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EVALUATION OF CONTAMINATION OF A SEMI-ARID REGION IN THE NORTHEAST OF BRAZIL

Fatima Maria de Miranda BraynerEscola Politecnica – Universidade de Pernambuco, Rua Benfica, 455 - Madalena - Recife/PE

fatimabrayner@upe.poli.br

Ana Maria de Freitas Barbosa1

Abstract In the period between August 2002 and November 2003, superficial sediment samples were collected from the rivers Sao Francisco, Capibaribe and Pajeú, which cut a semi-arid region in Brazil, when there was no water in their beds. During samples’ collection environmental conditions such as the weather – sunny or rainy, and the existence or absence of vegetation, animals, polluting sources and irrigation were observed. Due to the large amount of collected samples, after being dried and sieved, the samples were mixed according to their identification references and the observed environmental conditions, in order to form composed samples which were then sent to analysis, which was done through the digestion of samples using microwaves, with the elements being determined using ICP-AES method. The findings were in accordance with the kind of agricultural activities performed in the region, presenting high contents of the studied elements.

Index Terms Metals, Sediments, Semi-arid.

INTRODUCTION

The state of Pernambuco has an area of 98.938km2, representing approximately 6.49% of the Brazilian northeast region total area and 1.19% of the national territory. Due to its long and stretched shape, the state has a small littoral which spreads 187km along the Atlantic Ocean, and a long east-west extension (748km). Pernambuco is entirely comprised within the Tropical region, since its north and south extreme points are between the 7°15’ and 9°27’ parallels of South latitude, respectively. In the east-west direction, its extreme points are located between the 34°48’ and 41°19’ meridians of West Greenwich longitude. Pernambuco shares boundaries with almost all the Brazilian north-eastern states, with the exception of Sergipe, Maranhão and Rio Grande do Norte. It is bounded to the north by Ceará and Paraiba; to the east by the Atlantic Ocean; to the south by Alagoas and Bahia; and to the west by the state of Piauí.

As a consequence of its spatial settings and populating process, Pernambuco has a set of different landscapes, which change sharply from the littoral to the interior area, and are marked by an intense diversification of land uses. Therefore,

the Brazilian Geography and Statistics Institute – IBGE has identified in 1989, 5 different mesoregions and 19 microregions within the state’s territory. With the exception of the São Francisco River, which borders the hinterland of the state, and divides its territory from Bahia, there are no big rivers in Pernambuco, neither in length nor in volume of water. Regarding its topography, there are two catchment basins within the state, which present distinct characteristics: Littoral rivers’ basins, in the eastern part, with a

drainage network flowing in the west-east direction to the Atlantic Ocean. Among these rivers are the Goiânia, Capibaribe, Ipojuca, Sirinháem, Una, Mundaú and others of smaller importance;

Hinterland rivers’ basins, in the western part, with a drainage network flowing on the north-south direction to the São Francisco River. Among these, the rivers Ipanema, Moxotó, Pajeú, Terra Nova, Brígida, Garças and Pontal are worth mentioning.Most of these are state rivers, with a few federal ones,

such as the Mundaú, Ipanema and Moxotó.This study presents the findings of the project

“Productive Clusters in the Pernambuco semi-arid: Impacts on the Water and Environment Quality”, funded by FINEP and the Brazilian Ministry of Science and Technology[1]. Together with the states of Ceará, Rio Grande do Norte and Paraiba, Pernambuco integrates, with a large part of its territory, the centre of the north-eastern semi-arid. This area, formerly called Drought Polygon, had its name changed, following the issues treated in the article 159 of the Federal Constitution from 1988. In 1989 the Semi-arid Region was created, an official denomination derived from the Constitutional Fund for the Northeast Financing – FNE.

The semi-arid urban growth plays a decisive role in the definition of the development strategies and public resources allocation in the areas affected by drought. This is, thus, the key element of the demographic challenge, which is also urban, to be faced in the semi-arid region. In this area, this challenge is much bigger than in any other within the Brazilian northeast, considering its spatial dimensions and the fragility of its human and natural resources’ basis.

