0. 3 to 2. 9 ng / g, respectively. The average recoveries of 7 OPEs in different matrices ( dust and soil) at two spiked concentration levels ranged from 67. 9% to 117. 4% . The proposed method was successfully applied to detect OPEs in different environmental matrices collected in Shanghai.