Peran Salinitas terhadap Toksisitas Merkuri dan Pengaruhnya Terhadap Kondisi Fisiologis Ikan Bandeng (Chanos chanos Forsskal)

Abstract

Diantara berbagai macam logam berat, merkuri digolongkan sebagai pencemar yang paling berbahaya. Kadar merkuri terus meningkat akibat penggunaannya diberbagai bidang yang cukup luas. Merkuri akan masuk ke perairan tawar, payau dan akhirnya sampai di laut serta dapat mempengaruhi organisme yang hidup di dalamnya. Perbedaan salinitas akan mempengaruhi tingkat toksisitas merkuri. Apabila ikan bandeng yang dipelihara baik di air tawar, payau dan laut terkontaminasi oleh merkuri maka kondisi fisiologis ikan akan terganggu.

Mercury is a very dangerous heavy metal that can damage nerve and enzyme system in fish body. This research aimed to knows mercury toxicity to milkfish with different salinity. It consisted of two steps; they were preliminary research (range value test and acute toxicity test) and main research (the salinity influence of mercury toxicity and milkfish’s physiologic condition). Range value test was done in fresh water consisting of five treatments (0, 0.006, 0.06, 0.6 and 6 mg Hg/l). Acute toxicity test also consisted of five treatments (0, 0.110, 0.195, 0.347 and 0.618 mg Hg/l). Moreover, main research consisted of one control and three treatments with three replications at the same concentrate of mercury 0.012 mg Hg/l. Those treatments were salinity 0 ppt, 10 ppt and 20 ppt. The result demonstrated that LC50 96 hour in fresh water was 0.147 mg Hg/l. The main research showed that mercury can increased osmotic gradient, decreased oxygen consumption rate, increased blood glucose rate, decreased hematologic conditions, growth rate, feeding efficiency, and survival rate. Mercury is collected in body gland, for example in gill and liver. Treatment C (10 ppt) showed better physiologic conditions than other treatments. The effect of mercury toxicity would get minimal while maintained at optimal salinity.