Dietary intake and health risk assessment of lead and cadmium via consumption of cow meat for an urban population in Enugu State, Nigeria

Ecotoxicology and Environmental Safety 93 (2013) 101–106

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Dietary intake and health risk assessment of lead and cadmium via consumption of cow meat for an urban population in Enugu State, Nigeria J.N. Ihedioha n, C.O.B. Okoye Department of Pure and Industrial Chemistry, University of Nigeria, Nsukka, Nigeria

art ic l e i nf o

a b s t r a c t

Article history: Received 11 February 2013 Received in revised form 11 April 2013 Accepted 15 April 2013 Available online 7 May 2013

The study assessed the dietary intake of lead and cadmium and health risk from consumption of various parts of cow meat by the urban population of Enugu State, Nigeria. Meat samples (n ¼ 150) comprising of muscle, liver, kidney, intestine and tripe were purchased from abattoirs in Nsukka and Enugu. The samples were dried, ground and two gram was digested with 3:2 HNO3:HClO4 v/v. The Cd and Pb concentrations were read with an atomic absorption spectrophotometer. The dietary intakes were estimated using a one week food frequency questionnaire administered to 755 subjects. The dietary intake of lead (mg/kg body weight/week) were in the following ranges; men [0.15 (kidney)–0.55 (intestine)], non pregnant/non lactating women [0.16 (kidney)–0.62 (liver)], pregnant/lactating women [0.13 (kidney)–0.53 (intestine)], undergraduate students [0.12 (kidney)–0.62 (intestine)] and school children [0.29 (kidney)–1.16 (liver)]; cadmium: men [0.42 (liver)–1.21 (tripe)], non-pregnant/nonlactating women [0.53 (kidney)–1.20 (tripe)], pregnant/lactating women [0.43 (kidney)–0.90 (intestine)], undergraduate students [0.40 (kidney)–1.18 (tripe)] and school children [0.97 (kidney)–1.93 (tripe)]. The total dietary intakes of lead from the various cow meat parts by the groups were much lower than the provisional tolerable weekly intake (PTWI) guide line, but for cadmium, the intakes were quite appreciable when compared to the PTWI guideline while the intake for school children was very high, 113% of PTWI for the metal. The target hazard quotients were in the range of 0.05–0.10 for lead and 0.42– 0.90 for cadmium. These values are less than one, indicating that the subjects are not exposed to any significant health risk via cow meat consumption. & 2013 Elsevier Inc. All rights reserved.

Keywords: Cow meat Lead Cadmium Dietary intake Health risk Enugu State

1. Introduction Human exposure to heavy metals through food consumption has aroused widespread health concern. Meat is a very rich and convenient source of nutrients, including microelements. The environmental condition affects the quality of meat, as heavy metal bioaccumulation depends on the age, physiological state and feed intake, as well as on living conditions (Baykov et al., 1996). Due to the grazing of cattle on contaminated soil, higher levels of trace metals have been recorded in beef and mutton in Pakistan (Sabir et al., 2003) and in Nigeria (Okoye and Ugwu, 2010; Ihedioha and Okoye, 2012). When these trace metals occur above the permissible concentrations in the animal, they have deleterious effects not only on the animals but also on the health of the consumers, especially when consumption is regular and in enough quantity.

n

Corresponding author. E-mail addresses: [email protected], [email protected] (J.N. Ihedioha), [email protected], [email protected] (C.O.B. Okoye). 0147-6513/$ - see front matter & 2013 Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.ecoenv.2013.04.010

Contamination of meat by heavy metals could be a serious threat because of their toxicity, bioaccumulation and biomagnification along the food chain (Demirezen and Uruc, 2006). The main source of contamination of animals is feeding and water. Animal feed have been shown to be rich in trace heavy metals due to the prevalence of these pollutants in the environment. Free ranging animals grazing on contaminated soil are liable to high metal contamination. Lead is a metabolic poison and a neurotoxin that binds to and inactivates essential enzymes and several other cellular components (Cunningham and Saigo, 1997). Toxic effects of lead are seen on hemopoietic, nervous, gastrointestinal and renal systems (Baykov et al., 1996). Lead is released into the air in the form of metal fumes or suspended particulates from fuel combustion or smelting and disposal of wastes. Motor vehicle exhaust is no more a very important source of atmospheric lead since the banning of leaded petrol in most countries but in Nigeria, a very important source of environmental lead is disused lead acid batteries discharged indiscriminately (Okoye and Ugwu, 2010; Ihedioha and Okoye, 2012). Bolger et al. (1996) reported that infants and children are more susceptible to lead toxicity than adults because they consume more food per unit of body mass and absorb lead more readily than adults.

