Objectives: To conduct health risk assessment of drinking water pesticide residues and its annual trend analysis in Shenzhen City. Methods: The samples of product water, pipe water and secondary supply water from 2011 to 2013 were collected and analyzed. The evaluation models of health risk assessments for children and adults on the 12 non-carcinogenic materials (namely heptachlor, pentachlorophenol, hexachlorocyclohexane, hexachlorobenzene, DDT, malathion, glyphosate, dimethoate, bentazone, atrazine, chlorothalonil, furadan) were recommended by the U.S. Environmental Protection Agency (US EPA). Results: The results showed that the maximums of the measured indicators in the above were controlled in accordance with the National Health Standards (GB5749-2006) published by Ministry of Health in China. The adults and children’s health indices (HIs) of the 12 non-carcinogenic materials were greater than 1 (2.323 - 6.312). Dimethoate residue in factory and peripheral water was the largest risks of harm among the non-carcinogenic pollutants measured. And its HI i (Its Hl i) was also greater than 1 (1.995 - 5.094) and followed by hexachlorobenzene and heptachlor. Annual rising trend on health risk of the 12 pesticide residues indicated that their HI T on adults was 2323. 18 × 10 -3 in 2011, 2340. 18 × 10 -3 in 2012 and 2431. 97 × 10 -3 in 2013, and HI T on children was 2965. 07 × 10 -3 in 2011, 2986. 77 × 10 -3 in 2012 and 3103. 93 × 10 -3 in 2013, respectively. This study also suggested that the average risk of peripheral water samples (HI T was equal to 2619. 64 × 10 -3) was greater than the factory samples’ (HI T was the same as 2366. 92 × 10 -3), and the children’s health risk was greater than the adults’. Conclusions: Health risks of drinking water pesticide residues in Shenzhen have exceeded the threshold values. The dimethoate was the main hazard and had been rising annually, and the children’s health risk was greater than the adults’.
The term “pesticide” is a general term that includes many compounds used for a wide variety of purposes to control a range of living organisms. It includes animal and bird repellents, food storage protectants, insecticides and acaricides, mould-killing substances, antifouling products, plant growth regulators, compounds used to prevent the growth of lichen and mosses etconbuildings, rodenticides, soil sterilants, weed killers and wood preservatives and so on [
Drinking water samples were collected in Shenzhen from January 2011 to December 2013, with a total of 84 factory samples, 11 peripheral samples and 1 secondary supplement samples to analyze their pesticide residues (see
Heptachlor, hexachlorocyclohexane, hexachlorobenzene, DDT and chlorothalonil in drinking water were detected by GC2010 Gas Chromatograph which was made by Shimadzu Corporation in Japan. Pentachlorophenol by GC-17A
Gas Chromatograph of Shimadzu Corporation in Japan. Malathion and LeA by Agilent 7890 Gas Chromatograph of USA. Glyphosate, extinction Grass pine and atrazine by QTRAP 5500 liquid chromatography tandem mass spectrometry Instrument of American ABI company. Carbofuran by Agilent 1100 liquid color Spectrometer of USA. The test results were in accordance with the Standards for Drinking Water Hygiene (GB 5749-2006) for evaluation.
In view of data quality assurance, each sample was analyzed in triplicate and after every 10 samples two standards; one blank and another of 2.5 μg/L of respective metal were analyzed on atomic absorption. The reproducibility was found to be at 95 percent of confidence level, the relative standard deviations (RSD) were all less than 15 percent, conforming to the requirements of the US EPA which RSD is less than 30 percent [
Pesticide residues health risk assessment was used to evaluate risks of heptachlor, pentachlorophenol, hexachlorocyclohexane, hexachlorobenzene, DDT, malathion, glyphosate, dimethoate, bentazone, Atrazine, chlorothalonil, carbofuran. Health risk index (HI) means average personal annual health risk values due to exposure to individual non-genetic toxicant. The calculation method is shown in formula (1) to (3) [
HIT = ∑ HIi (1)
HIi = (CDIi/RfDi) (2)
CDIi = (Ci × IR × EF × ED)/(BW × AT) (3)
HIT―average personal health risk of total non-genetic toxicants by drinking, annual; HIi―average personal health risk of individual non-genetic toxicant by drinking, annual; CDIi―chronic daily exposure dose through drinking, mg/(kg・d); RfDi―reference dose of individual non-genetic toxicant by drinking, mg/(kg・d); Ci―concentration of individual measured substance in water, mg/L; IR―intake rate of water, adult 2.2 L/d, children 1.0 L/d [
There are no basic data on exposure parameters in China at present, so we generally introduced the RfDi, from USEPA to conduct risk assessment (see
Testing pesticide residues of water samples were in accordance with the Inspection methods of drinking water (GB 5750-2006) [
Data entry for water quality monitoring database were performed by Excel 2003. The all data were analyzed descriptive statistically by software program (SPSS 13.0 for windows). After the normality test, the water quality monitoring data was non-normally distributed, so the range and median were used. There was statistical significance if P value was below to 0.05.
