Histopathological condition of reared carp fishes in Hg and Se polluted environment at Pongkor Area Bogor and the strategy to manage

Abstract

Mercury emissions from upstream gold mining and processing areas were found in high levels in waters, sediments, agricultural products, and fishes in Pongkor area led to conduct a study on reared carp fishes in same area from histopathological view. Selenium effect as antagonist of mercury, has never been studied before in this area. The study presents the total Hg and Se amount in water, sediments, and fish organs (gill, liver, kidney, intestine, spleen, and muscle), histopathology finding, and enviromental parameters that could influence the fish condition. Mercury and selenium were analyzed using acid digestion followed by determination of total mercury by atomic absorption spectrophotometry. Routine histopathological procedure was use after paraffin embedding and hematoxylin-eosin (HE) staining. The mercury concentrations in waters and organs was undetected, but there hundreds fold above the maximum limited permitted by Canadian Environment Quality Guidelines were detected in sediments. Tens fold selenium concentrations above the threshold level proposed by Lemly (2002) were also observed in sediments. In tissue, Se concentrations also reached tens fold above the threshold proposed by DeForrest et al. (1999). However, these higher concentration of fishes tissues could be worthwhile to metabolisms of fishes and people as antagonistic role of Se to Hg and either heavy metals found in this area. The histopathological changes that found within were degenerations and, necrosis, blood circulation alterations, and some parasites infections. This conditions could influenced by some environmental factors such as sediment type, hardness and alkalinity, water resources, leaching and flushing, and interaction with the other metals. Beside the good aquaculture practices, the strategy of management that could implemented to diminishing pollution of Hg and Se are : modification of construction of ponds; tandonitation; and biological, physical and chemical remediations.