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The half-life of lead in blood and soft tissues are 35 and 40 days while in spongy bones and cortical bones, they are 3–5 and 30 years, respectively (Pueschel et al., 1996). Tuormaa (1995) reported that an excessive lead accumulation in children is known to cause hyperactivity, reduced intelligence and anti-social behaviours. In adults, it is associated with heart disease, cancer and infertility. Lead could cause adverse effects on the renal and nervous systems and across the placental barrier, having potential toxic effects on the fetus (Tuormaa, 1995; WHO, 2003). Food is the main source of cadmium intake. As cadmium moves through the food chain it becomes more and more concentrated and on reaching the carnivores, the concentrations could increase by a factor of 50 to 60 times (Botkin and Keller, 1995). Toxic effects of cadmium are kidney dysfunction, hypertension, hepatic injury and lung damage (John and Jeanne, 1994). Cadmium chloride at teratogenic dose has induced significant alterations in the detoxification enzymes in liver and kidney (Reddy and Yellamma, 1996). Some studies carried out on levels of heavy metals in meat in different parts of Nigeria have shown levels of lead and cadmium above acceptable international limits. Iwegbue et al. (2008) reported high lead (0.01–4.60 mg/kg) and cadmium (0.01–5.68 mg/kg) levels in chicken and turkey meat from southern Nigeria. Okoye and Ugwu (2010) also reported high levels of lead (0.2– 0.65 mg/kg) and cadmium (0.34–0.83 mg/kg) in goat bred in Nigeria. Nwude et al. (2010) reported high lead levels (nd4.98 mg/kg) with a mean (1.57 mg/kg) in Nigerian raised cattle. In this paper, we evaluated the dietary intake of lead and cadmium and assessed the health risk due to consumption of cow meat among the urban population of Enugu State, Nigeria where no similar study has been reported.

and are inexpensive for large populations as is the case in this study. Moreover, several authors have reported the validity of FFQ as a tool in assessing dietary intake (Xinying et al., 2004; Willett, 2001; Ke et al., 2005). One limitation of FFQ is that subjects often have problem estimating portion sizes. In this study, FFQ was used and estimate of the sizes of meat portion was provided using two dimensional pictures of cooked meat portions. Many authors have validated the use of two dimensional pictures as portion aids in dietary assessment tools (Hankin, 1986; Pietinen et al., 1988; Posner et al., 1992; Williamson et al., 2003; Dhingra et al., 2007). A food frequency questionnaire (FFQ) was prepared and administered personally to 755 subjects in Nsukka and Enugu, the two urban towns in Enugu State, Nigeria. The FFQ was divided into three sections. Section A supplies the sociodemographic information on the subjects. This includes: age, sex, physiological condition, occupation and educational qualification. Section B supplies the information on preferable meat part consumed while section C supplies the frequency and quantity of cow meat consumed by the subjects. The frequency categories used in this questionnaire are: never; six days in a week; 5days a week; 4 days a week; 3 days a week; 2 days a week and daily while two dimensional pictures of varying sizes of cooked meat in the range of large, moderate, small and very small were provided to aid the subjects estimate the size of meat regularly consumed. By this method, one week intake of the different parts of cow meat was estimated for each subject. The body weight of each subject was determined using a bathroom balance. 2.4. Data analyses 2.4.1. Estimation of dietary intake Data from the FFQ were converted into consumable quantities using Microsoft Excel while SPSS ver 15.0 for windows was used for other statistics. Estimated dietary intakes of the metals (EDI) were calculated as follows: EDI ¼

∑5i ¼ 1 MI  MC BW

ð1Þ

where MC is the mean concentration of metal in the meat part consumed (mg/g), MI is the estimated quantity of meat consumed (g/person/day), while subscript i¼1–5 corresponding to the five different meat parts used (muscle, liver, kidney, intestine and tripe) respectively, BW is the average body weight of each groups of the subjects under study (kg).

