Acute toxicity and risk assessment of three commercial detergents using the polychaete Capitella sp. C from Chetumal Bay, Quintana Roo, Mexico

The acute toxicity of three formulations of commercial detergent (ROMA, FOCA and BLANCA NIEVES) was evaluated using the polychaete Capitella sp. C in static bioassays over a 48-h exposure period. The probit method was used to determine the median lethal concentration (LC50) of each formulation as a whole as well as the LC50 of the active ingredient, linear alkylbenzene sulfonate (LAS), using 95 % confidence intervals. The formulations and LAS showed LC50 values of between 70.79 and 147.91 ppm and 15.48 and 22.38 ppm, respectively, at 48 h. FOCA was the most toxic detergent, followed by BLANCA NIEVES and finally ROMA. The variation in the toxicity of the three detergents could have been caused both by differences in the relative concentrations of the anionic surfactant LAS contained in each formulation and the presence of other ingredients (enzymes, sodium silicate, sodium tripolyphosphate, bleachers and perfumes) which can also increase formulation toxicity. Correlation analysis revealed that percent mortality of Capitella sp. C increased with increase in the concentrations of the detergent over the 48-h exposure period. The risk quotient was greater than one for all three evaluated detergents, indicating that there is a high risk that they adversely affect the aquatic biota, particularly sediment-dwelling organisms such as the test species.