Transfer of lead through different trophic levels: Microalgae (Nannochloropsis oculata), rotifer (Brachionus plicatilis), and prawn (Macrobrachium rosenbergii)

Resumen

Aquatic ecosystems suffer alterations by the input of several pollutants as potentially toxic elements which interact with the planktonic community with likelihood of bioconcentration, bioaccumulation, and biomagnification through the trophic chains despite the fact of being in low concentrations. The goal of this study involves assessing the toxicity, bioaccumulation, and transfer of the lead under controlled laboratory conditions by estimating the bioconcentration factor (BCF) and bioaccumulation factor (BAF) in organisms usually used in aquaculture, as Nannochloropsis oculata microalgae, Brachionus plicatilis rotifer, and the Malaysian prawn Macrobrachium rosenbergii. We assessed toxicity, bioconcentration, and transfer of the lead from the microalgae to higher trophic levels, the rotifer, and the prawn larvae. We performed three bioassays: (1) lead-exposed microalgae, (2) rotifer fed with lead-exposed microalgae, and (3) prawn larvae fed with either lead-exposed microalgae or rotifers fed with these microalgae. The toxicity endpoints were obtained for microalgae. The concentration of the lead in all organisms was analyzed by atomic absorption spectrophotometry for estimating BCF and BAF values. The endpoints No Observed Effect Concentration (NOEC) and Effective Concentration 50 (EC₅₀) are 1 and 5.42 mg/L, respectively, for N. oculata. The BCF in the microalgae decreases as lead concentration increases. A BAF of 2948 in rotifers, and a BAF of 42.1 in prawns were obtained. In conclusion, lead can concentrate in microalgae, transfer, and accumulate through consumption toward the consecutive trophic levels, but not among invertebrates due to their detoxification mechanisms.