Early Life Stage Bioactivity Assessment of Short-Chain Chlorinated Paraffins (SCCPs) at Environmentally Relevant Concentrations by Concentration-Dependent Transcriptomic Analysis of Zebrafish Embryos.

Short-chain chlorinated paraffins (SCCPs), a class of ubiquitous pollutants, are considered to be embryotoxic and teratogenic. However, little is known regarding the bioactivity and mechanisms at environmentally relevant concentrations at embryonic period. Here, a concentration-dependent reduced transcriptomic approach was used to evaluate the environmental dose (<100 ppb) effects of nine SCCP congeners and eight commercial mixtures on zebrafish embryos at 8 hpf. After 24 h of exposure, the overall biological potency of all the SCCPs, in terms of interference with 20% of the differentially expressed genes (PODDEG20), in zebrafish embryos ranged from 0.83 ppb to 67.61 ppb. C10H14Cl8 (PODGO20=3.80 ppb) and C10-13 51.5% Cl (PODGO20=3.31 ppb) exhibited the strongest interference with biological processes compared to other SCCP homologs and mixtures, respectively. The most sensitive early molecular responses induced by SCCPs were associated with pathways of genetic damage, energy metabolite interference, and m...