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At four estuarine sites on the coast of Galicia (northwestern Spain), all of which were affected by the Prestige oil spill, soil samples were taken from polluted and unpolluted areas and their petroleum hydrocarbon contents, heavy metal contents, and other chemical and physical characteristics were measured. Oil pollution altered both chemical and physical soil properties, aggregating soil particles in plaques, lowering porosity, and increasing resistance to penetration and hydrophobicity. The chromium, nickel, copper, iron, lead, and vanadium contents of polluted soils were between 2 and 2500 times higher than those of their unpolluted counterparts and the background concentrations in Galician coastal sediments. In the cases of Cr, Cu, Ni, Pb, and V, their origin in the polluting oil was corroborated by the high correlation (r >/= 0.74) between the concentrations of these metals and the total petroleum hydrocarbon (TPH) content of the polluted soils. Soil redox potentials ranged from -19 to -114 mV in polluted soils and 112 to 164 mV in unpolluted soils, and were negatively correlated with TPH content (p < 0.01). The low values in the polluted soils explain why the soluble fractions of their total heavy metal contents were very small (generally less than 3%, and in many cases undetectable).

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The Bahia Blanca Estuary is located in southern Buenos Aires province, Argentina. The area is linked to a petrochemical industrial complex, whose raw materials and final products contaminate the surrounding areas via atmospheric pollution and effluents, which are dumped in the estuary waters. To establish the effects of the industrial waste disposal on the nearest coastal soils, 17 samples were taken at different distances from the loading dock and the outfall pipes of the industrial complex. Later, the physicochemical characteristics of the soil samples, their hydrocarbon contents, sulfides, sulfates, Zn, Cu, and Pb were analyzed and a comparison was made to control samples, which were not affected by the industrial outfall. Hydrocarbons, Zn, Cu, and Pb contents were found at levels that modified the physical and chemical characteristics of the soils. The resistance to penetration shows that the thinner the film of water that surrounds the particles or aggregates, the smaller the migration of organic micelle, which settle on the surface of the contact material. This is demonstrated by the degree of cohesion reached by the particles and the strong influence on the index of hydrophobicity. The high porosity shows that the continuity of the porous space of the soil matrix is impeded by the presence of pollutants, which generate areas that are highly limiting to water flow. The oxidation-reduction potential and the low concentrations of soluble forms of Cu and Pb compared with their concentrations precipitated as sulfides confirm the action of the pollutants.

Stay-green (SG) is a term used to describe genotypes that have delayed leaf senescence as compared to reference genotypes. SG could be favorable for grain yield, silage yield and quality, double exploitation (grain for feed and stover for bioenergy), stress resistance, etc. However, some studies show contradictory results regarding the influence of senescence or SG in the uptake and remobilization of nutrients and the yield and moisture of stover and grain. This experiment is aimed to study the impact of senescence in grain and stover yield and moisture in inbred lines of maize and assess the potential of SG genotypes for double exploitation. We also study the influence of senescence in the uptake of N and remobilization of dry matter and N from stover to grain. We evaluated 16 maize inbred lines with contrasting expression of senescence in the field at two locations in Galicia in 2017. We confirmed that SG is functional, meaning that the SG genotypes maintained photosynthesis activity for a lengthy period. Coordinated with a delayed senescence, the grain filling of the SG genotypes was 9 days longer than NSG genotypes. SG genotypes took up more N after flowering, although the remobilization of N and, in general, of dry matter from stover to kernels was less efficient. However, the higher uptake compensated the poor remobilization, and the final effect of SG on the N content of the kernels was favorable. SG was also favorable for kernel weight and the kernels of SG genotypes were 20% heavier than for NSG. The stover yield was also higher in the SG genotypes, indicating a potential of SG for breeding for double purpose (grain for feed and stover for bioenergy).