Progress 10/31/16 to 10/25/19
Outputs
Target Audience:The target audience of this project includes DC residents, UDC students majoring food science or nutrition, DC Department of Energy and Environment, Environmental Protection Authority, urban agriculture researcher, and sustainable DC affiliates. Changes/Problems:We changed the two originally proposed research objectives. Objective 2, which was developing fast screening methods was modified to the implementation of quantitative analysis of pesticide residues in fruits and vegetables. The modified objective was extended to test the effect of different fruit washing techniques. Objective 3, which was training DC gardeners on pest management practices was also not implemented in order to avoid duplication of effort within our college as a new project specialist was hired to conduct the integrated pest management training at UDC in collaboration with DC Department of Environment and Energy. The project focused on establishing the laboratory testing capacity to provide laboratory testing service to the DC area residents and training graduate students in pesticide testing in fruits and vegetables as well as environmental samples, including water and soil. What opportunities for training and professional development has the project provided?The opportunity for training and professional development provided by this research project was actually one of the most significant accomplishments of the project. Three full time environmental scientists were trained in the state-of-the-art analytical methods pertaining to testing pesticide residues and semi-volatile organic compounds in fruits, vegetables, and environmental samples, including soil and water. In addition, eight graduate students from different majors were trained, including Ph.D. dissertation, Professional Science Master's in Water Resources Management, Master of Sceince in Nutrition and Dietetics. Students were trained in sample collection as well as samples preparation for GC-MS, High Performance Liquid Chromatography (HPLC), and Inductive Couple Mass Spectrophotometer (ICP-MS) analysis. PhD dissertation, five master thesis (MS) and two graduate capstone projects were supported during this project: · Sara Aggad (Presented in November, 2019). Health Effects of Pesticide Residues in Food, and Minimizing Pesticide Dietary Exposure through Household Processing of Fruits and Vegetables, PhD dissertation, Howard University, Washington, DC · Almushayti, Albatul (Graduated in May, 2017). Assessing the Most Common Pesticides Residues in Fruits and Vegetables from the Main Supermarket in DC Using GS/MS. MS Thesis, University of the District of Columbia, Washington, DC. · Gandura Almalaki (Graduated in May, 2017). Analysis of Water Soluble Vitamins in Ethnic Crops, MS in Nutrition and Dietetic, University of the District of Columbia, Washington, DC. · Ahdab Jabi (Graduated in May, 2017). Analysis of Fat Soluble Vitamins in Ethnic Crops, MS in Nutrition and Dietetic, University of the District of Columbia, Washington, DC. · Liah Alamlaki (Graduated in May, 2017). Analysis of anticancer compounds in Ethnic Crops, MS in Nutrition and Dietetic, University of the District of Columbia, Washington, DC. · Lamya Aljamie (Graduated in December, 2017). Antiatherogenic Compound Analysis in Four Cultivars of PHOENIX DACTYLIFERA L. Date Fruits and Seeds Using HPLC/DAD: A Comparative Study, MS thesis in Nutrition and Dietetic, University of the District of Columbia, Washington, DC. · Sania Rose (Graduated in May, 2018). Pesticide Analysis in Fruit and Vegetables purchased from local farmer's market in DC. Graduate Capstone Project, Major in Water Resources Management, University of the District of Columbia, Washington, DC. · Maryam Sabur (Gradates in May, 2019). Pesticides and Semivolatile organic compounds in DC water ways, Graduate Capstone Project, Majoring PSM in Water Resources Management, University of the District of Columbia, Washington, DC. How have the results been disseminated to communities of interest?The results were disseminated through poster presentation, oral presentation at various vanues including local and national conferences and MS Thesis Presentations, and PowerPoint presentations at the local workshop. What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
