1

Water resources pollution by solid waste dump sites in the Paraiba do Sul River basin Mahler, C.F and Schueler, A.S.

ABSTRACT: In Brazil about 60% of the domestic urban solid waste produced, that is, about 96,302 tons a day are inadequately disposed of in waste dumps or flooded areas. In many cases the percolate drains directly to the soil or to lakes or rivers near the open dump. There are risks of pollution of natural resources. Paracambi open dump is such an example. It is an open dump about 50-70 m from the Macacos River near the town centre. Macacos River belongs to the Guandu river basin, which supplies the city of Rio de Janeiro and receives water from Paraíba do Sul river basin. The Paraíba do Sul river basin is unique in Brazil in terms of physical and institutional complexities and is the pilot project for current attempts at integrated management. Paraíba do Sul River and many of its tributaries are under federal jurisdiction, and most of the rivers are owned by the States of São Paulo, Rio de Janeiro or Minas Gerais; also, an inter-basin transfer diverts a substantial volume of water from it (180 m3/s or less) to the Guandu river basin. This paper addresses relevant aspects of the Paraíba do Sul and Guandu river basins.

Lastly, the paper discusses the monitoring of the Macacos River micro-basin that crosses the town of Paracambi. This monitoring was done for a year during the wet and dry seasons. Monitoring consisted of chemical analyses of water samples collected from seven different points of Macacos River and its main tributaries, Cascata and Sabugo rivers. The primary purpose of this work was to assess the contribution of the percolate from the Paracambi open dump to the pollution of Macacos River.

1 INTRODUCTION

Paracambi has a population of 40,475: 36,868 inhabitants in the urban area and only 3,607 in the rural area (IBGE1, 2000). The Paracambi open dump is located in an area of approximately 25,000 m2 and the volume of waste disposal by the end of 2004 was approximately 59,000 m3. Each day it receives about 26 tons of many different kinds of waste. Using the HELP software (Hydrological Evaluation for Landfill Performance) a numerical analysis was done to estimate the percolate production in the open dump. The forecast obtained was 3,421.72 m3 of percolate produced in one year.

The open dump is located at the foot of a hill (Figure 1). Macacos River is located on the other side of the open dump at a distance of 50-70 m. Houses have been built around the open dump on the side of the river. The open dump is located in an area that should be occupied by the natural spread of the town. The town centre is located about one kilometre on one side. On the other side further away are the suburbs of Paracambi. Figures 2 and 3 show photos of the open dump and the town’s location in the region.

MACACOS RIVER

RAILWAY

HOUSINGWASTE OPEN DUMP

ROAD

CEMETERY

10 a 50 m50 a 70 m aprox 80 m

aprox 7 m

Figure 1: Sketch showing the location of the open dump in relation to Macacos River.

1 Brazilian Institute of Geography and Statistics

2

Figure 2. Overview of the open dump

Figure 3. Location of Paracambi

2 PARAIBA DO SUL/GUANDU RIVER BASINS – METROPOLITAN AREA OF RIO DE JANEIRO

Campos (2005) comments that the hydraulic works that are responsible for channelling the waters from the

rivers Paraiba do Sul, Piraí and Vigario to Guandu basin, for the purpose of power generation in the Lajes hydroelectricity complex in the State of Rio de Janeiro began in the 1910s. In the following decades, this system was gradually extended by building various dams, pumping stations and hydroelectricity plants. He also points out that the name of Lajes Hydroelectric Complex characterises the hydroelectricity schemes of Ribeirão das Lajes and the set of hydraulic structures for transferring water from the Paraíba do Sul river basin to the Atlantic coastal mountain range to benefit from the hydroelectricity potential due to a drop of approximately 300 m. It should be mentioned that the Lajes Complex is the largest group of hydraulic structures in Rio de Janeiro State. Today the name of Lajes Hydroelectricity Complex/Paraíba do Sul is also given to the group of regulatory reservoirs at the headwaters of the Paraiba do Sul river basin.

