Vegetable and synthetic tannins induce hormesis/toxicity in sea urchin early development and in algal growth

Abstract

Mimosa tannin and phenol-based synthetic tannin (syntan) were tested for toxicity to sea urchin ( Paracentrotus lividus and Sphaerechinus granularis) early development and to marine algal growth ( Dunaliella tertiolecta). Sea urchin embryogenesis was affected by vegetable tannin and syntan water extracts (VTWE and STWE) at levels ≥1 mg/L. Developmental defects were significantly decreased at VTWE and STWE levels of 0.1 and 0.3 mg/L when control cultures displayed suboptimal quality, i.e. <70% “viable” (normal or retarded) larvae. Fertilization success of sea urchin sperm was increased up to 0.3 mg/L STWE or VTWE, then was inhibited by increasing tannin levels (1–30 mg/L). Offspring abnormalities, following sperm exposure to VTWE or STWE, showed the same shift from hormesis to toxicity. Cell growth bioassays in D. tertiolecta exposed to VTWE or STWE (0.1–30 mg/L) showed non-linear concentration-related toxicity. Novel criteria are suggested in defining control quality that should reveal hormetic effects.