Asphalt, sulfonated, sodium salt

Endpoint summary

Additional information

Summary of available data

Acute toxicity test results are available for SAS for three trophic levels: fish, invertebrates, and algae. Marine species were used and standard test methods were followed. The 96 hour LC50 for fish (juvenile turbot, Scophthalmus maximus), was determined to be > 240 mg/L. The 48 hour LC50 for the marine invertebrate, Acartia tonsa, was 380 mg/L and the NOEC was 180 mg/L. For the marine alga, Skeletonema costatum, the 72 hour EbC50 was 240 mg/L, the ErC50 was 390 mg/L, and the NOEC was 125 mg/L. The effects upon algae were attributed to the reduction in light penetration (and therefore photosynthesis) caused by the colored nature of the test solutions, rather than any intrinsic toxicity of SAS.

In addition, aquatic toxicity tests have been conducted with Soltex® Additive, a commercial product that contains 85% SAS. These tests are considered as supporting information for SAS. Tests were conducted using the water-accomodated fraction (fish), liquid phase or suspended particulate phase (crustaceans), and liquid phase (algae). In tests with the water-accomodated fraction of Soltex® Additive, the 96 hour LC50 for Scophthalmus maximus was 1672 mg/L. In a test of drilling fluid containing SAS, a 96 hour LC50 of 420,000 ppm was obtained for the invertebrate, Mysidopsis bahia. For the invertebrate Acanthomysis sculptata, the 96 hour LC50 was 155,000 ppm for exposure to the liquid phase of Soltex® Additive, and 205,000 ppm for exposure to the suspended particulate phase. The 95 hour EC50 based upon growth rate and biomass was 4,000 and 8,300 mg/L, respectively, for the alga Skeletonema costatum exposed to a 1% solution of Soltex® Additive.

The acute toxicity of SAS to aquatic organisms has been determined for vertebrates, invertebrates and plants. Additional acute toxicity data are available for Soltex® Additive. No additional acute toxicity testing is necessary.