1) Determination quality inspection indicators on pesticide residues in drinking water
Testing the pesticide residues of water samples, the minimum detection limit and the recovery rate were in accordance with the Inspection methods of drinking water (GB 5750-2006) [
Pesticide types | Pesticides | RfD [mg/(kg・d)] |
---|---|---|
Organochlorine (OC) | Heptachlor | 0.0001 |
Pentachlorophenol | 0.0050 | |
Hexachlorocyclohexane | 0.0030 | |
Hexachlorobenzene | 0.0008 | |
DDT | 0.0200 | |
Organophosphate (OP) | Malathion | 0.0200 |
Glyphosate | 0.1000 | |
Dimethoate | 0.0002 | |
Herbicide | Bentazone | 0.0300 |
Atrazine | 0.0350 | |
Fungicide | Chlorothalonil | 0.0150 |
Carbamate | Carbofuran | 0.0010 |
Pesticide/(mg/L) | Minimum detection limit (mg/L) | Recovery rate/% |
---|---|---|
Heptachlor | 0.0004 | 83.0 - 97.0 |
Pentachlorophenol | 0.001 | 93.6 - 98.1 |
Hexachlorocyclohexane | 0.005 | 85.8 - 108.0 |
Hexachlorobenzene | 0.00001 | 81.1 - 91.0 |
DDT | 0.001 | 91.3 - 102.0 |
Malathion | 0.01 | 87.1 - 90.0 |
Glyphosate | 0.00015 | 91.8 - 99.2 |
Dimethoate | 0.01 | 85.2 - 92.0 |
Bentazone | 0.0005 | 97.6 - 100.0 |
Atrazine | 0.001 | 89.0 - 97.0 |
Chlorothalonil | 0.001 | 83.0 - 112.0 |
Carbofuran | 0.002 | 81.0 - 120.0 |
2) Concentrations of pesticide residues in product water, pipe water and secondary supply water in Shenzhen from 2011 to 2013
The samples with a total of 84 factory water, 11 peripheral water and 1 secondary supplement water from 2011 to 2013 have been tested, and the maximum value of the samples did not exceed the limit values according to the Standards for Drinking Water Hygiene (GB 5749-2006). The 6 samples of heptachlor (Upper limit is 0.4 μg/L), 10 samples of hexachlorocyclohexane (Upper limit is 5.0 μg/L), and 5 samples of DDT (Upper limit is 1.0 μg/L) approached to the critical values (see
3) Health risk assessment and annual trend for children and adults on the 12 pesticides in drinking water from 2011 to 2013 in Shenzhen
The HIi of children and adults on the 12 pesticides in factory water from 2011 to 2013 in Shenzhen were more than 1 (2.323 - 6.312), the HIi of dimethoate were the most important and more than 1 (1.995 - 5.094).There was an upward trend year by year on HIi, and the HIi of adults in 2011 < HIi in 2012 < HIi in 2013, and the HIi of children in 2011 < HIi in 2012 < HIi in 2013. This study also showed that the health risks of children were higher than risks of adults from the pesticides in drinking water (see
4) Non-carcinogenic risk assessment on the 12 pesticides in factory water, pipe water and secondary supply water in Shenzhen
We have detected the median and maximum values of concentrations on the 12 pesticides in 84 factory waters, 11 pipe waters and 1 secondary supply water from 2011 to 2013, which were employed to analyze the non-carcinogenic risk assessment from pesticides. No maximum values of concentrations on secondary supply water because of only one sample. The HIT resulted from the median values of concentrations of the 12 pesticides in the pipe water were higher than
Pesticide | Factory water | Peripheral water | Secondary supplement water | Standard limit value | |||||
---|---|---|---|---|---|---|---|---|---|
n | mean with SD | Range | n | mean with SD | Range | n | Median | ||
Heptachlor | 83 | 0.204 ± 0.186 | 0.200 - 0.400 | 11 | 0.216 ± 0.168 | 0.200 - 0.400 | 1 | 0.200 | 0.4 |
