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The Effects of Mesquite Tree Removal on Soil Microbial and Nutrient Cycling Processes in Semi-Arid EnvironmentsFinnerty-Rae, Eileen Claire January 2009 (has links)
The expansion of mesquite (Prosopis velutina) in southeastern Arizona and attempts to control or remove mesquite have been well documented. However, removal of woody plants may affect the distribution and quantities of nutrient resources within soil including changes in carbon (C) and nitrogen (N) cycling and changes in the amounts of C and N sequestered in these soils. We hypothesized that mechanical mesquite removal would alter soil microclimate and nutrient inputs, leading to changes in soil C and N cycling and microbial communities and activities.This study was conducted at two separate semi-arid grassland sites south of Tucson, AZ during a three-year period. There were six study plots at each site, three plots from which mature mesquite trees had been mechanically removed and three plots where mature mesquite trees were left intact. We measured the soil temperature and moisture, C and N pools, N2O and CO2 fluxes, N mineralization rate, and microbial resistance and resilience to determine if short term changes in any of these parameters were taking place.No significant differences in N mineralization rate or microbial resistance or resilience were found between the soils under intact mesquite and from plots where mesquite had been mechanically removed. Soil temperature was not statistically analyzed because temperature was taken in only one plot per treatment and without within-treatment replicates, t-tests could not be performed. Statistically significant differences in soil moisture, total soil C and N, microbial biomass C and N, heterotrophic plate counts, and CO2 and N2O fluxes were found between treatments on different dates throughout the experiment. Despite this finding of some significant differences between treatments for some parameters measured, no recognizable pattern of changes was observed during this study. Over the course of the experiment, the data did not support our overall hypothesis, that short term changes in microclimate following mesquite removal would alter soil C and N cycling and microbial communities and activities.
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Altering hydrologic regime to revgetate crusted soils on semiarid rangelandWentz, Amy Leigh 15 November 2004 (has links)
Dysfunctional rangelands lose nutrients and material faster than they capture or create them. The objective of this study was to determine the effectiveness of contour furrows, drill seeding, and aeration treatments in capturing overland flow, concentrating resources, and establishing perennial bunch grasses to convert dysfunctional semiarid rangeland to a functional rangeland. The site, located on the Edwards Plateau in west Texas, USA, had bare, structurally crusted soils with sparse short-grasses (Scleropogon brevifolius). The site had a low infiltration rate contributing to excess overland flow and loss of nutrients, organic matter, and soil. Contour furrows were installed with varying intra-furrow distances (0.6 to 61 m) and then broadcast seeded to determine if furrow spacing would produce a vegetative response. Portions of the intra-furrow areas were aerated and drill seeded. All seed mixes contained warm season, perennial bunch grasses (Bouteloua curtipendula, Leptochloa dubia, and Setaria leucopila). Soil beneath furrows had greater soil water content (p-value < 0.05) than intra-furrow areas. Furrow plots had greater density of seeded grasses and total vegetation (19 individuals m-2 and 191 individuals m-2, respectively) than intra-furrow plots (0 individuals m-2 and 89 individuals m-2, respectively). This study supports other findings that suggest 1.5 m to 1.8 m is optimum intra-furrow spacing. Vegetative responses to drill seeding and aeration treatments were insignificant. Observations suggest that contour furrows are effective at establishment and support of perennial vegetation by capturing and retaining water that otherwise would be lost to runoff from untreated soil.
