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Pesticide use generates wastewaters from its handling and from washing of spraying equipment, bringing concern about punctual discharge. Biobeds are biopurification systems for pesticide residues disposal, representing safe alternatives to avoid soil contamination. Peat that composes the original biomixture is not available all around Brazil. The aim of this work was to evaluate the efficiency of two alternative, accessible biomixtures, replacing peat, for treating phosmet (organophosphate insecticide) residues in biobeds and reducing its ecotoxicological effects. We hypothesized that the new biomixtures with pine litter (PB) or vermicompost (VB) could show the same degradation and detoxification efficiency as the standard biobed's biomixture (SB) using peat. Small size bioreactors received 35 mg kg−1 of phosmet (Imidan®) in a laboratory-scale experiment. The pesticide degradation was monitored by chemical analysis. The decrease of ecotoxicity was determined by reproduction tests with collembolans (Folsomia candida) and enchytraeids (Enchytraeus crypticus), following ISO guidelines. Degradation curves showed that all biomixtures reached almost complete degradation of phosmet after 90 days. Collembolans were more sensitive than enchytraeid, confirming their usefulness in biomonitoring insecticide degradation. This work showed that both pine litter and vermicompost are potentially substitutes for peat in alternative biomixtures, since they were efficient in degrading the pesticide and reducing its ecotoxicity. Our results contribute for the development of newly, accessible biobeds for south Brazil, bringing the first study reports involving such biobeds capacity to degrade phosmet, which is a commonly used pesticide in this region. [ABSTRACT FROM AUTHOR]

Digitonthophagus gazella, a dung beetle species introduced into many countries as a biological control agent for cattle dung removal, is adapted to open pastures and avoid shaded areas such as forests. With a short development period, high fecundity, and long dispersion capability, D. gazella is an effective competitor that is considered an invasive species in many countries. Until recently, only one study evaluated its possible presence in a small forest area, suggesting an invasion process might be occurring. We report here the presence of D. gazella in five distinct forest landscapes (FLs): a regenerating native forest, a reforested native forest, and three forests with exotic plant species. The FLs are embedded in an area with several other FLs, which is surrounded by a river and a pasture. However, cattle have access to these FLs. We found that the anthropogenic disturbances may be facilitating the species dispersal to shaded habitats as there was a higher abundance of D. gazella in areas where cattle were more active. The possibility of this species in invading FLs is worrisome because it has been shown that D. gazella can cause significant negative impacts to the native dung beetle community, which is of great ecological importance for the ecosystem. [ABSTRACT FROM AUTHOR]

Purpose: Dredged sediments are often disposed on land areas and can cause adverse effects on soil biota, since these materials generally may contain toxic agents. This work examines the ecotoxicological effects on earthworms exposed to technogenic deposits formed from the deposition of dredged sediments from an urban tropical lagoon. Such evaluation supports the understanding of the ecological effects derived from dredged sediments in the tropics, as well as the influence of soil properties in the toxicity. Materials and methods: To simulate dredged sediment disposal under tropical conditions, a dredged sediment sample from the Rodrigo de Freitas Lagoon (Rio de Janeiro, RJ, Brazil) was mixed with a Gleysol (a typical organic tropical soil) to obtain the following doses: 0, 6, 12, 18, and 24%, where 0% = pure Gleysol. Acute and avoidance bioassays with Eisenia andrei were applied to these mixtures following standard protocols (ISO). Physical, chemical, and mineralogical characterization of the materials and metal determination in the test mixtures were performed to support the interpretations of ecotoxicological data. Results and discussion: Metal concentrations in the test mixtures were generally in accordance with the limits defined by Brazilian law. Earthworm mortality was significant in doses ≥ 8% (LC50 = 7.1%), while doses ≥ 2% caused avoidance responses (EC50 = 1.7%, p < 0.05). The salinity in 8% treatment is similar to the salinity levels described by the literature that cause adverse effects on earthworms, suggesting that salinity played a key role in the toxicity. Earthworm biomass increased (p < 0.05) when the organisms were exposed to non-lethal doses, and this is probably due to water bioaccumulation related to high contents of salts. When comparing the toxicity found in this work with data obtained with other tropical soils, one could suppose that Gleysol mineralogy seems to control the bioavailability of salts and metals. Conclusion: The possible formation of technogenic soils (constructed soils) due to land deposition of dredged sediments may potentially compromise natural soil fauna. In this particular case, soil mineralogy, salinity, and metals played a relevant role in the toxicity to earthworms. The development of approaches that can integrate ecotoxicological, ecological, and pedological data is urgent for better understanding the damages associated with the disposal of dredged sediments in tropical lowlands areas. [ABSTRACT FROM AUTHOR]

