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Dietary exposure to organochlorine pesticide residues of the Hong Kong adult population from a total diet study a

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M.Y.Y. Chen , W.W.K. Wong , B.L.S. Chen , C.H. Lam , S.W.C. Chung , Y.Y. Ho & Y. Xiao

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Food and Environmental Hygiene Department, Centre for Food Safety, Queensway, Hong Kong, China b

Centre for Food Safety, Food and Environmental Hygiene Department, Food Research Laboratory, Kowloon, Hong Kong, China Published online: 16 Feb 2015.

Click for updates To cite this article: M.Y.Y. Chen, W.W.K. Wong, B.L.S. Chen, C.H. Lam, S.W.C. Chung, Y.Y. Ho & Y. Xiao (2015) Dietary exposure to organochlorine pesticide residues of the Hong Kong adult population from a total diet study, Food Additives & Contaminants: Part A, 32:3, 342-351, DOI: 10.1080/19440049.2015.1008056 To link to this article: http://dx.doi.org/10.1080/19440049.2015.1008056

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Food Additives & Contaminants: Part A, 2015 Vol. 32, No. 3, 342–351, http://dx.doi.org/10.1080/19440049.2015.1008056

Dietary exposure to organochlorine pesticide residues of the Hong Kong adult population from a total diet study M.Y.Y. Chena, W.W.K. Wonga, B.L.S. Chenb, C.H. Lamb, S.W.C. Chungb, Y.Y. Hoa and Y. Xiaoa* a

Food and Environmental Hygiene Department, Centre for Food Safety, Queensway, Hong Kong, China; bCentre for Food Safety, Food and Environmental Hygiene Department, Food Research Laboratory, Kowloon, Hong Kong, China

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(Received 20 November 2014; accepted 12 January 2015) Dietary exposure of the Hong Kong adult population to organochlorine pesticide (OCP) residues was estimated using a total diet study (TDS) approach. OCPs listed under the Stockholm Convention as persistent organic pollutants (POPs) including, aldrin, dieldrin, chlordane, chlordecone, dichlorodiphenyltricholroethane (DDT), endosulfan, endrin, heptachlor, hexachlorobenzene (HCB), α-hexachlorocyclohexanes (HCH), β-HCH, lindane, mirex, pentachlorobenzene and toxaphene, were studied. Out of 600 composite samples, 55% contained one or more OCP residues at detectable levels. The most commonly detected OCP was DDT (32% of all composite samples), followed by HCB (30%) and endosulfan (22%). The lower- and upper-bound mean exposure estimates of OCP residues ranged from 0% to 0.5% and were 0.1–8.4% of their respective health-based guidance values (HBGVs). The lower- and upper-bound 95th percentile exposure estimates ranged from 0% to 1.2% and were 0.1–13.6% of their respective HBGVs. This indicated that dietary exposures to the OCP residues analysed would be unlikely to pose unacceptable health risks to Hong Kong adults. Keywords: total diet study (TDS); organochlorine pesticides (OCPs); persistent organic pollutants (POPs); dietary exposure

Introduction Organochlorine pesticides (OCPs) have been widely used in agriculture worldwide from the 1940s until restrictions were introduced in the late 1970s in both Europe and the United States, initially for dichlorodiphenyltricholroethane (DDT) (EFSA 2006; CDC 2013). The principal acute toxic effect of OCPs is on the nervous system. In high dose, such as accidental exposures of DDTs in humans, adverse effects including vomiting, tremor and seizures were observed. However, human adverse effects from OCPs such as DDTs at low doses are unknown (WHO 2000). Due to the sufficient evidence in experimental animals but inadequate evidence in humans for carcinogenicity such as elevated rates of liver, thyroid or kidney cancer of certain OCPs, the IARC has classified these pesticides including chlordane, chlordecone, DDTs, heptachlor, hexachlorobenzene (HCB), hexachlorocyclohexanes (HCHs), lindane (γ-HCH), mirex and toxaphene as possible human carcinogens (group 2B agents) (IARC 2014). At present, aldrin, dieldrin, chlordane, chlordecone, DDTs, endosulfan, endrin, heptachlor, HCB, α-HCH, β-HCH, lindane, mirex, pentachlorobenzene and toxaphene are listed as persistent organic pollutants (POPs) in the Stockholm Convention for elimination or restriction (UNEP 2014). Although most OCPs are no longer used in agriculture in many countries, some are used for other purposes. For example, DDTs can still be used in the control of disease *Corresponding author. Email: [email protected] © 2015 Taylor & Francis