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Altering hydrologic regime to revgetate crusted soils on semiarid rangelandWentz, Amy Leigh 15 November 2004 (has links)
Dysfunctional rangelands lose nutrients and material faster than they capture or create them. The objective of this study was to determine the effectiveness of contour furrows, drill seeding, and aeration treatments in capturing overland flow, concentrating resources, and establishing perennial bunch grasses to convert dysfunctional semiarid rangeland to a functional rangeland. The site, located on the Edwards Plateau in west Texas, USA, had bare, structurally crusted soils with sparse short-grasses (Scleropogon brevifolius). The site had a low infiltration rate contributing to excess overland flow and loss of nutrients, organic matter, and soil. Contour furrows were installed with varying intra-furrow distances (0.6 to 61 m) and then broadcast seeded to determine if furrow spacing would produce a vegetative response. Portions of the intra-furrow areas were aerated and drill seeded. All seed mixes contained warm season, perennial bunch grasses (Bouteloua curtipendula, Leptochloa dubia, and Setaria leucopila). Soil beneath furrows had greater soil water content (p-value < 0.05) than intra-furrow areas. Furrow plots had greater density of seeded grasses and total vegetation (19 individuals m-2 and 191 individuals m-2, respectively) than intra-furrow plots (0 individuals m-2 and 89 individuals m-2, respectively). This study supports other findings that suggest 1.5 m to 1.8 m is optimum intra-furrow spacing. Vegetative responses to drill seeding and aeration treatments were insignificant. Observations suggest that contour furrows are effective at establishment and support of perennial vegetation by capturing and retaining water that otherwise would be lost to runoff from untreated soil.
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The Variability of Ring Characteristics within Trees as Shown by a Reanalysis of Four Ponderosa PineFritts, Harold C., Smith, David G., Budelsky, Carl A., Cardis, John W. 11 1900 (has links)
No description available.
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ANÁLISE DA ASSISTÊNCIA PRÉ-NATAL NA REDE BÁSICA DE SAÚDE DE UM MUNICÍPIO DO SEMIÁRIDO PIAUIENSE / ANALYSIS OF ASSISTANCE PRENATAL HEALTH BASIC NETWORK OF A MUNICIPALITY OF SEMIARID PIAUIENSELuz, Marle Araujo 11 August 2016 (has links)
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Previous issue date: 2016-08-11 / The objective of this study was to analyze the characteristics and profiles of prenatal
care from the perspective of women treated in the primary care network in a city of
Piauí semiarid region. This is a descriptive exploratory survey study with a sample of
50 pregnant women, involving six teams of the Family Health Strategy, which data
collection was carried out from January to May 2016 through a questionnaire. For
statistical analysis we used descriptive statistics and the chi-square test or G when n
<20. The results showed that 66% of pregnant women living in urban areas. The
service was characterized by single hospital that performed the delivery, which is
responsible for hosting 88% of pregnant women, and 56% were treated at one clinic
in the city. Access to prenatal 44% of them occurred through referral and consultation
schedule in 68% of cases was through the community health worker. The
sociodemographic profile was formed by the prevalence of 40% of pregnant women
aged 21-30 years old, 68% declared the brown race, 46% with higher education
seven years, focusing on the lowest rate in the countryside, 72% They claimed to
have stable partner and 74% defined the Catholic religion. The socioeconomic profile
demonstrates composed majority of 66% with occupancy of the home, 72% with
family income from 0 to 1 minimum wage, 50% dependent on the Bolsa Família, 56%
without children, 36% live with their spouse and 44% own their own homes .
Although 70% of pregnant women have access to treated water, there are problems
related to basic sanitation: 80% do not have sewage system, 88% do not reside in
asphalted local, 74% do not live close to the squares and 60% reside in wooded site.