2. Materials and methods 2.1. Sampling and sample pre-treatment One hundred and fifty samples of cow meat (White Fulani breed) comprising of 30 each of muscle, liver, kidney, intestine and tripe, were procured from the abattoir in Nsukka and Enugu between August 2007 and November 2008. The samples were oven-dried at 105 1C to constant weight, pulverised in a porcelain mortar, and stored in a dessicator prior to digestion. 2.2. Metal recovery and sample preparation A recovery experiment involving the digestion of 2 g of spiked and unspiked powdered liver samples with 10 mL of 3:2 mixture of Analar grade HNO3 (65%v/v): HClO4 (70%v/v) from Riedel-de Haen, Germany was carried out to validate the digestion method. The meat samples and the digestion mixture were put in a 100 mL polyethylene bottle and allowed to stand overnight. The samples were later heated at 70 1C in a water bath with swirling at 30 min interval for 3 h. At cooling, the digest was decanted into 20 mL standard flask, rinsing with de-ionised water and later made up to mark with de-ionised water. Metal analyses were carried out using an atomic absorption spectrophotometer (GBC Avanta ver 2.02, Australia) equipped with air-acetylene flame. The detection limit for each element was determined using the lowest possible dilution. Following good recovery, samples were digested in the same procedure. Sample blanks, prepared by taking 10 mL of the digestion mixture through the same procedure were analysed for the same metals. Recovery was calculated as % Recovery ¼

a−b  100; c

where a—concentration of the spiked sample, b—concentration of the un-spiked sample; c—concentration of the metal ion added. 2.3. Dietary intake Dietary assessment tools are used to obtain information on individual or group dietary intakes and commonly used methods are food records, food frequency questionnaires (FFQ), dietary recall and diet histories (Baghurst and Baghurst, 1981). The method chosen depends on the objectives of the study, the resources available and the demands of the technique (Marr, 1971). The choice of FFQ is based on the fact that these questionnaires can be self-administered, are easy for subjects to complete

2.4.2. Target hazard quotient (THQ) THQs were determined following the US EPA Region III Risk-based Concentration Table (US EPA, 2000), described by THQ ¼

Ef r  EDtot  MI  MC  10−3 Rf Do  BW  AT n

ð2Þ

THQ ¼

Ef r  EDtot  EDI  10−3 Rf Do  BW  AT

ð3Þ

where EFr is the exposure frequency (350 days/year); EDtot is exposure duration, total (70 years); MI is meat ingestion (g/person/day); MC is metal concentration in meat (μg/g); RfDo is the oral reference dose (mg/kg/day); BW is the average body weight for each group of the subjects, ATn is averaging time for non-carcinogens (365 days/year  EDtot) and EDI is estimated dietary intake of cow meat in mg/person/day (MI  MC). Oral reference doses (RfDo) for Cd is 0.001 mg/kg/day and Pb is 0.004 mg/kg/day (US EPA, 2000). It was assumed in accordance with the US EPA (1989) guideline that the ingested dose is equal to the absorbed contaminant dose and that cooking has no effect on the contaminants (Cooper et al., 1991).

3. Results and discussion Table 1 shows the results of the recovery experiment. The mean % recovery of lead was 101 72.08% while that of cadmium was 103 72.89%. Table 2 shows the mean concentrations of lead and cadmium (mg/g dry weight) as follows: Pb (muscle 0.09 70.16; kidney 0.13 70.07; liver 0.26 70.25; intestine 0.177 0.12 and tripe 0.17 70.16); Cd ( muscle 0.35 70.27; kidney 0.44 70.27; liver 0.24 70.26; intestine 0.29 70.33 and tripe 0.41 70.33) Some very high concentrations occurred as follows: kidney (44.89 mg/g), liver (501.79 mg/g), intestine (108.02 mg/g) and tripe (127.90 mg/g). Such extreme concentrations have been attributed to recent and acute point source contamination; whereby the animal had fed on highly contaminated fodder or waste not long before slaughter. With the exception of these extreme concentrations, the mean values were lower than the Codex Alimentarius guideline value of