According to the Brazilian national census 2000, Pernambuco has a population of 7.911.937 inhabitants. From these, 17.4% are distributed in the mesoregions named

1 Ana Maria de Freitas Barbosa, Private Consultant, amfbarbosa@gmail

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Sertão Pernambucano and São Francisco Pernambucano, and 25.2% in the Agreste Pernambucano Mesoregion. The spatial distribution of the population in the semi-arid region in very unequal, with a higher concentration in the following municipalities: Caruaru, with 253.312 inhabitants; Petrolina, with 218.336; and Garanhuns with 117.587. Serra Talhada has a population of 70.881 inhabitants, while Araripina has 70.589, and Belo Jardim has 68.665 residents. Among the cities with less than 60.000 inhabitants are Santa Cruz do Capibaribe, with 59.017, Pesqueira with 57.602, Ouricuri with 56.631 and Salgueiro with 50.284 people.

The Agreste Mesoregion has 24,444.7km2 in total, which corresponds to 24.7% of the Pernambuco state territory. This is a transition area between the Mata and the Sertão areas, being divided into 6 microregions: Alto Capibaribe, Médio Capibaribe, Vale do Ipojuca, Garanhuns, Ipanema and Brejo Pernambucano. From these, 4 are located in a region with a predominant semi-arid climate, namely Vale do Ipanema, Vale do Ipojuca and Alto and Médio Capibaribe. The main economic activities in the Vale do Ipojuca and Garanhuns microregions are related to dairy products, particularly in the cities of Garanhuns, Sao Bento do Una, Cachoeirinha and Altinho. The textiles’ industry production is structured in the Alto Capibaribe microregion, characterizing a productive cluster.

The Sertão Pernambucano mesoregion has the largest area, 38,575.8 km2 in total, corresponding to 39% of the state’s territory. It comprises 4 microregions: Pajeú, Moxotó, Salgueiro and Araripina. The Araripina microregion presents a development potential based on mineral resources, with a dynamic exploitation and active social actors. The city of Araripina is the centre of the Gypsum Pool, defining the overall socio-environmental structure.

The Sao Francisco mesoregion has an area of 24,634.4km2, which corresponds to 24.9% of the area of the state. The two microregions located there, Petrolina and Itaparica, are the two other areas contained in the Pernambuco semi-arid. These microregions have a high potential for hydro-agricultural uses, under the guidance of a dynamic urban centre, with active social actors and existing pre-investments. The irrigated fruits production chain is located in the Petrolina microregion, with the cities of Santa Maria da Boa Vista and Lagoa Grande also playing an important role.

Like any other semi-arid region around the world, the Brazilian Northeast will always be subject to periodic droughts, due to the natural characteristics of this kind of region, especially irregular and unevenly distributed rainfalls. In the semi-arid region, the water shortage represents one of the main hindrances to economic and social development and the use of the available natural resources has not paid much attention to the basic principles of sustainable development. Several types of environmental degradation have been registered in this area, which have a direct impact over the quality of the water. These are either due to the dominant productive clusters, or to the

concentration of urban centres which are marked by the precarious basic infrastructure services, with poor or non-existent sewerage systems.

In an attempt to minimize the consequences of the frequent droughts and allow, as prime priority, the survival of people and herds, the construction of small earth pools became commonplace. However, the effort to keep the largest amount of water for the largest period possible has led to the progressive salinization of the accumulated waters, to eutrophism processes, and to the contamination by pesticides and heavy metals.

The degradation process of the accumulated waters is due to several factors, among which the following are worth mentioning: the high levels of annual evaporation that can reach 2,000 mm/year in the driest regions; morphology; vegetal and pedological cover of the catchment basin; and, mainly, the anthropic action. The most frequent anthropic actions over the Brazilian Northeast reservoirs are related to deforestation of large areas of the catchment basin, indiscriminate use of pesticides, contributions of solid residues and of domestic sewerage effluents.