Regarding habits 78% do not exercise, 96% do not smoke, do not drink alcohol
100% and 90% did not use other drugs. It was found that 68% had laboratory tests
and 62% exams ultrasound properly, 74% had prenatal booklet filled properly, and
82% started the consultation in the first trimester of pregnancy. The satisfaction index
regarding professional consulting physician and nursing was high, with 96% and 98%
respectively. However, 64% did not participate in educational activities offered by the
service, 78% had no suggestions for improvement and 90% said they did not miss
any service. It was found that the variable education had an influence only on four
criteria: type of delivery, abortion, suggestions and dental care. It was found that the
Piauí semiarid region is a very favorable scenario, as a result of health indicators,
restricted network services and low population's quality of life, the study of prenatal
care characteristics, both the social and economic problems listed, as the old
problem involving the climate issue in the region. / O objetivo deste trabalho consistiu em analisar as características e perfis da
assistência pré-natal na perspectiva de mulheres atendidas pela rede de atenção
básica de um município do semiárido piauiense. Trata-se de um estudo survey
descritivo-exploratório, com amostra de 50 gestantes, envolvendo seis equipes da
Estratégia Saúde da Família, cuja coleta de dados foi realizada no período de janeiro
a maio de 2016, através da aplicação de questionário. Para análise estatística dos
dados utilizou-se estatística descritiva, além do teste qui-quadrado ou teste G,
quando n<20. Os resultados demonstraram que 66% das gestantes residem na zona
urbana. O serviço foi caracterizado por único hospital que realizava o parto, o qual é
responsável por acolher 88% das gestantes, sendo que 56% foram atendidas no
único ambulatório da cidade. O acesso ao pré-natal de 44% delas ocorreu por meio
de encaminhamento e o agendamento da consulta em 68% dos casos foi através do
agente comunitário de saúde. O perfil sociodemográfico foi formado pela prevalência
de 40% das gestantes na faixa etária de 21 a 30 anos, 68% se declararam da etnia
parda, 46% com escolaridade maior de sete anos, concentrando-se o menor índice
na zona rural, 72% afirmaram ter parceiro estável e 74% se definiram da religião
católica. O perfil socioeconômico demonstra maioria composta de 66% com
ocupação do lar, 72% com renda familiar de 0 a 1 salário mínimo, 50% dependentes
do Bolsa Família, 56% sem filhos, 36% moram com o cônjuge e 44% possuem casa
própria. Embora 70% das gestantes tenham acesso à água tratada, existem
problemas relacionados ao saneamento básico: 80% não possuem rede de esgoto,
88% não residem em locais asfaltados, 74% não moram próximas às praças e 60%
não residem em local arborizado. Em relação aos hábitos 78% não praticam
exercício físico, 96% não fumam, 100% não ingerem álcool e 90% não consomem
outras drogas. Identificou-se que 68% realizaram os exames laboratoriais e 62% os
exames de ultrassonografia de forma adequada, 74% possuíam o cartão da
gestante preenchido adequadamente, sendo que 82% iniciaram a consulta no
primeiro trimestre de gestação. O índice de satisfação em relação à consulta do
profissional médico e de enfermagem foi alto, sendo de 96% e 98%
respectivamente. Porém, 64% não participaram de atividades educativas oferecidas
pelo serviço, 78% não apresentaram sugestões de melhoria e 90% afirmaram não
faltar nenhum serviço. Verificou-se que a variável escolaridade exerceu influência
apenas em quatro quesitos: tipo de parto, aborto, sugestões e atendimento
odontológico. Constatou-se que o semiárido piauiense é um cenário bastante
propício, em decorrência dos indicadores de saúde, restrita rede de serviços e baixa
qualidade de vida da população, ao estudo das características da atenção pré-natal,
tanto pelos problemas sociais e econômicos elencados, como pela velha
problemática que envolve a questão climática na região.
