A extracção clandestina de areia, nas faixas costeiras e nos leitos das ribeiras, tem sido prática de muitos agregados familiares cabo-verdianos. Nas últimas décadas, a praia de Calhetona (Ilha de Santiago) foi um dos muitos locais que sofreram degradação ambiental significativa, devido à realização desta actividade sem quaisquer planos de extracção e de posterior recuperação das áreas degradadas. Este trabalho, através da conjugação de recolha de dados por inquérito, observação directa e pesquisa documental e bibliográfica, teve como objectivos a caracterização da comunidade (que habita no bairro de Ponta Calhetona) que se dedica à extracção de areia na praia de Calhetona, a descrição da dinâmica da actividade extractiva, a avaliação da percepção que a comunidade tem relativamente às consequências da sua actividade e a descrição do impacte ambiental resultante da extracção de areia. Da análise dos inquéritos, efectuados em Fevereiro de 2012, a 25 chefes de agregados familiares que efectuam a extracção de areia na praia de Calhetona, constata-se que estes são maioritariamente mulheres, predominantemente com idade compreendida entre os 40 e os 59 anos, domésticas, com baixa escolaridade, com famílias numerosas e/ou alargadas a seu cargo e dedicando-se à extração de areia à mais de 10 anos. Os inquiridos, face à situação de vulnerabilidade económica, à falta de emprego e à grande procura de areia para a construção civil, vêem nesta actividade uma fonte de rendimento. Contudo, o proveito obtido desta actividade difícil e potencialmente perigosa é reduzido. Quem efectivamente beneficia são os camionistas que compram a areia a quem procede à extracção e a vendem ao consumidor final pelo dobro do preço. Os inquiridos demonstram uma consciência generalizada dos diversos impactes ambientais negativos resultantes da sua actividade, mas alegam que a extracção de areia é uma das poucas alternativas existentes para providenciar o sustento dos seus agregados familiares. Com base na comparação do estado actual da praia de Calhetona com relatos de habitantes locais, relativos às características da mesma no passado, verifica-se que nos últimos 40-50 anos, desde que se iniciou a intensa extracção de areia nesta praia, o seu aspecto físico se degradou claramente. Essa degradação caracteriza-se principalmente pelo recuo da linha de costa, pela quase ausência de areia e pela salinização dos solos localizados nas proximidades da praia, para além dos consequentes impactes negativos sobre a desova das tartarugas e o turismo balnear.
Sand is a very important raw material for construction industry. Worldwide, it has been widely used in the urban and industrial expansion process, creating jobs, generating capital and thus contributing to the development of society. However, its over-exploitation is also cause of many environmental problems identified all over the world. In Cape Verde archipelago illegal sand mining has been intensively carried out in coastal areas and in stream beds without extraction plans or rehabilitation of degraded areas. In the archipelago sand exploitation was insignificant until the early 1980s, because this material was used only in the lining of outer (stone) walls. Since then, there was a huge increase in construction of infrastructures and public and private buildings due to: the migration of rural populations to the cities; the remittances; the improvement of living conditions; the evolution of the building techniques; and the liberalization of construction materials. The use of sand, gravel and cement (concrete blocks) quickly replaced the use of stone. The use of sand in construction became so widespread that the consequences of its use/exploitation quickly became quite evident in the archipelago. The environmental impact of this mining activity has become so serious that in 1997, the Cape Verdean government was forced to introduce legislation prohibiting sand exploitation in the dunes, beaches and inland waters, with the exception of duly authorized cases. However, despite the existing legislation and inspection, the environmental problems resulting from this activity are still present, since there are many people dedicated to illegal sand mining. The economic vulnerability experienced by the Cape Verdean families has contributed to the ineffectiveness of environmental legislation. A large part of the population lives below the poverty line, so the exploitation of natural resources has been used in an abusive manner to ensure the survival of populations in need. In parallel, the high demand for sand and gravel has favoured illegal exploitation on the beaches and creeks of the archipelago. This illegal activity is traditionaly dominated by women heads of poor households without alternative employment or low ability to generate self-employment. Santiago Island, where resides more than half of the archipelago's population, is by far the largest sand consumer market. This, coupled with the shortage of this mineral resource in the archipelago and the difficult living conditions of the population, puts the mining areas of the islands under enormous pressure. In recent decades, Calhetona Beach (Santiago Island) was one of the many places that suffered significant degradation due to this activity. Thus, having gathered data through the combination of enquiry, direct observation and document analysis, this work intended to: characterize the community (living in Ponta Calhetona neighborhood) dedicated to sand mining in Calhetona Beach; describe the dynamics of the mining activity; assess the perception of the community regarding the consequences of its activity; and describe the environmental impacts resulting from sand mining. The analysis of the survey of 25 heads of households that extract sand from Calhetona Beach shows that these are mostly women, mostly between 40 and 59 years old, unemployed, with low education levels, with dependent numerous and/or extended families and mostly extracting sand for over 10 years. Sand extraction on Calhetona Beach is not dependent on the tide, because, contrary to what happens in other beaches on the island, it does not take place in the water, but is strongly conditioned by the authorithies surveillance. During the night is more difficult to be seen by the inspection agents and easier to escape them. The extraction is commonly made using buckets and padbles and the transportation to the storage location is commonly done in tubs and bags. Because it is a clandestine activity, storage is done in places away from the site of extraction in order to avoid problems with the authorities. On Calhetona Beach, as a result of the authorities pressure, the sand is predominantly sold to the bag. Even in the cases the sand is sold to the carload, the sand is still transported to the place of deliverance in bags to complete the carload. Considering that a Toyota Dyna 280 can carry 4500 to 5000 kg and a bag carries only about 50 kg, it takes 90 to 100 bags to complete a carload. The selling price of a sand bag is about 300$00 to 400$00 (circa 3 to 4€), whereas a carload (Toyota Dyna 280) is about 7,000$00 to 8,000$00 (circa 64 to 73€). The sand is sold mainly to truckers, construction contractors and nearby residents. The truckers (men) are the ones who actually benefit from this activity, buying the sand to the miners and sell it to the end consumer for about 15,000$00 (circa 135€). The delivery of sand to buyers is always carried out at night and early morning to avoid the fines and the seizure of the sand (and the vehicle) by the authorities. The preference for Toyota Dyna 280 is due to the ability of these vehicles to easily move through the alleys of the neighborhood and to escape the authorities because of the speeds that can reach with its turbo engine. The respondents demonstrate a widespread awareness of the various negative economic and environmental impacts resulting from their activity. But they claim that sand mining is one of the few existing alternatives to provide the sustenance of their households. The comparison of the past and the current conditions of Calhetona beach shows that in the last 40- 50 years, since the beginning of intensive sand mining in this beach, there was a clear environmental degradation depicted by the retreat of the shoreline, the near absence of sand or the predominence of gravel, the presence of a permanent saltwater pond parallel to the seashore, the salinization of nearby soils, and the consequent negative impacts on turtle nesting, beach tourism and agriculture.
Factores que inciden en la conducta de compra de productos agroecológicos en Mérida, Yucatán, México
; Flores Novelo, Anel