Inorganic arsenic content in Ecuadorian rice-based products.

Arsenic intake in the world is linked with drinking water and food; the main sources of inorganic As (i-As) exposure in food are rice and rice-based products. The consumption of rice in Ecuador is 53.2 kg year-1 and it is the most commonly used cereal for the preparation of many popular dishes especially for subjects with celiac disease. Objectives of this research were: (i) to determine the content of i-As in foods widely consumed by Ecuadorians with celiac disease, (ii) to calculate the i-As dietary intake, and (iii) to model and predict the health risks of the population under study as a result of their exposure to i-As from rice-based food. The estimated daily intakes of Ecuadorian children (below 3 years of age) and adults were established at 0.52 and 0.55 µg kg-1 body weight d-1, respectively. These values were above the lower BMDL01 value established for i-As established by the EFSA; consequently, it can be concluded that health risk cannot be excluded for the Ecuadorian population with celiac disease.

Development of organic fertilizers from food market waste and urban gardening by composting in Ecuador.

Currently, the management of urban waste streams in developing countries is not optimized yet, and in many cases these wastes are disposed untreated in open dumps. This fact causes serious environmental and health problems due to the presence of contaminants and pathogens. Frequently, the use of specific low-cost strategies reduces the total amount of wastes. These strategies are mainly associated to the identification, separate collection and composting of specific organic waste streams, such as vegetable and fruit refuses from food markets and urban gardening activities. Concretely, in the Chimborazo Region (Ecuador), more than 80% of municipal solid waste is dumped into environment due to the lack of an efficient waste management strategy. Therefore, the aim of this study was to develop a demonstration project at field scale in this region to evaluate the feasibility of implanting the composting technology not only for the management of the organic waste fluxes from food market and gardening activities to be scaled-up in other developing regions, but also to obtain an end-product with a commercial value as organic fertilizer. Three co-composting mixtures were prepared using market wastes mixed with pruning of trees and ornamental palms as bulking agents. Two piles were created using different proportions of market waste and prunings of trees and ornamental palms: pile 1 (50:33:17) with a C/N ratio 25; pile 2: (60:30:10) with C/N ratio 24 and pile 3 (75:0:25) with C/N ratio 33), prepared with market waste and prunings of ornamental palm. Throughout the process, the temperature of the mixtures was monitored and organic matter evolution was determined using thermogravimetric and chemical techniques. Additionally, physico-chemical, chemical and agronomic parameters were determined to evaluate compost quality. The results obtained indicated that all the piles showed a suitable development of the composting process, with a significant organic matter decomposition, reached in a shorter period of time in pile 3. At the end of the process, all the composts showed absence of phytotoxicity and suitable agronomic properties for their use as organic fertilizers. This reflects the viability of the proposed alternative to be scaled-up in developing areas, not only to manage and recycle urban waste fluxes, but also to obtain organic fertilizers, including added value in economic terms related to nutrient contents.