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Table 1 % Recoveries of lead and cadmium from meat samples after digestion. Elements

Spiked concentration (lg/mL)

Concentration of unspiked sample Concentration of spiked sample Recovered concentration (lg/mL) (lg/mL) (lg/mL)

% Recovery

Pb

0.100 0.100 0.100

0.051 0.058 0.077

0.150 0.158 0.180

0.099 0.100 0.103

99 100 103 1017 2.08 2.06

0.100 0.100 0.100

0.077 0.076 0.076

0.178 0.182 0.177

0.101 0.106 0.101

101 106 101 1037 2.89 2.8

Mean 7 SD Cd

Mean 7 SD

Precision (%)

Table 2 Mean concentrations (mg/g dry weight) of Pb and Cd in different meat parts. Metals

Muscle

Kidney

Liver

Intestine

Tripe

Pb

n Range Mean 7 S.D

21 nd–0.72 0.09 7 0.16

28 0.040–44.89 0.137 0.07

28 0.08–501.79 0.26 7 0.25

28 0.01–108.02 0.177 0.12

28 0.01–127.90 0.17 70.16

Cd

n Range Mean 7 S.D

13 Nd–0.80 0.3570.27

30 0.10–1.12 0.447 0.27

28 Nd–0.90 0.2470.26

22 0.01–0.90 0.29 7 0.33

15 0.01–1.10 0.417 0.33

n¼ number of detectable values; detection limits: Pb ¼0.005 mg/kg and Cd ¼0.004 mg/kg.

0.1 mg kg−1 (muscles) and 0.5 mg kg−1 (edible offal) for Pb in cattle (Codex Alimentarius Commission (CAC), 1995). The levels of lead reported in this study were lower than levels reported by Mariam et al. (2004) who showed mean lead concentrations of 2.19, 2.18 and 2.02 mg/kg in muscle, liver and kidney of cattle respectively in Lahore. The values determined in liver are lower than those reported by Adei and Forson-Adaboh (2008) in the range of 1.3– 13.8 mg/kg, determined in the livers of some domestic animals, including cows in Ghana. The mean concentrations in liver (0.26 mg/kg) and kidney (0.13 mg/kg) were lower than 0.472 mg/kg and 0.398 mg/kg in liver and kidney respectively reported by Alnaemi (2011). However, the concentrations of lead in this study are higher than 0.008 mg/kg, 0.042 mg/kg and 0.102 mg/kg for muscle, liver and kidney respectively reported by Khalafalla et al. (2011); and (0.017 mg/kg) in muscle, (0.057 mg/kg) in liver and (0.066 mg/kg) in kidney reported by Lòpez-Alonso et al. (2000). Lead is stored mainly in the liver and appears to be much lower in the muscle than in the other tissues (Doyle and Spaulding, 1978). Other studies have shown high accumulation of lead in liver as compared to muscle. For example Stabel-Tancher et al. (1975) reported lead concentration of 0.12 mg/kg in muscle and 0.28 mg/ kg in liver in Finnish cattle, while Okoye and Ugwu (2010) reported 0.47 mg/kg in muscle and 0.65 mg/kg in liver in goats in Nigeria. In addition, Al-naemi (2011) reported 0.071 mg/kg in muscle and 0.471 mg/kg in liver for cattle in Mosul city of Iraq. Cadmium accumulates in kidneys due to strong affinity for free protein-thiol groups. Despite the excretory mechanism for such metals, which is based on low molecular compounds having –SH groups, excretion in vertebrates could not meet up with today's anthropogenic levels of pollution (Pompe-Gotal and Crnic, 2002). Furthermore, Satarug et al. (2003) pointed out that the higher accumulation of cadmium in the kidney is due to the detoxification function of the organ, which is considered a target organ for cadmium toxicity. The cadmium levels reported in this study were quite higher than those reported by Al-naemi (2011) as follows: muscle (0.009 mg/kg), liver (0.0591 mg/kg) and kidney (0.0979 mg/kg); and those reported by Rahimi and Rokni (2008) in bovine muscles

