Environmental exposure to organophosphorus and pyrethroid pesticides in South Australian preschool children: A cross sectional study
Highlights
► Organophosphorus and pyrethroid exposures measured in 340 South Australian children ► Biological monitoring of exposure using urinary metabolites ► Widespread chronic exposure to organophosphates and pyrethroids ► Contemporaneous exposure to organophosphates and pyrethroids ► Exposure higher than in comparable populations in US and Germany
Introduction
Insecticides are chemicals used to control insect pests that damage or destroy crops or transmit diseases among humans and animals. Organophosphorus (OP) and pyrethroid (PYR) compounds are the most widely used groups of insecticides in Australia and worldwide. OP and PYR insecticides are neurotoxins. Neurotoxicity is defined as any permanent or reversible adverse effect on the structure or function of the nervous system. The main mode of action of OPs in humans is inhibition of acetylcholinesterase, while the main mode of action of PYRs is modulation of voltage gated ion channels. Apart from main modes of action, both groups act on other biochemical and molecular targets within the nervous system. Extensive experimental data demonstrate that low-level exposure to some commonly used OPs and PYRs can negatively affect the development of nervous system in young laboratory animals via “non-classical” mechanisms that are independent of the main mode of action. International scientific literature shows that there is a concern and need for research into the effects of chronic low level (environmental) exposures to neurotoxic insecticides on the neurobehavioral and emotional development of young children as well as on children's health in general (Bjørling-Poulsen et al., 2008). Understanding the extent of exposure in the general population is essential for evaluating whether chemicals may be linked to adverse health outcomes and for the development of scientifically sound public health policy on regulation and use of these chemicals.
South Australia has a well-developed agriculture sector, which includes wide acreage crops, livestock and horticulture. An estimated 54.1 million ha or 55% of South Australia's land area is used for agricultural activity and there were 14,262 agricultural establishments in the 2002–2003 financial years (ABS, 2003). In addition, ‘lifestyle farming’ on small acreage and backyard gardening are very popular in Australia.
The Australian Pesticide and Veterinary Medicine Authority (APVMA) is Australia's federal regulatory body whose roles are to review and allow (or disallow) chemicals onto the Australian market, to develop regulatory residue limits and to make recommendations on the use of registered chemicals, mostly by means of information collated on the chemical label. The APVMA maintains an online publicly accessible database of registered products, Public Chemical Registration Information System (PUBCRIS) [http://www.apvma.gov.au/pubcris]. The state health authorities are responsible for training and licensing restricted-use chemical users. However, Australian authorities neither have effective control over pesticide use beyond the point of sale nor do they collect information on where, when, how or how much product is being used.
Overall, thirty OP actives and twenty two synthetic PYR actives are included in over 300 and over 1000 of registered commercial formulations respectively (APVMA, 2012). Six OP actives and sixteen PYR actives are allowed for public use in Australia. Publicly accessible OP actives include: chlorpyrifos, diazinon, dichlorvos, fenthion, maldison and omethoate (APVMA, 2012). The OP and PYR formulations are available for domestic use by the general public as indoor surface sprays (fly, spider, cockroach), outdoor plant and barrier sprays, indoor and outdoor powder preparations, concentrate solutions, insect traps, flea bombs, mosquito coils, lice control lotions and shampoos as well as veterinary products. These formulations can be purchased over the counter in hardware stores, supermarkets and pharmacies in Australia. In addition, Australian homes are routinely treated with various insecticides including chlorpyrifos (an OP insecticide) and bifenthrin (a PYR insecticide) for termite control, both before and after construction.
This widespread availability of pesticides to the general public, large variety of registered products (both for public and restricted use) and extensive mixed agricultural land use pattern of South Australia suggests that there is a potential for significant widespread exposure in the general population. The extent of environmental exposure to OPs and PYRs in the Australian general population and its possible health effects so far have not been addressed in the scientific literature and in particular the extent of environmental exposure in children in Australia is unknown.
This study aimed to explore the extent of exposure to OP and PYRs pesticides in South Australian children and to investigate the factors that influence the risk of being exposed and the levels of exposure in the study population.
