The determination of traces of dieldrin in blood.

Stringent conditions with regard to cleanliness are laid down for the attention of public authorities concerned with the spraying of dieldrin formulations. Protective clothing must be worn and this must be changed frequently. Personal cleanliness is imperative. Since sprayers are often operating in rugged country for days at a time it is not easy for these conditions to be followed and it has been suggested that analysis of the blood of operators might revea1 traces of dieldrin which would enable authorities to take precautionary measures. Little detail is available in the literature concerning the analysis of blood for dieldrin. In fact, the only evidente we have is from a private communication and concerns the determination of aldrin and dieldrin residues in the blood of cattle, following subcutaneous injection of these insecticides. In these determinations blood samples (400 ml. each) were analyzed, at intervals after injection, by bioassay and colorimetric procedures. The sensitivity of these methods is quoted as being 0.02 ppm to 0.03 ppm for the bioassay (i.e. on 400 ml. 8 to 12 ,ug of toxicant) and 0.02 to 0.05 ppm for the colorimetric procedure (i.e. on 400 ml. 8 to 20 pg of toxicant). Recoveries of dieldrin added to uncontaminated blood in order to produce a concentration of 0.1 ppm (i.e. on 400 ml. 40 pg of toxicant) are reported in this private communication as being about 50% by both methods.