vectors in accordance with WHO recommendations and guidelines (WHO 2011); and as an antifouling paint. Therefore, continuous monitoring of OCP residues in food and assessing the associated risks are warranted because food commodities may still contain OCP residues due to their persistence in the environment and potential for bioaccumulation. In the general population, diet is the main source of exposure to OCPs (CDC 2013). A total diet study (TDS) is one of the most cost-effective ways of obtaining a realistic population dietary exposure, which focuses on chemicals across the entire diet, not individual foods. In TDS, foods are processed as for consumption, so it takes into account the impact of cooking on the chemical levels in food. TDS data are necessary to assess whether or not specific chemicals pose a health risk (EFSA/FAO/WHO 2011). In a recently conducted TDS by developed countries such as Ireland, France, Australia and New Zealand, OCPs were detected at low levels in a limited number of samples, indicating that the associated risk was low (FSAI 2011; FSANZ 2011; MAF 2011; Nougadere et al. 2012). However, TDSs from China and Cambodia revealed that their estimated dietary exposures of OCP residues were higher than those reported by developed countries, although DDT and HCH concentrations in foods in China were decreasing (Wang et al. 2011; Zhou et al. 2012). The Centre for Food Safety (CFS), which is the government food safety control authority of Hong Kong,

Food Additives & Contaminants: Part A China, has conducted its first Hong Kong TDS aiming to provide dietary exposure estimates of contaminants and nutrients for the Hong Kong people and various age– gender subgroups. This study estimated the dietary exposures of the local population to the residues of OCPs, including the POP pesticides listed by the Stockholm Convention, and assessed their associated potential health risks.

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Materials and methods Food consumption data The food consumption data of the Hong Kong population were taken from the Hong Kong population-based Food Consumption Survey (FCS) conducted by the CFS in 2005–07 (FEHD 2010). In the FCS, 5008 Hong Kong adults aged 20–84 years were invited through quota sampling by gender and age groups. They were asked to recall in detail all the food and beverages consumed during the 24-h period the day before the interview on 2 non-consecutive days. The 2-day average amounts of individual foods consumed by the respondents were used for dietary exposure estimation.

Food sampling and preparation One hundred and fifty most commonly consumed food items were selected for the study, based on the food consumption pattern of the Hong Kong people. Three samples of each TDS food item were collected from various retail outlets in different areas of Hong Kong and prepared on each of four occasions between March 2010 and February 2011. They were homogenised individually and combined into a composite sample. A total of 1800 individual samples were collected and combined into 600 composite samples. Based on the buying habits of the majority of the Hong Kong people, the samples were collected from a range of retail outlets, such as supermarkets, wet markets, groceries, restaurants, etc., in different regions of the territory: Hong Kong Island, Kowloon and New Territories. No verification of species/varieties and the country of origin of the samples were made because it was not the focus of this TDS (Wong et al. 2013). The collected food samples were prepared as food normally consumed, i.e. table ready, in a manner consistent with cultural habits, and the preparation methods ranged from simple rinsing to cooking. Distilled water was used for food preparation. No salt and cooking oil were added during food preparation because salt and cooking oil were also considered as food items selected for testing OCPs, and the consumption amount had been captured separately (FEHD 2011).

