Heavy Metals in the Striped Snakehead Murrel Channa striata and Sediments of Lake Mainit Philippines with Notes on Piscine Micronuclei Occurrence

Abstract

Lake Mainit is the deepest lake in the Philippines, with sporadic documentation of various types of aquatic pollution. This paper reports the heavy metal content in the muscles of the striped snakehead murell Channa striata and bottom sediments from five stations across Lake Mainit using quadrupole-inductively coupled plasma-mass spectrometry (Q-ICP-MS). The micronuclei (MN) formation in erythrocytes of C. striata was also assessed for potential genotoxicity. The relative order of the average concentrations of heavy metals in C. striata samples across all stations is Zn>Cu>Cr>Ni>As>Pb>Cd. As per international safety standards, fish muscle samples across all stations have exceeded the permissible limits of Cu, Ni, and Zn, which has implications for health risks in humans consuming this important fish commodity. The relative order of the concentrations of heavy metals in sediments is Cr>Ni>Cu>Zn>As>Pb>Cd, where Cr, Ni, Cu, Pb, and Zn exceeded safety standards. The MN assay revealed that 98% of the erythrocytes assessed (N=147,000 RBCs) have normal cell morphology. Of the 2% of erythrocytic nuclear alterations (ENAs), 55% are found to be fragmented-apoptotic cells, while 31% are elongated or reshaped. The MNs in C. striata are relatively minimal at 2%. While the MN assay implies that C. striata from Lake Mainit are not at risk for potential genotoxic injury, the present study calls for seasonal monitoring for heavy metals in sediments and other fishery resources in Lake Mainit.