Phosphorus lability increases with the rehabilitation advance of iron mine land in the eastern Amazon.

Impacted areas by iron mining may face challenges in the management of phosphate fertilization and reduced efficiency of rehabilitation practices, thus extending the time required for the rehabilitation of these areas. The objective of this study was to evaluate phosphorus (P) lability in soils of native forest and ferriferous canga areas (savanna vegetation above ironstone outcrops covering iron ore deposits) and in iron mine waste piles undergoing rehabilitation. Benches of the analysed waste pile differ in age of rehabilitation: as the initial rehabilitation stage (INI), we consider benches with fewer than 3 years of rehabilitation; the intermediate stage (INT) were benches with up to 5 years of rehabilitation; and the advanced rehabilitation stage (ADV) corresponds to benches with more than 8 years of rehabilitation activities. Organic and inorganic P fractions were analysed in these areas by chemical fractionation and were classified according to the degree of soil lability. The results show that in the canga environment, there was a predominance of inorganic fractions of moderate lability and moderate stability, with a strong dependency of the soil organic matter (SOM) on the P fractions, whereas there was a greater participation of the moderately labile organic fractions in the forest than in the canga. On the other hand, in the rehabilitation areas, there was an increase in the labile organic and inorganic fractions as the rehabilitation process advanced. The distribution of P in areas undergoing rehabilitation indicates that there is a tendency for P levels to resemble those of native environments, such as the forests.

Aqueous Coriandrum sativum L. extract promotes neuroprotection against motor changes and oxidative damage in rat progeny after maternal exposure to methylmercury.

This study aimed to investigate the effects of Coriandrum sativum aqueous extract (CSAE) on the rat progeny of mothers exposed to methylmercury (MeHg). The presence of bioactive compounds and CSAE's antioxidant capacity been evaluated, and the offspring were assessed for their total mercury levels, motor behavioral parameters and oxidative stress in the cerebellum. The analysis of the bioactive compounds revealed significant amounts of polyphenols, flavonoids, and anthocyanins, as well as a variety of minerals. A DPPH test showed the CSAE had important antioxidant activity. The MeHg + CSAE group performed significantly better spontaneous locomotor activity, palmar grip strength, balance, and motor coordination in behavioral tests compared the MeHg group, as well as in the parameters of oxidative stress, with similar results to those of the control group. The MeHg + CSAE group also had significantly reduced mercury levels in comparison to the MeHg group. Based on the behavioral tests, which detected large locomotor, balance, and coordination improvements, as well as a reduction in oxidative stress, we conclude that CSAE had positive functional results in the offspring of rats exposed to MeHg.

Effect of cadmium on young plants of Virola surinamensis.

The steady increase in cadmium (Cd) levels in the environment from anthropogenic actions has contributed to environmental degradation. Virola surinamensis is a forest species that has desirable characteristics such as deep and dense roots, relatively rapid growth and high biomass production to remedy contaminated environments by Cd. The aim of this study was to assess the physiological responses and the phytoextraction and tolerance capacity of young plants of V. surinamensis submitted to Cd concentrations. The experimental design was a completely randomized design with five Cd concentrations (0, 15, 30, 45 and 60 mg L-1) for 60 days. Leaf water potential (Ψpd), stomatal conductance (gs) and transpiration (E) reduced in plants exposed to Cd. Lower values of maximum photochemical efficiency of photosystem II (Fv/Fm), electron transport rate (ETR) and photochemical quenching coefficient (qP) were accompanied by reduction of photosynthesis (A) with increasing concentrations of Cd, although the non-photochemical quenching coefficient (NPQ), and intercellular CO2 concentration (Ci) showed increase. Instantaneous water-use efficiency (A/E), net photosynthesis to intercellular CO2 concentration ratio (A/Ci) and total chlorophyll (Chl) reduced with increasing levels of Cd. Cadmium concentrations increased in different plant tissues (root > stem > leaf). The tolerance index (TI) indicated that V. surinamensis presented medium and high tolerance to Cd. The results of bioconcentration factor (BCF) and translocation factor (TF) showed low plant efficacy in Cd phytoextraction and suggest that V. surinamensis may be promising for phytostabilization of Cd.