Use of Brachionus Plicatilis (Rotífera) to assess the quality of marine water in the Callao Bay, Peru

Abstract

The present investigation used Brachionus plicatilis (Rotifera) to evaluate the water quality in the Bahía del Callao, Peru. The water samples were taken in four sampling areas: P1 in La Punta, P2 in Chucuito, P3 in front of the Callao Port Terminal and P4 in the San Lorenzo and El Frontón Islands, and in four seasonal periods: autumn-2015, winter- 2015, spring-2015, and summer-2016. Physical-chemical parameters, chlorophyll, phycocyanin, heavy metals, and bioassays with seawater at 24 h and 48 h of exposure with B. plicatilis obtained from a standardized culture were evaluated in each area and seasonal period. The metals Ag, Pb, Hg, Cu, Cr, Ni and Zn: Pb, Hg, Cu, Co, P, Ni and Zn were found in higher concentration at the sampling sites P1, P2 and P3. At 48 h of exposure with the B. plicatilis bioassay based on the LC50 (Mean Lethal Concentration), it was observed that 62.5% (n = 10) of the samples showed to be non-toxic, 31.25% (n = 5) were slightly toxic, and finally 6.25% (n = 1) were marginally toxic based on an ecotoxicological scale. The values ​​of NOEC (Concentration where a significant effect of mortality is not observed with respect to the control) and LOEC (Minimum concentration where a significant effect of mortality is observed with respect to the control) were lower for the P1 (winter-2015) and P2 (winter-2015). A positive relationship was found between LC50 and Pb in seawater. Similarly, a negative association was observed between NOEC and seawater salinity. The rest of the associations between LC50, NOEC and LOEC of seawater with B. plicatilis with the quality parameters of seawater in the Bay of Callao showed absence of statistically significant relationships. It is proposed to use B. plicatilis as a bioindicator organism to assess water quality in the marine environment.