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In most cases, chlorination is used for effluent disinfection. However, this process can lead to the formation of byproducts hazardous to the environment and public health. Therefore, new disinfectants, such as calcium hypochlorite (CH) and peracetic acid (PAA), were investigated as alternatives. This study aimed at determining doses of the disinfectants PAA and CH to be applied to the soil and analyzing the possible changes in the major chemical and microbiological attributes of the soil, thus encouraging the practice of reusing wastewater in agriculture. Initially, toxicity bioassays were conducted with lettuce (Lactuca sativa L.) seeds in order to determine which concentrations affected germination and also which would be analyzed. From these trials, three concentrations of each disinfectant were chosen to be subjected to basal respiration, microbial biomass carbon and metabolic quotient analyses. Doses of 3, 5 and 10 mg L-1 were used for PAA, and concentrations of 25, 32 and 64 mg L-1 for CH. Thus, it was observed that the greater concentration of each disinfectant provided a significant increase in the metabolic potential of microorganisms. However, it was observed that PAA increased ecotoxicity besides promoting changes in the chemical attributes of the soil, compared to CH. On the other hand, concentrations of 3 mg L-1 and 25 mg L-1 of PAA and CH, respectively, did not cause large impacts and could be an alternative in effluent disinfection with the aim of recycling it in agriculture.

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Pharmaceutical residues are constantly released into natural waters, mainly from wastewater treatment plants (WWTPs) whose processes are unable to completely eliminate them. Among these drugs, the occurrence of benzimidazoles, a class of antiparasitics for human and veterinary use, has been reported in WWTP effluents and surface waters. In this study, an SPE-UHPLC-MS/MS method was developed and optimized for extraction and quantitation of benzimidazoles in influents and effluents of a local WWTP and in hospital wastewater. The extraction procedure was optimized using response surface methodology (Box-Behnken design) and the optimal parameters were as follows: 2.0 mL of loading solvent consisting of a mixture of water:methanol (95:5, v/v) and temperature at 43 °C. In hospital wastewater, albendazole (ABZ) and its principal metabolite ricobendazole (RBZ) were the main benzimidazole-related contaminants and were found at concentrations of up to 3810 and 3894 ng L-1, respectively. The WWTP system was able to remove from 46% to 95% of the ABZ quantified in the influent, discharging an effluent with 16-441 ng L-1 of ABZ. The concentrations of other benzimidazoles and metabolites in the WWTP effluents remained below 350 ng L-1. WWTP effluents fortified with 50 µg L-1 of ABZ required 26.7 mgO3 L-1 to remove ABZ and RBZ. After ozonation, the COD and BOD5 of the effluents were reduced by 27%. Photolysis by UVA radiation was not effective to remove ABZ and FBZ from the effluent samples.

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A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has not been fixed in the paper.

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The environmental conditions on the Earth before 4 billion years ago are highly uncertain, largely because of the lack of a substantial rock record from this period. During this time interval, known as the Hadean, the young planet transformed from an uninhabited world to the one capable of supporting, and inhabited by the first living cells. These cells formed in a fluid environment they could not at first control, with homeostatic mechanisms developing only later. It is therefore possible that present-day organisms retain some record of the primordial fluid in which the first cells formed. Here we present new data on the elemental compositions and mineral fingerprints of both Bacteria and Archaea, using these data to constrain the environment in which life formed. The cradle solution that produced this elemental signature was saturated in barite, sphene, chalcedony, apatite, and clay minerals. The presence of these minerals, as well as other chemical features, suggests that the cradle environment of life may have been a weathering fluid interacting with dry-land silicate rocks. The specific mineral assemblage provides evidence for a moderate Hadean climate with dry and wet seasons and a lower atmospheric abundance of CO2 than is present today.