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Using False Rings to Reconstruct Local Drought Severity Patterns on a Semiarid RiverMorino, Kiyomi January 2008 (has links)
In this research, I describe the use of false rings to reconstruct local histories of seasonal drought in riparian ecosystems in semiarid regions. In tree-ring analysis, false rings are boundary-like features often formed as a response to drought within the growing season. Drought can be a common feature in hydrologic regimes of dryland rivers but in recent decades drought has been intensifying due to climate change and increasing water use by cities, agriculture and industry. Identifying when and where water availability has decreased along the river course is critical for understanding, and therefore managing, these generally endangered ecosystems. The higher density of trees compared to instrumental data make them ideal candidates for reconstructing site-specific drought patterns.The first part of this dissertation is an observational study conducted on the San Pedro River in southeastern Arizona during 2002. I used dendrometer data and local hydrological data to show that a period of negligible radial growth in cottonwood during the middle of the growing season coincided with a channel drying event. Tree-ring core samples confirmed that false-rings had formed in each of the instrumented trees. The second part of this dissertation is an experimental study designed to evaluate the effect of different levels of water stress on false-ring formation in cottonwood and willow. I showed that experimental decreases in water availability for periods as short as ten days were enough to induce false-ring formation in willow. Longer periods of reduced water availability were generally required to induce false-ring formation in cottonwood. In the final part of this dissertation, I reconstructed false-ring occurrence in Fremont cottonwoods at three sites along the San Pedro River. I infer from false-ring frequencies that the severity of summer drought has been increasing over the last four to six decades but that the drought severity varies along a hydrological gradient. Overall, the findings in this body of research confirm that false rings in riparian tree species can be used as indicators of seasonal drought and underscore the importance of identifying site-specific responses to reduced water availability along the riparian corridor.
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Sources and Dynamics of Carbon Dioxide Exchange and Evapotranspiration in Semiarid EnvironmentsYepez-Gonzalez, Enrico Arturo January 2006 (has links)
Precipitation, more than any other environmental factor, controls patterns of ecosystem production and biogeochemical cycling in arid and semiarid environments. Growing-season rains in these regions are highly unpredictable as they come in intermittent pulses varying in size, frequency and spatial extent, thereby producing unique hydrological patterns that constrain the location and residence time of soil water available for biological activity. In order to understand how arid and semiarid ecosystems respond to inputs of precipitation within the context of ecosystem science and global change studies, knowledge is needed on how plants and other organisms respond as an integrated system to such environmental control. The focus of my research was to understand how the distribution of precipitation events influences the dynamics of carbon cycling in semiarid ecosystems. At a semiarid riparian woodland, measurements of CO2 exchange and evapotranspiration revealed that following precipitation events occurring soon after prolonged dry periods the efficiency of rain-use (amount of carbon gain per unit of precipitation over a specific period time) was low. Precipitation did not readily stimulate primary productivity, water was mainly lost as soil evaporation and large respiratory CO2 effluxes were observed. This commonly observed features in seasonally dry ecosystems might have profound consequences for the seasonal and annual carbon balance. In this woodland, 47% of the precipitation within a single growing season (May-October) was returned to atmosphere as soil evaporation and the CO2 efflux observed just during the first rainy month (July) was equivalent to almost 50% of the net carbon gain observed over the six-month growing season. Results from experimental irrigations in understory plots of riparian mesquite woodland revealed that the magnitude and duration of the large CO2 fluxes occurring soon after rainfall was higher in plots located under tree canopies where, relative to intercanopy plots, the amount of plant litter was higher, soil evaporation and plant photosynthetic rates were lower. Efficiency of rain-use in semiarid ecosystems during the growing season apparently was determined by the degree of coupling between gross photosynthesis and ecosystem respiration, by the fraction of precipitation lost as soil evaporation and by the water-use efficiency of the component vegetation.
