croaker

Nurul Izzah A., Mohd Fairulnizal M.N., Wan Rozita W.,
*Hamdan J., **Ismail I., Wan Nurul Farah W. A., Yuvaneswary
V. and Mohd Hairulhisam H.
Project Scope
Exposure assessment for
selected contaminants
from consumption of
seafood in Peninsular
Malaysia.
Phase 1
Dietary survey
Type of seafood
Estimated intake
Mean & 97.5%
Phase 2
Analysis of
contaminants
in seafood
Part 1
Phase 3
Calculation for TMDI,
PTWI/PTDI, EDI
and MOE (inclusive BMD
& BMDL)
(Pesticides, heavy metal, drugs,
PAHs)
Analysis of
heavy metal
in human
blood
Part 2
BMD – Benchmark dose
BMDL – Benchmark dose Lowest
TMDI – Tolerable Maximum Daily Intake
EDI – Estimated Daily Intake (risk for toxic chemicals)
MOE - Margin of Exposure (risk for carcinogenic/mutagenic chemicals)
PTWI/PTDI – Provisional Tolerable Weekly/Daily Intake (calculated risk for heavy metals)
1 pound = 0.453592kg
• Fish is an important source of
Malaysia.
in
• Daily consumption of fish is on
(Norimah et al., 2008).
• The Malaysian per capita consumption of
fish was
(Tey et al., 2008).
Seafood averages less than 2% fat.
Cholesterol is an essential part of all living
animal tissue. Seafood has very little fat of any kind and what it does have
is mostly unsaturated fat. Eating fish two or three times a week can help
lower cholesterol and reduce the risk of heart disease.
Seafood is an excellent source of top
quality protein, and compares favorably with meat and chicken.
Seafood is an excellent
source of many important minerals, including iodine, zinc, potassium and
phosphorus. It is also rich in many vitamins, especially the B group.
Omega-3s are a type of polyunsaturated fat and
are essential nutrients that play many critical roles in our bodies. And, just
like minerals and most vitamins, our body cannot make them
Other benefits of seafood
• The bioactive
properties from fish
proteins and peptides
have been used as an
antihypertensive,
antioxidative,
anticoagulant and
antimicrobial
components in
functional foods or
nutraceuticals and
pharmaceuticals.
Other benefits of seafood
• Their therapeutic potential is used in the treatment or
prevention of diseases. Marine foods are also excellent
sources of essential nutrients such as minerals (iodine
and selenium) and vitamins (vitamins A, D and B12).
Other benefits of seafood
• Other marine bioactive components
linked to health promoting effects include
taurine, phytosterols, antioxidants and
phospholipids (Larsen et al., 2011;
McManus, 2011; Torpy, 2006).
What Is the Potential
Downside of Eating
Seafood?
• Most
seafood
contains
detectable levels of contaminants
because these are part of the
environment and food chain.
• Fish consumption is the major
route of mercury exposure to
human and it is often found in
the form of methyl mercury.
The Mercury Cycle
• There
are
two
important sources of
mercury, which are
anthropogenic and
natural sources.
• Volcanic eruptions
are believed to be an
important
natural
source of mercury
(Clarkson
and
Magos, 2006).
Measurements have shown
that 7 tonnes of mercury
escapes from the Masaya
volcano in Nicaragua, every
year. (Credit: Copyright
University of Oxford)
• The cyclic order of mercury contamination chain
starts from its emission in industries, this is
followed by contamination in atmosphere, soil,
water, phytoplankton, zooplankton, fish and to
human (Castro-Gonzalez and Mendez-Armenta,
2008).
• The most important source is from the
anthropogenic sources particularly from urban
discharges, agricultural materials, mining and
combustion and industrial discharges (CastroGonzalez and Mendez-Armenta, 2008; Streets et
al., 2005).
• Fish may concentrate methyl mercury either directly through the water or
through components of the food chain (Castro-Gonzalez and MendezArmenta, 2008).
• Mercury attached to aquatic sediments is subject to microbial conversion to
methyl mercury, at which point it enters the aquatic food chain and reaches
its highest concentration in predatory fish (Clarkson et al., 2003).
• Most of us have or have
had silver fillings (dental
amalgam) which contain
50% mercury. Dental
amalgam is the major
source of mercury in the
human body, followed by
thimerosal
(49.6%
mercury), a preservative
found in many vaccines,
such as flu shots and
some
infant
immunizations.
Mercury used in products and processes in 2005 for each region.