(0.0033 mg/kg), livers (0.0497 mg/kg) and kidneys (0.1371 mg/kg) in Isfahan. However, this study showed values similar to Mariam et al. (2004) in muscle (0.33 mg/kg) and liver (0.42 mg/kg) in Lahore. The mean cadmium concentrations in the various meat parts exceeded the European Union (EU) permissible limit of 0.05 mg/kg in meat (Anonymous, 2005) One way analysis of variance (ANOVA) carried out on the Pb and Cd in the different meat parts showed no significant differences (P 40.05). Table 3 presents the results of the Food Frequency Questionnaire (FFQ). The order of daily consumption of the various parts of meat by certain percentages of the subjects was kidney (8.3671.34 g/day) by undergraduate students to intestine (40.94714.39 g/day) by pregnant/lactating women. The dietary intakes calculated are shown in Table 4. The importance of the different meat parts as sources of Pb intake for adult men were in the order: intestine4tripe4liver4muscle4kidney. For non-pregnant/non-lactating women, it was: liver4tripe4intestine4muscle4kidney; for pregnant/lactating women, the order was: intestine4liver4 4tripe4muscle4kidney; for undergraduate students; it was, liver4tripe4intestine4muscle4kidney while for school children, it was liver4tripe4intestine4muscle4kidney. In all cases, kidney was the least in importance as source of Pb due to the fact showing that it is the least consumed among the meat parts. The total average intake of Pb from cow meat per kg body weight per week among the studied population was so small compared to the provisional tolerable weekly intake (PTWI) of 25 mg/kg body weight per week (WHO, 1993). The total intake from cow meat among the subjects was in the range 6.4–13.3% of PTWI. This range was lower than 6–40% reported for a Croatian population (Blanuša and Jureša, 2001). Thus, the low % Pb intake from cow meat sources is mainly due to low meat consumption attributable to either poverty or cultural bias. Most of the subjects were low income earners like civil servants, petty traders and artisans. The values (97.66–123.85) shown in Table 4 were low compared to 209 g per person per day (pppd) reported in some US cities (Mahaffey et al., 1975). The dietary intake of lead (16.63– 20.97 mg pppd) was lower than 32 mg (pppd) reported in Lahore

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Table 3 Results of the Food Frequency Questionnaire (FFQ). Characterisation

Adult men

Non pregnant/non lactating women

Pregnant/non lactating women

Undergraduate students

School children

No of subjects Age categories (years) Average body weight (kg) Formal education Occupation: Civil servants Traders Artisans Students

186 25–55 707 10.36 175 (94%)

214 25–55 63 710.80 205 (96%)

96 25–45 927 12.19 93 (97%)

99 16–25 65 710.83 99 (100%)

165 6–15 357 5.91 165 (100%)

120 (65%) 55 (29%) 11 (6%) –

131 (61%) 75 (35%) 8 (4%) –

55 (57%) 35 (37%) – 6 (6%)

– –

– –

99 (100%)

165 (100%)