Pentachlorophenol | 84 | 0.617 ± 0.406 | 0.500 - 5.000 | 11 | 0.952 ± 0.617 | 0.500 - 5.000 | 1 | 5.000 | 9.0 |
Hexachlorocyclohexane | 84 | 2.122 ± 1.745 | 0.200 - 5.000 | 11 | 2.514 ± 1.921 | 0.200 - 5.000 | 1 | 2.500 | 5.0 |
Hexachlorobenzene | 53 | 0.071 ± 0.053 | 0.002 - 0.500 | 11 | 0.095 ± 0.0643 | 0.005 - 0.850 | 1 | 0.005 | 1.0 |
DDT | 84 | 0.453 ± 0.319 | 0.200 - 1.000 | 11 | 0.543 ± 0.368 | 0.500 - 1.000 | 1 | 0.500 | 1.0 |
Malathion | 84 | 6.128 ± 4.227 | 5.000 - 50.000 | 11 | 5.451 ± 3.817 | 5.000 - 10.000 | 1 | 5.000 | 250.0 |
Glyphosate | 84 | 0.154 ± 0.106 | 0.080 - 0.250 | 11 | 0.128 ± 0.104 | 0.100 - 0.200 | 1 | 0.080 | 700.0 |
Dimethoate | 83 | 5.014 ± 4.581 | 0.500 - 10.000 | 11 | 5.452 ± 4.167 | 5.000 - 10.000 | 1 | 5.000 | 80.0 |
Bentazone | 84 | 0.206 ± 0.164 | 0.150 - 0.500 | 11 | 0.452 ± 0.282 | 0.160 - 2.500 | 1 | 0.250 | 300.0 |
Atrazine | 84 | 0.277 ± 0.201 | 0.025 - 1.000 | 11 | 0.413 ± 0.375 | 0.025 - 1.000 | 1 | 0.500 | 2.0 |
Chlorothalonil | 84 | 0.503 ± 0.452 | 0.500 - 1.000 | 11 | 0.542 ± 0.382 | 0.500 - 1.000 | 1 | 0.500 | 10.0 |
Carbofuran | 84 | 1.011 ± 0.926 | 1.000 - 2.000 | 11 | 1.089 ± 0.837 | 1.000 - 2.000 | 1 | 1.000 | 7.0 |
Pesticides | The risk of adults | |||||
---|---|---|---|---|---|---|
2011 | 2012 | 2013 | ||||
Median | Maximum | Median | Maximum | Median | Maximum | |
Heptachlor | 159.67 | 239.50 | 159.67 | 159.67 | 239.50 | 319.34 |
Pentachlorophenol | 9.58 | 79.83 | 12.77 | 15.97 | 9.58 | 79.83 |
Hexachlorocyclohexane | 42.58 | 133.06 | 66.53 | 66.53 | 66.53 | 133.06 |
Hexachlorobenzene | 6.79 | 9.98 | 0.20 | 0.20 | 8.08 | 49.90 |
DDT | 1.60 | 2.00 | 2.00 | 2.00 | 2.04 | 3.99 |
Malathion | 23.95 | 199.59 | 19.96 | 19.96 | 24.35 | 199.59 |
Glyphosate | 0.19 | 0.20 | 0.20 | 0.20 | 0.06 | 0.12 |
Dimethoate | 1995.85 | 3991.71 | 1995.85 | 1995.85 | 1995.85 | 3991.71 |
Bentazone | 0.43 | 0.45 | 0.45 | 0.45 | 0.69 | 1.33 |
Atrazine | 0.05 | 0.06 | 0.06 | 0.06 | 1.14 | 2.28 |
Chlorothalonil | 2.66 | 2.66 | 2.66 | 2.66 | 2.71 | 5.38 |
Carbofuran | 79.83 | 79.83 | 79.83 | 79.83 | 81.43 | 159.67 |
Total | 2323.18 | 4738.86 | 2340.18 | 2343.37 | 2431.97 | 4946.18 |
Pesticides | The risk of children | |||||
---|---|---|---|---|---|---|
2011 | 2012 | 2013 | ||||
Median | Maximum | Median | Maximum | Median | Maximum | |
Heptachlor | 203.78 | 305.68 | 203.78 | 203.78 | 305.68 | 407.57 |
Pentachlorophenol | 12.23 | 101.89 | 16.30 | 20.38 | 12.23 | 101.89 |
Hexachlorocyclohexane | 54.34 | 169.82 | 84.91 | 84.91 | 84.91 | 169.82 |
---|---|---|---|---|---|---|
Hexachlorobenzene | 8.66 | 12.74 | 0.25 | 0.25 | 10.32 | 63.68 |
DDT | 2.04 | 2.55 | 2.55 | 2.55 | 2.60 | 5.09 |
Malathion | 30.57 | 254.73 | 25.47 | 25.47 | 31.08 | 254.73 |
Glyphosate | 0.24 | 0.25 | 0.25 | 0.25 | 0.08 | 0.15 |
Dimethoate | 2547.31 | 5094.61 | 2547.31 | 2547.31 | 2547.31 | 5094.61 |
Bentazone | 0.54 | 0.58 | 0.58 | 0.58 | 0.88 | 1.70 |
Atrazine | 0.07 | 0.07 | 0.07 | 0.07 | 1.46 | 2.91 |
Chlorothalonil | 3.40 | 3.40 | 3.40 | 3.40 | 3.46 | 6.86 |
Carbofuran | 101.89 | 101.89 | 101.89 | 101.89 | 103.93 | 203.78 |
Total | 2968.07 | 6048.21 | 2986.77 | 2990.85 | 3103.93 | 6312.81 |
