A A Trend of Zinc Uptake into Tachypleus Gigas Tissues After a Month of Exposure

Abstract

Tachypleus gigas is one of the species of horseshoe crabs found in Peninsular Malaysia. Metals in the surrounding water can accumulate into horseshoe crab tissues. This study was conducted to determine zinc (Zn) uptake into horseshoe crab tissues after continuous exposure to the metals. T. gigas that were sampled from Gelang Patah, Johor and Cherating, Pahang were reared in the control tank and Zn treatment tank (20 mg/L) with aeration supply for a month. Twelve horseshoe crabs from Zn treatment tank and 6 horseshoe crabs from control tank were dissected for tissues namely operculum, gills, chelicerae, leg, digestive tract, hepatopancreas and carapace in different intervals (Day 0, Day 10, Day 20 and Day 30). These tissues were freeze dried and digested with 65% nitric acid on a hotplate at 200oC. Zn were measured using Inductively Coupled Plasma - Optical Emission Spectrometry (ICP-OES). Different concentrations of Zn were measured in different tissues. The tissues of T. gigas showed increased concentrations of Zn by following exposure in 30 days. The increasing pattern of Zn uptake into the tissues from day 0- 30 are clear. The gills showed highest concentrations of metals accumulation with the value of 6398.60 ± 909.51 µg/g (dw). Thus, uptake of Zn into T. gigas was confirmed, therefore it has the potential to become the suitable bio-indicator (especially their gills) to detect the metal pollution in the surrounding water.