Analytical human biomonitoring method for the identification and quantification of the metabolite BDCPP originated from the organophosphate flame retardant TDCPP in urine.

Tris(1,3-dichloropropyl) phosphate (TDCPP, CAS 13674-87-8) is one of the most commonly used organophosphate flame retardants (OPFRs) in cars, residential furniture and other products containing polyurethane foam to meet the required flammability standards. For the tasks of the working group Analyses in Biological Material from the German Research Foundation (DFG), a human biomonitoring process for TDCPP is developed. The metabolism of TDCPP is described in different in vivo studies and it is already shown that Bis (1,3-dichloropropyl) phosphate (BDCPP, CAS 72236-72-7) is the primary compound specific metabolite of TDCPP which is often detectable in urine samples. BDCPP is also the most appropriate metabolite because it is unique to TDCPP since no other OPFR known today is transformed or hydrolyzed to BDCPP. A combined method by liquid chromatography-tandem mass spectrometry (LC-MS/MS) is implemented by optimizing atmospheric pressure chemical ionization (APCI) and Electron Spray Ionization (ESI) operating in negative ionization mode. Simultaneous, multiple reaction monitoring is studied to achieve the best performance with respect to selectivity, detectability and robustness of BDCPP. During an expanded validation assessment, the methodological performance characteristics are determined in details and the method is applied in a specific human biomonitoring study among non-occupationally exposed humans of randomly chosen volunteers from the Netherlands.

Acute and chronic toxicity of neonicotinoids to nymphs of a mayfly species and some notes on seasonal differences.

Mayfly nymphs are among the most sensitive taxa to neonicotinoids. The present study presents the acute and chronic toxicity of 3 neonicotinoids (imidacloprid, thiacloprid, and thiamethoxam) to a mayfly species (Cloeon dipterum) and some notes on the seasonality of the toxicity of imidacloprid to C. dipterum and 5 other invertebrate species. Imidacloprid and thiamethoxam showed equal acute and chronic toxicity to a winter generation of C. dipterum, whereas thiacloprid was approximately twice as toxic. The acute and chronic toxicity of imidacloprid was much higher for the C. dipterum summer generation than for the winter one. The acute toxicity differs by a factor of 20 for the 96-h 50% effective concentration (EC50) and by a factor of 5.4 for the chronic 28-d EC50. Temperature had only a slight effect on the sensitivity of C. dipterum to imidacloprid because we only found a factor of 1.7 difference in the 96-h EC50 between tests performed at 10 °C and 18 °C. The difference in sensitivity between summer and overwintering generations was also found for 3 other insect species. The results indicate that if the use and environmental fate of the 3 neonicotinoids are comparable, replacing imidacloprid by another neonicotinoid might not reduce the environmental impact on the mayfly nymph C. dipterum. The results also show the importance of reporting which generation is tested because sensitivity values of insects in the summer might be underestimated by the experiments performed with neonicotinoids and an overwintering population.