The operation of the Lajes/Paraiba do Sul hydroelectricity schemes plays a leading role in the performance of the Southeast/Midwest hydroelectric power production system considering its location close to the loading centre, and the questions of multiple use of water in one of the most industrialised regions of Brazil. The importance of this system lies in the fact that the water supply of approximately 85% of the Rio de Janeiro metropolitan region, corresponding to a population of around 8.5 million inhabitants, depends totally on maintain this arrangement. Guandu River from the Guandu water treatment plant (Guandu WTP) to the estuary in Sepetiba Bay (Figures 4 and 5) is called São Francisco Canal because of the Guandu river training works during the 20th century (Campos, 2005).

Paraíba do Sul River has a long history of government interventions, the purpose of which was always the rational use of water resources. The first actions focusing on the drainage area management of this river began in São Paulo State and date from the 1930s.

Interventions in the early 20th century marked the first stage in the exploration of this potential. Therefore, the first project involved the construction of the Lajes reservoir, completed in 1908, consisting of the dam on the Lajes creek and installation of some auxiliary dikes (Figure 6). On that occasion, it was already acknowledged that the contributions from the Lajes creek were not enough to regulate the spillway that was intended for the turbines in the Fontes hydroelectricity plant.

Fontes power plant was designed for the city of Rio de Janeiro, which was still the capital of Brazil at that time. The name Fontes Velha (old) is used to distinguish it from the Fontes Nova (new) hydroelectricity plant built by Light (company responsible for power distribution in Rio de Janeiro State) in the 1950s (Figure 7). The Fontes Velha plant has been shut down since 1989

Lajes reservoir has reasonable dimensions, although its contributing basin is very small, around 300 km2. Its working volume is 601 hm3. Nevertheless, the long-term average natural flow into the reservoir is approximately 6m3/s (Campos, 2005). Since this tributary was not enough to regulate the 17 m3/s or so intended for the turbines in the Fontes Velha hydroelectricity plant, the solution was to transfer a basin to increase the flow into the Lajes reservoir. This occurred in 1913 when Tocos reservoir was implemented on the Piraí river, in Rio Claro county,

3

from which a tunnel was built to deviate the water by gravity to Lajes reservoir. This diversion tunnel has a maximum collection capacity of 25 m3/s. The regulation capacity of the Tocos reservoir is very limited and its service volume only 5.29 hm3. This intervention, therefore, characterises the first transfer ever of a basin in the Lajes Complex.

Figure 4. Guandu dams and WTP intake (Source: CEDAE)

Figure 5. Estuary of São Francisco Canal (Source: Gerdau)

Figure 6. Lajes Dam (Source: LIGHT )

Figure 7.Fontes Nova HEP (Source: LIGHT)

4

Campos (2005) comments that the second implementation stage of the Lajes Complex covers the period

1952-1962. That was when the hydraulic structures began operating, helping to transfer the water from Paraíba do Sul River to the Atlantic slopes of the coastal mountain range. This transfer authorised Light to divert the water from Vigario creek and Piraí river and from Paraíba do Sul River in order to increase the Ribeirão das Lajes plant. This second transfer began in 1952 and used the Santa Cecilia pumping station (Figure 8) located in Barra do Piraí county in Rio de Janeiro State, which has a diversion capacity of up to 160 m3/s from Paraíba do Sul River. This figure corresponds to approximately two thirds of the regulated flow at that site. There is a small reservoir in Santa Cecilia, whose useful volume is only 2.17 hm3, which provides the pumping station intake. The propeller race of the Paraíba do Sul river reaches a head of 15.50 m carried through a tunnel with a section of 43.50 m2 and extending for 3,314 m, to Santana reservoir, built from a second dam on Pirai River (Campos, 2005).

The water accumulated in Santana reservoir was again pumped by the Vigario pumping station (Figure 9), upstream from the reservoir close to the town of Piraí. The pressure head in this second pumping is 35m, and the maximum pressure capacity 189m3/s. Vigario pumping station pumps the water from Santana reservoir to the reservoir created by the Vigario dam, until then a small tributary of Piraí river. The effect of pumping through the upstream part of the Santana reservoir causes the inversion of the course of Piraí River in the stretch of this reservoir. It should be mentioned that the long-term natural average flow of Piraí River at Santana is 20 m3/s and in the Tocos-Santana extension 6 m3/s, while the water accumulated in this reservoir is also from Paraíba do Sul and Piraí rivers. It is estimated that 180 m3/s is transferred from the Paraíba do Sul basin to Guandu basin using the two aforementioned transfers (Campos, 2005).