In Objective 1, identifying the most commonly used pesticides in the DC area, we identified commonly used pesticides in DC area. There is limited published information, however, review of a report published in 2016 for the Maryland pesticide statistics in 2014 identified 286 active ingredents of commonly used pesticides in Maryland. The Maryland statistics showed, according to pounds used, ten ranked pesticides include Glyphosate, Atrazine, Simazine, Prodiamine, Fipronil, 2,4-D, Pendimethalin, Imidacloprid, S-Metalachlor, and Chlorothalonil. Glyphsate ranked the top with 634,954 lb used. The top ten ranked pesticides used on fruits include Mineral oil, Captan, Mancozeb, Monopotassium salt, sulfur, Glyphosate, Ziram, Oryzalin, Chlorpyrifos, and Kaolin. The top ten pesticides used on vegetables include Metolachlor, Glyphosate, Chlorothalonil, S-Metolachlor, Clomazone, Paraquat Dichloride, Propamocarb hydroch, Methomyl, Trifluralin, and copper hydroxide. These pesticides area mostly herbicides. In objective 2, assessing fast screening method of pesticide analysis in fruits and vegetables, the proposed screen method was not realized due to the limitation of required laboratory technology including Time of Flight Mass Spectrophotometer with Direct Sample Analysis. This method was discontinued due to the required excessive cost in instrument maintenance. Consequently, we assessed the QECERS (Quick Easy Cheap Effective Rugged Safe) method (Machado et al., 2017) in monitoring market basket fruits and vegetables and effect of different washing techniques on pesticide residues. We analyzed five groups of pesticides with 138 compounds in five types of fruits and vegetables purchased from two sources: (1) market basket of the main supermarket, and (2) market basket of local farmers markets. Five main groups of pesticide residues were considered, including insecticides, herbicides, plant growth regulators, repellants, and fungicide. Based on the USDA's pesticide data program 2015 (USDA, 2016), we selected five types of fruit and vegetables that were known to have detectable pesticide residues, including tomato, potato, strawberry, nectarine, apple and lettuce. We collected 79 samples of fruit and vegetables from five main supermarkets (48 samples) located in five DC Wards (1, 2, 3, 5, 6 and 8), and eight local farmers markets (31 samples) from all eight wards of the District of Columbia. We found 138 types of detectable pesticide residues, including 39 fungicides, 52 herbicides, 38 insecticides, 4 pesticide metabolites, 1 plant growth, and 1 repellant. Samples from the main supermarket include 15 samples from organic farming, and 33 samples from traditional farming. Samples from the farmers market include all 31 samples from the local farmers markets. All samples were extracted using QuEChERS, and analyzed using Gas Chromatography Mass Spectrophotometry (GC-MS). The results showed that all samples from the main supermarket have at least one detectable pesticide residues, and 50% of the collected samples exceeded the EPA tolerance limit in four or more pesticide residues; and 65% samples exceeded the EPA tolerance limit in one or more pesticides. Most frequently detected pesticide residues include tetrahydrophthalimide and thiabendazole. All samples from the farmers market have 4 or more detectable pesticide residues that exceeded the EPA tolerance limit. This is an interesting finding and needs further studies as locally produced fresh produces are expected to have no or lower pesticide residues. The market basket samples from the farmers market showed more percentage of samples that exceeded the EPA tolerance limits than the samples from the main supermarket. The most frequently detected pesticide residue in apple, nectarine and potato was Chlorfenapyr. This compound is an insecticide which exceeded the EPA tolerance limit in our study, as well as in the USDA pesticide monitoring program reported in 2014 through 2017. The results showed that at least one tested pesticide residue was detected in both organic and non-organic fruits and vegetables purchased from the main supermarkets. The detected level of pesticide residues exceeded the EPA tolerance limit in lettuce, potatoes, and tomatoes. This study indicates that there was a detectable amount of pesticide residues on both organic and conventional fruits and vegetables. Based on samples collected from main supermarkets, 57% of testing samples were well below the EPA tolerance level while 43% were above the EPA level. There was no significant difference between organic and non-organic except in apple. Further studies are needed to quantify more pesticide residues in a greater percentage of food commodity. It should also be noted that purchasing organic fruits and vegetables may not ensure none detect pesticide residues due to the fact that the sample may get contaminated with pesticides at any stage between farm site and plate. To reduce human exposure to a higher level of pesticide residues through fruit and vegetables intake, investigating the effect of household food preparation on the level of pesticide residues on selected fruits is crucial. Furthermore, we investigated the effect of different household food preparation methods on pesticide residues on apple and strawberry. We evaluated four washing techniques, including (a) washing with tap water, (b) tap water with baking soda, (c) alkaline water, and (d) tap water