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Etnopedolgia na unidade de produção agrícola familiar Canto da Ilha de Cima, São Miguel do Gostoso, RN / Ethnopedology in the Family Agricultural Production Unit Canto da Ilha de Cima, São Miguel do Gostoso, RNCunha, Marialdo Santana da 12 May 2016 (has links)
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Previous issue date: 2016-05-12 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The union and the exchange of knowledge between the peasantry and the academy are very important tools for environmental studies, proper management of agroecosystems and the inclusion of technologies adapted to semi-arid conditions. The aim of this study was to describe morphologically the soil and classify it according to Ethnopedological studies in the Family Agricultural Production Unit Canto da Ilha de Cima, São Miguel do Gostoso (RN). Participatory research was conducted from January to December 2015. In the exploratory phase of the research were carried out field activities, meetings and workshops in the community involving farmers, technicians, students and teachers. In the soil classification study the emic [local] and the etic [academic] knowledges were used. Eight soil profiles were excavated in five different areas of the production unit (grazing of sheep and goats, beekeeping area, agroecological cultivation of vegetables, preserved caatinga and conventional production area - the area called Old Chica). In the emic [local] classification prevailed the impressions and qualitative analyzes of morphological and physical properties of soil in an objective and inteperative way through the light of ethnopedology. Farmers classified the lands as good land, piebald ox earth and old chica land as the most important in terms of fertility for crops, differentiating those from the arisco [a sandy soil] and the piçarro [a muddy-stony soil] lands. In the etic [academic] classification was used the Brazilian System of Soil Classification. In the etic classification were identified the Typical Carbonate Haplic Cambisols soils, YELLOW Typical Eutrophic Oxisols, RED YELLOW Typical Eutrophic Latosols, YELLOW Eutrophic Acrisols Latosols, Typical Eutrophic Haplic Cambisols Tb and Typical Carbonate Haplic Vertisols. The emic [local] and etic [academic] classifications performed in this study had a close relationship with each other, since the morphological attributes characterized from different methodological criteria contributed to affirm the importance of Ethnopedology / A união e a troca de saberes entre o campesinato e a academia são instrumentos de grande relevância para estudos de ambientes, um manejo adequado dos agroecosistemas e a inserção de tecnologias adaptados as condições do semiárido. O objetivo desta pesquisa foi descrever morfologicamente o solo e classifica-lo de acordo com os estudos etnopedológicos na Unidade de Produção Agrícola Familiar Canto da Ilha de Cima, São Miguel do Gostoso (RN). A pesquisa participativa foi realizada durante o período de janeiro a dezembro de 2015. Na fase exploratória da pesquisa foram realizadas atividades de campo, reuniões e oficinas na comunidade envolvendo os agricultores, técnicos, estudantes e professores. No estudo de classificação do solo foram utilizados os conhecimentos emicista e o eticista. Foram escavados oito perfis de solo em cinco áreas distintas da unidade de produção (pastejo de ovinos e caprinos, área de apicultura, cultivo agroecológico de hortaliças, caatinga preservada e área de produção convencional - área denominada Velha Chica). Na classificação emicista prevaleceu às impressões e análises qualitativas dos atributos morfológicos e físicos dos solos de forma objetiva e inteperativa a luz da etonopedologia. Os agricultores classificaram os solos como terra boa, terra malhada do boi e terra velha chica como as mais importantes em termos de fertilidade para o cultivo agrícola, diferenciando essas das terras de arisco e de piçarro. Na classificação eticista foi utilizado o Sistema Brasileiro de Classificação de Solos. Na classificação eticista foram identificados os solos CAMBISSOLOS HÁPLICOS Carbonáticos Típicos, LATOSSOLOS AMARELOS Eutróficos típicos, LATOSSOLOS VERMELHOS AMARELOS Eutróficos típicos, LATOSSOLOS AMARELOS Eutróficos argissólicos, CAMBISSOLOS HÁPLICOS Tb Eutróficos típicos e VERTISSOLOS HÁPLICOS Carbonáticos típicos. As classificações emicista e eticista realizadas neste estudo apresentaram estreita relação entre si, uma vez que os atributos morfológicos caracterizados a partir de diferentes critérios metodológicos contribuíram para afirmar a importância da etnopedologia / 2016-11-09
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Resiliência à secas futuras, índices de seca e análise de vulnerabilidade em bacias hidrográficas do semiárido brasileiro.ANDRADE, Tafnes da Silva. 11 September 2018 (has links)