The water accumulated in the Vigario reservoir is then diverted by gravity to the Atlantic slope of the coastal mountain range using collection pipes that benefit from the difference in level of approximately 300m. The power generated by this sharp drop economically justifies the effort of the transfer, in other words, the energy spent in the first pumping of 15.50m, plus that spent in the second pressure of 35 m. This layout facilitated the construction of the Nilo Peçanha, Fontes Velha (now closed), Fontes Nova (Figure 9) and Pereira Passos hydroelectric power plants.

Figure 8. Santa Cecilia Pumping Station (Source: Light)

Figure 9. Vigario Pumping Station (Source: Light)

Paraíba do Sul and Piraí river basins to the Guandu river basin. In this way, the 180 m3/s flow, indicated as

that approved for Light, does not correspond to the value effectively guaranteed throughout the year. Light always wanted to have this flow available for power generation. However, since 1996 the hydroelectricity plant reservoirs at the headwaters of Paraíba do Sul River are responsible for regulating this river to facilitate the transfer at Santa Cecilia, and are in an ongoing process of depletion, which makes it practically unfeasible to apply the operating rules to the planned reservoirs. According to the National Interconnected Power System Operator (ONS) this fact is due to the low rainfall indices in that region of the Paraíba do Sul river basin.

Accordingly, it is evident that the average flow transferred to the Guandu will tend to be less than 150 m3/s, even considering the flows of Piraí River also involved in the two existing transfers in the Lajes complex – that of Paraíba do Sul River (and part of Piraí) through the Santa Cecilia and Vigario pumping stations, and of Piraí River, through the tunnel between the Tocos and Ribeirão das Lajes reservoirs -, maintaining the dry conditions

5

similar to those found in 2003, as a result of the depletion of the reservoirs at the headwaters of the Paraíba do Sul river.

Due to government department resolutions, at first the inflow to the Santa Cecilia dam on Paraíba do Sul River gradually dropped from 190 m3/s to 160 m3/s. The reduced flow corresponding to the downstream stretch from Santa Cecilia on the Paraíba do Sul, and the collection for the Lajes Complex in the Santa Cecilia pumping plant were 20 m3/s and 10 m3/s, respectively, resulting in 51 m3/s as minimum flow in Santa Cecilia for the downstream stretch of the Paraíba do Sul, much less than the 90 m3/s guaranteed in normal hydrological periods, and 109 m3/s as the pumping flow to the Lajes Complex. Added to the 109 m3/s was another 6 m3/s from the Lajes reservoir, resulting in 115 m3/s for available water in the Guandu course to attend users downstream from the Pereira Passos HEP. It is worth mentioning that during 2003 as a result of scarce water resources, the standard hydrogram shown in Figure 7 was replaced by a hydrogram whose flows were the same as 115 m3/s 24 hours a day.

Campos (2005) says that the reduction in these flows, later associated with the increase in rainfall indices, permitted gradual recovery of the storage of the reservoirs at the headwaters of the Paraíba do Sul. On May 2, 2005, the accumulated volume in the reservoir was around 80% of the total volume, with a tendency to reach higher values that same year, representing more storage than that measured in the past seven years.

In the light of the above, the use of the Paraíba do Sul and Guandu drainage basins has a long history, even for a country as young as Brazil. The contamination of water courses causes serious environmental and economic damages to the system, making healthy recreation on the river unfeasible, such as, for example, against fishing, which not only supplies food to many families but also offers fishing and tourist opportunities.

3 METHODOLOGY AND RESULTS Monitoring the river courses that cross the Paracambi waste dump area of influence involves two water

sampling campaigns collected at seven points along the Macacos River and its tributaries Sabugo and Cascata. The first sampling campaign was undertaken on 3rd February 2004, during the wet season, when the water

balance in this region is positive. The second sampling campaign was carried out on 26th August that same year in the dry season, when the water balance in the region is negative.