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Knowledge of the behavior of plant species associated with arbuscular mycorrhizal fungi (AMF) and the ability of such plants to grow on metal-contaminated soils is important to phytoremediation. Here, we evaluate the occurrence and diversity of AMF and plant species as well as their interactions in soil contaminated with lead (Pb) from the recycling of automotive batteries. The experimental area was divided into three locations: a non-contaminated native area, a coarse rejects deposition area, and an area receiving particulate material from the chimneys during the Pb melting process. Thirty-nine AMF species from six families and 10 genera were identified. The Acaulospora and Glomus genera exhibited the highest occurrences both in the bulk (10 and 6) and in the rhizosphere soils (9 and 6). All of the herbaceous species presented mycorrhizal colonization. The highest Pb concentrations (mgkg-1) in roots and shoots, respectively, were observed in Vetiveria zizanoides (15,433 and 934), Pteris vitata (9343 and 865), Pteridim aquilinun (1433 and 733), and Ricinus communis (1106 and 625). The diversity of AMF seems to be related to the area heterogeneity; the structure communities of AMF are correlated with the soil Pb concentration. We found that plant diversity was significantly correlated with AMF diversity (r=0.645; P>0.05) in areas with high Pb soil concentrations. A better understanding of AMF communities in the presence of Pb stress may shed light on the interactions between fungi and metals taking place in contaminated sites. Such knowledge can aid in developing soil phytoremediation techniques such as phytostabilization.

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Arbuscular mycorrhizal fungi (AMF) are ubiquitous and establish important symbiotic relationships with the majority of the plants, even in soils contaminated with arsenic (As). In order to better understand the ecological relationships of these fungi with excess As in soils and their effects on plants in tropical conditions, occurrence and diversity of AMF were evaluated in areas affected by gold mining activity in Minas Gerais State, Brazil. Soils of four areas with different As concentrations (mg dm(-3)) were sampled: reference Area (10); B1 (subsuperficial layer) (396); barren material (573), and mine waste (1046). Soil sampling was carried out in rainy and dry seasons, including six composite samples per area (n = 24). AMF occurred widespread in all areas, being influenced by As concentrations and sampling periods. A total of 23 species were identified, belonging to the following genus: Acaulospora (10 species), Scutellospora (4 species), Racocetra (3 species), Glomus (4 species), Gigaspora (1 species) and Paraglomus (1 species). The most frequent species occurring in all areas were Paraglomus occultum, Acaulospora morrowiae and Glomus clarum. The predominance of these species indicates their high tolerance to excess As. Although arsenic contamination reduced AMF species richness, presence of host plants tended to counterbalance this reduction.

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Visando estudar a influência de diferentes sistemas de manejo do solo com e sem calagem, sobre a colonização micorrízica radicular e a produção de micélio extrarradicular, por meio de técnica de análise multivariada, utilizou-se um experimento implantado em 1978, no município de Guarapuava, PR. A análise de componentes principais comprovou a existência de efeitos negativos do sistema de preparo convencional do solo sobre a colonização de fungos micorrízicos arbusculares (FMAs) do solo, principalmente em estruturas como arbúsculos e vesículas. A calagem apresentou benefícios para os parâmetros de colonização micorrízica e comprimento de micélio extrarradicular, sendo mais significativo nos sistemas de manejo conservacionistas, principalmente o sistema de plantio direto. Nas áreas de sistemas convencionais ocorreu uma redução na colonização micorrízica e, conseqüentemente, diminuição dos efeitos benéficos dos FMAs para as plantas, reduzindo a qualidade do solo e a sustentabilidade.

The objective of this work was to evaluate the influence of different soil management systems with and without liming on root colonization and production of extraradicular mycelium. Through multivariate analysis technique, an experiment established in 1978 in Guarapuava, state of Paraná was used. Correspondence analysis proved the existence of negative effects of the conventional tillage on the root mycorrhizal colonization (AMF) of the soil, mainly in structures as arbuscules and vesicles. The liming showed to be beneficial for the parameters of root micorrhyzal colonization and hyphal length, being more significant for conservationist management systems, such as no-tillage. In the areas under conventional management systems there was a reduction in micorrhyzal root colonization and consequently a decrease in beneficial effects of AMF for the plants, reducing the quality of the soil and the sustainability.

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Este trabalho objetivou avaliar o efeito da calagem e sua influência sobre atributos químicos e de fauna do solo em um Cambissolo sob sistema de semeadura direta. O experimento vem sendo conduzido em Lages, SC, desde maio de 2001. Os tratamentos foram: semeadura direta com calcário incorporado na dose de 1 SMP (SD-inc) e superficial nas doses de 1/5 SMP (SD-1/5sup) e 1/2 SMP (SD-1/2sup). Como padrão, utilizou-se solo sem cultivo e sem aplicação de calcário, e uma área de pastagem perene com calcário incorporado na dose de 1 SMP (PI-inc). O solo foi amostrado nas camadas de 0-5; 5-10; 10-20cm para análise de Ca2+, Mg+2, Al3+, pH em água e em CaCl2; e de 0-10cm para carbono orgânico total e fauna do solo. A aplicação superficial de calcário no sistema de semeadura direta na maior dose (1/2 SMP) elevou os teores de Ca2+ até 10cm de profundidade e de Mg+2 até a camada de 10 a 20cm. A abundância e a diversidade da fauna edáfica foram maiores nas áreas sob semeadura direta e pastagem, em relação ao solo sem cultivo, mostrando sensibilidade às alterações advindas do manejo do solo, mas sem correlação direta com as modificações químicas decorrentes da calagem.