Dung beetles (Coleoptera: Scarabaeidae) perform essential ecological functions in pastures, such as dung removal, nutrient recycling and parasite control. However, the patterns of alimentary use by dung beetles in introduced Brazilian pastures are poorly known. Here, we compared dung beetle species richness, abundance and species composition in cattle and sheep dung, and identified the dung beetle species preference by each dung type. In January 2019, dung beetles were sampled with pitfall traps baited with cattle and sheep dung in 12 introduced pastures (Urochloa spp.), in Aquidauana, Mato Grosso do Sul, Brazil. A total of 592 individuals belonging to 14 species of dung beetles were collected. Of the 14 species sampled, nine were recorded in both dung types, five were found exclusively in sheep dung and no species was exclusive to cattle dung. Species richness and abundance were higher in sheep dung. Species composition was different between the dung types. Dichotomius bos (Blanchard), Genieridium bidens (Balthasar), Onthophagus aeneus Blanchard and Trichillum externepunctatum Preudhomme de Borre were associated with sheep dung. Our results provide evidence that sheep dung is more attractive to dung beetles with a distinct community species between the two dung types, although the studied pastures have never been used before for sheep breeding. Thus, our data shows that the introduction of a new alimentary resource (e.g. sheep dung) can be an important strategy to help to obtain a more diverse dung beetle assemblage in introduced Brazilian pastures. [ABSTRACT FROM AUTHOR]

Eudrilus eugeniae is a foreign species that is well adapted to captivity system adopted in Brazil. The objective was evaluate the productive and economic performance of earthworms in different substrates in two 100 days. In aim 1, the control substrate composed by cattle manure and forage grass (CMG) was supplemented with minerals (MM), soybean meal (SB) and ground corn (GC). The substrate containing GC was higher than in average weight (AW) of 127% and average weight gain (AWG) of 332% when compared to CMG substrate, superior in 193% AW and 252% AWG when compared to MM and 251% AW and 403% AWG when compared to the substrate with SB. In aim 2, were used different amounts of GC in substrate. The production of the substrate that contained 5% GC was superior in 9%, 12% and 20% with regard to those that had a composition of 10%, 15% and 20% of GC, respectively. As for the difference between the costs and the benefits of each of the substrates, the 5% GC substrate showed a positive return of BRL$ 35.32 for each BRL$1.00 invested and an economic performance that was 205% superior to MM, the second best option among substrates. 5% GC performed better and more efficient and economically viable production of worms. [ABSTRACT FROM AUTHOR]

Vermicomposting is the bio-oxidation and stabilization of organic matter involving relationships between the action of earthworms and microorganisms and the activation and dynamics of several enzyme activities. Semi-arid farmers to make (extra) money and organic production, produce their vermicompost using plant residues and animal manure, but there is no information about the final product generated. Thus, this study aimed to analyze the potential of vermicomposting with mixtures of animal manure and vegetable leaves in the development of Eisenia foetida , microbial biomass, and enzymatic activity in the semi-arid region, Brazil. The experimental design applied was randomized block in a 6 × 4 factorial scheme with four replicates, with six treatments (mixtures of cattle manure, goat manure, cashew leaves, and catanduva leaves) and evaluated at four-time intervals (30, 60, 90, and 120 days of vermicomposting). The treatments were placed in polyethylene pots in the same site, environmental conditions, and residues proportions as used by farmers. The characteristics analyzed were the number of earthworms (NE), total earthworm biomass (TEB) and earthworm multiplication index (MI), microbial biomass carbon (MBC), and activities of enzymes β-glucosidase, dehydrogenase, alkaline and acid phosphatases. The cattle manure vermicomposted shows the highest average values observed for NE, MI, TEB, MBC, and enzymatic activity, regardless of the plant leaves mix. In general, the enzymes activities were found in the descending order of β-glucosidase > alkaline phosphatase > dehydrogenase > acid phosphatase. The maturation dynamics of vermicompost were characterized by a decline in the microbial population and number and biomass of earthworms in the substrate and consequently a decrease in new enzyme synthesis and degradation of the remaining enzyme pool. Microbial biomass and enzymatic activity were indicators for changes in the quality of vermicompost. [Display omitted] • Mixtures of cattle manure, goat, and vegetable leaves were vermicomposted for 120 days. • Cattle manure was up to 2-times higher on multiplication and total biomass of Eisenia foetida than the goat. • Cattle manure shows higher activities of β-glucosidase, dehydrogenases, and phosphatases. • The maturation of vermicompost declined the microbial and earthworm populations, and enzymes. [ABSTRACT FROM AUTHOR]

