ABSTRACT Heavy metals are naturally found in soils, but their levels may increase as a result of anthropogenic actions. This study aimed at determining the concentrations of Cd, Cu, Mn, Ni, Pb and Zn in Yellow Latosol from vegetable crops areas, as well as the influence of the cultivation and position in the landscape on the accumulation of these elements. Soil samples were collected from five farming areas and four areas with natural vegetation, which served as a reference. Soil was collected along the planting rows from three transect positions (upper, middle and lower sections of the slope), as well as from the upper portion of forest areas, at three depths (0.0-0.10 m, 0.10-0.30 m and 0.30-0.60 m). The results from the chemical analyses indicated that Cd, Cu, Mn, Pb and Zn levels in the soil increased as a result of cultivation. Only Cd and Cu concentrations were above the quality reference values for the Pernambuco State. The multivariate analysis techniques used were efficient at separating the environments and at differentiating the origin of the metals. Soils from forest areas were clearly separated from croplands, demonstrating the effect of agricultural practices on the metal contents in the soils. The principal component analysis indicated a predominantly anthropogenic origin (phosphate fertilizing) for Cd, in more superficial soil samples.

Abstract The consumption of contaminated water is a major source of heavy metal contamination in humans and animals. This study therefore aimed to assess Cd, Cu, Mn, Ni, Pb, and Zn levels in water used for human and animal consumption and vegetable crop irrigation in Camocim de São Félix, Pernambuco, Brazil. Water samples were collected on the studied farms from an artesian well and reservoirs used for human and animal consumption as well as for crop irrigation. The results showed that concentrations of Cd (> 0.001 mg L-1), Ni (> 0.025 mg L-1) and Pb (> 0.01 mg L-1) were above the maximum allowable limits established under Brazilian law, indicating the need for a preventive monitoring program and immediate intervention initiatives aimed at the sources of contamination. The results demonstrate the need to quantify heavy metal content in vegetable crops, since their contamination by irrigation water may make them harmful to human health. Rainfall has a seasonal effect on heavy metal concentrations in water, showing a significant effect on Pb levels, whereas Cd and Ni content was less dependent on seasonal variation.

ABSTRACT Heavy metals are naturally found in soils, but their levels may increase as a result of anthropogenic actions. This study aimed at determining the concentrations of Cd, Cu, Mn, Ni, Pb and Zn in Yellow Latosol from vegetable crops areas, as well as the influence of the cultivation and position in the landscape on the accumulation of these elements. Soil samples were collected from five farming areas and four areas with natural vegetation, which served as a reference. Soil was collected along the planting rows from three transect positions (upper, middle and lower sections of the slope), as well as from the upper portion of forest areas, at three depths (0.0-0.10 m, 0.10-0.30 m and 0.30-0.60 m). The results from the chemical analyses indicated that Cd, Cu, Mn, Pb and Zn levels in the soil increased as a result of cultivation. Only Cd and Cu concentrations were above the quality reference values for the Pernambuco State. The multivariate analysis techniques used were efficient at separating the environments and at differentiating the origin of the metals. Soils from forest areas were clearly separated from croplands, demonstrating the effect of agricultural practices on the metal contents in the soils. The principal component analysis indicated a predominantly anthropogenic origin (phosphate fertilizing) for Cd, in more superficial soil samples.

The consumption of contaminated water is a major source of heavy metal contamination in humans and animals. This study therefore aimed to assess Cd, Cu, Mn, Ni, Pb, and Zn levels in water used for human and animal consumption and vegetable crop irrigation in Camocim de São Félix, Pernambuco, Brazil. Water samples were collected on the studied farms from an artesian well and reservoirs used for human and animal consumption as well as for crop irrigation. The results showed that concentrations of Cd (> 0.001 mg L-1), Ni (> 0.025 mg L-1) and Pb (> 0.01 mg L-1) were above the maximum allowable limits established under Brazilian law, indicating the need for a preventive monitoring program and immediate intervention initiatives aimed at the sources of contamination. The results demonstrate the need to quantify heavy metal content in vegetable crops, since their contamination by irrigation water may make them harmful to human health. Rainfall has a seasonal effect on heavy metal concentrations in water, showing a significant effect on Pb levels, whereas Cd and Ni content was less dependent on seasonal variation.

RESUMO A conversão da condição natural do solo para a agricultura, em destaque para a monocultura de cana-deaçúcar impõe alterações nos atributos do solo. O objetivo do trabalho foi avaliar a variação do estoque de carbono de Latossolos com mata nativa, cana-de-açúcar e área reflorestada adjacentes, no município de Guariba - SP. Em cada área, foram coletadas, aleatoriamente, quatro amostras (compostas por quinze pontos), nas camadas de 0,0-0,10 e de 0,10-0,20 m. Foram avaliados os atributos densidade do solo, porosidade total, granulometria, teor de matéria orgânica, carbono orgânico total e estoque de carbono total no solo, de cada amostra nas duas profundidades estudadas. Os dados foram submetidos à análise de variância, correlação linear e análises multivariadas. Os resultados indicam que os teores de carbono são maiores nas camadas superficiais nas três áreas, decrescendo em profundidade. O solo da área de mata nativa apresenta o maior estoque de carbono, com 20,65 Mg ha-1, seguido pelo reflorestamento e cultivo de cana-de-açúcar, com 15,93 e 13,71 Mg ha-1, respectivamente, na profundidade de 0,0-0,10 m e 17,71 Mg ha-1, seguido pelo reflorestamento e cultivo de cana-de-açúcar, com 14,86 e 12,06 Mg ha-1, respectivamente, na profundidade de 0,10-0,20 m. Foi possível verificar tendo como referência a mata nativa, a perda de carbono no solo, sendo a área reflorestada e cultivada com cana-de-açúcar, na ordem de 22,9 e 33,6 %, na profundidade de 0,0-0,10 m e de 31,9 e 16,1 % nas áreas reflorestada e cultivada com cana-de-açúcar na profundidade de 0,10-0,20 m, respectivamente. Assim, conclui-se que intervenção humana através de práticas agropecuárias reduz o estoque de carbono no solo a patamares inferiores ao encontrado em condições de mata nativa.