RESUMO
The aim of the present study is to assess soil Cd and Pb contamination in kale (Brassica oleracea var. acephala) production sites in mountain agroecosystem, as well as its potential risk to human health. The study was carried out within 24 kale-production sites located in mountainous region of Rio de Janeiro (Brazil). Soil, plant, and fertilizer samples were collected in all assessed properties. Pseudo-total and bioavailable soil Cd and Pb content and their concentration and amount accumulated in plants were analyzed. The recorded results were used to calculate the pollution index. Risks to human health associated with kale consumption were assessed by comparing the limits set by the Brazilian regulating agency and by calculating estimated daily intake (EDI), noncarcinogenic target hazard quotient (THQ), and carcinogenic risk factor (CRF). Soil Cd and Pb enrichment was observed. Inappropriate management adopted in the assessed sites and terrain slope and the intensive use of mineral (phosphate and potassium) and organic (poultry litter) fertilizers were the main factors contributing to increase soil Cd and Pb pseudo-total and bioavailability contents. Most Cd and Pb contents in leaves, in natura, exceed the maximum values set by the Brazilian regulating agency. The present EDI, THQ, and CRF results recorded for these metals were within the tolerable ranges.
Assuntos
Brassica , Metais Pesados , Poluentes do Solo , Brasil , Cádmio/análise , Monitoramento Ambiental , Fertilizantes/análise , Humanos , Chumbo , Metais Pesados/análise , Solo , Poluentes do Solo/análise , Fator de TransferênciaRESUMO
The current study was developed to evaluate agronomic efficiency and food security of isolated or simultaneous use of two residues-steel slag and fresh or composted poultry litter-in the cultivation of broccoli (Brassica oleracea var. italica). The composition and contribution of toxic and potentially toxic metals by different treatments and contents, translocation, and accumulation of Pb, Cd, Cu, Fe, Mn, and Zn in different plant organs were analyzed. Then, risks to human health associated with consumption of inflorescences were based on the indices of estimated daily intake, noncarcinogenic target hazard quotient, total hazard index (THI), and carcinogenic risk factor (CR), considering adults and children. Steel slag was similar to limestone in terms of the corrective effect of acidity and, despite containing toxic metals, it did not contribute to their higher translocation to inflorescences. Composting favored the concentrations of Pb, Cu, and Zn in poultry litter. The combined use of steel slag and fresh poultry litter and, mainly, composted poultry litter, favored absorption and translocation of Pb for inflorescences, that is, 60.37% and 66.13% of all Pb absorbed, respectively. Consumption of inflorescences from these treatments resulted in the critical THI values of 1.03 and 1.52, respectively, with Pb and Cd being the metals that mostly contributed to the risk. The registered CR was higher than the threshold level of 10-6. The use of steel slag associated with poultry litter favors contamination of broccoli inflorescences and increases risks to human health due to their consumption.
Assuntos
Brassica , Metais Pesados , Poluentes do Solo , Adulto , Animais , Criança , Monitoramento Ambiental , Humanos , Metais Pesados/análise , Aves Domésticas , Medição de Risco , Poluentes do Solo/análise , Poluentes do Solo/toxicidade , Clima TropicalRESUMO
The objectives of this study was to diagnose Cd and Pb contamination in soil and to identify the main factors that contribute to the transfer of these elements to tomato plants and fruits and contamination levels of the fruits in tropical mountain conditions. Contamination of the study area soils by Cd and Pb was verified. This contamination stemmed from the intensive use of agricultural inputs, mainly organic fertilizers and soluble mineral fertilizers. The relief of the terrain and inadequate soil management influenced the spatial distribution of these two metals. The Cd concentration in tomato fruits was very low, but the Pb contamination detected in approximately 80% of the fruit samples was considerably higher than the limits that pose a danger to human health. The translocation of Pb to the tomato fruits was associated with the use of organic fertilizer, mainly poultry litter.