Statistical Techniques to Analyze Pesticide Data Program Food Residue Observations

Pesticide residues in juvenile Chinook salmon and prey items of the Sacramento River watershed, California - A comparison of riverine and floodplain habitats

Juvenile Chinook salmon (Oncorhynchus tshawytscha) of the Sacramento River system encounter many anthropogenically-induced stressors while rearing and migrating to the Pacific Ocean. Located in a prominent agricultural region, the watershed serves as a source of notable contaminants including pesticides. Salmon rearing in riverine and floodplain areas are potentially exposed to these compounds via dietary exposure, which can vary based on selected food webs. Previous studies have suggested that juvenile Chinook salmon rearing in riverine and floodplain environments of the Sacramento River watershed are characterized by different dietary preferences, with potential for contrasting pesticide exposure between habitats. To examine the potential for pesticide exposure, juvenile Chinook salmon and known dietary items were collected in the mainstem Sacramento River and an adjacent floodplain, the Yolo Bypass, in 2019 and 2020, and analyzed for 33 pesticides, including degradates and isomers. Organochlorine pesticides including the DDX group (p,p'-DDT, p,p'-DDD and p,p'-DDE) were prevalent in all examined biota. There was a significantly greater number of total pesticide detections across all classes in zooplankton compared to macroinvertebrates, coupled with higher bifenthrin concentrations in zooplankton across regions and years, which may indicate different exposure potential depending on fish dietary preferences. Detection frequencies and concentrations of organochlorines were higher in prey items during flooding than in drought conditions, suggesting resuspension of legacy compounds. Significantly higher concentrations of organochlorines were recorded in floodplain rearing fish compared to the Sacramento River. These findings suggest that within these habitats, juvenile Chinook salmon feeding primarily on zooplankton within the water column may be exposed to a greater range of pesticides than those feeding on benthic macroinvertebrates, and that the benefits of floodplain rearing may come at a cost of increased organochlorine exposure.

PRIAS: An Intelligent Analysis System for Pesticide Residue Detection Data and Its Application in Food Safety Supervision

Pesticide residue is a prominent factor that leads to food safety problems. For this reason, many countries sample and detect pesticide residues in food every year, which generates a large amount of pesticide residue data. However, the way to deeply analyze and mine these data to quickly identify food safety risks is still an unresolved issue. In this study, we present an intelligent analysis system that supports the collection, processing, and analysis of detection data of pesticide residues. The system is first based on a number of databases such as maximum residue limit standards for the fusion of pesticide residue detection results; then, it applies a series of statistical methods to analyze pesticide residue data from multiple dimensions for quickly identifying potential risks; it uses the Apriori algorithm to mine the implicit association in the data to form pre-warning rules; finally, it applies Word document automatic generation technology to automatically generate pesticide residue analysis and pre-warning reports. The system was applied to analyze the pesticide residue detection results of 42 cities in mainland China from 2012 to 2015. Application results show that the system proposed in this study can greatly improve the depth, accuracy and efficiency of pesticide residue detection data analysis, and it can provide better decision support for food safety supervision.

Co-occurrence of Conazole Fungicide Residues in Raw Agricultural Commodities Sampled by the United States Department of Agriculture Pesticide Data Program

In this study, the residue data for conazole fungicides were collated and analyzed in all crop samples reported by the United States Department of Agriculture Pesticide Data Program over the period of 2009-2019. Considering all individual samples, the overall detection frequencies (DFs) of conazoles are less than 13%. Among the 18 conazoles, imazalil had the highest overall DF of 6%, followed by tebuconazole and myclobutanil, with 4% each. Conazoles were detected most frequently in raisins with 28% DF, followed by cherries (frozen and fresh) and grapes, with 12, 10, and 10%, respectively. The presence of multiple conazoles in single commodity samples is very low, below 2%. The analyses found no more than four conazoles present in any given sample. Out of the 18 conazoles, 8 of them were not detected in more than 99.9% of the commodity samples from 2009 to 2019 and, therefore, can be eliminated from screening-level cumulative risk assessment for dietary contributions from food items. While conazoles are widely used on food commodities, co-occurrence of conazole residues was observed only in a very limited number of food commodities, including raisins, grapes, cherries (frozen), nectarines, and peaches. Considering the remaining individual food commodities, the co-occurrence of conazole residues in single commodity samples is very low or not even present.