Literature study on the chemical hazards in bulbs, tubers, stem and root vegetables

Abstract

This report describes the results of a literature study performed for NVWA-BuRO in order to identify chemical hazards in bulbs, tubers, stem and root vegetables that are produced and/or consumed in the Netherlands. For the sake of convenience, these vegetables are referred to as underground vegetables in the remainder of this report. Potatoes were not included in this report since these were evaluated previously (Nijkamp et al., 2017). Search terms were predefined and used to obtain relevant scientific papers from the databases Scopus and Web of Science. Furthermore, the advanced search feature of Google was used to obtain relevant reports from the websites of four organizations (BfR, EFSA, FAO and FAVV). In case the number of hits for a certain chemical hazard group was limited or only experimental studies were found, an additional more specific literature search was performed for the particular hazard group. Based on title, keywords and abstract, the relevancy of the papers for the aims of our study was evaluated. Papers that were judged relevant were read in full and information from these papers on, amongst others, vegetables studied, chemical hazards included, country of origin, and reported concentrations, were extracted. This information was then stored in an Excel file. Long list of chemical hazards in underground vegetablesThe literature search in Scopus and Web of Science resulted in a total of 237 scientific papers. Of these, 97 were judged to be relevant. Additionally, 21 relevant hits were obtained using the Google search and 8 papers were included after the additional literature search. Most information was obtained for carrot, cassava and radish. Based on the information obtained, a long list of chemical hazards could be identified; this list contains chemical hazards that might be present in underground vegetables. The long list for underground vegetables includes heavy metals and essential elements, perfluorinated compounds, polycyclic aromatic hydrocarbons (PAHs), nitrate, pharmaceutical compounds, radionuclides, plant protection products, mycotoxins, plant toxins, processing contaminants, cleaning agents and disinfectants, and other chemical hazards such as phthalates, microcystin and nanoparticles. Intermediate list of chemical hazards in underground vegetablesThose chemical hazards that were frequently found in underground vegetables and/or reported at concentrations exceeding the (EU) legal limits and/or resulting in an exceedance of health-based guidance values (HBGVs) were included on the so-called intermediate list. The heavy metals, arsenic (As), cadmium (Cd) and lead (Pb) were added on the list since multiple papers reported their occurrence in underground vegetables (in case of As), or levels were found above the EU Maximum Levels (MLs) (in case of Cd and Pb). PAHs were added on the intermediate list since a literature review indicated that levels > 5 µg/kg may be found in underground vegetables when grown in urban or industrial areas.Radish and beetroot have a high contribution (>50%)...