Trace Metal Concentrations in Nile Tilapia (Oreochromis niloticus) in Three Catchments, Sri Lanka

Abstract

Samples of the muscle and liver of the Nile tilapia (Oreochromis niloticus) were obtained from a single reservoir in each of three Sri Lankan catchments (Kaudulla, Rajanganaya, and Udawalawe reservoirs in the Mahaweli, Kala Oya, and Walawe Ganga river basins, respectively) in 2002. The concentrations of 12 elements were consistently detected in the tilapia muscle and liver (Ca, Cd, Cu, Fe, Hg, K, Mg, Mn, Na, P, Sr and Zn). However, a three factorial principal components analysis suggested that there were no differences in the metal profiles (range of elements and concentration) of the fish obtained from any of the three reservoirs, although the chemistries of each tissue (muscle and liver) were different. Metal concentrations were below WHO and Food Standards Australia and New Zealand guideline values, and substantial quantities of tilapia would need to be consumed each week on a regular basis to exceed intake limits (e.g. more than 1.5 kg to exceed intake lits for Cu), suggesting consumption of tilapia from these reservoirs poses little risk to human health.

Trace Metal Contents in Muscle Tissues of Inland Fish Species in the North Central Province of Sri Lanka

“…Previous studies have concluded that there is no correlation between the age of the reservoir and metal concentration (Allinson et al, 2009). Although some reservoirs sampled in this study were reconstructed long ago, Kaudulla and Minneriya were first constructed in the year AD 273 and 276, respectively (reconstructed 1958, 1903).…”

“…Moreover, in 2008, the highest inland fish production was recorded in the Anuradhapura district (9380 metric ton) while the Polonnaruwa district claimed for the second highest fish production (7320 metric ton) in the same year (NARA, 2009). Reservoir fish are the main source of animal protein of the rural people living in the dry zone of the country (Allinson et al, 2009) where most of the people living in that area are farmers.…”

“…Consumption of fish contaminated with toxic heavy metals has found to be posing a risk to human health. Fish assimilate toxic metals by ingestion of food and particulate material suspended in water and by ion exchange of dissolved metals (Allinson et al, 2009).Trace metals such as lead (Pb), cadmium (Cd) and mercury (Hg) are non-essential and considered as harmful elements (Andre et al, 2005). Trace metals such as cobalt (Co), copper (Cu), manganese (Mn), molybdenum (Mo), and zinc (Zn) are essential nutrients for organisms including humans, but are toxic if consumed in large quantities (Silva and Shimizu, 2004).…”

“…They found varying concentrations of Cd, Cr, Cu, Fe, Mn, Ni, Pb, Ti and Zn in different organs such as muscles, gills, gonads, kidney and liver. In addition, Allinson et al, (2009) This study focused on Hg, As, Cd, Pb, Cr, Co, Cu, Fe and Zn in muscle tissues of five selected fish species sampled from the NCP of Sri Lanka and to determine the quantity of fish of each species that would be safe for consumption.…”

ASSESSMENT OF METALS CONCENTRATION IN TILAPIA (Oreochromis sp.) AND ESTIMATION OF DAILY INTAKE BY MALAYSIAN

“…The condition factor of fish was calculated following Fulton's condition factor by dividing fish body weight (g) over [body length] 3 (cm) and multiplied to 100. The daily intake by Malaysian people was computed by the multiplication of measured concentration by 160 g of average weight of fish consumed daily [17]. Statistical analysis was conducted using IBM SPSS Statistics 24.…”