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Previous issue date: 2017-08-11 / A seca liga os fenômenos meteorológicos e a sociedade de tal forma que sua ocorrência,
quase sempre, implica em consequências sociais e econômicas negativas. É um
fenômeno natural cíclico comum no Semiárido nordestino do Brasil. Sua gestão deve
priorizar medidas proativas tomadas antes e durante a ocorrência das secas. Obras de
infraestrutura hídrica podem auxiliar nessa gestão pois contribuem para diminuição da
vulnerabilidade e consequente diminuição dos impactos da seca na região. O
monitoramento é outra ferramenta fundamental nesse processo pois pode integrar
sistemas de alerta e orientar o momento correto para executar ações de preparação e
mitigação. Diferentes índices de seca são usados no monitoramento, e deveriam
considerar não apenas os fenômenos meteorológicos, mas também as atividades
econômicas significativas para a região. Tomando por base o conceito de gestão do
risco, este trabalho buscou identificar as relações entre a gestão do risco e a diminuição
da vulnerabilidade à seca, considerando que as obras de infraestrutura e índices de secas
relacionados com as atividades econômicas regionais são chaves importantes desse
processo. Como resultados podemos citar que as ações de infraestrutura hídrica
contribuíram para o aumento da oferta hídrica na região, que se refletiu nas baixas
vulnerabilidades a seca dos municípios mais atendidos pelo programa. E que os índices
de seca VCI, VHI e SPEI, possuem potencial de uso como ferramenta para aplicação de
medidas de monitoramento e gestão da seca na região em regiões semiáridas, que tem
na pecuária sua principal atividade econômica. / Drought connects meteorological phenomena and society in such a way that their
occurrence, almost always, implies negative social and economic consequences. It is a
natural phenomenon common in the Brazilian northeastern Semiarid. Its management
should focus on proactive measures taken before and during the occurrence of droughts.
Water infrastructure constructions may help in this management as they contribute to
decrease vulnerability and consequently reduce drought impacts. Monitoring is another
fundamental tool in this process because it can integrate warning systems and guide the
right time to perform preparedness and mitigation actions. Different drought index are
used in monitoring, and should look not only the meteorological phenomena, but also
the significant economic activities for the region. Based on the concept of risk
management, this work sought to identify the relationships between risk management
and the reduction of vulnerabilities to drought, considering that infrastructure works and
drought indexes related to regional economic activities are important keys to this
process. As a result, we can mention that water infrastructure constructions contributed
to the increase in the water supply in the region, which was reflected in the low
vulnerability to drought in the municipalities most served by the program. And that the
drought index VCI, VHI and SPEI have potential for monitoring and management
drought in the semiarid region, which has livestock as its main economic activity.
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Valores de referência de qualidade para metais pesados em solos de mangue do Estado do Ceará: subsídios para gestão da zona costeira / Quality reference values for heavy metals in mangrove soils of the State of Ceará: subsidies for coastal zone managementMoreira, Camila Campos Lopes January 2014 (has links)
MOREIRA, Camila Campos Lopes. Valores de referência de qualidade para metais pesados em solos de mangue do Estado do Ceará: subsídios para gestão da zona costeira. 2014. 164 f. Tese (Doutorado em geografia)- Universidade Federal do Ceará, Fortaleza-CE, 2014. / Submitted by Elineudson Ribeiro (elineudsonr@gmail.com) on 2016-06-10T19:11:47Z
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Previous issue date: 2014 / Currently, activities related to urbanization and industrialization have contributed to increased concentrations of heavy metals in different types of soil. These elements have significant toxicity and can accumulate in the environment, configuring serious risk to human health and ecosystems in general. Thus, there is an increasing concern among countries in adopting an efficient environmental policy and, thus, the determination of natural concentration (background levels) of metals in soils and the consequent establishment of Quality Reference Values (QRV) are reality in some countries, including Brazil. However, there is a lack of studies like these related to soils under mangrove forests in the country, where these areas play very important roles and services in the environment. In this context, the