with lemon juice. Both apple and strawberry samples were spiked with a known concentration of synthetic pesticides. The effectiveness of the washing methods was determined on the basis of the percentage recovery of pesticide residues. The results showed that washing fruits can significantly remove pesticide residues up to 50%. Washing with tap water and baking soda removed most effectively as compared to tap water with lemon juice. Whereas tap water with lemon juice has removed 20%. This finding is consistent with previous findings. Researches showed that different household food preparation can reduce or increase dietary sources of pesticide exposure. Pesticides are normally applied on the surface of vegetables and fruits, but it can enter the outer layer depending on the type of pesticides. In case of the pesticides that stay on the surface of the produces, peeling and washing processes can result in reduction of pesticide residues. Other food preservation techniques like drying or dehydration, and concentration may increase the pesticide content many folds due to the concentration effect (Bajwa and Sandhu, 2014). This shows the importance of understanding the effect of different household food handling practices. In Objective 3, providing training to DC Gardeners on pest management practices, we modied this objective from training DC Gardeners on pest management practices to building laboratory capacity in training graduate students and establishing pesticide testing program for the DC area. The Environmental Quality Testing Laboratory of UDC has successfully implemented three key pesticide testing methods for in three environmental sample matrices, including fruit and vegetables using the QuEChERS sample preparation technique, potable water using EPA Method 525.3, and EPA Method 8270 for non-potable water. We have applied for the National Laboratory Accreditation through the state of New Hampshare's National Environmental Laboratory Accreditation Program (NELAP). When the lab is accredited by NELAP, the lab can test pesticide residues in food and environmental samples for the DC residents and DC Department of Environment and Energy and other agencies that may require testing by accredited labs.
Publications
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Progress 10/01/17 to 09/30/18
Outputs
Target Audience:The target audience of this project includes DC residents, UDC students majoring in food science or nutrition, DC Department of Energy and Environment, Environmental Protection Authority, urban agriculture researchers, and sustainable DC affiliates. Changes/Problems:Integrated Pest Management (IPM) trainingwas not implemented even if it was part of the original objectives of this project; we modified the projectobjectives because a new project specialist was hired to conduct the IPM training at UDC supported by DC Department of Environment and Energy. To avoid duplication efforts, the project focused on monitoring pesticide residues in fruits and vegetables as well as environmental samples, including potable and non-potable waters and soil. We also added further study in testing the effect of household food preparation on the level of pesticide residues on fruit and vegetables. What opportunities for training and professional development has the project provided?The opportunity for training and professional development provided by this research project is actually significant. Three full time environmental scientists were trained in the state-of-the-art analytical methods pertaining to testing pesticide residue and semi-volatile organic compounds in fruits, vegetables, and environmental samples, including soil and water. In addition, four MS thesis students majoring in nutrition and dietetics were trained in sample preparation and sample analysis in fruit and vegetables using advanced analytical technologies including HPLC, GC-MS, and ICP-MS. Five master thesis (MS) and two graduate capstone projects were supported during this project: Almushayti, Albatul (Graduated in May, 2017). Assessing the Most Common Pesticides Residues in Fruits and Vegetables from the Main Supermarket in DC Using GS/MS. MS Thesis , University of the District of Columbia, Washington DC. Gandura Almalaki (Graduated in May, 2017). Analysis of Water Solubale Vitamins in Ethinic Crops, MS in Nutrition and Dietetics. Ahdab Jabi (Graduated in May, 2017). Analysis of Fat Soluble Vitamins in Ethenic Crops, MS in Nutrition and Dietetics. Liah Alamlaki (Graduated in May, 2017). Analysis of Anticancer Compounds in Ethinic Crops, MS in Nutritionand Ditetics. Lamya Aljamie (Graduated in December, 2017). Antiatherogenic Compound Analysis in Four Cultivars of PHOENIX DACTYLIFERA L. Date Fruits and Seeds Using HPLC/DAD: A Comparative Study, MS thesis in Nutritionand Dietetics. Sania Rose (Graduated in May, 2018). Pesticide Analysis in Fruit