Evaluating Benefits and Risks of Polyunsaturated Fatty Acids and Methyl Mercury from Fish and Seafood Consumption in Peninsular Malaysia

Table 1

Total mercury (tHg) and methylmercury (meHg) levels in fish and seafood from Peninsular Malaysia.

Species no.	Groups/family/species	Common name	n	tHg ± IQR (mg/kg) DW	MC (%)	tHg (mg/kg) WW	meHg (mg/kg) WW
^♦Pelagic fish
1	Selaroides leptolepis	Yellow-stripe scad	13	0.252 ± 0.125	79.5	0.0635	0.0591
2	Decapterus russelli	Slender scad	10	0.195 ± 0.108	74.7	0.0458	0.0426
3	Megalaspis cordyla	Torpedo scad	20	0.319 ± 0.198	74.8	0.0750	0.0697
4	Parastromateus niger	Black pomfret	15	0.242 ± 0.121	76.5	0.0569	0.0529
5	Rastrelliger kanagurta	Indian mackerel	13	0.180 ± 0.066	73.1	0.0522	0.0485
6	Scomberomorus guttatus	Indo-Pacific king mackerel	12	0.262 ± 0.355	75.9	0.0650	0.0604
7	Thunnus tonggol	Long-tail tuna	8	0.358 ± 0.173	71.0	0.3580	0.3329
8	Euthymus affinis	Kawakawa	3	0.289	75.2	0.0699	0.0650
						Median	0.0597
^♦Demersal fish
9	Lutjanus argentimaculatus	Mangrove red snapper	3	0.856	75.8	0.1875	0.1743
10	Lutjanus russellii	John’s snapper	4	0.884 ± 1.789	80.2	0.1848	0.1718
11	Lates calcarifer	Giant-sea perch	11	0.537 ± 0.436	78.1	0.1240	0.1154
12	Gymnura poecilura	Long-tail butterfly ray	25	0.492 ± 1.251	79.1	0.4920	0.4576
13	Nemipterus japonicus	Japanese threadfin bream	11	0.464 ± 0.724	76.9	0.1063	0.0988
						Median	0.1718
Freshwater fish
14	Clarias batrachus	Walking catfish	9	0.334 ± 0.325	77.1	0.0621	0.0578
Cephalopods
15	Sepia officinalis	Common cuttlefish	8	0.280 ± 0.101	81.4	0.0959	0.0777
Crustaceans
16	Metapenaeus affinis	Rainbow shrimp	4	0.280 ± 0.501	80.5	0.2800	0.1400

Total Hg in median ± IQR; DW: dry weight; IQR: interquartile range; MC: moisture content; MC content was based on the works by Tee et al. [21] and Nurnadia et al. [24]. WW: wet weight; conversion of DW mercury concentrations in fish samples to WW was by means formula: DW = WW × (100/100 MC). ^#Details on total mercury concentrations in seafood are referred to Ahmad et al. [25, 26]; calculation of meHg concentrations was based on the mean percentage of methyl mercury to total mercury at 93% for fish, 81% for cephalopods, and 50% for crustaceans [11, 30]. ^#Comparison of meHg levels for different fish/seafood species:  = 71.385, value ≤0.001, N = 172 and median meHg for all seafood = 0.0621 ± 0.0573 mg/kg WW. ^♦Comparison of meHg levels for different groups of pelagic and demersal:  = 1145.000, value ≤0.001, N = 150 (pelagic; n = 96; demersal, n = 54). Median meHg for pelagic fish = 0.0513 ± 0.0392 mg/kg WW and median meHg for demersal fish = 0.0988 ± 0.1332 mg/kg WW.