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In order to simulate the same exposure experienced by the population, common kitchen utensils made of stainless steel, Teflon-coated materials or glass were used. The equipment used for preparing and homogenising the composite samples was thoroughly washed between each preparation (e.g. cleaning with a laboratory-grade detergent, rinsing thoroughly with hot tap water and rinsing thoroughly with deionised water) to avoid the risk of crosscontamination. Prepared samples were kept at −20°C prior to analysis. Chemical analysis of organochlorine pesticides All 150 TDS food items taken from the four occasions were tested for the following 14 OCPs and their metabolites or related compounds including aldrin, dieldrin, chlordane (cis-chlordane, trans-chlordane, oxychlordane, cis-nonachlor, trans-nonachlor), chlordecone, DDTs (2,4ʹDDD, 4,4ʹ-DDD, 2,4ʹ-DDE, 4,4ʹ-DDE, 2,4ʹ-DDT, 4,4ʹDDT), dicofol (2,4ʹ-dicofol, 4,4ʹ-dichlorobenzophenone), endosulfan (alpha-endosulfan, beta-endosulfan, endosulfan sulfate), endrin (endrin, endrin aldehyde, endrin ketone), heptachlor, (heptachlor, cis-heptachlor epoxide, trans-heptachlor epoxide), HCB, HCH (alpha-, beta-, gamma- and delta-), mirex, pentachlorobenzene and toxaphene (Parlars 26, 32, 42, 50, 56 and 62). Except for chlordecone, analyses of all the other analytes were performed by extracting the composite samples by matrix solid-phase dispersion technique and cleaning up by gel permeation chromatography and florisil column. OCP levels were determined by GC-MS (Agilent 6890 N5973, Santa Clara, CA, USA) (Chung & Chen 2015), whereas toxaphene levels were determined by a gas chromatograph (Agilent 6890 N)-high-resolution mass spectrometer (Thermo Finnigan MAT95 XP, Bremen, Germany). Analysis of chlordecone adopted QuEChERS methodology (AOAC 2007). Composite samples were extracted with acidified acetonitrile in the presence of magnesium sulphate and sodium acetate. Part of the extract was then cleaned-up with appropriate dispersive solid-phase material, and subsequently determined by LC-MS/MS (Agilent 1100 LC & API 4000, AB Sciex, Framingham, MA, USA). The method limit of detection (MLOD) of OCPs in general food was 0.1 µg kg−1, and in drinking water, bottled distilled water, whole milk, skimmed milk and Chinese tea was 0.01 µg kg−1. The method limit of quantification (MLOQ) in general food was 0.5 µg kg–1, and in drinking water, bottled distilled water, whole milk, skimmed milk and Chinese tea was 0.05 µg kg−1. Analytical quality assurance Except for chlordecone and toxaphene, the validation study was generally performed on the basis of the SANCO/12571/2013 guideline (Chung & Chen 2015).

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Initial validation was conducted by spiking 17 selected commodity group samples at MLOQ and 4× MLOQ levels. Results demonstrated that average recovery and precision were within 81–117% and < 13% RSD respectively. The on-going method performances of the methods were monitored by spiked recovery experiments (spiked at 4× MLOQ level) of 59 different real samples covered in the TDS project. Results of spiked recoveries fell within the range of 71–119% and precisions were < 29% relative per cent difference (RPD) respectively. The test method was further validated against certified reference materials including cod liver oil (SRM 1588c, National Institute of Standards and Technology (NIST), USA), spiked milk powder (BCR 188, LGC, the UK), Lake Superior fish tissue (SRM 1946, NIST, USA) and animal feed (BCR 115, LGC, UK). All results were within the certified value ranges. The MLOQ was established as the lowest quantifiable concentration tested. Method blanks were carried out for every batch of samples to assess any background contamination and the acceptance criteria was less than the MLOD. With the adoption of QuEChERS, full validation was not performed for chlordecone analysis. To monitor the on-going method performance, duplicate spiked recovery experiments in various food matrixes were carried out at the MLOQ level. Recoveries ranged from 93% to 130% with RPD < 5%. Similarly, for the analysis of toxaphene, full validation was not performed. Method performance was monitored by duplicate spiked recovery experiments in 54 different real TDS food samples carried out at 4× MLOQ level. Recoveries ranged from 70% to 120% with RPD ranging from 0% to 20% (except oatmeal and steamed plain rice roll of less than 39%). Treatment of non-detected values This study presents both lower- and upper-bound dietary exposure estimations (values of 0 and LOD were assigned to all analytical values below the LOD, respectively). No dietary exposure estimation for an OCP would be conducted if it were not detected in any samples. Dietary exposure estimates The 150 TDS food items that represent 88% of the average diet of the population were mapped with 1400 food items captured by FCS in order to cover the whole diet of the Hong Kong people. The food mapping process assigned concentration levels to a wider number of foods than that analysed. For example, the TDS food salmon was mapped to FCS foods salmon and other diadromous fish, while grapes were mapped to grapes and all berries. The mean levels of the TDS food items from the four occasions were assigned to the mapped FCS food items