From the UNEP 2013 Mercury Assessment
• Methyl mercury is a robust toxicant and the
primary target is the central nervous system
(Clarkson and Magos, 2006) especially the brain
tissue (Clarkson et al., 2003).
• Methyl mercury is highly mobile in the human
body where its passage across the blood-brain
and placental barriers, cause damage, both
prenatally and postnatally (Tollefson and Cordle,
1986).
• It appears to be most neurotoxic prenatally when
the brain is developing rapidly (Myers and
Davidson 2000).
• The journey of methyl mercury into the human
body is explained through the formation of
water soluble-methyl mercury complexes in
body tissues that are attached to thiol groups in
protein, certain peptides and amino acids
(Clarkson and Magos, 2006).
• It may enter into body cells as methyl mercurycysteine complex and exit via glutathione
pathway.
• The main route of its elimination from the body
is via faeces, which is as much as 90% of total
excretion according to animal observation
(Clarkson and Magos, 2006).
• In adults, the main symptoms of methyl mercury
exposure related with intoxication are to nervous
system, with paraestesia or numbness in the
hands and feet, coordination difficulties and
concentric constriction of the visual field, auditory
symptoms, ischaemic stroke, dementia and
depression.
• It might also cause nephrotoxicity and
gastrointestinal toxicity with ulceration and
haemorrhage (Castro-Gonzalez and MendezArmenta, 2008; Clarkson and Magos, 2006;
Tollefson and Cordle, 1986).
Objectives
• To determine the concentrations of total
mercury in the edible tissues of 297
commonly consumed marine fish samples
collected from fish landing ports and
wholesale markets throughout Peninsular
Malaysia.
• To estimate and assess risk on mercury
contamination through seafood consumption
among Malaysians.
Food Consumption survey
List of most preferred seafood
Types of seafood
Frequencies (%)
1. Ikan kembung; Indian mackerel
2. Udang; prawn
3. Ikan selar kuning; yellow-tail scad
4. Ikan Selayang; sardine
5. Ikan Bawal Hitam; black pomfret
6. Ikan Tongkol; tuna
7. Ikan Cencaru; hair-tail scad
8. Ikan Tenggiri; Spanish mackerel
9. Sotong; squid
10. Ikan Merah; red snapper
11. Ikan Kerisi; thread fin bream
12. Ikan Pari; stingray
13. Ikan Keli; cat fish
14. Ikan Siakap Putih; sea perch
15. Ikan Gelama; croaker
70.9
26.6
26.2
24.6
22.6
21.8
20.9
20.9
21.3
14.7
11.2
10.6
7.3
7.2
5.4
Sampling locations
Kg. Bakau, Perlis
Kuala Besar. Kelantan
Mergong, Kedah
Pulau Kambing, Terengganu
Bukit Mertajam,Penang
Chendering Terengganu
Kuala Pari, perak
Kuantan, Pahang
Selayang, Kuala Lumpur
Port Klang, Selangor
LKIM Complexes
Pandan, Johor
Whole sale markets
Sampling was conducted from June to December 2009 during three successive visits to each location.
Sampling settings
Size measurements
Length measurement
Weight measurement
Pre-processing samples
Sample digestion
Dried fish samples were
weighed accurately into
the digestion vessels for
0.5 g.
A total of 5 ml
concentrated nitric acid
and 2.0 ml of hydrogen
peroxide were added to
each vessel.
(Multiwave 3000 - Anton Paar)
The vessels were sealed
and placed into the
Rotor for microwave
digestion
Mercury analysis
• Mercury was analyzed by the cold vapour atomic
absorption spectrometry (AAS) technique using the
Perkin Elmer Flow Injection Mercury System
(FIMS) instrument equipped with FIMS-400 and a
programmable sample dispenser.
• Analytical
control
was
accompanied by analysis of
reagent blanks and standard
reference
samples
(NIST
SRM® 1946 – Lake Superior
Fish Tissue).
• Average recovery of reference
standards reached 90.7%.
Statistical analysis
• Data was cleaned and checked for discrepancies before
analysis. The initial descriptive statistic analysis showed
that the data was not normally distributed due to the
existence of the outliers. Hence, non-parametric statistics
were used.
• The medians, inter-quartile range and percentile range were
calculated using SPSS (version 11.5 for windows, 2002,
SPSS Inc).
• The statistical significance of difference was assessed using
Mann-Whitney's (MW) test for two groups and KruskallWallis's (KW) test for three groups or more.
• The correlation coefficients were studied using Spearman
correlation analysis.
The level for significance was
designated as p<0.05.