and Vegetables purchased from local farmer's market in DC. Graduate Capstone Project, Major in Water Resources Management.. Maryam Sabur (Gradutes in May, 2019). Pesticide and semivolatile organic compounds in DC water ways, Graduate Capstone Project, Majoring PSM in Water Resources Management. How have the results been disseminated to communities of interest?The results were disseminatedthrough a poster presentation, MS Thesis Presentations, and powerpoint presentations atlocal workshops in the DC community. What do you plan to do during the next reporting period to accomplish the goals?As the continuation of this research project, we will test the effect of different household food processing techniques on pesticide residues in fruit and vegetables, continueour laboratory study, and develop more publications.
Impacts
What was accomplished under these goals?
The main objectives of this research project were mainly three-fold: 1) to assess the level of pesticide residue on fruit and vegetables (FV) purchased from main supermarket and local farmers markets; (2) to determine the difference between organic and non-organic FV purchased from the main supermarkets; and (3) to establish a pesticide residue testing program at UDC. During this study, we tested and implemented pesticide testing methods atUDC's Environmental Quality Testing Laboratory using Gas Chromatograph Mass Spectrophotometer. UDC now can test pesticide residue in the environmental samples such as fruits, vegetables, water and soil. Based on the USDA's pesticide data program (USDA, 2015), we selected five types of fruit and vegetables that were known to have detectable pesticide residues, including tomato, potato, strawberry, nectarine, apple and lettuce. We collected 79 samples of fruit and vegetables from five main supermarkets (48 samples) located in five DC Wards (1,2,3,5,6 and 8) and eight local farmers markets (31 samples) from all eight wards of the District of Columbia. The samples were analyzed for 138 types of pesticide residues, including 39 fungicides, 52 herbicides, 38 insecticides, 4 pesticide metabolites, 1 plant growth, and 1 repellant. Samples from the main supermarket included 15 samples from organic farming and 33 samples from traditional farming. Samples from the farmers market included all 31 samples from the local farmers markets. All samples were extracted using QuEChERS and analyzed using Gas Chromatography Mass Spectrophotometry (GC-MS). The results showed that all samples from the main supermarket had at least one detectable pesticide residue; 50% of the collected samples exceeded the EPA tolerance limit in four or more pesticide residues; and 65% samples exceeded the EPA tolerance limit in one or more pesticides. The mostfrequently detected pesticides include tetrahydrophthalimide and thiabendazole. All samples from the farmers market hadfouror more detectable pesticide residues that exceeded the EPA tolerance limit. This is an interesting finding and needs further studiesas locally produced fresh produce are expected to have no or lower pesticide residues. The market basket samples from the farmers market showed more percentage of samples that exceeded the EPA tolerance limits than the samples from the main supermarket. The most frequently detected pesticide in apples, nectarines and potatoes was Chlorfenapyr. This compound is an insecticide which exceeded the EPA tolerance limit in our study, as well as in the USDA pesticide monitoring program reported in 2014 through 2017. The results showed that at least one tested pesticide was detected in both organic and non-organic fruits and vegetables purchased from the main supermarkets. The detected level of pesticide residue exceeded the EPA tolerance limit in lettuce, potatoes, and tomatoes. This study indicates that there was a detectable amount of pesticide residue on both organic and conventional fruits and vegetables. Based on samples collected from main supermarkets, 57% of tested samples were well below the EPA tolerance level while 43% were above the EPA level. There was no significant difference between organic and non-organic except in apple. Further studies are needed to quantify more pesticide compounds in greater food commodity samples. It should also be noted that purchasing organic fruit and vegtables may not ensure non detectable pesticide residues due to the fact that the sample may get contaminanted with pesticides at any stage between farm and plate. To reduce human exposure to higher levels of pesticide residue through fruit and and vegetable intake, looking into the effect of household food preparation on the levels of pesticide residue is crucial. During this reporting period, we launched further research to assess the effect of washing, peeling and other household food preparation techiniques on the levels of pesticide residue on fruit and vegetables.