184 (85.98%) 1.32–215.10 22.96 7 2.44

83 (86.46%) 1.32–140.61 22.56 7 2.90

75 (75.76%) 1.32–140.61 26.277 2.93

134 (83.75%) 1.32–131.60 19.137 1.83

145 (67.75%) 1.16–397.32 21.477 3.38

57 (59.38%) 1.16–231.77 24.757 4.87

63 (63.64%) 1.16–264.88 22.017 4.46

91 (56.88%) 1.16–198.66 22.317 3.76

132 (61.68%) 1.26–99.33 10.777 1.44

43 (44.79%) 1.26–112.2 12.86 7 2.68

44 (44.44%) 1.26–50.10 8.36 71.34

50 (31.25%) 1.26–112.2 11.077 2.45

147 (68.69%) 1.29–250.86 23.50 7 3.03

59 (61.46%) 1.29–836.2 40.94 7 14.39

46 (46.46%) 1.29–250.86 25.89 75.78

79 (49.38%) 1.29–250.86 21.677 4.16

155 (72.43%) 1.32–224.73 26.42 7 2.89

56 (58.33%) 1.32–224.73 22.74 74.38

54 (54.55%) 1.32–224.73 26.717 5.56

116 (72.50%) 1.32–379.55 23.487 4.55

Daily meat consumption(g/day) Muscle n 169 (90.86%) Range 1.32–197.40 Mean 7 SD 25.54 7 2.20 Liver n 107 (57.52%) Range 0.68–198.66 Mean 7 SD 17.31 72.86 Kidney n 93 (50%) Range 1.26–100.20 Mean 7 SD 11.42 7 1.61 Intestine n 128 (68.82%) Range 1.29–557.47 Mean 7 SD 32.58 7 6.10 Tripe n 120 (64.52%) Range 1.32–499.40 Mean 7 SD 29.42 7 5.27

(Talib, 1991); 100 mg (pppd) from 19–22 food stuffs in Croatia (Sapunar-Postruzink et al., 1996) in the 1990s which later rose to 232 mg (pppd) in 2001 (Blanuša and Jureša, 2001). However, lower values such as 0.27 mg pppd of beef and 4 mg per person per day have been reported in Dutch (Winter-Sorkina de et al., 2003) and in US for 15–20 year old males (Mahaffey et al., 1975) respectively. The intake for undergraduate students from muscle (2.36 mg pppd) is lower than 5.8 mg pppd reported for female undergraduate students in Malaysia (Zawaih and Rosmiza, 1995). Cadmium intake from meat by men is in the order: tripe4intestine4muscle4kidney4liver; for non-pregnant/non-lactating women, it was: tripe4muscle4intestine4liver4kidney; for pregnant/lactating women: intestine4tripe4muscle4liver4kidney; for undergraduate students: tripe4muscle4intestine4liver4kidney and for school children: tripe4muscle4intestine4liver4 kidney. The average intakes of Cd from cow meat per kg body weight per week by the different groups were quite appreciable when compared to the provisional tolerable monthly intake (PTMI) of 25 mg/kg body weight per month which is equivalent to 5.83 mg/kg body weight per week (JEFCA, 2010). The total cadmium intake from cow meat range from 53% of PTWI guideline for non pregnant/non lactating women to 113% for school children. These indicate that exposure to cadmium from cow meat is appreciable in spite of low consumption of cow meat among the subjects. The dietary intake of cadmium from cow meat by the subjects is higher than 2.49 mg pppd from meat, fish and poultry reported in some US cities (Mahaffey et al., 1975), 0.21 mg pppd reported in Dutch from beef (Winter-Sorkina de et al., 2003), 0.9 and 3.1 mg pppd reported for liver and kidney respectively (MAFF, 1998). However, the values are comparable to 8.6 mg pppd reported in Lahore for meat (beef, mutton and chicken) (Talib, 1991). The higher values from our study are significant and could point to extensive contamination of the Nigerian environment by cadmium

as evident in high concentrations of the metal in the various meat parts. Most of the cadmium that enters the body is concentrated in the kidneys and liver. Cadmium has a biological half-life of 10–35 years (WHO, 1996). Even though cadmium is bound to a low molecular weight protein, metallothionein, which mitigates the toxicity of the unbound ion, the cadmium-metallothionein complex is filtered at the glomerulus of the kidney, but is reabsorbed by the proximal renal tubules (JEFCA, 1972). Thus, only a small portion of the cadmium that enters the body is excreted slowly in urine and faeces. The lack of an effective elimination pathway and long biological half-life lead to cadmium accumulation in the body even at low concentrations in food. 3.1. Target hazard quotient Risk assessment is the process that evaluates the potential health effects from doses to humans of one contaminant received through one or more exposure pathways. The health risks from consumption of cow meat by the different groups of the subject were assessed based on the target hazard quotient (THQ). The THQ is a ratio of determined dose of a pollutant to a reference dose level. If the ratio is less than 1, the exposed population is unlikely to experience obvious adverse effects (Zhuang et al., 2008). The methodology for estimation of target hazard quotient (THQ) although does not provide a quantitative estimate on the probability of an exposed population experiencing a reverse health effect, but it offers an indication of the risk level due to pollutant exposure. The estimated target hazard quotients of lead and cadmium are shown in Figs. 1and 2 respectively. The values were: men (0.06), non pregnant/non lactating women (0.07), pregnant/lactating women (0.05), undergraduate students (0.07) and school children (0.1) for lead while for cadmium, THQs were men (0.54), non pregnant/non lactating women (0.54), pregnant/lactating women