Results
• A total of 297 samples that comprise 7 families of 46 species
of marine fish collected from selected major LKIM fish
landing ports and wholesale markets in Peninsular
Malaysia
120
100
80
60
40
20
0
97
80
24
15
25
25
31
25
Carangidae 80 samples, 12 species
20
20
15
15
13
10
10
7
5
4
3
1
0
4
1
1
1
12 species of Carangidae
Bigeye scad
Oxeye scad
Yellowstripe scad
Greater amberjack
Bigeye trevally
Slender scad
Black pomfret
Round scad
Torpedo scad
Yellowtail scad
Redtail scad
Shortfin scad
Scrombidae 97 samples, 11 species
20
18
16
14
12
10
8
6
4
2
0
18
14
13
12
10
8
6
6
3
5
2
11 species of Scrombidae
Indo-Pacific mackerel
Indian mackerel
Blue mackerel
Faughn’s mackerel
Dogtooth tuna
Frigate tuna
striped bonito
Indo-PacificSpanish
king mackerel
Narrowbarred
mackerel
Longtail tuna
Kawakawa
Lutjanidae 24 samples, 5 species
12
11
10
8
6
4
2
5
4
3
1
0
Mangrove Humpback Emperor red
red snapper red snapper snapper
Malabar
blood
snapper
John's
snapper
5 species of Lutjanidae
Humpback red snapper
Mangrove red snapper
Malabar blood snapper
Emperor red snapper
John's snapper
Latidae 15 samples, 2 species
11
12
10
8
6
4
2
0
4
Giant sea perch
Waigeu sea perch
Waigeu sea perch
Giant sea perch
Dasyatidae 25 samples, 4 species
12
10
8
6
4
2
0
10
7
5
3
Sharpnose
stingray
Bluespotted
stingray
Pale-edged
stingray
Honeycomb
stingray
Pale-edged stingray
Bluespotted stingray
Sharpnose stingray
Honeycomb stingray
Sciaenidae 25 samples, 4 species
20
15
15
10
5
6
3
1
0
Reeve's
croaker
Tigertooth
croaker
Soldier
croaker
Bronze
croaker
Reeve's croaker
Tigertooth croaker
Soldier croaker
Bronze croaker
Nemipterinidae 31 samples, 8 species
12
10
8
6
4
2
0
11
6
3
Yellowbelly Japanese
threadfin threadfin
bream
bream
Forktail
threadfin
bream
4
2
Threadfin
bream
2
2
Fivelined Doublewhip
Red
threadfin threadfin filament
bream
bream
threadfin
bream
1
Redspine
threadfin
bream
Yellowbelly threadfin bream
Forktail threadfin bream
Fivelined threadfin bream
Redspine threadfin bream
Japanese threadfin bream
Red filament threadfin bream
Threadfin bream
Doublewhip threadfin bream
Prawn species (n=52)
12 species
1.
2.
Indian white Prawn- Penaeus indicus H. Milne Edwarsd (n=8)
Greasyback Shrimp- Metapenaeus ensis de Haan (n=3)
3. Rainbow shrimp- Parapenaeopsis sculptilis Heller (n=4)
4. sand valvet prawn- Metapenaeopsis barbata de Haan (n=9)
5. Yellow Shrimp- Metapenaeus brevicornis H. Milne Edwards (n=4)
6. Kuruma Prawn- Penaeus japonicus Bate (n=1)
7. Spear Shrimp- Parapenaeospsis hardwickii Miers (n=3)
8. Green Tiger Prawn- Penaeus semisulcatus de Haan (n=2)
9. Pink shrimp- Metapenaeus affinis H. Milne Edwards (n=4)
10. Banana Prawn- Penaeus merguiensis de Mann (n=7)
11. Western King Prawn- Penaeus indicus (H. Milne Edwards) (n=5)
12. Giant Tiger Prawn- Penaeus monodon Fabricius (n=2)
Squid species (n=45)
Sibogae squid
Loligo sibogae Adam
Mitre squid
Loligo Chinensis Gray
Sword Tip Squid
Loligo Edulis
Old women octopus
Cistopus indicus
Golde Cuttle Fish
Sephia esculenta hoyle
Pharoah cuttlefish
Sephia Phuraonis Enhrenberg
Indian squid
Loligo duvaucelli Arbigny
Little squid
Laligo Uyii Wakiya & Ishikawa
• The size of fish in the samples were
varied, however, the Carangidae, Sciaenidae and
Nemipteridae were small-sized fish with body length
ranging from 12-30 cm and with weights of less
than 0.5 kg.
