Accumulation of heavy metals and total phosphorus in intensive aquatic farm sediments: comparison of tilapia Oreochromis niloticusxOreochromis aureu, Asian seabass Lates calcarifer and white shrimp Litopenaeus vannamei farms

摘要

This paper compares and discusses the accumulation of eight heavy metals (Cd, Co, Cr, Cu, Pb, Fe, Mn and Zn) and total phosphorus (TP) in surface sediments from five intensive farms of tilapia Oreochromis niloticusxOreochromis aureu, Asian seabass Lates calcarifer and white shrimp Litopenaeus vannamei (n=75). Results indicate that the sediments were significantly contaminated by Cd, Co, Cr, Cu, Pb, Fe, Mn and Zn as well as P. The mean concentrations of Cd (0.47 mg kgp#), Co (2.25 mg kgp#), Cu (31.56 mg kgp#), Pb (23.45 mg kgp#), Fe (1.15%), Mn (145.5 mg kgp#), Zn (41.5 mg kgp#) and TP (750.69 mg kgp#) in tilapia farm surface sediments were significantly lower than the levels observed in Asian seabass and white shrimp farm surface sediments, where the concentrations were, respectively, Cd - 2.69 and 2.35 mg kgp#, Co - 17.66 and 15.22 mg kgp#, Cu - 116.84 and 110.03 mg kgp#, Pb - 38.5 and 33.26 mg kgp#, Fe - 3.4% and 3.31%, Mn - 853.61 and 728.5 mg kgp#, Zn - 105.21 and 83.92 mg kgp# and TP - 1445.63 and 1069.8 mg kgp#. The heavy metal content of the sediments follow the order: Asian sea bass>white shrimp>tilapia. Cadmium and Cu in Asian seabass and white shrimp farm sediments would pose a major potential risk. Further, the sediment is highly enriched by Fe, P, Mn and Co.