with an application of conversion factors taking reference of the differences in water content (FEHD 2011). After the food mapping, over 99% of the food intake of the Hong Kong people was covered in the dietary exposure estimation. Dietary exposure to OCPs of individual respondents was estimated by combining the food consumption data with the OCP levels assigned to the mapped FCS food items according to the formula: Er ¼

 n  X Fr;i  Ci 1000  bwr i¼1

(1)

where Er is the total daily dietary exposure to OCPs of the respondent r (μg kg−1 bw day−1); Fr,i is the 2-day average consumption amount (g day−1) of the mapped FCS food item i by respondent r; Ci is the OCP level of the mapped FCS food item assigned (μg kg−1); bwr is the body weight of respondent r (kg); and n is the total number of mapped FCS food items consumed by respondent r. The mean exposure level among the respondents after weighting by age–gender was used to represent the average dietary exposure of the Hong Kong people. The 95th percentile exposure level was used to represent the dietary exposure of the high consumer of the Hong Kong people. Dietary exposure estimation was performed with the aid of an inhouse-developed web-based computer system, EASY (Exposure Assessment System), that takes food mapping and weighting of data into consideration (Wong et al. 2013).

Results and discussion Concentrations of OCP residues in TDS food A total of 600 composite samples (comprising 150 TDS food items from 15 food groups, collected and prepared on four occasions) were tested for OCP residues. It was found that 332 (55%) composite samples, involving 109 TDS food items, contained detectable levels of OCPs, either singly or in combination. The most commonly detected OCP was DDTs (detected in 32% of all composite samples), followed by HCB (30%) and endosulfan (22%). Chlordecone was not detected in any samples. The rest of the OCPs were detected in 10% or fewer of the composite samples (Figure 1). Both DDTs and HCB were widely used pesticides in the past. Because they are persistent in the environment, even though they are banned for agriculture use, they were still detected in various foods, particularly those from animal origin. In this study, only a small proportion (5% and 7%) of ‘vegetables and their products’ samples were detected with DDTs and HCB, respectively. However, higher proportions of DDTs and HCB were found in ‘meat, poultry and game and their products’ (92% and 96%, respectively), ‘egg and their products’ (both 92%),

Food Additives & Contaminants: Part A DDTs HCB Endosulfan Pentachlorobenzene HCH(α,β,γ,δ) Chlordane Dicofol Mirex Dieldrin Endrin Lindane (HCH-γ) Toxaphene Heptachlor Aldrin Chlordecone 0

5

10 15 20 25 Frequency of detection (%)

30

35

and ‘fish and seafood and their products’ (88% and 61%, respectively). In contrast, a higher proportion (42%) of ‘vegetables and their products’ samples had detectable endosulfan when compared with food samples from animal origin (33% for ‘fish and seafood and their products’, 2% for ‘meat, poultry and game and their products’, and not detected in ‘egg and their products’). Endosulfan was mainly used to control insects in fruits and vegetables. During the sampling period of the TDS (March 2010–February 2011), the use of it in crops had not yet been widely restricted. For instance, endosulfan was registered and permitted for use in Hong Kong until 1 January 2013 (AFCD 2014). In the United States, endosulfan is being restricted to certain crops and has been scheduled to be cancelled for all uses by 2016 (ATSDR 2013). The percentage of composite samples in major TDS food groups with detectable DDTs, HCB and endosulfan are shown in Figure 2.

% of samples in food groups with detectable pesticide residues

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Figure 1. (colour online) Percentages of composite samples with detectable residue levels in individual organochlorine pesticides (OCPs).

