Use of the mollusk Biomphalaria glabrata in the water monitoring of the Capibaribe River

Anthropogenic and industrial activities in areas close to rivers have led to the degradation of the quality of surface and underground water, as well as the disturbance of the organisms that inhabit this ecosystem. In this work, the physicochemical parameters of the surface waters of the Capibaribe River, quantification of trace elements in suspended and bottom sediments, the mutagenic, genotoxic, and bioaccumulative effects on the mollusks Biomphalaria glabrata were analyzed. To evaluate the tests, samples of river water were collected (P1=Recife, P2=Salgadinho, P3=Toritama and P4=Santa Cruz do Capibaribe) in the dry and rainy seasons. The pH and conductivity were analyzed at the time of collection. At these same points, the collection of sediment from the bottom of the river was carried out. In the laboratory, 90% of the collected waters were stored for subsequent analysis of suspended sediment, and the other part was used for bioassays on mollusks. Suspended and river bottom sediments, as well as bioaccumulation in mollusks, were evaluated using Atomic Absorption Spectrometry techniques. The results showed pH values of water from the Capibaribe river within the acceptable threshold (6.2 to 7.7) in both seasons, and high values of conductivity (between 0.13 and 6.5 mS.cm-1), mainly in the dry season, indicating an environmental impact. The sediment pollution index was highly polluted in P4. Trace element concentrations were higher in the rainy season than in the dry season. The water samples collected from point P4 were toxic to embryos and adult mollusks, where 100% mortality was verified in both tests in the rainy season, making it impossible to evaluate the other tests with this point. In the other points, embryotoxicity did not exceed 6% of infeasibility and adult mortality was less than 10%, both in the dry and rainy seasons, for the P1, P2, and P3 groups. The significant difference in micronucleus and binucleation between the two stations at P3 evidences the mutagenic and genotoxic potential of polluted waters with textile industrial residues, considering that at P1 and P2 there was no significant difference. The Comet Assay also highlighted the impact that P3 has been suffering through DNA fragmentation and the increase in damage levels at level 4, in other points, the highest degree was level 0. The mollusks bioaccumulate chromium, present in the dry season in P3. Therefore, the results showed that the Capibaribe River suffers many environmental impacts close to textile regions, as well as showing the sensitivity that the mollusk Biomphalaria glabrata has to environmental monitoring tests. (author)