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Table 4 Dietary intake of Pb and Cd from different parts of cow meat among the populace in Enugu State, Nigeria. Groups

Men

Non pregnant/non lactating women

Pregnant/lactating women

Under graduate students

School children

a b

Meat parts

Average daily consumption rate (g per person per day)

Weekly consumption rate (g per person per week)

Pb dietary intake

Cd dietary intake

lg per person per day

lg/kg body weight/week

lg per person per day

lg/kg body weight/week

0.23 0.45 0.15 0.55 0.50

8.94 4.15 5.02 9.45 12.06

0.89 0.42 0.50 0.94 1.21

1.88 (25)a

39.62

3.96(5.83)b

0.23 0.62 0.16 0.44 0.50

8.04 5.15 4.74 6.82 10.83

0.89 0.57 0.53 0.76 1.20

1.95 (25)a

35.58

3.95 (5.83)b

0.15 0.49 0.13 0.53 0.29

7.90 5.94 5.66 11.87 9.32

0.60 0.45 0.43 0.90 0.72

1.59 (25)a

40.69

3.10 (5.83)b

0.25 0.62 0.12 0.47 0.49

9.19 5.28 3.68 7.51 10.95

0.99 0.55 0.40 0.81 1.18

Muscle Liver Kidney Intestine Tripe

25.54 7 2.20 17.31 72.26 11.42 7 1.61 32.58 7 6.10 29.42 7 5.27

178.78 121.17 79.94 228.06 205.94

2.30 4.50 1.48 5.54 5.00

Total

116.27

813.89

18.82

Muscle Liver Kidney Intestine Tripe

22.96 7 2.44 21.47 73.38 10.7771.44 23.50 7 3.03 26.42 7 2.89

160.72 150.29 75.39 164.50 184.94

2.07 5.58 1.40 4.00 4.49

Total

105.12

735.84

17.54

Muscle Liver Kidney Intestine Tripe

22.56 7 2.90 24.757 4.87 12.86 7 2.68 40.94 7 14.39 22.74 74.38

157.92 173.25 90.02 286.58 159.18

2.03 6.44 1.67 6.96 3.87

Total

123.85

866.95

20.97

Muscle Liver Kidney Intestine Tripe

26.27 72.93 22.017 4.46 8.36 7 1.34 25.89 7 5.78 26.717 5.56

183.89 154.07 58.52 181.23 186.97

2.36 5.73 1.09 4.40 4.54

Total

109.24

764.68

18.12

1.95 (25)a

36.61

3.93 (5.83)b

Muscle Liver Kidney Intestine Tripe Total

19.137 1.83 22.317 3.76 11.077 2.45 21.677 4.16 23.487 4.55 97.66

133.91 156.17 77.49 151.69 164.36 683.62

1.72 5.80 1.44 3.68 3.99 16.63

0.34 1.16 0.29 0.74 0.80 3.33 (25)a

6.70 5.35 4.87 6.28 9.63 32.83

1.34 1.07 0.97 1.26 1.93 6.57 (5.83)b

PTWI guideline value for Pb. PTWI guideline value for Cd.

Fig. 1. Target hazard quotient for lead. Fig. 2. Target hazard quotient for Cd.

(0.42), undergraduate students (0.54) and school children (0.90). These values are less than one, thus indicating that the subjects are not exposed to any health risk via cow meat consumption. THQs obtained in this study for Pb and Cd were lower than 1.43– 1.99 for Pb, and 2.61–6.25 for Cd reported by Zhuang et al. (2008) for food crops in south China but are similar to 0.004–0.68 for Cd reported by Hans et al. (1998) for sea foods in Taiwan.

4. Conclusion The dietary intakes of lead from cow meat among the urban population of Enugu State, Nigeria are low, even though the values were appreciable for cadmium in comparison to PTWI. Intakes of the two metals were higher for school children. Children are especially vulnerable to acute, sub-acute and chronic effects of

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