that in the factory water (2.619 vs 2.366), but lower HIT by the maximums values in pipe water comparing to that in factory water (5.240 vs 5.395). Dimethoate was the main resource of in factory water (HI = 2.003 - 3.991) and pipe water (HI = 2.177 - 3.991) on non-carcinogenic risk assessment. The total HIT from the median values of concentrations on the rest 11 pesticides except dimethoate was less than one (HI = 0.363 - 0.442), but the total HIT greater than one by analysing their maximum values of concentrations of the 11 pesticides either in factory water or in pipe water (HI = 1.249 - 1.403). Therefore, hexachlorobenzene and heptachlor ranked the second and third among the 12 pesticides on health risk (see
The study indicated that the maximum values of all the samples measured do not exceed the limit specified in Standards for Drinking Water Hygiene (GB 5749-2006), but the annual non-carcinogenic risks of adults and children on 12 pesticide residues such as heptachlor were greater than 1 (2. 323 - 6. 312) by the US EPA recommended risk assessment model. Meanwhile, the approximate 80% of the risks came from dimethoate, of which the annual personal non-carcinogenic risks were greater than 1 (1.995 - 5.094) with a slow upward trend year by year, and which risks on children were higher than those on adults. The reasons of this could be related to the increase in the production and use of pesticides in China, and the dimethoate was the main pesticide of fruit trees and vegetables
Pesticides | The risk of factory water | The risk of pipe water | The risk of secondary supply water | |||
---|---|---|---|---|---|---|
Median | Maximum | Median | Maximum | Median | Maximum | |
Heptachlor | 165.26 | 319.34 | 174.04 | 319.34 | 159.67 | |
Pentachlorophenol | 9.88 | 79.83 | 15.25 | 79.83 | 79.83 | |
Hexachlorocyclohexane | 56.50 | 133.06 | 67.01 | 133.06 | 66.53 | |
Hexachlorobenzene | 21.16 | 498.96 | 69.66 | 498.96 | 0.50 | |
DDT | 1.82 | 3.99 | 2.18 | 3.99 | 2.00 | |
Malathion | 24.47 | 199.59 | 21.77 | 39.92 | 19.96 | |
Glyphosate | 0.12 | 0.20 | 0.10 | 0.16 | 0.06 | |
Dimethoate | 2003.04 | 3991.71 | 2177.48 | 3991.71 | 1995.85 | |
Bentazone | 0.55 | 1.33 | 1.21 | 6.65 | 0.67 | |
Atrazine | 0.64 | 2.28 | 0.95 | 2.28 | 1.14 | |
Chlorothalonil | 2.69 | 5.32 | 2.90 | 5.32 | 2.66 | |
Carbofuran | 80.79 | 159.67 | 87.10 | 159.67 | 79.83 | |
Total | 2366.92 | 5395.27 | 2619.64 | 5240.89 | 2408.70 | |
Total except dimethoate | 363.88 | 1403.56 | 442.16 | 1249.18 | 412.85 |
in the south of China [
Crentsil et al. [
Guohong Zhou et al. [
Of course, this study was referenced to the methods of pesticide residues in drinking water exposure to human health risk assessment in USEPA, and we only considered the exposure way of water intake average, and other exposure ways, such as food intake, swimming, bathing, and skin exposure pathway, were out of consideration. The reference dose selection, ethnicity, living habits, and the mechanism of various pesticides are different because of the lack of exposure parameter standards in China. Therefore, there may be some bias in the results of this evaluation [
We would like to thank to Department of Environment and Health of Shenzhen CDC for chemical dataset for this study. The authors thank the 10 district CDCs in Shenzhen for water samples collection. Also, we like to thank laboratory of Shenzhen CDC for their collaboration.
The authors declare no conflicts of interest regarding the publication of this paper.
Liu, G.H., Xu, Z.Q., Xu, X.Y., Peng, Z.Q., Li, J., Huang, G.W. and Wang, W. (2018) Health Risk Assessment on Pesticide Residues in Drinking Water in Shenzhen. Occupational Diseases and Environmental Medicine, 6, 119-129. https://doi.org/10.4236/odem.2018.64010