Bioremediation of hydrocarbon contaminated soil using local organic materials and earthworms.

Bioremediation technologies have demonstrated significant success on biological quality recovery of hydrocarbon contaminated soils, employing techniques among which composting and vermiremediation stand out. The aim of this study was to evaluate the efficiency of these processes to remediate diesel-contaminated soil, employing local organic materials and earthworms. During the initial composting stage (75 days), the substrate was made up using contaminated soil, lombricompost, rice hulls and wheat stubbles (60:20:15:5% w/w). Diesel concentration in the contaminated substrate was about 5 g kg-1, equivalent to a Total Petroleum Hidrocarbons (TPH) experimental concentration of 3425 ± 50 mg kg-1. During the later vermiremediation stage (60 days), the earthworm species Eisenia fetida and Amynthas morrisi were evaluated for their hydrocarbon degradation capacity. Physicochemical and biological assays were measured at different times of each stage and ecotoxicity assays were performed at the end of the experiments. TPH concentration reduced 10.91% after composting and from 45.2 to 60.81% in the different treatments after vermiremediation. Compared with TPH degradation in the treatment without earthworms (16.05%), results indicate that earthworms, along with indigenous microorganisms, accelerate the remediation process. Vermiremediation treatments did not present phytotoxicity and reflected high substrate maturity values (>80% Germination Index) although toxic effects were observed due to E. fetida and A morrisi exposure to diesel. Vermiremediation was an efficient technology for the recovery of substrate biological quality after diesel contamination in a short period. The addition of organic materials and suitable food sources aided earthworm subsistence, promoted the decontamination process and improved the substrate quality for future productive applications.

Poultry litter stabilization by two-stage composting-vermicomposting process: Environmental, energetic and economic performance.

Poultry litter (PL) is a heterogeneous mixture that contains bedding materials, antibiotics, dead skin, feed scraps, water, feathers and the resulting microbiota from poultry production cycle. Although its treatment does not receive attention, it is an important organic resource generated in the north-east region of Santa Fe Province since animal primary production is one of the main economic activities there and in the whole country. The objective of this work was to analyse the economic and energy aspects and the environmental impact of two scenarios corresponding to treat two different mixtures of organic wastes: Eucalyptus sp. sawdust (ES), rice hulls (RH) and PL. PL was considered in two different volume proportions: 1RH:3 PL for scenario 1 and 0.5RH:1 ES:2 PL for scenario 2. The two-stage combined system of composting + vermicomposting was applied to both scenarios and compared; on one hand, the current regulated practice for waste final deposition (landfill) and on the other hand, a base line scenario, which describes the current situation, where the raw material is transported and spread over the field as fertilizer without previous stabilization. The scenario construction was based according to on-site data, lab-scale experiments previously published and software databases. The environmental study was carried out with life cycle assessment; and the energy study, using cumulative energy demand methodology and the energy balance. Based on the results, it was possible to affirm the importance of the integrated agricultural waste treatment to address environmental benefits, especially related to the base line scenario. Furthermore, there were no significant differences between the two proposed scenarios. Economic and environmental results were contradictory when no long-term socio-economic consequences are considered. Combined composting and vermicomposting strategy reduce the organic matter and nutrients content not only to avoid discharges into the environment, but also to replace the fossil fuels consumption during unsustainable techniques as sanitary landfill, producing improved substrates for agricultural use.

Current knowledge of earthworm richness and distribution in Santa Fe province, Argentina / Conocimiento actual sobre riqueza y distribución de lombrices de tierra en la provincia de Santa Fe, Argentina