• Other family groups covered a relatively wide size
range that comprise of small, medium to large-sized
fish; the smallest weighed 40 g and the largest 5 kg.
• Generally, the larger fish were Spanish
mackerels, tuna, red snapper, sea perch and stingray.
• The food items and feeding habits of both the
pelagic and demersal fishes were referenced from
the Global Information System on Fishes at the
website: http://www.fishbase.us.
• Most of the fish sampled in this study were
classified as predatory, that live by killing and
eating upon other fish or animals.
• Only
five
species
(redtail
scad,
round
scad, shortfin scad, Faughn’s mackerel and IndoPacific mackerel) that were captured in this study
were
non-predators,
feeding
on
zooplankton, phytoplankton and other plants.
• Information on tropic levels (TL) that
expressed the position of a species in a
marine food web, were gathered from the
same website.
• In the marine ecosystem, TL of consumers
generally ranges between 2.0 for species
feeding exclusively on plants or detritus, to
5.5 for carnivores (Stergiou and Karpouzi
2002).
TL
3.70-4.50
2.90-3.69
≤ 2.89
%
66.7
32.3
1
• The TL for fish captured in this study ranged from 2.7 to 4.5. More than
half (66.7%) of the samples had TL range from 3.7 to 4.5, which indicated
that most of the samples captured were carnivores or large pelagic.
• These groups of fish live and feed in the open sea and are associated with
the surface or middle depths of a body of water; they are free-swimming in
the seas, oceans or open waters and they were not associated with the
bottom (Stergiou and Karpouzi 2005).
• Another 32.3% were had TL between 2.9 to 3.7 with a mean value of 3.4.
This group was omnivorous that fed on a variety of prey. Only 1% of the
samples fed on vegetable materials.
=
• Mercury levels of 46 marine fish species
ranged from 0.055 to 2.537 mg/kg of dry
weight.
Significant variations of mercury
levels exist in different species
(
=103.581; p < 0.001).
• Mercury levels were significantly higher in
higher tropic level fish (
=21.664; p<0.001).
• Among pelagic fish, the median for
mercury levels was higher (> 0.5 mg/kg) in
scad (Selar boops) and bonito (Sarda
Orientalis).
• While for the demersal fish, the highest
mercury levels were shown in John’s
snapper (Lutjanus ruselli), mangrove red
snapper (Lutjanus argentimaculatus) and
doublewhip threadfin bream (Nemipterus
nematophorus).
Table 4: Comparison of mercury levels in marine fish collected
from Peninsular Malaysia at different factors
No
1
2
3
4
Factors
Habitats
Pelagic
Demersal
n
Median (IQR)
(χ
χ2)P value
170
118
0.292(0.169)
0.460(0.414)
MW5401.0(0.000)
Family group
Carangidae
Scrombidae
Lutjanidae
Latidae
Dasyatidae
Sciaenidae
Nemipteridae
79
91
22
15
25
25
31
0.291(0.153)
0.293(0.190)
0.465(0.566)
0.537(0.267)
0.492(0.740)
0.424(0.217)
0.454(0.459)
KW46.122(0.000)
Origins
Local
Import
231
19
0.332(0.275)
0.359(0.237)
MW1863.0(0.274)
Coastals
West coast
East coast
South
97
158
33
0.330(0.255)
0.333(0.272)
0.380(0.481)
KW0.679(0.712)
KWKruskal-Wallis & MWMann-Whitney
U test were applied
Table 4: Comparison of mercury levels in marine fish collected
from Peninsular Malaysia at different factors
n
Median (IQR)
(χ
χ2)P value
Sampling points
LKIM fish landing complexes
Wholesale wet market
150
138
0.354(0.298)
0.334(0.263)
MW10114.0(0.738)
Sampling locations
Selayang
Klang
Kuala Pari
Bukit Mertajam
Kuala Perlis
Mergong
Kuala Besar
Pandan
Kuantan
Chendering
Pulau Kambing
25
20
37
14
29
33
20
33
36
15
26
0.295(0.0.253)
0.563(0.509)
0.356(0.292)
0.348(0.156)
0.306(0.185)
0.320(0.188)
0.521(0.415)
0.380(0.481)
0.301(0.142)
0.285(0.142)
0.321(0.222)
KW22.263(0.014)
Body length of fish
Body length <20 cm
Body length ≥20 cm
92
187
0.311(0.223)
0.354(0.306)
MW6642.0(0.002)
No Factors
5
6
7
KWKruskal-Wallis & MWMann-Whitney
U test were applied
r=0.237
n=297
Scatter plots (Figure 2a) showed that mercury
levels were positively correlated with length of the
fish, with significant Spearman correlation
coefficients of 0.237
r=0.379
n=297
Scatter plots (Figure 2b) showed that mercury levels
were positively correlated with weight of the fish, with
significant Spearman correlation coefficients of 0.297
r=0.050
n=52
Figure 3
(A)
r=0.170
n=45
(B)
Relationship
between
total mercury levels
(mg/kg dry weight) with
body size of prawn (A;
n=45) and squid (B;
n=52) samples from
Peninsular Malaysia.