The objective of monitoring, after having studied the behaviour of the percolate drainage produced by the waste dump, to assess its contribution towards the pollution of Macacos River in the town context, since this is a dump located fairly near the river banks.

Seven water monitoring points were distributed along the Macacos river micro-basin. During the first sampling campaign, the Macacos river had an average width of 6 m and average depth of 0.5

m; Sabugo River monitoring near point 4 had an average width of 4 m and average depth of 0.4 m and Cascata River with an average width of 2.5 m and depth of 0.30 m. In the second sampling campaign, approximate depths were 0.3 m in Macacos River, and its tributaries were quite shallow with less than 0.1 m in depth. The water collection points were distributed as shown in Figure 10:

It is found that the highest pH value (Figure 10) in both samplings is at point 3. This point has little human influence, and indicates water with higher alkalinity. It was the only point where the presence of rainwater raised the pH. It is noticeable that there is a change in the trend of the curves between points 5 and 6 of Macacos River, upstream and downstream from the waste dump.

In the first sampling, the pH in Macacos River stayed between 6.7 and 6.9, in Cascata River the value was 6.8 and in Sabugo River the variation range was between 7.8 – at point 3, without human influences – and 6.8.

The measured values are very close to neutral pH, which is generally a state of equilibrium. In the second sampling, the pH values are higher. In Macacos River it remained between 7 and 7.3, in Cascata River the value was 7.0 and Sabugo River had a variation range of between 7 and 7.5.

The presence of biodegradable organic matter is shown in Figures 12 and 13 through the BOD5 and COD/BOD5 ratio. The trends of the BOD5 curves in both sampling campaigns are similar. The tributaries seem to have some influence, increasing the concentration of BOD5 at point 5. The missing sample from point 1 in the first sampling does not permit assessment of the contribution of the Macacos river tributaries. There is an inversion in the trends of the curves between points 5 and 6, upstream and downstream from the waste dump. Eleven of the thirteen points sampled show higher concentration levels than the quality benchmark value for class 3 water provided by Conama (national Council for the Environment).

It is found that the concentration values in relation to COD/BOD5 are higher during the wet season and that they show a more intense biodegradation process when there is more water. In the second sampling campaign, the COD/BOD5 ratio does not seem to vary greatly due to the fact that it passes through the dump. At point 7,

6

there seems to be a return to the initial conditions of the river. The missing values for point 1 in the first sampling do not permit us to make a similar interpretation. Nevertheless, in the latter sampling, Macacos River seems to be somehow influenced by the waste dump, since there is an increase in values between points 5 and 6, upstream and downstream from the dump, followed by a drop between points 6 and 7 in the rainy season.

Figures 14 to 19 show concentrations of chloride, sulphate, ammonia, potassium, calcium, magnesium, iron, manganese, zinc and cadmium found in the Macacos river micro-basin.

Water collection points on Macacos River. Point 1: before receiving the tributaries; Point 5: in a densely urbanised area in the town centre, approximately 1 km upstream from the waste dump; Point 6: next to the waste dump, downstream; Point 7: approximately 1 km downstream from the dump, next to a steel mill closed in 1977. Water collection point on Cascata River. Point 2: in an urbanised zone, a little before flowing into Macacos River. This river flows close to a textile

dying factory before entering the area demarcated as an influence on the dump. Water collection point on Sabugo River. Point 3: in a natural area, almost without human influence; Point 4: in an urbanised zone, a little before it reaches Macacos River.

Figure 10. Diagram showing the layout of the water sampling points in the Macacos river micro-basin.

pH

5.5

6

6.5

7

7.5

8

8.5

9

9.5

1 2 3 4 5 6 7POINTS

pH

Macacos: wet season

Cascata: wet season

Sabugo: wet season

Macacos: dry season

Cascata: dry season

Sabugo: dry season

Range ofreferencevalues: 6 to 9

MSW

Figure 11. pH concentration along the Macacos river micro-basin.