Section snippets
Subjects
The study took place during 2003–2006. The subjects of this study were 340 healthy children aged 2.5 to 6 years old residing in metropolitan Adelaide (urban group), Adelaide Hills area (peri-urban group) and agricultural areas of South Australia including the Yorke Peninsula, mid-north region, Barossa Valley, Riverland, McLaren Vale and the Murray-Hills area (rural group) (Fig. 1). Study groups were chosen based on a priori descriptive knowledge of pesticide use patterns and the knowledge of
Study population: Descriptive analysis
The samples were collected from various areas of metropolitan Adelaide, Adelaide Hills and rural areas, aiming to include families from different socio-economic backgrounds ensuring that the final sample population reflected the socio-economic gradients existing in the general population in South Australia. A total of 340 children (115 urban, 111 peri-urban, 114 rural) participated in the study. Of those preschools that agreed to participate, the response (participation) rate among eligible
Discussion
Since the human body metabolises OP and PYR insecticides rapidly, urinary metabolites only reflect recent exposure. However, the detection of short lived urinary metabolites in a significant proportion of urine samples from a large group of subjects in a cross-sectional study would be indicative of ongoing (chronic) exposure in the population. As such, the results of this study demonstrate that there is widespread chronic exposure to OPs and PYRs in South Australian children. Furthermore,
Conclusions
Our findings demonstrate widespread chronic exposure to OP and PYR pesticides in young children in South Australia. There are differences in exposure risks and levels in different populations, but only for some chemicals, while the exposure seems to be ubiquitous for other chemicals. There appear to be higher levels of exposure in the study population as compared to similar populations in the US and Germany. Further research into pesticide exposure in the general population in Australia is
Competing interests
Authors declare that they have no competing interests.
Acknowledgements
Authors express their appreciation to the participating families. The urine sample analyses were performed in Flinders Advanced Analytical Laboratory with invaluable help from Dr Daniel Jardine. Analytical standards for DAPs were kindly donated by the WorkCover Laboratories NSW. Kateryna Babina was supported by the FUSA Postgraduate Award (funded by the Flinders University). The study was funded by the Financial Markets for Children Foundation.
References (49)
- et al.
Dietary exposure to organophosphorus pesticides for young children in Tokyo and neighboring area
Sci Total Environ
(2007) - et al.
Twenty-four-hour urinary excretion of ten pesticide metabolites in healthy adults in two different areas of Italy (Florence and Ragusa)
Sci Total Environ
(2004) - et al.
Estimating occupational exposure to the pyrethroid termiticide bifenthrin by measuring metabolites in urine
J Chromatogr B Analyt Technol Biomed Life Sci
(2002) - et al.
Comparative pharmacokinetics of the organophosphorus insecticide chlorpyrifos and its major metabolites diethylphosphate, diethylthiophosphate and 3,5,6-trichloro-2-pyridinol in the rat
Toxicology
(2007) Australian Bureau of Statistics: Demography: South Australia
Australian Bureau of Statistics: Agricultural State Profile, South Australia
Australian Bureau of Statistics: the measures of financial hardship
- et al.
Biological monitoring of exposure to organophosphorus insecticides by assay of urinary alkylphosphates: influence of protective measures during manual operations with treated plants
Int Arch Occup Environ Health
(1994) - et al.
Biologic monitoring of exposure to organophosphorus pesticides in 195 Italian children
Environ Health Perspect
(2000) Australian Pesticide and Veterinary Medicine Authority: Public Chemical Registration Information System (PUBCRIS)
Farm children's exposure to herbicides. Comparison of biomonitoring and questionnaire data
Epidemiology
Report on Generalized Land Use for 2003. Web-based resource by South Australian Government
Isotope dilution high-performance liquid chromatography–tandem mass spectrometry method for quantifying urinary metabolites of synthetic pyrethroid insecticides
Arch Environ Contam Toxicol
Measurement of p-nitrophenol in the urine of residents whose homes were contaminated with methyl parathion
Environ Health Perspect
Potential developmental neurotoxicity of pesticides used in Europe
Environ Health
Comparison of current-use pesticide and other toxicant urinary metabolite levels among pregnant women in the CHAMACOS cohort and NHANES
Environ Health Perspect
National Pesticide Information retrieval System (NPIRS)
Distributions, associations, and partial aggregate exposure of pesticides and polynuclear aromatic hydrocarbons in the Minnesota Children's Pesticide Exposure Study (MNCPES)
J Expo Anal Environ Epidemiol
Statistical power analysis for the social sciences
Applied regression/correlation analysis for the behavioral sciences
Organophosphorus pesticide exposure of urban and suburban preschool children with organic and conventional diets
Environ Health Perspect
Association between indoor residential contamination with methyl parathion and urinary p-nitrophenol
J Expo Anal Environ Epidemiol
Children's exposure to chlorpyrifos and parathion in an agricultural community in central Washington State
Environ Health Perspect
The 23rd Australian Total Diet Survey. Food Standards Australia New Zealand
Cited by (0)
- 1
Please note, at the time of the study, Dr Babina was not an employee of SA Health and as such, her current affiliation with SA Health bears no relevance to the presented study.