Nebeker, Alan V., Gerald S. Schuytema, William L. Griffis, and A. Cataldo. 1998. Impact of guthion on growth of the frog Pseudacris regilla and the salamanders Ambystoma gracile and Ambystoma maculatum. Archives of Environmental Contamination and Toxicology 35:48-51.
The effects of the insecticides Guthion (technical grade) and Guthion 24 (Commercial formulation) on survival and growth of tadpoles in the Pacific treefrog Pseudacris regilla, and larvae of the Northwestern salamander Ambystoma gracile and the spotted salamander Ambystoma maculatum were determined in continuous-flow exposures in the laboratory. Ninety-six-hour LC50 values were >3.6 mg/L for P. regilla with technical grade Guthion and 1.47 mg/L with the formulation Guthion S (measured as active ingredient Guthion). Ten-day LOAEL and NOAEL values based on length and weight for P. Regilla with Guthion were 3.60 and 0.98 mg/L. LOAEL and NOAEL values based on length and weight for P. regilla with Guthion s were 0.17 and 0.07 mg/L. The 96-h LC50 for Guthion s was 1.67 and 1.90 mg/L for A. Gracile and A. maculatum, respectively. LOAEL and NOAEL values based on length and weight for A. Gracile with Guthion s were 0.22 and 0.10 Mg/L; they were 0.11 and 0.03 mg/L for A. maculatuim based on weight. These species are as similar in sensitivity as some fish species, but are more tolerant to Guthion than most invertebrates.