Cascata River

Sabugo River

Macacos River

3 4 2

7

5 6

1 Open Dump

7

BIOCHEMICAL OXYGEN DEMAND

0

20

40

60

80

100

1 2 3 4 5 6 7POINTS

BO

D m

g/L

Macacos: wet season

Cascata: wet season

Sabugo: wet season

Macacos: dry season

Cascata: dry season

Sabugo: dry season

Referencevalue forwater class 3

MSW

Figure 12. BOD5 concentration along the Macacos river micro-basin.

BIODEGRADABLE ORGANIC MATTER

0

1

2

3

4

5

1 2 3 4 5 6 7

POINTS

CO

D/B

OD

Macacos:wet season

Cascata: wet season

Sabugo: wetseason

Macacos: dry season

Cascata: dry season

Sabugo: dry season

MSW

Figure 13. Biodegradable organic matter concentration along the Macacos river micro-basin.

Figure 14 shows the values of chloride concentration found in the samples. A slight variation can be seen in the trend of the curves between points 5 and 6, upstream and downstream from the waste dump, principally in the second sampling during the dry season. In both samplings, the tributaries seem to have considerable influence on point 4 on Macacos River. All values, however, are way below the maximum value permitted by the Ministry of Health.

Figure 15 shows the values of sulphate concentration. There is a variation in the trend of the curves between points 5 and 6, upstream and downstream from the waste dump, being much more accentuated in the first sampling. At that time, Macacos River seems to be more influenced by its tributaries, which are more torrential. Accordingly, the high relative concentration of sulphate at point 1 apparently drops at point 5 to reach values close to those found in the tributary water, points 2 and 4. The concentrations increase after flowing through the waste dump. However, this fact seems more to do with a return to the conditions found at point 1 than as a result of an influence of the waste dump. As the river leaves the region in which it receives its tributaries, with relative low sulphate content, the water tends to return to the earlier conditions. The same process apparently occurs during the dry season. All values, however, are below the maximum value permitted by the Ministry of Health.

Figure 16 shows samples with ammonia concentration content. In the second sampling in the dry season, an upward trend can be seen in the concentration values in Macacos River. This increased value at point 4 seems to be influenced by the high relative values found in the drainage of the tributaries, points 2 and 4, but apparently there is also influence from the waste dump drainage. In the first sampling during the rainy season, except for point 5, the concentration values are quite similar to each other. All values are below the maximum value

8

permitted by the Ministry of Health. Figure 17 shows the potassium contents measured in the samples. It is noticeable that the slightly downward

trend of the concentration curve changes very little along Macacos River. In the second sampling campaign, the increase between points 1 and 5 of Macacos River seems to be influenced by the higher values from the tributaries. There is apparently some influence from the drainage of the waste dump so that the potassium concentration diminishes, since there is an increase at point 7.

Figure 18 shows the calcium concentration values obtained along the rivers. Calcium shows quite similar values in both samplings. The only variation observed occurs in the second sampling, between points 5 and 6, upstream and downstream from the waste dump, and that at point 7 a return to the conditions found along the river is noticeable. Apparently there is an influence from the drainage from the waste dump.

Figure 19 shows magnesium contents measured in the samples. In the first sampling the values are very similar at all points. The slight drop in content after flowing through the waste dump apparently only has some importance when compared with the second sampling curves. During the dry season, an increase in concentration values is found between points 1 and 5 on Macacos River, which can be influenced by the tributary drainage, points 2 and 4, with higher concentrations. When flowing through the dump, as in the first sampling, but on a larger scale, there is a sharp relative drop in concentrations, which continues until point 7. This fact may indicate influence from the waste dump drainage.

Figure 20 shows iron concentrations found along the rivers. The iron concentration in Macacos River does not seem influenced by the tributary drainage. The values found at points 1 and 5 from the Macacos River are very similar in both samplings, which does not occur with the values found at points 2 and 4. In the two samplings a drop in contents is noticeable between points 5 and 6, upstream and downstream from the waste dump, with a later increase in point 7. This fact may have some effect from drainage from the waste dump. However, it should be considered that point 7 is located very close to a disused steel mill, which may justify a higher iron concentration.