The main objective of this research was to evaluate the agronomic potential of the vermicompost produced from domestic sewage sludge and mixtures of domestic sewage sludge and soil, following the criteria of the Brazilian Ministry of Agriculture, Livestock and Food Supply (MAPA), aiming at a sustainable use for domestic sewage sludge, transforming an undesirable residue into a valuable commercial product. The results obtained for the so produced vermicomposts, in comparison to the specifications, warranties and contaminating limits requirements of the resolution No. 375, were satisfactory for at least one of the domestic sewage sludge and soil mixtures, proving the potential of this residue for application in agriculture as fertilizer or soil conditioner. [ABSTRACT FROM AUTHOR]

It was aimed at in this work to verify the production of the biomass of mint plants submitted to different vermicompound doses under two types of soils. The experiment was accomplished at the laboratory of Botany of Escola Superior de Agricultura de Mossoró, RN, Brazil. The doses of the vermicompound of 0, 5, 10, 15, 20, 25 and 30% were studied in a vertisoil and in a Psamment soil. The experimental design used was a completely randomized in factorial an outline 7 x 2, seven vermicompound doses and two soil types, with six replications. Evaluations for fresh and dry biomass of the whole plants, the root length and the height of the plants were made. The application of increasing doses of the vermicompound, in both soils, did not influence the height of mint plants. The vermicompound dose of 16% promoted an increase in the amount of fresh and dry biomass in both soils. Higher mint root length was obtained in the vermicompound dose of 30 %. [ABSTRACT FROM AUTHOR]

Waste materials from coal mining and consumer products can pose significant risks to the environment. Residual coal deposits lead to the formation of acid drainage and release of contaminants, causing negative changes in soil and aquatic systems. Low density polyethylene (LDPE) polymers are an environmental concern due to their high useage, and slow degradation in the environment. In this study both waste materials were used to develop a composite to mitigate the environmental impacts of coal mining waste (CMW). The composite material was produced in different formulations (0–80 % wt CMW), and samples were tested for formation of acid drainage and release of contaminants. Chemical characterisation of the CMW and leachate of the composite materials was performed by X-ray fluorescence and atomic absorption spectrometry. Ecotoxicological effects in soil and water were investigated using standard tests with the earthworm, Eisenia fetida , the collembolan, Folsomia candida and the bacterium, Aliivibrio fischeri. Composites with 20 % wt LDPE showed a 50% increase in the pH value of the leachate compared to the CMW leachate. Iron, aluminium and sulfate concentrations were lower in leachates of the composite materials, and a reduction in the ecotoxicological impact on the tested organisms was observed. The hydrophobic nature of the composite's polymeric matrix as well its physical properties contributed to a better coating of the coal residue particles, blocking the contact with water and reducing the environmental risks of CMW. These results show that the production of composite material is a viable alternative route for treating coal and LDPE waste. • Formulation of a composite material of low-density polyethylene and coal mining waste. • Decreased formation of mineral acid drainage and traces of contaminants in the leachate. • Mitigation of environmental impacts related to the ecotoxicological evaluation of the leachate samples. [ABSTRACT FROM AUTHOR]

Produced water (PW) is a mixture of formation water and injected water from oil and gas reservoirs, which contain a complex composition of dissolved and particulate organic and inorganic chemicals. High quantities of PW are extracted with the oil, which can be discharged into the environment, re-injected into the wells or treated for reuse. The present study aimed to evaluate the soil ecotoxicity under an irrigation system using treated PW (water-oil separation, sand filter, activated charcoal filter, reverse osmosis) for sunflower production, predicting conditions for PW reuse in the semi-arid region of Brazil. The experiment was conducted in a greenhouse using natural soil in vessels. Water from public water supply was used as control. Soil samples from two production cycles of sunflowers were assessed using ecotoxicity tests with soil invertebrate's species representing macro and mesofaunal groups: Eisenia andrei (earthworms), Folsomia candida (collembolans) and Enchytraeus crypticus (enchytraeids). Leachates samples were evaluated with aquatic ecotoxicity tests to assess the soil retention function. Results showed impact of irrigation with PW in all treatments except reverse osmosis. Significant negative correlations were found among reproduction of soil invertebrates, high Na+ concentrations and electrical conductivity. The effects of other contaminants not analyses should not be discarded. It is important to highlight that salinity is not usually included in target values of soil quality. This study reinforces the importance of ecotoxicity tests in predictive and retrospective risk assessment, joining effects of contaminant mixtures or even that contaminants not considered in chemical scope of analysis or legislation. Image 1 • Treated PW was studied for use in sunflower production in the semi-arid region of Brazil. • Ecotoxicity of soil and leachates after irrigation with treated PW was evaluated. • All treatments except reverse osmosis compromised soil functioning. • Negative effects were highly correlated to Na content and electrical conductivity. [ABSTRACT FROM AUTHOR]