Metal(oid)s contamination in rural and urban vegetable gardens of Teresina (Brazil)

Abstract

In Brazil, more than 80% of population today lives in urban areas. Consistently, growing concerns about the quality and cost of food and food insecurity have increased interest in producing food locally as well as in urban community or allotment gardens. Urban horticulture, besides its recognized role in improving social relations and healthiness of diet, may pose some risks on human health. Urban gardeners may be exposed to chemical risks associated with pesticides and fertilizers, as well as ingestion of metal(oid)s due to air and water pollution and contamination. In the urban environment, vehicle emissions are considered one of the main sources of contamination of metal(oid)s, and consistently, plants grown nearby roads can present high levels of lead, zinc, chrome, nickel and tin in their tissues. Metal(oid)s, which can cause chronic diseases, are transported into the human body through food consumption. The present study analyzed the metal(oid)s contamination in urban gardens compared to a rural farm. Ions analysis was conducted on lettuce and chives collected in allotment gardens and in a rural farm in the Brazilian city of Teresina (Piaui). In plants from rural and urban gardens cadmium, arsenic and nickel were found below the detection limits. Plants grown in allotment gardens resulted to be more exposed to copper, zinc, molybdenum and antymony than those cultivated in the rural farm. On the other hand, reduced values of lead, strontium and barium were observed in plant samples obtained from urban allotments as compared to the rural farm. Furthermore, the metal(oid)s content was lower than in the Brazilian wholesale vegetables cited in the literature. Accordingly, urban vegetables grown in the city of Teresina resulted to be safe for human consumption.