title: Increased occurrence of pesticide residues on crops grown in protected environments compared to crops grown in open field conditions.
abstract: Crops grown under plastic-clad structures or in greenhouses may be prone to an increased frequency of pesticide residue detections and higher concentrations of pesticides relative to equivalent crops grown in the open field. To test this we examined pesticide data for crops selected from the quarterly reports (2004-2009) of the UK's Pesticide Residue Committee. Five comparison crop pairs were identified whereby one crop of each pair was assumed to have been grown primarily under some form of physical protection ('protected') and the other grown primarily in open field conditions ('open'). For each pair, the number of detectable pesticide residues and the proportion of crop samples containing pesticides were statistically compared (n=100 s samples for each crop). The mean concentrations of selected photolabile pesticides were also compared. For the crop pairings of cabbage ('open') vs. lettuce ('protected') and 'berries' ('open') vs. strawberries ('protected') there was a significantly higher number of pesticides and proportion of samples with multiple residues for the protected crops. Statistically higher concentrations of pesticides, including cypermethrin, cyprodinil, fenhexamid, boscalid and iprodione were also found in the protected crops compared to the open crops. The evidence here demonstrates that, in general, the protected crops possess a higher number of detectable pesticides compared to analogous crops grown in the open. This may be due to different pesticide-use regimes, but also due to slower rates of pesticide removal in protected systems. The findings of this study raise implications for pesticide management in protected-crop systems.
authors.affiliation: Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, UK.
authors.forename: Gina
authors.initials: G
authors.lastname: Allen
authors.affiliation: Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, UK. Electronic address: c.halsall@lancaster.ac.uk.
authors.forename: Crispin J
authors.initials: CJ
authors.lastname: Halsall
authors.affiliation: Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, UK.
authors.forename: Justina
authors.initials: J
authors.lastname: Ukpebor
authors.affiliation: Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, UK.
authors.forename: Nigel D
authors.initials: ND
authors.lastname: Paul
authors.affiliation: Mathematics and Statistics, Lancaster University, Lancaster LA1 4YF, UK.
authors.forename: Gareth
authors.initials: G
authors.lastname: Ridall
authors.affiliation: Institute of Natural Resources, Massey University, Private Bag 11 222, Palmerston North 4442, New Zealand.
authors.forename: Jason J
authors.initials: JJ
authors.lastname: Wargent
mesh_terms: D000383:Agriculture / Q000379:methods*; D001937:Brassica / Q000737:chemistry; D003247:Conservation of Natural Resources / Q000379:methods* / Q000706:statistics & numerical data; D018556:Crops, Agricultural / Q000737:chemistry*; D005506:Food Contamination / Q000032:analysis*; D005638:Fruit / Q000737:chemistry; D018545:Lactuca / Q000737:chemistry; D010573:Pesticide Residues / Q000032:analysis*; D014466:Ultraviolet Rays / Q000009:adverse effects*
chemical_list: D010573:Pesticide Residues
keywords: Horticulture; Pesticide residues; Photolysis; Plasticulture; Salad crops