The deforestation in the reservoir catchment basin area leads to an increase of the runoff and the erosion of the neighbouring areas, increasing the amount of sediments and contributing to silt it up. The excess of pesticides, used to fight plagues which reduce harvests and cattle productivity, can be carried by the rains to the interior of the reservoirs, leading to water contamination and making it inappropriate for consumption. Lastly, urban populations produce huge amounts of domestic sewerage effluents and solid residues, which are not always properly disposed, resulting in the contamination of the soil and of the superficial and underground water resources.

At present, the multiple uses of water and the land use forms have created problems related to aspects of water quality and quantity, which are highly interrelated. Water can have its quality easily altered, depending on the use one makes of it, due to its physical and chemical characteristics. Population growth and industrial development intensify water quality and quantity problems and contribute substantially to variations in ecosystems, and to the consequent degradation of water resources.

OBJECTIVES

To evaluate the contamination by heavy metals in the superficial sediments of the rivers Sao Francisco, Pajeú and Capibaribe in the areas covered by the productive clusters of irrigated fruits culture and wine viniculture, caprine-ovine culture, and of the clothing industry in the semi-arid region of Pernambuco.

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METHODOLOGY

The proposed methodology for the evaluation of the impacts of the productive clusters on the water and environment quality was initially based on a survey of the available data related to the existing productive clusters, which led to the identification of the most representative polluting sources among those which have an impact on the water resources, such as industrial and domestic effluents disposal, and crude damping sites, among others, for each cluster area.

In the period between August 2002 and November 2003, sediment samples were collected from the main drain of the Bebedouro Project, from the drains of two farms in the Sao Francisco basin, and from the beds of the Capibaribe and Pajeú rivers when there was no water in it. During samples’ collection environmental conditions such as the weather – sunny or rainy, and the existence or absence of vegetation, animals, polluting sources and irrigation were observed.

Collected samples were dried naturally in a ventilated space, protected from direct sun light. They were then ground, separated in quarters and sieved in 200 Mesh sieves. Due to the large number of collected samples, after these preparation stages they were mixed, taking into account the identification references and the observed environmental conditions, in order to form composed samples which were then sent to analysis.

For analysis of the samples the method for microwaves samples digestion was applied, and the elements were determined using ICP-AES. Initially, the elements Zinc, Lead, Cadmium, Manganese, Cobalt, Nickel, Chrome and Cooper were determined in the collected samples. Later, only Zinc, Manganese, Chrome, Nickel and Cooper were determined, considering the fact that the remaining elements presented results bellow the ICP-AES detection limit. Concurrently, values for the organic material present in the samples were also determined.

PRODUCTIVE CLUSTERS IN THE SEMI-ARID

In 1999 the government of Pernambuco implemented a decentralized planning program for the state, named Government in the Municipalities. The program identified eleven Development Regions: Sertão do Araripe, Sertão Central, Sertão de Itaparica, Sertão do Pajeú / Moxotó, and Sertão do Sao Francisco; Agreste Central, Agreste Meridional, Agreste Setentrional, Mata Norte, Mata Sul and Metropolitana, as well as the main productive clusters within each of them. Figure 1 indicates the location of the main productive clusters identified in the semi-arid of Pernambuco.

FIGURE. 1LOCATION OF THE MAIN PRODUCTIVE CLUSTERS IN THE SEMI-ARID OF

PERNAMBUCO

The Wine Viticulture and Irrigated Fruits Culture Productive Cluster

The irrigated agriculture, making use of the sub-medium Sao Francisco waters, constitutes one of the most important economic activities in the region. The expansion of the irrigated areas by private groups has spread all over the riverside, with an emphasis in the production of fruits and vegetables. Grapes, mangoes, coconut, guava, banana, melon, tomato and watermelon are the main products. The irrigated fruits culture productive cluster, comprising the municipalities of Petrolina, Santa Maria da Boa Vista and Lagoa Grande has fostered the development of the viticulture and the wine viticulture, leading to the construction of industrial plants targeted at the production of the wines known as tropical in several cities of the region.