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The concentrations of OCP residues in different food groups are shown in Table 1. All detectable levels of OCP residues were very low except for DDTs in the food group ‘fish and seafood and their products’, where the mean concentration was 18 µg kg−1. The highest DDTs’ concentration was found in yellow croaker, of which the concentrations of the four composite samples ranged from 110 to 190 µg kg−1. Similar levels of DDTs in yellow croaker were also reported by the recent literature (Cheung et al. 2007; Yu et al. 2012). The mean DDTs’ concentration of ‘fish and seafood and their products’ was 18 µg kg−1, while in the 2006 study by the Hong Kong CFS, the mean DDTs’ concentration of 30 samples of ‘seafood (including fish)’ was 29.7 µg kg−1 (FEHD 2006). Due to sample variation and differences in analytical methods, one should be cautious when making a direct comparison of the results from the two studies. Nevertheless, reports from different countries such as mainland China, the United States and some European countries had also showed declining trends of DDTs in food as well as dietary exposure levels to DDTs since it was banned for agriculture use (ATSDR 2002; EFSA 2006; Zhou et al. 2012). The percentage distribution of different DDT isomers in different TDS food groups is shown in Table 2. DDE and DDD are the metabolites of DDT. Higher ratios of DDT to DDE are thought to indicate more recent exposure than lower ratios or continuous inputs of DDT to the environment (Ahlborg et al. 1995). In this study, the DDT/DDE ratios of all food group were low: < 1. The highest DDT/DDE ratio (0.95) was found in ‘fish and seafood and their products’. Among 19 fish and seafood samples, only three samples had a DDT/DDE ratio > 1, i.e. golden thread (3.3), yellow croaker (1.8) and oyster (1.1). Similar ratios of these types of fish and seafood sold

100

80

60

DDTs HCB

40

Endosulfan

20

0

Meat, poultry and game and their products

Egg and their products

Fish and seafood Vegetables and and their their products products

Major TDS food groups

Figure 2. (colour online) Percentage of composite samples in major total diet study (TDS) food groups with detectable levels of DDTs, HCB and endosulfan.

346 Table 1.

M.Y.Y. Chen et al. Concentrations (µg kg−1) (lower bound) of organochlorine pesticide (OCP) residues in different food groups. Concentration (µg kg−1)

Food groups Cereals and their products

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Vegetables and their products

Legumes, nuts and seeds and their products

Fruits

Meat, poultry and game and their products

Egg and their products

Fish and seafood and their products

Composite samples

OCP residues

Mean

Range

Number

>LOD (%)

Dieldrin DDTs Dicofol Endosulfan Endrin HCB HCH (α, β, γ and δ) Lindane Mirex Pentachlorobenzene Dieldrin Chlordane DDTs Dicofol Endosulfan HCB HCH (α, β, γ and δ) Lindane (HCH-γ) Pentachlorobenzene Dieldrin DDTs Dicofol Endosulfan Heptachlor HCB HCH (α, β, γ and δ) Lindane (HCH-γ) Pentachlorobenzene Toxaphene DDTs Dicofol Endosulfan HCB HCH (α, β, γ and δ) Lindane (HCH-γ) Aldrin Dieldrin DDTs Dicofol Endosulfan HCB HCH (α, β, γ and δ) Mirex Pentachlorobenzene DDTs HCB HCH (α, β, γ and δ) Pentachlorobenzene Dieldrin Chlordane DDTs Endosulfan Heptachlor HCB HCH (α, β, γ and δ) Mirex Pentachlorobenzene Toxaphene

0.0 0.2 0.0 0.5 0.0 0.1 0.0 0.0 0.0 0.1 0.0 0.0 0.0 0.1 3.2 0.0 0.0 0.0 0.0 0.0 0.4 0.0 0.2 0.0 0.0 0.5 0.0 0.4 0.2 0.0 0.0 0.4 0.0 0.0 0.0 0.0 0.2 1.0 0.1 0.0 0.7 0.9 0.0 0.0 1.1 0.6 0.0 0.0 0.1 0.3 18 0.7 0.0 0.4 0.2 0.0 0.1 0.2

0.0–0.2 0.0–2.8 0.0–0.3 0.0–13 0.0–0.3 0.0–4.1 0.0–1.1 0.0–1.1 0.0–0.1 0.0–0.5 0.0–0.4 0.0–1.3 0.0–1.9 0.0–6.2 0.0–86 0.0–0.7 0.0–0.9 0.0–0.9 0.0–0.7 0.0–0.7 0.0–5.3 0.0–0.2 0.0–1.4 0.0–0.2 0.0–0.2 0.0–4.2 0.0–0.5 0.0–10 0.0–1.7 0.0–0.3 0.0–0.1 0.0–19 0.0–0.1 0.0–0.9 0.0–0.9 0.0–0.1 0.0–0.9 0.0–13 0–6.9 0.0–0.3 0.0–4.4 0.0–33 0.0–0.2 0.0–0.2 0.0–7.4 0.0–2.3 0.0–0.3 0.0–0.1 0.0–7.30 0.0–3.3 0.0–190 0.0–20 0.0–0.2 0.0–1.8 0.0–2.7 0.0–0.5 0.0–1.0 0.0–5.2

