Toxicity, bioaccumulation and biomagnification of silver nanoparticles in green algae (Chlorella sp.), water flea (Moina macrocopa), blood worm (Chironomus spp.) and silver barb (Barbonymus gonionotus)

Abstract

The toxicity, bioaccumulation and biomagnification of material containing silver nanoparticles were studied in a model food chain. Two forms of silver namely, Ag+ and nano Ag0 particles (AgNPs) were examined for their toxicity effects on Chlorella sp., Moina macrocopa, Barbonymus gonionotus and Chironomus spp. The results showed that the toxicity order on the four organisms was free Ag+ > AgNPs. For toxicity of Ag+, the EC50 (effective concentration) was 0.39±0.32 mg L-1 for Chlorella sp. and the LC50 (lethal concentration) of M. macrocopa, B. gonionotus and Chironomus spp. were 0.026±0.43 mg L-1, 0.057±1.15 mg L-1, and 0.042±0.19 mg L-1, respectively. For toxicity, the EC50 of AgNPs was 0.89±0.68 mg L-1 for Chlorella sp. and the LC50 of M. macrocopa, B. gonionotus and Chironomus spp. were 1.11±0.86 mg L-1, 1.76±0.19 mg L-1, and 1.08±1.21 mg L-1, respectively. The results of the bioaccumulation study indicated that the highest bioaccumulation factor (BAF) of Ag+ was 101.84 L g-1 in Chlorella sp. and the lowest BAF of AgNPs was 1.89 L g-1 in B. gonionotus. The food chain transfer of AgNPs occurred only from Chlorella sp. to M. macrocopa and there was no evidence of biomagnification from food sources to consumers in a simple tropical food chain.