Soil and water pollution in a banana production region in tropical Mexico

The effects of abundant Mancozeb (Mn, Zn— bisdithiocarbamate) applications (2.5 kg ha-1week-1 for 10 years) on soil and surface-, subsurface- and groundwater pollution were monitored in a banana production region of tropical Mexico. In soils, severe manganese accumulation was observed, wheras the main metabolite ethylenethiourea was near the detection limit. Surface and subsurface water was highly polluted with ethylenethiourea, the main metabolite of Mancozeb (22.5 and 4.3 lg L-1, respectively), but not with manganese. In deep ground water, no ethylenethiourea was detected. The level of pollution in the region presents a worrisome risk for aquatic life and for human health

Respuesta olfativa de larvas de phyllophaga raviday p. tumulosa ( melolonthidae) a volátiles de raíces de cuatro plantas hospederas

The olfactory responses of third instar larvae of Phyllophaga ravida (Blanchard 1850) and Phyllophaga tumulosa (Bates 1888) to Zea mays L. (Gramineae), Cynodon dactylon (L.) Pers. (Gramineae), Phaseolus vulgaris L. (Leguminosae) and Physalis philadelphica Lam. (Solanaceae) roots were studied in the laboratory. The olfactory response was investigated using a Y olfactometer. P. ravida larvae did not show any preference for roots of any of the four plant species, while P. tumulosa larvae preferred green tomato roots. The preference of both species of larvae for roots of maize, bean or green tomato was investigated in a glass terrarium. Phyllophaga ravida larvae were more frequently found in maize roots than in bean or green tomato roots, and larvae of this species increased significantly their weight in the combinations between bean-maize and green tomato-maize. Phyllophaga tumulosa larvae preferred green tomato roots to those of maize or beans and increased significantly their weight in the green tomato-maize combination. The olfactory preference of P. tumulosa for green tomato roots was corroborated in the terrariums. En este trabajo se investigó la respuesta olfativa de larvas de terceros estadios de Phyllophaga ravida (Blanchard 1850) y Phyllophaga tumulosa (Bates 1888) ante las raíces de Zea mays L. (Gramineae), Cynodon dactylon (L.) Pers. (Gramineae), Phaseolus vulgaris L. (Leguminosae) y Physalis philadelphica Lam. (Solanaceae). Se utilizó un olfatómetro Y, con una raíz de papel filtro como testigo; las larvas de P. ravida no mostraron preferencia olfativa por ninguna de las raíces probadas; mientras que las larvas de P. tumulosa prefirieron la del tomate verde. En terrarios de cristal se sembraron una planta de maíz (control) y otra de frijol o tomate verde, y se infestaron con dos larvas de P. ravida o de P. tumulosa, excepto los testigos, para registrar la preferencia hacia un tipo de raíz en el suelo. Las larvas de Phyllophaga ravida tuvieron mayor presencia en las raíces del maíz que en las del frijol o del tomate verde y aumentaron significativamente de peso en las combinaciones frijol-maíz y tomate verde-maíz. Las larvas de P. tumulosa prefirieron las raíces del tomate verde que las del maíz o del frijol, y aumentaron significativamente de peso en la combinación tomate verde-maíz. La preferencia olfativa de P. tumulosa por la raíz del tomate verde se corroboró en los terrarios

Analysis of Microplastics in Food Samples

This chapter presents a compilation of the analytical techniques used to detect and analyze microplastics in food. A detailed description of microplastics found in different samples is provided as well as an estimate of the annual intake of these particles. A total of 22–37 milligrams of microplastics per year was found. The factors that can influence the presence of particles in food, especially table salt, are discussed, showing that a background presence of microplastics in the environment can explain a large amount of experimental data.Support for this work was provided by the CTQ2016-76608-R project from the Ministry of Economy, Industry and Competitiveness (Spain) and by the University of Alicante under the project UAUSTI18-06

Global data on earthworm abundance, biomass, diversity and corresponding environmental properties

14 p.Earthworms are an important soil taxon as ecosystem engineers, providing a variety of crucial ecosystem functions and services. Little is known about their diversity and distribution at large spatial scales, despite the availability of considerable amounts of local-scale data. Earthworm diversity data, obtained from the primary literature or provided directly by authors, were collated with information on site locations, including coordinates, habitat cover, and soil properties. Datasets were required, at a minimum, to include abundance or biomass of earthworms at a site. Where possible, site-level species lists were included, as well as the abundance and biomass of individual species and ecological groups. This global dataset contains 10,840 sites, with 184 species, from 60 countries and all continents except Antarctica. The data were obtained from 182 published articles, published between 1973 and 2017, and 17 unpublished datasets. Amalgamating data into a single global database will assist researchers in investigating and answering a wide variety of pressing questions, for example, jointly assessing aboveground and belowground biodiversity distributions and drivers of biodiversity change

