Sedimentable Atmospheric Particulate Matter Impairs Respiratory Response to Hypoxia in Freshwater Fish, Nile Tilapia, Oreochromis niloticu

C. DE ANGELIS; M. PEREIRA SOARES; I. LUZ CARDOSO; D. MCKENZIE; I. DA COSTA SOUZ; D.A. WUNDERLIN,; M.V. MONFERRAN; .N. FERNANDE; C. LEITE

Congreso; SETAC Latin America 14th Biennial Meeting, Edición Virtual; 2021

SETAC

In Brazil, recent studies have demonstrated that aquatic environment canbe cross-contaminated by atmospheric particulate matter (APM)produced by steel industry. APM consists of a complex mixture ofparticles that includes a large number of metallic nanoparticles and ithas been described as a relevant sublethal pollutant that could damageaquatic biota and human population. Further, the present legislation islimited in dealing with both problems: air to water cross-contaminationand sublethal levels of AMP contamination. We evaluated metabolic and cardiorespiratory response to progressive hypoxia in tilapia,Oreochromis niloticus, after contamination by sedimentableatmospheric particulate matter (SeAMP). We recorded cardiorespiratoryand metabolic variables during trials of progressive short-term hypoxia(PwO2 100, 70, 50, 30, 20, 10 and 5%, 30 min each step), underintermittent respirometry protocol, after 96 hours of exposure (n = 10for each experimental group and control) to raw SeAPM generated bysteel industry complex near Vitoria ? ES. SeAPM exposure affectedrespiratory efficiency and impaired the respiratory response to hypoxia.SeAPM exposure had compromised the ability to maintain restingmetabolic rate in normoxia and moderate hypoxic levels. Thesealterations lead to a presumed higher and nonnegligible ventilatory cost,and therefore it changes the energy allocation strategy. The respiratoryinefficacy raised critical tension (from 26 to 34% of O2 or from 1.84 to2.76 mg O2 × L-1), which might change the dynamics of environmentusage since fish might spend a longer part of the day unable tocompensate for oxygen availability. Therefore, those alterationscompromised energy obtainment, allocation, and consequently fish?strategy? to confront ecological challenges. Based on the presentresults, we indicate that this sublethal level of contamination might limitlong-term population survival and therefore, it should be appropriatelyconsidered by the regulatory agencies.