Figure 21 shows the values relating to manganese concentration along the rivers. In the first sampling the manganese content of the tributaries, points 2 and 4, does not seem to influence the water in Macacos River, and is much higher at point 5, then decreasing at points 6 and 7, and has concentrations similar to that found at point 1.

In the second sampling during the dry season, the increased concentration at point 5 may be the result of the tributary drainage. However, this may just be a coincidence, since in the first sampling the highest value at point 5 was not influenced by the others. Apparently the lower concentration values between points 5 and 6 in Macacos River upstream and downstream from the waste dump are not influenced by it.

Zinc contents are found in the samples. The first sampling in the dry season does not show much variation in the course of Macacos River or its tributaries. In the second sampling increased concentrations are found between points 1 and 5 of Macacos River that were probably influenced by the higher concentrations of the tributaries upstream. After point 5, the contents drop again, without apparent influence from the waste dump. All values are far below the intervention value set by the Ministry of Health.

The values of cadmium concentration in the samples are measured. A high relative increase in cadmium contents is found along the Macacos River in the second sampling. The now high concentrations at point 5 also increase with the course of the river through the waste dump, and remain as such until point 7. When it flows through the waste dump, the cadmium concentration in the water is 0.006 mg/L, which is higher than the intervention value of 0.005 mg/L set by the Ministry of Health for substances that are health hazards. Since the cadmium concentrations measured in the underground water downstream from the waste dump are also quite high, it is possible that there is a contribution from this drainage.

9

CHLORIDE CONCENTRATION

0

5

10

15

20

25

30

35

1 2 3 4 5 6 7POINTS

mg/

L

Macacos: wet season

Cascata: wet season

Sabugo: wet season

Macacos: dry season

Cascata: dry season

Sabugo: dry season

Reference valuefor water class3:250 mg/L

MSW

Figure 14. Chloride concentration along the Macacos River micro-basin micro-basin

SULPHATE CONCENTRATION

0

5

10

15

20

25

30

35

1 2 3 4 5 6 7POINTS

mg/

L

Macacos: wet season

Cascata: wet season

Sabugo: wet season

Macacos: dry season

Cascata: dry season

Sabugo: dry season

Reference valuefor water class 3:250 mg/L

MSW

Figure 15. Sulphate concentration along the Macacos river micro-basin

AMMONIA CONCENTRATION

0

2

4

6

8

1 2 3 4 5 6 7POINTS

mg/

L

Macacos: wet season

Cascata: wet season

Sabugo: wet season

Macacos: dry season

Cascata: dry season

Sabugo: dry season

Reference valuefor water class1: 3.7 mg/L

MSW

Figure 16. Ammonia concentration along the Macacos river micro-basin

10

POTASSIUM CONCENTRATION

0

2

4

6

8

1 2 3 4 5 6 7POINTS

mg/

L

Macacos:wet season

Cascata:wet season

Sabugo:wet season

Macacos: dry season

Cascata: dry season

Sabugo: dry season

MSW

Figure 17. Potassium concentration along the Macacos river micro-basin

CALCIUM CONCENTRATION

0

2

4

6

8

1 2 3 4 5 6 7POINTS

mg/

L

Macacos:wet season

Cascata:wet season

Sabugo:wet season

Macacos: dry season

Cascata: dry season

Sabugo: dry season

MSW

Figure 18. Calcium concentration along the Macacos river micro-basin

MAGNESIUM CONCENTRATION

0

0.5

1

1.5

2

2.5

1 2 3 4 5 6 7POINTS

mg/

L

Macacos:wet season

Cascata:wet season

Sabugo:wet season

Macacos: dry season

Cascata: dry season

Sabugo: dry season

MSW

Figure 19. Magnesium concentration along the Macacos river micro-basin

11

IRON CONCENTRATION

0

0.5

1

1.5

2

2.5

1 2 3 4 5 6 7POINTS

mg/

L

Macacos: wet season

Cascata: wet season

Sabugo: wet season

Macacos: dry season

Cascata: dry season

Sabugo: dry season

Reference valuefor water class1:1.4 mg/L

MSW

Figure 20. Iron concentration along the Macacos river micro-basin

MANGANESE CONCENTRATION

0

0.05

0.1

0.15

0.2

0.25

1 2 3 4 5 6 7

POINTS

mg/

L

Macacos: wet season

Cascata: wet season

Sabugo: wet season

Macacos: dry season

Cascata: dry season

Sabugo: dry season

Reference valuefor water class 1:0.1 mg/L

MSW

Figure 21. Manganese concentration along the Macacos river micro-basin

4 CONCLUSIONS

The conclusions from the work are as follows. It is noticeable that the vast majority of curves, principally those relating to the second sampling during the