76 76 76 76 76 76 76 76 76 76 140 140 140 140 140 140 140 140 140 24 24 24 24 24 24 24 24 24 24 68 68 68 68 68 68 48 48 48 48 48 48 48 48 48 12 12 12 12 76 76 76 76 76 76 76 76 76 76

1 32 8 14 11 34 1 1 1 28 1 1 5 2 42 7 2 2 6 8 33 4 25 8 25 29 4 4 13 4 1 15 1 1 1 2 2 92 2 2 96 13 4 2 92 92 8 33 3 32 88 33 1 61 16 11 21 5 (continued )

Food Additives & Contaminants: Part A

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Table 1. Continued . Concentration (µg kg−1) Food groups Dairy products Fats and oils Beverages, non-alcoholic Mixed dishes

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Snack foods

Sugars and confectionery Condiments, sauces and herbs

Table 2.

Composite samples

OCP residues

Mean

Range

Number

>LOD (%)

Dieldrin DDTs HCB DDTs HCB HCH (α, β, γ and δ) Dieldrin DDTs Endosulfan HCB HCH (α, β, γ and δ) Lindane (HCH-γ) Pentachlorobenzene Chlordane Heptachlor HCB HCH (α, β, γ and δ) DDTs HCB DDTs

0.5 0.7 0.0 4.4 0.6 0.8 0.0 0.1 0.4 0.1 0.1 0.0 0.0 0.4 0.1 0.1 1.2 0.1 0.0 0.1

0.0–7.9 0.0–6.9 0.0–0.3 0.0–13 0.0–1.7 0.0–6.4 0.0–0.7 0.0–1.4 0.0–1.8 0.0–0.4 0.0–1.2 0.0–1.0 0–0.3 0.0–1.4 0.0–0.3 0.0–0.4 0.0–4.8 0.0–0.7 0.0–0.1 0.0–0.8

20 20 20 8 8 8 40 48 48 48 48 48 48 4 4 4 4 8 8 20

10 45 15 63 50 13 3 21 42 56 17 2 13 50 25 25 25 25 13 20

Percentage distribution of different DDT isomers in different total diet study (TDS) food groups. Percentage (%)

Food group

DDD

DDE

DDT

DDT/DDE

Cereals and their products Vegetables and their products Legumes, nuts and seeds and their products Fruits Meat, poultry and game and their products Egg and their products Fish and seafood and their products Dairy products Fats and oils Mixed dishes Sugars and confectionery Condiments, sauces and herbs

5.6 0.0 0.0 0.0 1.9 1.5 32.7 0.8 0.0 0.0 0.0 69.6

86.0 87.9 100.0 100.0 90.1 59.5 34.5 97.0 100.0 85.9 100.0 30.4

8.4 12.1 0.0 0.0 8.0 38.9 32.8 2.3 0.0 14.1 0.0 0.0

0.10 0.14 0.00 0.00 0.09 0.65 0.95 0.02 0.00 0.16 0.00 0.00

in Hong Kong market were also reported by Chung et al. (2008). The new source of DDTs in freshwater fish ponds was partly attributed to dicofol, whereas sewage discharged from the Pearl River Delta in South China and antifouling paint were likely the DDT sources for seawater farmed fish (Guo et al. 2008).

OCP residues ranged from 0% to 0.5% and from 0.1% to 8.4% of their respective HBGVs. For high consumers, the lower- and upper-bound exposure estimates ranged from 0% to 1.2% and from 0.1% to 13.6% of their respective HBGVs. The findings indicate that dietary exposures to all OCPs analysed in this study would be unlikely to pose unacceptable health risks to the general population of Hong Kong.

