ANALYSIS OF HISTOPATHOLOGY AND HEAVY METALS CONTENTS OF CADMIUM (Cd) IN TILAPIA (OREOCHROMIS NILOTICUS) IN DOWNSTREAM AT THE REJOSO RIVER OF PASURUAN REGENCY, EAST JAVA, INDONESIA

Abstract

The river is one of the water media susceptible to the pollution of harmful pollutant substances, one of which is the heavy metal Cadmium (Cd). As a result of the large amount of Cd content that enters the river body has an impact on decreasing water quality conditions and disrupting fish health. Histopathological observations in fish are significant to know the picture of fish health through structural changes in organ tissues. The research was carried out in March-April 2021 at the Lower Rejoso River, Pasuruan. The method used survey method with descriptive data analysis. Samples were taken three times with a period of 2 weeks at three different stations. Parameters observed included histopathology of gills, kidneys, and liver of tilapia (Oreochromis niloticus). Heavy metal Cd in water and fish organs, physical and chemical parameters of water including temperature, pH, DO, and COD. The results of histopathological analysis obtained types of damage to the organs of tilapia, namely cell degeneration, necrosis, congestion, and hyperplasia with mild-moderate impact. Observation results of heavy metal Cd in water and tilapia organs have exceeded the specified quality standards. The results of the measurement of physical and chemical parameters of water are still optimal for fish growth. Based on these results, it can conclude that the increasing amount of histopathological damage to fish organs was in line with the high levels of Cd heavy metal in the waters and fish organs. The river is a natural water source that has an important role and provides many benefits for human life and other living things [1]. Anthropogenic activities around the river that occur significantly pollute and reduce the quality of river water, especially human and industrial activities. It produce domestic wastes, industrial wastes, and use hazardous chemicals [2]. The Rejoso River is one of the major rivers in Pasuruan Regency, East Java which flows and empties into the Madura Strait. There are lot of industrial activities in the area downstream of the Rejoso River as sugar factories and MSG [3]. These conditions can pollute the river ecosystem and disrupt the natural structure of the river [4]. Heavy metal is one of the pollutants found in river waters. The heavy metal content of Cadmium (Cd) in the water and body of organisms indicates the presence of heavy metal sources originating from nature and human activities [5]. The decline in river water quality that occurs due to heavy metal Cd pollution can reduce the ecological balance of the waters and trigger structural and functional damage to fish organs [6] [7]. Fish can be used as