The main impacts of the wine viticulture productive cluster on the water quality are related to the uncontrolled use of pesticides; salinization due to the alteration of the natural water balances; disposal of wine industry effluents and disposal of non-treated domestic effluents in the water bodies.

Analysis of the sediments

Regarding the sediments, the results are consistent with the use of pesticides, as depicted in Figure 2 and Table 1.

FIGURE 2SÃO FRANCISCO BASIN METALS IN SEDIMENT

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TABLE 1LOCATION OF THE MAXIMUM AND MINIMUM VALUES FOR THE METALS

FOUND IN SEDIMENT IN THE SAO FRANCISCO

METAL MAXIMUM VALUE MINIMUM VALUE

ZINCGaribaldina Farm main drain (Lagoa Grande)

Vitória Stream Nilo Coelho Project (Petrolina)

MANGANESEBebedouro Project drainage channel (Petrolina)

Milano Farm main drain (Santa Maria da Boa Vista)

CHROMEBebedouro Project drainage channel (Petrolina)

Milano Farm main drain (Santa Maria da Boa Vista)

COOPERGaribaldina Farm main drain (Lagoa Grande)

Vitória Stream Nilo Coelho Project (Petrolina)

The Caprine-Ovine Culture Productive Cluster

The productive cluster of the caprine-ovine culture is located in Pajeú and Moxotó rivers basin and, although the extensive culture of ovine and caprine can be observed all over the area, it is highly concentrated in the cities of Serra Talhada and Floresta. Together they occupy an area of 6,628 km2 and have a population of 95,641 inhabitants, corresponding, respectively, to 28.25% of the territory and 17.87% of the population of the whole region.

In the Pajeú – Moxotó basin region, the main problem related to water resources’ pollution is caused by the disposal of non-treated domestic and butcheries’ effluents. The caprine-ovine culture generates recoverable by-products such as leather, blood, grease products and flours, bones and horns, among others. However, the recovery is not always economically feasible.

Analysis of the sediments

The findings of metals in the sediment show more significant levels for chrome, probably due to leather processing, and for manganese, which is related to the soil characteristics. Figure 3 and Table 2 depict the main analysis results.

FIGURE 3PAJEU BASIN METALS IN SEDIMENT

TABLE 2LOCATION OF THE MAXIMUM AND MINIMUM VALUES FOR THE METALS

FOUND IN SEDIMENT IN THE PAJEÚ BASIN

METAL MAXIMUM VALUE MINIMUM VALUE

ZINCDownstream of Serra Talhada

Upstream of de Serra Talhada

MANGANESERiacho Fundo (Floresta) Downstream of Serra

Talhada

CHROMEDownstream of Serra Talhada

Downstream of de Floresta

COOPERRiacho Fundo (Floresta) Upstream of de Serra

Talhada

NICKELUpstream of Serra Talhada

Downstream of Floresta

The Clothing Industry Productive Cluster

In the state of Pernambuco, the clothing industry is undoubtedly one of the most important industrial activities. It is characterized by scales diversity, with micro, small, medium and big enterprises, with a clear predominance of the small and micro ones in the industrial structure of the region.

The main impacts on water quality, derived from the clothing industry productive cluster, are related to the disposal of non-treated domestic and industrial effluents in the water bodies. This is especially true concerning the indigo / jeans clothing industry, which is concentrated in the Agreste Setentrional region, due to the use of colourings in the textiles tinting. Since a large part of the industries operating in the region is informal, it is not possible to quantify the industrial effluent from this productive cluster.

The Agreste clothing industry productive cluster is concentrated in the Agreste Central and Setentrional regions in the state of Pernambuco, in an area where the predominant vegetation is the caatinga, with irregular rainfalls. The regions have as one of its characteristics an intermittent hydrographical network, with frequent periods of rainfall shortage.

The laundries’ disposals contain mainly: organic material; detergents and soaps; solids in suspension; dissolved solids – chlorates; oils and grease; caustic soda; colour; heavy metals such as cobalt, chrome, zinc and manganese, derived from pigments; and chlorine composites.

