Lead poisoning risk for dairy cows in the semi-arid region of Pernambuco, Brazil.

The lead (Pb) isotopes ²°6Pb and ²°8Pb are the final products of the radioactive decay of ²³8U and ²³²Th, respectively. Soils in the municipalities of Pedra and Venturosa, Brazil, present high levels of these radionuclides. We hypothesized that forage plants growing in these soils may take up high amounts of Pb and, consequently, intoxicate dairy cows. To test this, we quantified Pb concentrations in 23 forage samples from this region. Pb concentrations varied from 5 to 344 mg kg⁻¹. The highest values are one order of magnitude above the reported limit, therefore, indicating high risk of Pb contamination for dairy cows.

Estimation of dose due to ingestion of (210)pb in milk from dairy cattle in the semi-arid region of Pernambuco, Brazil.

(210)Pb is widely distributed in the environment. In this context, the aim of this research has been: (1) to determine (210)Pb concentrations in milk and dairy products from farms located in the cities of Pedra and Venturosa in Pernambuco, Brazil; and (2) to calculate the dose due to the ingestion of (210)Pb in these products. The ion exchange resin method was used and the concentration of (210)Pb varied from 62 to 650 mBq l(-1) in fresh milk, from 202 to 1,494 mBq kg(-1) in curdled cheese and from 11 to 253 mBq l(-1) in milk whey. The estimated dose due to ingestion of milk and dairy products in this region was 0.2 Sv, which is at least two orders of magnitude above the maximum recommended levels.

210Pb in forage consumed by dairy cows.

The aim of this research was to determine (210)Pb concentrations in forage from farms located in the municipalities of Pedra and Venturosa, in the Brazilian state of Pernambuco, where rolled blocks of mafic rock with a high percentage of U(3)O(8) were found. The concentrations of (210)Pb varied from 2 to 503 Bq kg(-1) in the forage dry matter samples evaluated. Due to the elevated levels of (210)Pb in the forage samples, it is concluded that this radionuclide is highly available to be ingested by dairy cows and this could represent a hazard to the human population due to possible milk contamination.

Pb-210 in rock and soils of the semi-arid agreste region of Pernambuco, Brazil.

The aim of this research was to determine (210)Pb concentrations in rocks and soils of farms located in the municipalities of Pedra and Venturosa. In these farms, rolled blocks of mafic rock with a high percentage of U(3)O(8) were found. The concentrations of (210)Pb varied from 3.2 to 201 kBq kg(-1) in rock samples and from 195 to 86,400 Bq kg(-1) in soil samples. The high levels of radioactivity found in the samples, indicate the need to conduct more detailed studies to evaluate the risk of radionuclide ingestion due to milk consumption by the population in the state of Pernambuco.

Salt stress response and proline accumulation in Brachiaria humidicola plants with and without mycorrhizal inoculation.

The work was carried out to investigate the effects of different concentrations of NaCl on Brachiaria humidicola Rendle in the presence and absence of Glomus etunicatum Becker and Gerdemann, as well as to evaluate some growth parameters and the accumulation of free proline in the plant leaves. The soil used was a Neosoil Fluvic Eutrophic with pH of 6.5, organic matter, 12.8 g kg-1 and soil texture, sandy loam, in which Brachiaria humidicola Rendle cv. 409 was grown. Five NaCl concentrations were tested 0; 0.22; 1.09; 1.96 and 2.84 g. kg-1 of soil, whose electrical conductivity (EC) were 2.22; 4.00; 8.13; 12.53 and 16.50 dS m-1, respectively. Brachiaria humidicola showed salt tolerance when submitted to an EC of 4 dS m-1. There was a reduction of leaf area, dry matter of shoots and roots for the soil treatments beyond EC at 8 dS m-1. Free proline content in the leaves increased together with the increase in soil salinity (EC at 8 dS m-1) demonstrating that plants submitted to EC of 2 and 4 dS m-1 were less affected by salt stress, and consequently accumulated less proline in the leaves. Root colonization was not affected by the increase of NaCl dosage in the soil.