Dietary exposure to OCP residues The lower- and upper-bound dietary exposure estimates of OCP residues for average and high consumers of the Hong Kong people and their contribution to their respective HBGVs are shown in Table 2. For average Hong Kong people, the lower- and upper-bound exposure estimates of

Contribution of food groups to daily exposure of the three commonly detected OCPs The contributions of food groups to total dietary exposures of the three commonly detected OCPs, DDTs, HCB, and endosulfan, are shown in Figure 3. The lower-bound

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100

Others Eggs and their products

% Contribution

80

Fruits 60 Vegetables and their products 40

Cereals and their products Meat, poultry and game and their product

20

Fish and seafood and their products

0 DDTs

HCB

Endosulfan

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Figure 3. (colour online) Major food contributors to dietary exposures of DDTs, HCB and endosulfan.

concentrations were used in the calculations. For DDTs, ‘fish and seafood and their products’ was the major contributor (91%), while ‘meat and poultry and game and their products’ only contributed to 4% of the dietary exposure. It was mainly due to the significantly higher DDT levels (mean = 18

μg kg kg−1) in fish than in other food samples (mean from 0.0 μg kg−1 in vegetables to 4.4 μg kg−1 in fats and oils). For HCB, the main dietary contributor was ‘meat, poultry and game and their products’ (65%), followed by ‘fish and seafood and their products’ (17%). ‘Meat, poultry and game and their products’ contained the highest mean level (0.4 μg kg−1) of HCB and its detection rate was 96%. For endosulfan, the major contributor was ‘vegetables and their products’ (73%), while ‘fruits’ and ‘fish and seafood and their products’ each contributed 7% of the dietary exposure only. It was because vegetables had the highest detection rate (42%) of endosulfan compared with other food groups and the consumption amount of vegetables (177 g) was higher than that of fish and seafood (71 g) and meat, poultry and game (113 g) in Hong Kong (FEHD 2010). International comparison Dietary exposure estimates to OCPs from TDS of different places are shown in Table 3. Dietary exposure estimate of

Table 3. Ranges (lower- and upper-bound) of dietary exposure estimates (μg kg−1 bw day−1) to the organochlorine pesticide (OCP) residues for average and high consumers of the Hong Kong population and their contribution to health-based guidance values (HBGVs). Dietary exposure estimate (μg−1kg−1 bw day−1) (contribution to HBGVs) OCPs

HBGVs (mg kg−1 bw day−1)

Source

Aldrin plus dieldrin

0.0001

JMPR 1994

Chlordane

0.0005

JMPR 1994

DDTs

0.01

JMPR 2000

Dicofol

0.002

JMPR 1992

Endosulfan

0.006

JMPR 1998

Endrin

0.0002

JMPR 1994

Heptachlor

0.0001

JMPR 1994

HCB

0.0008

USEPA 1991

HCH (α, β, γ and δ)

0.005

Lindane (HCH-γ)

0.005

MOH of PRC 2012 JMPR 2002

Mirex

0.0002

USEPA 1992

Pentachlorobenzene

0.0008

USEPA 1998

Toxaphene

0.002

ATSDR 2010

Average 0.0003–0.0059 (0.3–5.9%) 0.0002–0.0142 (0–2.8%) 0.0238–0.0399 (0.2–0.4%) 0.0005–0.0060 (0–0.3%) 0.0085–0.0166 (0.1–0.3%) 0.0010–0.0091 (0.5–4.5%) 0–0.0084 (0–8.4%) 0.0024–0.0048 (0.3–0.6%) 0.0008–0.0120 (0–0.2%) 0.0001–0.0029 (0–0.1%) 0–0.0028 (0–1.4%) 0.0003–0.0030 (0–0.4%) 0.0002–0.0171 (0–0.9%)

High consumer 0.0012–0.0096 (1.2–9.6%) 0.0010–0.0230 (0.2–4.6%) 0.0912–0.1099 (0.9–1.1%) 0.0018–0.0098 (0.1–0.5) 0.0258–0.0359 (0.4–0.6%) 0.0021–0.0145 (1.0–7.3%) 0–0.0136 (0–13.6%) 0.0052–0.0084 (0.6–1.0%) 0.0023–0.0195 (0–0.4%) 0.0002–0.0046 (0–0.1%) 0.0001–0.0045 (0–2.3%) 0.0008–0.0049 (0.1–0.6%) 0.0011–0.0276 (0.1–1.4%)

Notes: JMPR is the Joint FAO/WHO Meeting on Pesticide Residues: http://www.fao.org/agriculture/crops/core-themes/theme/pests/lpe/en/. USEPA is the US Environmental Protection Agency: http://www.epa.gov/iris/. MOH of PRC is the Ministry of Health of the Peoples’ Republic of China: http://www.nhfpc.gov.cn/cmsresources/mohwsjdj/cmsrsdocument/doc16697.doc/ [in Chinese]. ATSDR is the Agency for Toxic Substances and Disease Registry of the US Department of Health Services: http://www.atsdr.cdc.gov/toxprofiles/tp94-a.pdf/.

n.a.