Sediment samples

In this basin sediment samples were collected in two collection points only: upstream of Santa Cruz do Capibaribe, since the river was dry in this spot during almost the whole collection period; and upstream of the Mamute Laundry, in Toritama. The findings showed consistent with the pigments used in the indigo / jeans production, as shown in Figure 4 and Table 3.

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FIGURE 4CAPIBARIBE BASIN METALS IN SEDIMENT

TABLE 3LOCAIS DOS VALORES MÁXIMOS E MÍNIMOS DOS METAIS ENCONTRADOS EM

SEDIMENTO NA BACIA DO CAPIBARIBE

METAL MAXIMUM VALUE MINIMUM VALUE

ZINCUpstream of the Mamute Laundry, in Toritama

Upstream of Santa Cruz do Capibaribe

MANGANESEUpstream of the Mamute Laundry, in Toritama

Upstream of Santa Cruz do Capibaribe

CHROMEUpstream of the Mamute Laundry, in Toritama

Upstream of Santa Cruz do Capibaribe

DISCUSSION

The behaviour of trace metals in soil depends upon complex reaction among cations and anions present in souls and its different components of various phases [2]. Small quantities of many metals are essential for human, animals and plants, but a great concentration of them can be toxic. Metal toxicity is often associated with types of metals present in the soil [3].

This study has showed evidence of human occupation and productive clusters’ impact on a large area of the semi-arid region in Pernambuco, including those regions susceptible to desertification, according to documents from the Secretary of Science, Technology and Environment of Pernambuco [4]. In every sample collected in the studied productive clusters, heavy metals’ presence was detected.

The findings from the analysis of the samples collected in the Sao Francisco River are coherent with the agricultural and farming activities performed in the region. High levels of Cu and Zn were found in the main drain of the Garibaldina Farm in the municipality of Lagoa Grande, during the collection periods. According to literature, Zinc in acid soils tends to be retained under an exchangeable fashion, in clay and organic material. Chemical absorption in oxides and aluminium silicates, and the complexation in humic acids lower Zinc’s solubility in alkaline soils. Moreover, the co-precipitation of Zinc within the silicates’ octahedral layers is theoretically possible [5]. These possibilities can explain the high levels of Zinc found in the mentioned spot. Regarding Cooper, most of this element,

when dissolved in the soil surface, in a pH range reasonably wide and predominantly acid, form complexes with organic composites. The linkage among Cooper and organic composites is relatively stronger than for any other divalent transition metal. The results found for the element Manganese in most of the samples were the expected, also in the caprine-ovine culture cluster, considering the fact that Mn is one of the constituents of the sediment. Cooper was detected in some samples collected in the irrigated fruits production cluster, as a result of the use of cooper sulphate as fungicide. Chrome derives from the presence of leather processing units in the clothing industry productive cluster region. In the case of Zinc, the main pollutant sources are galvanoplasty, colourings’ pigments, pesticides and mining.

The findings discussed previously indicate the possible degradation of the studied areas, showing the need for the adoption of corrective procedures aimed at minimizing and, if possible, eliminating this process. The results of the study highlighted the necessity of exploring the impacts of the different productive clusters on the Caatinga Biome and of developing technological solutions adapted to the Brazilian Northeast semi-arid conditions.

REFERENCES

.[1] ITEP - Instituto de Tecnologia de Pernambuco. Arranjos Produtivos

no semi-árido de Pernambuco: Impactos sobre a qualidade da água e o meio ambiente. Convênio FINEP, Relatório Técnico Final, 2005

[2] Salomons, W; Förstner, U; Mader, P, “Heavy Metals: Problems and Solutions”, Springer – Verlag, 1995

[3] Bishop, P, L, “Pollution Prevention: Fundamentals and Practice”, University of Cincinnati U.S.A, Mc Graw Hill, 2000

[4] Secretaria de Ciência, Tecnologia e Meio Ambiente - SECTMA, “Politica Estadual de Controle da Desertificacao”, Documento Sintese, 1999

[5] McBride, M, B, “Environmental Chemistry of Soils”, Oxford University Press, 1994

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