Publications
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Progress 10/31/16 to 09/30/17
Outputs
Target Audience:The target audience of this project includes DC residents, UDC students majoring in food science or nutrition, DC Department of Energy and Environment, Environmental Protection Authority, urban agriculture researcher, and sustainable DC affiliates. Changes/Problems:The proposed Integrated Pest Management trainging was not conducted during this reporting period, but we are planning to organize one in the next reporting period. The reason for this change was we would like to have a monitoring data for the prevalence of pesticides residue in the main supermarkets as well as farmers market prior to organizing training. No other changes were made. What opportunities for training and professional development has the project provided?During this reporting period, this research project provided training opportunity for our lab personnel, researchers, and students to conduct pesticide analysis in environmental samples using state-of-the-art sample preparation and sample analysis including Horizon sample extraction and dry vap, GC-MS. The lab personell and four graduate students were trained in sample preparation and lab analysis. One MS thesis was supported by this project. One Master of Science thesis student worked on this project starting September 2017 through December 2017. How have the results been disseminated to communities of interest?The results were desiminated through powerpoint presentation at the local and national conferences. We are also planning to prepare a factsheet related to best practices in food preparation to reduce pesticide residues in fruit and vegetables. What do you plan to do during the next reporting period to accomplish the goals?In the next reporting period, we will test the effect of different food processing techniques on pesticide residues in fruit and vegetables, and organize training on integrated pest management practice for community and home gardens.
Impacts
What was accomplished under these goals?
In this reporting period, the main goal of this research project was to collect and analyze five types of fruit and vegetables from two sources: (1) market basket of the main super market and (2) market basket of a local farmers market. Five types of fruit and vegetables were selected for the market basket study including: tomato, potato, strawberry, nectarine, apple and lettuce. The selection was made based on the USDA's pesticide data program (USDA, 2015). According to USDA (2015), these produces were reported to have detectable pesticed residues. We collected 79 samples of fruit and vegetables from five main supermarkets (48 samples) located in five DC Wards (1,2,3,5,6 and 8), and eight local farmers market (31 samples) from all eight wards of the District of Columbia. The samples were analyed for 138 types pesticide resdiues including 39 fungicides, 52 herbicides, 38 insecticides, 4 pesticide metabolites, 1 plant growth, and 1 repellant.. Samples from the main supermarket include 15 samples from organically produced farming and 33 samples from traditional farming, wheras samples from the farmers market include all 31 samples from the local farmers markets. All samples were extracted using QuEChERS and analyzed using Gas Chromatography Mass Spectrophotometery (GC-MS). The results showed that all samples from the main supermarket have at least one detectable pesticide residues, and 50% of the collected samples exceeded the EPA tolerance limit in four or more pesticide residue;65% samples exceeded the EPA tolerance limit in 1 or more pesticides. Most frequently detected pesticide includetetrahydrophthalimide and thiabendazole. All samples from the farmers market have 4 or more detectable pesticide residues which means 100% of the samples collected from the local farmers market exceeded the EPA tolerance limit. This is an interesting finding and needs further studies as locally produced fresh produces are expected to have no or lower pesticide residues. The market basket samples from the farmers market showed more percentage of samples that exceeded the EPA tolerance limits than the samples from the main supermarket.
Publications
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