Salt stress response and proline accumulation in Brachiaria humidicola plants with and without mycorrhizal inoculation

The work was carried out to investigate the effects of different concentrations of NaCl on Brachiaria humidicola Rendle in the presence and absence of Glomus etunicatum Becker and Gerdemann, as well as to evaluate some growth parameters and the accumulation of free proline in the plant leaves. The soil used was a Neosoil Fluvic Eutrophic with pH of 6.5, organic matter, 12.8 g kg-1 and soil texture, sandy loam, in which Brachiaria humidicola Rendle cv. 409 was grown. Five NaCl concentrations were tested 0; 0.22; 1.09; 1.96 and 2.84 g. kg-1 of soil, whose electrical conductivity (EC) were 2.22; 4.00; 8.13; 12.53 and 16.50 dS m-1, respectively. Brachiaria humidicola showed salt tolerance when submitted to an EC of 4 dS m-1. There was a reduction of leaf area, dry matter of shoots and roots for the soil treatments beyond EC at 8 dS m-1. Free proline content in the leaves increased together with the increase in soil salinity (EC at 8 dS m-1) demonstrating that plants submitted to EC of 2 and 4 dS m-1 were less affected by salt stress, and consequently accumulated less proline in the leaves. Root colonization was not affected by the increase of NaCl dosage in the soil.

Salt stress response and proline accumulation in Brachiaria humidicola plants with and without mycorrhizal inoculation

The work was carried out to investigate the effects of different concentrations of NaCl on Brachiaria humidicola Rendle in the presence and absence of Glomus etunicatum Becker and Gerdemann, as well as to evaluate some growth parameters and the accumulation of free proline in the plant leaves. The soil used was a Neosoil Fluvic Eutrophic with pH of 6.5, organic matter, 12.8 g kg-1 and soil texture, sandy loam, in which Brachiaria humidicola Rendle cv. 409 was grown. Five NaCl concentrations were tested 0; 0.22; 1.09; 1.96 and 2.84 g. kg-1 of soil, whose electrical conductivity (EC) were 2.22; 4.00; 8.13; 12.53 and 16.50 dS m-1, respectively. Brachiaria humidicola showed salt tolerance when submitted to an EC of 4 dS m-1. There was a reduction of leaf area, dry matter of shoots and roots for the soil treatments beyond EC at 8 dS m-1. Free proline content in the leaves increased together with the increase in soil salinity (EC at 8 dS m-1) demonstrating that plants submitted to EC of 2 and 4 dS m-1 were less affected by salt stress, and consequently accumulated less proline in the leaves. Root colonization was not affected by the increase of NaCl dosage in the soil.(AU)

Salt stress response and proline accumulation in Brachiaria humidicola plants with and without mycorrhizal inoculation.

The work was carried out to investigate the effects of different concentrations of NaCl on Brachiaria humidicola Rendle in the presence and absence of Glomus etunicatum Becker and Gerdemann, as well as to evaluate some growth parameters and the accumulation of free proline in the plant leaves. The soil used was a Neosoil Fluvic Eutrophic with pH of 6.5, organic matter, 12.8 g kg-1 and soil texture, sandy loam, in which Brachiaria humidicola Rendle cv. 409 was grown. Five NaCl concentrations were tested 0; 0.22; 1.09; 1.96 and 2.84 g. kg-1 of soil, whose electrical conductivity (EC) were 2.22; 4.00; 8.13; 12.53 and 16.50 dS m-1, respectively. Brachiaria humidicola showed salt tolerance when submitted to an EC of 4 dS m-1. There was a reduction of leaf area, dry matter of shoots and roots for the soil treatments beyond EC at 8 dS m-1. Free proline content in the leaves increased together with the increase in soil salinity (EC at 8 dS m-1) demonstrating that plants submitted to EC of 2 and 4 dS m-1 were less affected by salt stress, and consequently accumulated less proline in the leaves. Root colonization was not affected by the increase of NaCl dosage in the soil.