This research was aimed at evaluating the effect of liming and its influence on chemistry and fauna properties of a Cambisol under no-tillage system. The experiment has been carried out in Lages, SC, southern Brazil, since May 2001. The treatments were: no-tillage with incorporated lime in the rate of 1 SMP (NT-inc); superficial liming in the rate of 1/5 SMP (NT-1/5sup), and 1/2 SMP (NT-1/2sup). As control treatment, bare soil without cultivation without lime application (BS), and plots with perennial pasture with incorporate lime in the rate of 1 SMP (Pp-inc) were used. Soil samples were collected in the layers of 0-5; 5-10; 10-20cm depth for analysis of Ca2+, Mg+2, Al3+, water and CaCl2 pH. Total organic carbon and soil fauna were analysed in the layer 0-10cm. The superficial liming in the no-tillage system in the highest rate (1/2 SMP) increased Ca2+ contents up to 10 cm depth and Mg+2 up to the layer of 10 to 20cm. The abundance and diversity of soil fauna were higher in cultivated plots under no-tillage and pasture, in relation to the bare soil, showing influences of soil management, but with no direct relation with chemical soil conditions created by liming.

RESUMO

This research was aimed at evaluating the effect of liming and its influence on chemistry and fauna properties of a Cambisol under no-tillage system. The experiment has been carried out in Lages, SC, southern Brazil, since May 2001. The treatments were: no-tillage with incorporated lime in the rate of 1 SMP (NT-inc); superficial liming in the rate of 1/5 SMP (NT-1/5sup), and 1/2 SMP (NT-1/2sup). As control treatment, bare soil without cultivation without lime application (BS), and plots with perennial pasture with incorporate lime in the rate of 1 SMP (Pp-inc) were used. Soil samples were collected in the layers of 0-5; 5-10; 10-20cm depth for analysis of Ca2+, Mg+2, Al3+, water and CaCl2 pH. Total organic carbon and soil fauna were analysed in the layer 0-10cm. The superficial liming in the no-tillage system in the highest rate (1/2 SMP) increased Ca2+ contents up to 10 cm depth and Mg+2 up to the layer of 10 to 20cm. The abundance and diversity of soil fauna were higher in cultivated plots under no-tillage and pasture, in relation to the bare soil, showing influences of soil management, but with no direct relation with chemical soil conditions created by liming.(AU)

Este trabalho objetivou avaliar o efeito da calagem e sua influência sobre atributos químicos e de fauna do solo em um Cambissolo sob sistema de semeadura direta. O experimento vem sendo conduzido em Lages, SC, desde maio de 2001. Os tratamentos foram: semeadura direta com calcário incorporado na dose de 1 SMP (SD-inc) e superficial nas doses de 1/5 SMP (SD-1/5sup) e 1/2 SMP (SD-1/2sup). Como padrão, utilizou-se solo sem cultivo e sem aplicação de calcário, e uma área de pastagem perene com calcário incorporado na dose de 1 SMP (PI-inc). O solo foi amostrado nas camadas de 0-5; 5-10; 10-20cm para análise de Ca2+, Mg+2, Al3+, pH em água e em CaCl2; e de 0-10cm para carbono orgânico total e fauna do solo. A aplicação superficial de calcário no sistema de semeadura direta na maior dose (1/2 SMP) elevou os teores de Ca2+ até 10cm de profundidade e de Mg+2 até a camada de 10 a 20cm. A abundância e a diversidade da fauna edáfica foram maiores nas áreas sob semeadura direta e pastagem, em relação ao solo sem cultivo, mostrando sensibilidade às alterações advindas do manejo do solo, mas sem correlação direta com as modificações químicas decorrentes da calagem.(AU)

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