Relation of the irrigation water’s metal content and geographical cultivation area of Brassica rapa subsp. chinensis growing in Northern Vietnam

Metal content in irrigation water and in edible part of pakchoi harvested from Chuong My, Dan Phuong and Me Linh districts, which are the main vegetable growing area for Ha Noi market, was investigated. Principal component analysis (PCA) was used to observe the metal content in the edible part of pakchoi and in the irrigation water as principal component (PC) 1 and 2. Zn, Mn, and Ba were discovered as the key metals contributing to the identification of geographical origin of pakchoi. Samples from Chuong My had high Zn content (130.38±12.65 mg.kg-1 DW for edible parts and 92.48±10.10 mg.L-1 for irrigation water), samples from Dan Phuong were distinct for their high Mn content (99.44±8.11 mg.kg-1 DW for edible parts and 207.37±21.55 mg.L-1 for irrigation water), and samples from Me Linh stood out for their high Ba content (396.88±39.59 mg.kg-1 DW for edible parts and 138.88±17.35 mg.L-1 for irrigation water). The ratio of Ba: Mn of pakchoi’s edible parts and irrigation water also played an important role in helping identify the geographical origin of pakchoi. They supported the fact that the fertilization method of Dan Phuong and Chuong My was different from that of Me Linh district.