Comparison to the National & International Guidelines
In order to compare the results with the national and
international guidelines for the purpose of public health
perspective, it was necessary to convert mercury
concentrations in fish samples to a wet basis values using
the formula:
Dry weight concentration (DW) =
wet weight concentration (WW) x (100/100- % moisture of samples).
The results were then grouped into five categories,
following Chvojka et al., (1990) as cited by Al-Majed
and Preston (2000).
They described mercury in wet weight of fish from:
Mercury
concentrations (µg/g )
0.05-0.15
0.15-0.25
0.25-0.35
0.35-0.45
> 0.45
Categories
very low
low
medium
high
very high
Guidelines
• The recommended guideline levels by the joint
FAO/WHO Expert Committee on Food Additives
(FAO/WHO 2006) was set at 0.5mg/kg methyl
mercury in fish.
• Malaysia, under the Fourteenth Schedule of
Regulation 38, Malaysian Food Regulation 1985
[Food Act 1983 (Act 281) and Regulations 2006], the
maximum permitted proportion of methyl mercury
was set at the same level.
Mercury concentrations (µg/g )
Categories
% samples
0.05-0.15
0.15-0.25
0.25-0.35
0.35-0.45
> 0.45
very low
low
medium
high
very high
83.7
10.1
4.2
1
1
• Three samples of bluespotted sting-ray (Neotrygon
kuhlii), honeycomb stingray (Himantura uarnak) and
John's snapper (Lutjanus ruselli) had very high
mercury levels.
• The latter two samples exceeded the guidelines of
0.5mg/kg.
However, considering that 95% or more of total
mercury in the edible portions of fish and other
seafood is in the form of methyl mercury (Li et al.,
2009; Khaniki et al., 2005), only one sample (median
mercury level in Lutjanus ruselli, 0.5012mg/kg)
exceeded the guidelines.
None of the samples exceeded the guidelines if the
ratio of methyl mercury to total mercury ranged from
70% to 83% were considered (Hajeb et al., 2010).
High Mercury Levels
Two species of tuna or bonito (Sarda
orientalis and Gymnosarda unicolor)
and one species of yellowstripe scad
(Selaroides leptolepis).
Medium levels
1. One sample of snapper (Lutjanus sebae),
2. Four samples of narrow-barred Spanish
mackerel (Scomberomorus commerson),
barramundi (Lates calcarifer),
3. Two species of sting-ray (Himantura gerrardi
and Neotrygon kuhlii),
4. Two species of tuna (Gymnosarda unicolor and
Sarda orientalis), thread-fin bream
(Nemipterus nematophorus) and soldier
croaker (Sarda orientalis)
EXPOSURE ASSESSMENT FOR MERCURY FROM
CONSUMPTION OF MARINE FISH IN PENINSULAR MALAYSIA
Fish categories
(n) Mercury levels (µg/g)
median
Demersalfish
89
0.311
Pelagic fish
124 0.496
Cephalopods
45
0.272
Crustaceans
52
0.252
Marine fish
213 0.359
Total fish intake 394 0.311
range
0.069-1.471
0.193-0.555
0.099-2.715
0.055-1.359
0.069-2.537
0.055-2.715
*Fish
Mercury intake
consumption (µg/kg body weight/day)
(g/day)
**(%)
4.7
0.072 (4.50%)
2.1
0.019 (1.19%)
7.5
0.259 (16.18%)
0.115 (7.18%)
3.6
9.4
0.097 (6.06%)
47.4
1.876(117.25%)
Optimistically, findings from this study can be used to
design fish consumption advisories for Malaysian to
reduce the risk of adverse health effects or health
problems from eating fish caught from surrounding
waters; local origin or imported.
These advisories are based on the risk from eating
contaminated fish and do not take into consideration
the health benefits of eating fish.
The researchers recommends eating fish that are low in
contaminants.