Abstract Updated list of earthworms (Oligochaeta: Lumbricina) from Santa Fe (Argentina) is presented in this work, including current data of species richness and territorial distribution status and information collected by Ljungström and collaborators 40 years ago. Field samplings were conducted between 2012 and 2015 at 23 sites, located in 11 of the 19 districts of the province. Earthworms were collected following a standard methodology. The conservation of specimens was done with 4 % formalin solution and their identification was performed according to taxonomy keys. Richness, similarity and complementarity of species between the phytogeographic provinces were analyzed. A total of 15 earthworm species were identified and grouped into ten genera and five families: Acanthodrilidae (Dichogaster bolaui, Microscolex dubius), Glossoscolecidae (Glossodrilus parecis), Lumbricidae (Aporrectodea caliginosa, Aporrectodea rosea, Aporrectodea trapezoides, Bimastos parvus, Eisenia fetida, Octolasion tyrtaeum), Megascolecidae (Amynthas gracilis, Amynthas morrisi, Metaphire californica), Ocnerodrilidae (Eukerria saltensis, Eukerria rosae, Eukerria stagnalis). From all the species found five, G. parecis, E. saltensis, E. rosea, E. stagnalis and M. dubius, are native to South America, and the rest were introduced from Asia and Europe. The Espinal presented the greatest richness of earthworms (12), while the Pampeana showed high values of complementarity (greater than 70 %) with the Chaco Húmedo and Valle de Inundación del Río Paraná. Endogeic species were present in all environments surveyed. In particular, the exotic species A. trapezoides and A. morrisi showed a wide geographical distribution, having been found at 70 and 50 %, respectively, of the total number of the studied sites. One species, E. rosea, which is in the list, was not recorded in the sampling of 40 years ago. The results of current survey show that the number of species was lower compared to study by Ljungström and collaborators (60 % of the 23 species registered). Possibly the remarkable change in the richness and distribution of earthworms could be a process associated with changes in soil use and land management developed over 40 years. Rev. Biol. Trop. 66(3): 1171-1181. Epub 2018 September 01.

Resumen En este trabajo se presenta una lista actualizada de lombrices de tierra (Oligochaeta: Lumbricina) de Santa Fe (Argentina), incluyendo datos actuales de riqueza de especies y estado de distribución territorial e información recolectada por Ljungström y colaboradores hace 40 años. Los muestreos de campo se realizaron entre 2012 y 2015 en 23 sitios, ubicados en 11 de los 19 departamentos de la provincia. Las lombrices fueron recolectadas siguiendo métodos estándar. La conservación de los especímenes se realizó con solución de formalina al 4 % y la identificación mediante claves taxonómicas. La riqueza, similitud y complementariedad de especies, se analizó entre las provincias fitogeográficas y se identificaron un total de 15 especies de lombrices en diez géneros y cinco familias: Acanthodrilidae (Dichogaster bolaui, Microscolex dubius), Glossoscolecidae (Glossodrilus parecis), Lumbricidae (Aporrectodea caliginosa, Aporrectodea rosea, Aporrectodea trapezoides, Bimastos parvus, Eisenia fetida, Octolasion tyrtaeum), Megascolecidae (Amynthas gracilis, Amynthas morrisi, Metaphire californica), Ocnerodrilidae (Eukerria saltensis, Eukerria rosae, Eukerria stagnalis). De todas las especies encontradas, cinco: G. parecis, E. saltensis, E. rosea, E. stagnalis y M. dubius, son nativas de América del Sur, y el resto introducidas desde Asia y Europa. Las especies endógeas estuvieron presentes en todos los ambientes estudiados. En particular, las especies exóticas: A. trapezoides y A. morrisi, mostraron amplia distribución geográfica, se encuentran en el 70 y 50 %, respectivamente, de los sitios estudiados. Una especie, E. rosea, que está en la lista, no fue registrada en el muestreo de hace 40 años. La zona del Espinal presentó la mayor riqueza de lombrices (12), en tanto que la Pampeana mostró valores altos de complementariedad (mayores al 70 %) con el Chaco Húmedo y el Valle de Inundación del Río Paraná. Los resultados del relevamiento actual muestran que el número de especies fue menor en comparación con el estudio de Ljungström y colaboradores (60 % de las 23 especies registradas). Posiblemente el notable cambio en la biodiversidad del paisaje de la provincia, asociado al uso de la tierra y a la gestión de los sistemas de producción desarrollados a lo largo de 40 años, podría haber influido en la distribución y riqueza de especies de lombrices.