contamination of mangrove soils by heavy metals is one of the major environmental issues today and may even compromise the estuaries throughout its length. Thus, a study was carried out in mangrove soils of the State of Ceará aiming their classification and characterization, beyond the determination of natural levels of metals in these soils and the consequent proposition of their QRV. For this, physical, chemical and mineralogical analyzes were realized, beyond the metals extraction by methods of semitotal digestion (EPA 3051A and aqua regia) and the determination of QRV was performed in accordance with the resolution 420/2009 of CONAMA. The results indicated that the semiarid climate preponderant in this region explains the behavior of the main attributes of these soils (ex: EC, TOC, mineral composition). It was also found that the levels of metals in these soils are influenced by the intensity of anthropogenic interference in the coastal environments, given that mangrove soils of Ceará River estuary, inserted into urban context and subjected to environmental stresses, showed the highest enrichment factors of metals. On the other hand, it was observed that the distribution of these elements in this environment is also regulated by interactions between the metals themselves and with attributes as clay and Fe and Mn oxides. Furthermore, the aqua regia digestion was efficient in extracting metals in these soils, while EPA 3051A, indicated by CONAMA for soil quality assessments, underestimated the available levels of metals in the analyzed soils. Given the above, the natural levels of metals determined in this study can serve as a basis for defining QRV for mangrove soils of the State of Ceará, assisting the environmental agency in the formulation of a specific legislation for monitoring mangrove areas in the State, thus setting a new perspective for the management of estuarine environments. / Nos dias de hoje, atividades relacionadas à urbanização e à industrialização têm contribuído para o aumento das concentrações de metais pesados nos diversos tipos de solo. Tais elementos apresentam relevante toxicidade e podem se acumular no ambiente, configurando sério risco à saúde humana e dos ecossistemas em geral. Nesse cenário, percebe-se uma preocupação crescente dos países em adotar uma política ambiental eficiente e, dessa forma, a determinação da concentração natural (níveis de background) de metais nos solos e o estabelecimento de valores de referência de qualidade (VRQs) já são realidade em alguns países, inclusive no Brasil. Entretanto, percebe-se a escassez de estudos dessa natureza que contemplem os solos sob florestas de mangue no país, onde tais áreas são bastante expressivas e desempenham importantes funções e serviços no ambiente. Nesse contexto, a contaminação dos solos de mangue por metais pesados é uma das grandes questões ambientais da atualidade, podendo, inclusive, comprometer os estuários em toda a sua extensão. Assim, foi realizado um estudo em solos de mangue do Estado do Ceará visando a classificação e caracterização dos mesmos, além da determinação dos teores naturais de metais e a consequente proposição de seus VRQs. Para isso, foram realizadas análises físicas, químicas e mineralógicas, extração dos metais por métodos de digestão semitotal (EPA 3051A e água régia) e a determinação dos VRQs foi realizada de acordo com o disposto na resolução n° 420/2009 do CONAMA. Os resultados obtidos indicaram que o clima predominantemente semiárido da região explica o comportamento dos principais atributos desses solos (ex: CE, COT, constituição mineralógica). Verificou-se ainda que os teores de metais nos solos em questão são influenciados pela intensidade da interferência antropogênica nos ambientes costeiros, tendo em vista que os solos de mangue do estuário do rio Ceará, inserido em contexto urbano e submetido a diversos tipos de tensões ambientais, apresentaram os maiores fatores de enriquecimento de metais. Por outro lado, observou-se que a distribuição de tais elementos nesses solos é também regida por interações entre os próprios metais e dos mesmos com atributos como a fração argila e os óxidos de Fe e Mn. Além disso, a digestão por água régia mostrou-se eficiente na extração de metais nesses solos, enquanto o EPA 3051A, indicado pelo CONAMA para avaliações de qualidade dos solos, subestimou os teores dos metais disponíveis nos mesmos. Diante do exposto, os teores naturais dos metais determinados no presente estudo podem servir de base para a definição de VRQs para os solos de mangue do Estado do Ceará, auxiliando o órgão ambiental responsável na formulação de uma legislação específica para o monitoramento das áreas de manguezal do Estado, configurando, portanto, uma nova perspectiva para a gestão dos ambientes estuarinos.
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