Decay of low-density polyethylene by bacteria extracted from earthworm’s guts: a potential for soil restoration

Low-density polyethylene (LDPE) is the most abundant source of microplastic pollution worldwide. A recent study found that LDPE decay was increased and the size of the plastic was decreased after passing through the gut of the earthworm Lumbricus terrestris (Oligochaeta). Here, we investigated the involvement of earthworm gut bacteria in the microplastic decay. The bacteria isolated from the earthworm's gut were Gram-positive, belonging to phylum Actinobacteria and Firmicutes. These bacteria were used in a short-term microcosm experiment performed with gamma-sterilized soil with or without LDPE microplastics (MP). We observed that the LDPE-MP particle size was significantly reduced in the presence of bacteria. In addition, the volatile profiles of the treatments were compared and clear differences were detected. Several volatile compounds such as octadecane, eicosane, docosane and tricosane were measured only in the treatments containing both bacteria and LDPE-MP, indicating that these long-chain alkanes are byproducts of bacterial LDPE-MP decay

Effects of plastic mulch film residues on wheat rhizosphere and soil properties

Plastic residues could accumulate in soils as a consequence of using plastic mulching, which results in a serious environmental concern for agroecosystems. As an alternative, biodegradable plastic films stand as promising products to minimize plastic debris accumulation and reduce soil pollution. However, the effects of residues from traditional and biodegradable plastic films on the soil-plant system are not well studied. In this study, we used a controlled pot experiment to investigate the effects of macro- and micro- sized residues of low-density polyethylene and biodegradable plastic mulch films on the rhizosphere bacterial communities, rhizosphere volatile profiles and soil chemical properties. Interestingly, we identified significant effects of biodegradable plastic residues on the rhizosphere bacterial communities and on the blend of volatiles emitted in the rhizosphere. For example, in treatments with biodegradable plastics, bacteria genera like Bacillus and Variovorax were present in higher relative abundances and volatile compounds like dodecanal were exclusively produced in treatment with biodegradable microplastics. Furthermore, significant differences in soil pH, electrical conductivity and C:N ratio were observed across treatments. Our study provides evidence for both biotic and abiotic impacts of plastic residues on the soil-plant system, suggesting the urgent need for more research examining their environmental impacts on agroecosystems

Indicators of environmentally sound land use in the humid tropics: The potential roles of expert opinion, knowledge engineering and knowledge discovery

Despite abundant literature on indicators for sustainable resource management, practical tools to help local users to apply its general concepts at a local to regional level are scarce. This means that decisions over land evaluation and land use at a local level are often not based on the formal application of indicators or decision support systems for environmentally sound management but instead on the opinion of local expertise, for instance forest managers, cattle breeders, farmers and/or academics. This is particularly seen to be the case in the tropics where access to modern communication and information technologies is restricted. As the opinions of experts are often based on and influenced by personal experience, intuition, heuristics and bias, their evaluations and decision are often unclear to the non-expert working at a local level. In order to make their reasoning more comprehensible to the non-expert, the ecological condition of 176 plots in the tropical Southeast of Mexico were evaluated by experts on soil fertility, forest management, cattle breeding and agriculture. With the assistance of a knowledge engineer (one who converts expert knowledge and reasoning into a model), these expert opinions and reasoning were then translated into a formal computer model. As an alternative approach we applied a knowledge discovery technique, namely the induction of regression trees and automatically developed models using the expert evaluations as training data. Where knowledge engineering was tedious and time consuming, regression models could be rapidly generated. Moreover, the correspondence between regression trees and expert opinions was considerably higher than the correspondence between expert opinion and their own models. The regression trees used less explicative variables than the models generated by the experts. The minimisation of sampling effort due to variable space reduction means that the application of regression tree induction has a high potential for a rapid development of indicators for narrowly defined ecological assessments, needed for decision making on a local or regional scal

Macro- and micro- plastics in soil-plant system: effects of plastic mulch film residues on wheat (Triticum aestivum) growth.

Plastic residues have become a serious environmental problem in the regions with intensive use of plastic mulching. Even though plastic mulch is widely used, the effects of macro- and micro- plastic residues on the soil-plant system and the agroecosystem are largely unknown. In this study, low density polyethylene and one type of starch-based biodegradable plastic mulch film were selected and used as examples of macro- and micro- sized plastic residues. A pot experiment was performed in a climate chamber to determine what effect mixing 1% concentration of residues of these plastics with sandy soil would have on wheat growth in the presence and absence of earthworms. The results showed that macro- and micro- plastic residues affected both above-ground and below-ground parts of the wheat plant during both vegetative and reproductive growth. The type of plastic mulch films used had a strong effect on wheat growth with the biodegradable plastic mulch showing stronger negative effects as compared to polyethylene. The presence of earthworms had an overall positive effect on the wheat growth and chiefly alleviated the impairments made by plastic residues