Hormetic Versus Toxic Effects of Vegetable Tannin in a Multitest Study

• Published in: Archives of environmental contamination and toxicology 2004-04, Vol.46 (3), p.336-344
• Main Authors: De Nicola, E, Gallo, M, Iaccarino, M, Meric, S, Oral, R, Russo, T, Sorrentino, T, Tunay, O, Vuttariello, E, Warnau, M, Pagano, G
• Format: Article
• Language: English
• Subjects: Algae; Contamination; Control equipment; Freshwaters; Leather; Mortality; Toxicity; Toxicology; Trees
• ISSN: 0090-4341
• DOI: 10.1007/s00244-003-2293.5

Tannin from mimosa trees (Acacia sp.) utilized in traditional leather tanning was tested for toxicity in sea urchin (Sphaerechinus granularis and Paracentrotus lividus) embryos and sperm, marine, and freshwater algae (Selenastrum capricornutum and Dunaliella tertiolecta), and Daphnia magna. Based on a two-step tanning procedure used in traditional tanneries, two mimosa tannin preparations, i.e., fresh tannin (FT) and used tannin (UT), were tested as suspensions. The early results in S. granularis embryos showed that UT exerted lower acute toxicity than FT, namely, 1 vs 100 mg/L, to obtain 100% mortality, respectively. Subsequent bioassays were conducted on fresh tannin water extracts (TWE) corresponding to nominal tannin concentrations ranging from 0.1 to 30 mg/L. Developmental toxicity, up to embryonic mortality was exerted by TWE at levels > 1 mg/L, S. granularis being more sensitive than P. lividus embryos/larvae. At the concentration of 0.1 mg/L, the frequencies of larval malformations were significantly lower than in controls. This positive stimulatory effect (currently termed as hormesis) was observed in extended numbers of culture replicates (up to 14) and was significant in the embryo cultures characterized by a relatively poor control quality (with < 70% viable larvae in controls), whereas this effect was not observed in good-quality cultures (with < 70% viable larvae in controls.