dry season, showed a variation in trend between points 5 and 6 in Macacos River upstream and downstream from the dump. Apparently such a variation is due to an increase in concentrations of substances present at point 5, from the drainage of the tributaries upstream – Cascata River, point 2, and Sabugo River, point 4 – and from the actual urbanisation that shows a higher population density at these three points in the town centre. Exceptions that may indicate a contribution from the waste dump are found in the second sampling in the dry season, with ammonia, potassium, calcium, magnesium and cadmium, while only the last showed an increase in concentrations.

Although the results obtained show that the densely populated region in the town centre contributed relatively more to increasing the Macacos river pollution than the waste dump 20-70 m from its river bank, its influence cannot be ignored. It is worth pointing out, however, the fact that there are homes on the riverbanks between the landfill and Macacos River. Therefore, the difference between the obtained values of a concentration of contaminants between points 5 and 6 in the graphs herein refers not only to contamination from the waste dump but also from a group of houses on the riverbank, whose sewage drains directly into the river water. It was not possible in this paper to dissociate the contributions from these houses from the waste dump.

12

However, it is possible to presume that a large part comes from the waste dump, since the contamination by these substances was discovered in underground water collected between the dump and group of houses.

Since there is no drainage system to collect the percolate produced in the waste dump before it reaches the river, it is possible to admit the major importance of the natural attenuation processes through which the effluent passes. These processes help reduce the contamination potential of the river when it receives surface and underground drainage from the dump.

The results presented, however, do show certain trends but more definitive analyses would require a large number of samples.

As described in this paper, the integration between the Paraíba do Sul and Guandu river basins has been a major task for the Rio de Janeiro Metropolitan Region. Unfortunately, the waste dumps in a number of towns belonging to the two basins, namely, that of Rio Paraíba in Rio de Janeiro State, consisting of more than 60% or so of the towns in the state, have their waste in dumps close to the Paraíba do Sul river or rivers or creeks belonging to its basin. The example chosen presents a study relating to Macacos River at Paracambi. Unfortunately, as the study has shown, not only does the waste dump contaminate the water in the Macacos River but certainly one of the reasons for the river’s death and its environmental damage. The losses caused by this practice of waste disposal in dumps close to water resources or directly into water courses are incalculable, and there is no reasonable justification for such a procedure.

ACKNOWLEDGEMENT

The authors thank the National Research Council (CNPq) for its ongoing support, and Ms. Elvyn Marshall for the English revision.

REFERENCES Campos, J. D. (2005). Challenges in the implementation of integrated water resources management in Brazil in

the cases of natural and artificial water transfers, PhD Thesis, COPPE/UFRJ, 457 pages, Brazil (in Portuguese)

CETESB. Relatório de estabelecimento de valores orientadores para solos e águas subterrâneas no estado de São Paulo [Report on setting guide values for soils and underground water iun the State of São Paulo]. São Paulo: CETESB, 2001.

Christensen, T.H.; Cossu R., Stegmann, R. (1997) Landfilling of waste: Leachate. In: proceedings Sardinia, 97, Sixth International Landfill Symposium. S. Margherita di Pula, Cagliari, Italy: CISA.

IPT/Cempre (2000). Lixo Municipal: manual de gerenciamento integrado [Local waste: integrated management handbook]. 2nd ed. São Paulo: IPT, 370 p.

Tchobanoglous G., Theisen H., Vigil S. A. (1994). Integral management of solid waste. 1st ed. Madrid: McGraw-Hill, Inc, 1994. v(s).1-2, 1106p. (in Spanish)