Abstract The salt is indispensable for several industrial sectors, and its production is associated with some natural conditions. These conditions result in productive areas often close to the estuary. Thus, the objective was to evaluate the estuaries environmental monitoring associated with solar salt production in the Brazilian semiarid. The study was developed in the area of influence of a solar saltwork, in the Conchas’ river estuary, RN, where the quality of the water in the estuary was monitored for the non-productive and productive periods of the saltwork for 3 years. Thus, a collection site was established immediately in front of the saltwork discharge channel, and samples were collected monthly, at 30 cm depth, always during high tides, totaling 36 samples. For this, the following parameters were evaluated: salinity, pH, calcium, magnesium, dissolved oxygen, chlorophyll a and rainfall. Salinity was measured in the field with the aid of a portable refractometer. During the operational phase, the average salinity remained above 30.00, characterizing the environment as saline. The calcium and magnesium ions showed an average concentration of 440.00 mg/L and 1280.00 mg/L respectively, values that were according to the limits historically observed for a saline estuary in the analyzed region. The pH and dissolved oxygen were not influenced by the production period (7.93 and above 6.00mg/ L, respectively), while the concentration of chlorophyll a characterized the area as oligotrophic. The functioning of the analyzed solar saltwork did not cause significant changes in the water quality parameters of the estuary.

RESUMO: A extração de sal marinho depende da ocupação de grandes áreas às margens de estuários, muitas delas inseridas em Áreas de Preservação Permanente (APPs). Assim, objetivou-se avaliar a viabilidade econômica da Compensação Ambiental (CA) como alternativa à desocupação de APP pelas salinas. Para tanto, 27 salinas instaladas na região da Costa Branca brasileira foram avaliadas quanto à ocupação de APPs - mensuradas por meio de imagens de satélites, georreferenciadas, vetorizadas com a geração de bandas de APP - e estimados a CA (Grau de Impacto x Somatório dos investimentos necessários para implantação do empreendimento) e o Impacto Econômico (Valor Presente Líquido, com taxa de juros de longo prazo de 7%) da desocupação das APPs. A CA foi considerada viável quando seus custos resultantes foram menor do que o impacto econômico causado pela desocupação das APPs. A área produtiva média das salinas ocupa 13,70% de APP. Para todos os empreendimentos avaliados, o valor correspondente a CA foi menor que o Impacto Econômico resultante da desocupação das APP. Assim, a CA é uma alternativa economicamente viável e mais atrativa frente à desocupação das APP pela indústria salineira, podendo ainda propiciar ganhos ambientais em decorrência do financiamento de Unidades de Conservação nas áreas de influência dos empreendimentos. Evidencia-se, contudo, a necessidade do aprimoramento da metodologia usada para estimar a CA, já que fixado um limite máximo, os impactos ambientais provocados pelos empreendimentos são subestimados.

ABSTRACT: The extraction of sea salt depends on the occupation of large areas at the estuary banks, many of them inserted in Permanent Preservation Areas (PPAs). Thus, the objective was to evaluate the economic viability of Environmental Offsets (EO) as an alternative to the unoccupied PPAs in the saltworks. In order to do so, 27 solar saltworks installed in the region of the Brazilian White Coast were evaluated for the occupation of PPAs - measured using images from satellite, georeferenced, vectored with corresponding PPA bands generated - and estimated to EO (Impact Degree x Sum of the investments necessary to implement the project) and Economic Impact (Net Present Value, with long-term interest rate of 7%) of vacating PPAs. It was considered that EO was feasible whenever the costs resulting from it were lower than the economic impact caused by the vacancy of the PPAs. The PPAs were tthe productive area of the saltworksthat occupied 13.70% of PPAs. For all the evaluated enterprises the value corresponding to EO was lower than the Economic Impact resulting from the vacancy of the PPAs. Thus, EO is an economically viable and more attractive alternative to the eviction of PPAs by the saltworks industry and may also provide environmental gains due to the financing of conservation units in the areas of influence of the enterprises. However, there is a need to improve the methodology used to estimate the EO, since a maximum limit is set, the environmental impacts caused by the projects are underestimated.

Abstract The aim of the present study was to compare three and faster sample evaluation, hence adding value to the microscopy tests. Mangroves, because they have high productivity, become attractive places for housing and the development of human activities, such as shrimp farming. However, this activity has generated major environmental impacts. Considering the importance and expressive fragility of mangroves, the objective of this study was to evaluate the impact of a marine shrimp production unit in the mangrove forest of the Rio das Conchas, Porto do Mangue, Rio Grande do Norte. The extent of the affected area was determined by means of remote sensing. Two scenes obtained by the LANDSAT 7 satellite, each composed of three spectral bands, were used. The scenes are representative of the years 1999 and 2003, which comprise, respectively, the previous period and after the installation of the shrimp farm. An on-site evaluation was also carried out to find traces that could be related to degradation, especially signs of soil degradation. According to the evaluation of the area occupied by mangrove vegetation by means of the remote sensing technique, a loss of 25 hectares of mangrove vegetation was verified between the periods of 1999 (prior to the installation of the project) and 2007 (year in which the tax assessment notice was drawn). This reduction reflects the implantation of the shrimp farming activity, associated to the discharge of effluents, originated from the same, as well as poor planning for the development of the activity in the place.

Resumo Os manguezais por apresentarem elevada produtividade, tornam-se locais atrativos para habitação e desenvolvimento de atividades humanas, como a carcinicultura. No entanto, essa atividade tem gerado grandes impactos ambientais. Assim, considerando a importância e a expressiva fragilidade dos manguezais, objetivou-se avaliar o impacto de uma unidade de produção de camarão marinho na floresta de mangue do rio das conchas, Porto do Mangue, Rio Grande do Norte. A extensão da área afetada foi determinada por meio de sensoriamento remoto. Foram utilizadas duas cenas obtidas pelo satélite LANDSAT 7, representativas dos anos de 1999 e 2003, que compreendem, respectivamente, o período anterior e após a instalação da fazenda de camarão. Realizou-se também uma avaliação in loco, buscando encontrar vestígios que pudessem estar relacionados à degradação, em especial indícios de degradação do solo. Conforme a avaliação da área ocupada por vegetação de mangue por meio da técnica de sensoriamento remoto, constatou-se uma perda de 25 hectares de área ocupada por vegetação de mangue, entre os períodos de 1999 (anterior à instalação do empreendimento) e 2007 (ano em que o auto de infração foi lavrado). Essa redução é reflexo da implantação da atividade de carcinicultura, associado ao descarte de efluentes da mesma, bem como, mau planejamento para o desenvolvimento da atividade no local.