0.011 (mean) 0.031 (P90) 0.033 (mean) 0.072 (P90) n.a.

n.a.

n.a.

n.a.

DDTs

Dicofol

Endosulfan

HCB

HCH (α, β, γ and δ)

Lindane (HCH-γ)

0.001 0.001 0.009 0.015 0.002 0.007 n.a.

n.a.

0.006 0.013 0.016 0.052 n.a.

(mean) (P95) (mean) (P95) (mean) (P95)

(mean) (P95) (mean) (P95)

Men 18–45 years n.d. = 0 n.a.

China (Zhou et al. 2012)

0.001 – 0.176 (mean) 0.01 – 0.287 (P95)

0.000 – 0.103 (mean) 0.000 – 0.185 (P95) n.a.

n.a.

n.a.

n.a.

n.a.

0.0031 (mean)

0.001 – 0.415 (mean) 0.005 – 0.713 (P95) n.a.

n.a.

n.a.

n.a.

n.a.

0.0036 (mean)

0.00003 (mean)

0.0073 (mean)b

0.0099 (mean)b 0.00002 (mean)

n.a.

Women 25 + years n.d. = 0 0.00005 (mean)a

n.a.

Men 25 + years n.d. = 0 0.00004 (mean)a

New Zealand (MAF 2011)

n.a.

n.a.

n.a.

Adults n.d. = 0 and n.d. = LOD n.a.

France (Nougadere et al. 2012)

Notes: aExposure estimates were for dieldrin only as aldrin was not detected in any samples. b Exposure estimates were for DDE-4,4ʹ only as other related DDT compounds were not detected in any samples. n.a., Not available; P95, 95th percentile; P90, 90th percentile. Mean exposure estimates for Australia were expressed as kg−1 bw day−1 by taking an average body weight of 74 kg reported in its study.

Heptachlor

Chlordane

Adults 17 years or above n.d. = 0 0.0059 (mean)a 0.012 (P90)a n.a.

Australia (FSANZ 2011)

Dietary exposure estimates (μg kg−1 bw day−1) to organochlorine pesticide (OCP) residues from total diet studies (TDS) of different places.

Target group Treatment of n.d. values Aldrin and dieldrin

Table 4.

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Adults 20–84 years n.d. = 0 and n.d. = LOD 0.0003–0.0059 (mean) 0.0012–0.0096 (P95) 0.0002–0.0142 (mean) 0.0010–0.0230 (P95) 0.0238–0.0399 (mean) 0.0912–0.1099 (P95) 0.0005–0.0060 (mean) 0.0018–0.0098 (P95) 0.0085–0.0166 (mean) 0.0258–0.0359 (P95) 0–0.0084 (mean) 0–0.0136 (P95) 0.0024–0.0048 (mean) 0.0052–0.0084 (P95) 0.0008–0.0120 (mean) 0.0023–0.0195 (P95) 0.0001–0.0029 (mean) 0.0002–0.0046 (P95)

This study

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M.Y.Y. Chen et al.

DDTs in this study (0.0238 µg kg−1 bw day−1) was higher than those of mainland China (0.016 µg kg−1 bw day−1) and New Zealand (0.0073 µg kg−1 bw day−1 for females and 0.0099 µg kg−1 bw day−1 for males) (MAF 2011; Zhou et al. 2012). For other OCPs, the dietary exposure estimates of this study were lower or comparable with the estimates of other places (FSANZ 2011; MAF 2011; Nougadère et al. 2012; Zhou et al. 2012). However, caution should be exercised in making any direct comparison of the data due with the differences in the types and numbers of food samples, the methods of collection of the consumption data, and the methods of contaminant analysis (Table 4). A known limitation of TDS is the assumption of applying levels of a chemical detected in one food item to other similar foods, which may introduce uncertainty into the results. For example, the occurrence of OCPs in different food items even within the same food group may vary with different factors such as the amount of OCP residues exposed by the animals or crops and the fat content of the food.

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