Toxicity of new generation flame retardants to Daphnia magna

Abstract

There is a tendency to substitute frequently used, but relatively hazardous brominated flame retardants (BFRs) with halogen-free flame retardants (HFFRs). Consequently, information on the persistence, bioaccumulation and toxicity (PBT) of these HFFRs is urgently needed, but large data gaps and inconsistencies exist. Therefore, in the present study the toxicity of a wide range of HFFRs to the water flea Daphnia magna was investigated. Our results revealed that four HFFRs were showing no effect at their Sw (saturated water concentration) and three had a low toxicity (EC50>10 mg L(-1)), suggesting that these compounds are not hazardous. Antimony trioxide had a moderate toxicity (EC50=3.01 mg L(-1), 95% CL: 2.76-3.25) and triphenyl phosphate and the brominated reference compound tetra bromobisphenol A were highly toxic to D. magna (EC50=0.55 mg L(-1), 95% CL: 0.53-0.55 and EC50=0.60 mg L(-1), 95% CL: 0.24-0.97 respectively). Aluminum trihydroxide and bisphenol A bis(diphenyl phosphate) caused limited mortality at Sw (26 and 25% respectively) and have a low solubility (<10 mg L(-1)). Hence, increased toxicity of these compounds may be observed when for instance decreasing pH could increase solubility. By testing all compounds under identical conditions we provided missing insights in the environmental hazards of new generation flame retardants and propose as best candidates for BFR replacements: APP, ALPI, DOPO, MHO, MPP, ZHS and ZS.

Keywords: 3-(N-morpholino)propanesulfonic acid; 9,10-dihydro-9-oxa-10-phosphaphenanthrene; ALPI; APP; ATH; ATO; BDE; BDP; BFR; Brominated flame retardants; CAS no; DOPO; Daphnia magna; EC(50); ECHA; EP; European chemicals agency; European parliament; FR; HBCD; HFFR; HOC; Halogen-free flame retardants; ICP-AES; ISO; LC-MS/MS; MHO; MOPS; MPP; OECD; PBB; PBDE; PBT; PBT properties; RDP; REACH; S(w); TBBPA; TOC; TPP; Toxicity; ZHS; ZS; aluminum diethyl phosphinate; aluminum trihydroxide; ammonium polyphosphate; antimony trioxide; bisphenol A bis(diphenyl phosphate); brominated diphenylether; brominated flame retardant; chemical abstracts service number; concentration that causes an effect (here immobility) to 50% of the test population; dTPP; deuterated triphenyl phosphate; flame retardant; halogen-free flame retardant; hexabromocyclododecane; high performance liquid chromatography (coupled to) tandem mass spectrometry; hydrophobic organic contaminant; inductively coupled plasma (coupled to) atomic emission spectroscopy; international organization for standardization; magnesium hydroxide; melamine polyphosphate; organization for economic co-operation and development; persistence, bioaccumulation and toxicity; polybrominated biphenyl ether; polybrominated biphenyls; registration, evaluation, authorization and restriction of chemical substances; resorcinol bis(diphenyl phosphate); saturated water concentration; tetra bromobisphenol A; total organic carbon; triphenyl phosphate; zinc hydroxystannate; zinc stannate.