Specimens of Apodemus sylvaticus trapped in a wheat field two months after it had been drilled with wheat dressed with dieldrin and mercury still showed considerable residues of dieldrin (0·74 ± 0·45 w/w ppm in whole body; maximum 2·84 w/w ppm) although these were much lower than those published for the immediate post-drilling period (10·18 ± 1·19 w/w ppm; max.: 22·30 w/w ppm). Mercury concentrations, on the other hand, were much higher (0·83 ± 0·44 w/w ppm in whole body; max.: 2·93 w/w ppm) than those previously found immediately after drilling (0·39 ± 0·04 w/w ppm; max.: 0·75 w/w ppm). Small amounts of cadmium (0·10 ± 0·01 w/w ppm in whole body) were also found in the seven mammals tested. © 1976.
Jefferies, D. J., & French, M. C. (1976). Mercury, cadmium, zinc, copper and organochlorine insecticide levels in small mammals trapped in a wheat field. Environmental Pollution (1970), 10(3), 175–182. https://doi.org/10.1016/0013-9327(76)90035-5