Environmental Geochemistry and Health 1994 16(3/4) page129
Lead, copper and zinc in atmospheric and fluvial ,particulates from the Caracas Valley, Venezuela Armando J. Ramirez i, Alberto J. Fernfindez C. 2 and Rebeca Fraile 3 l lnstituto de Ciencias de la Tierra, Facultad de Ciencias, Universidad Central de Venezuela P.O. Box 3895, Caracas IOIO-A, Venezuela 2Centro de Quimica Analitica, Facultad de Ciencias, Universidad Central de Venezuela P.O. Box 47102, Caracas 1041-A, Venezuela 3Centro de Quimica, Instituto Venezolano de Investigaciones Cientfficas, P.O. Box 21827, Caracas 1020-A, Venezuela
Abstract
The atmospheric particulates from the Caracus Valley in Venezuela and the fluvial particulates transported by the Tuy River into the Caribbean sea have been evaluated for Pb, Cu and Zn with the purpose of determining the contamination levels in the study area. The atmospheric particulate samples were collected in the city of Caracas using a low volume sampler whereas the fluvial particulate were collected at the mouth of the Tuy River. The particulate samples were analysed by flame or graphite furnace atomic absorption spectrometry depending upon the concentration levels of the heavy metal under study. The results obtained for the fluvial particulates enabled estimates to be made of the total anthropogenic flux of Cu (383 ton year-l), Pb (528 ton year -1) and Zn (865 ton year-l). These results yield annual per capita inputs for Cu (96 g),Pb (132 g) and Zn (216 g) which greatly exceed those from global anthropogenic emissions. The weighted average concentration of Pb (1.13 %) found in the atmospheric particulates was much higher than those for Cu (140 mg kg 1) and Zn (200 mg kg -1) and reflects the high motor car traffic in the Caracas Valley. The anthropogenic/natural ratios estimated in this study were as follows: 2.6 for Pb; 1.5 for Cu and 1.5 for Zn. This indicates that anthropogenic inputs for Cu, Pb, and Zn in the study area exceed those from natural sources, cars being the major source for Pb and industrial activities the major sources for Cu and Zn.
Introductiion
The quantity and distribution of heavy metals in air, water, sediments, soils and biological materials have notably increased in the last decades due to human activities (F6rstner and Wittmann, 1983; Salomons and F 6 r s t n e r , 1984; Warren, 1981). This a n t h r o p o g e n i c input of heavy metals tothe enviromnent may surpass the natural fluxes and p r o d u c e .significant c h a n g e in global biogeochemical cycles. The urban d e v e l o p m e n t , g r o w i n g industrialisation and the discharge of gaseous, liquid and solid wastes into the environment without treatment, have been the main reasons for the degree of contamination that exists in the developing countries (Ajmal et al., 1987; Kouadio and Trefry, 1987; De Lacerda et al., 1987; Romieu et al., 1991). Venezuela has also e x p e r i e n c e d a high demographic expansion, especially in the north where a high degree of pollution has been reported for Lake Maracaibo (Parra, 1979), Lake Valencia
(Lewis and Weibezhan, 1983; Mogoll6n et al., 1988), Tuy River (Humphreys, 1975; Mogoll6n et al.,] 987, 1990; Ramirez, 1991 ; Ramirez et al., 1988; Taboada and Garcia, 1978), Coastal areas (Gamboa and Bonilla, 1983; Mogoll6n, 1989) and Caracas City (Ishizaki and Sanhueza, 1979; Sanhueza et al., 1979; Lara et al.,1984) Caracas, the capital and largest Venezuelan city, is locatcd in the northwestern part of the Tuy River basin and it is the major source of pollutants into the Tuy River. This study is mainly concerned with the atmospheric particulates in the Caracas Valley and the fluvial particulates transported by the Tuy River into the Caribbean sea. The objectives of this study are: (1) to evaluate the concentrations of Pb, Cu and Zn in the atmospheric particulates; (2) to estimate the annual anthropogenic fluxes of Pb, Cu and Zn out of the basin; (3) to compare the anthropogenic to the natural sources and in addition, to compare the influence of cars to other identified anthropogenic sources.
130
Atmospheric and fluvial particulates
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500 I
Figure 1 Map of Venezuelan hydrographic basins.
Study Area and Methodology The Venezuelan fluvial system (Figure 1) has been divi~led into three groups: contributors to the Atlantic Ocean, The Caribbean Sea and Lake Valencia (Zinck,1982: Ramirez et al., 1992). The rivers d r a i n i n g into the C a r i b b e a n Sea are subdivided into those rivers draining directly into sea (Caribbean Sea basin) and those draining through Lake Maracaibo. The Tuy River has the highest stream flow amongst those rivers entering the Caribbean Sea basin (Figure 1). The Tuy R i v e r B a s i n , l o c a t e d in the northcentral part of Venezuela (Figure 2), has an area of 6,600 km 2, a population of 4.3 • 106 inhabitants and the highest population and car densities for any of the Venezuelan catchments draining directly into the Caribbean Sea (Grunwald et al., 1989). The annual average temperature, rainfall and runoff are 27~ 140 cm and 36 cm r e s p e c t i v e l y . The a n n u a l p r e c i p i t a t i o n is characterised by two seasons, dry and wet, with March and April being the driest months of the year, and July and August the wettest ones (Ramirez, 1991; Zambrano, 1970; Zinck, 1982). The northern area of the Tuy River basin experiences lower precipitation and runoff and has
Table 1 Weighted averages (mg kg -1) for Pb, Cu and Zn in the atmospheric and fluvial particulate. Fluvial Total Pb Cu Zn
144 125 288
Natural 40 51 115
Atmospheric Total 11,300 140 200
much higher population and car densities than the southern area. The northern lithology is mostly low-grade metasediments with a relatively high carbonate content whereas the southern lithology is a combination of metavolcanic and maficultramafic rocks (Dengo, 1953; Picard and Pimentel, 1968; Seiders, 1965, Smith, 1952,1953). The atmospheric particulates were collected in the Caracas downtown area over a one-week period, from January to July of 1988, using a low volume sampler with cellulose acetate filters. The acid extracts of the airborne particulate were analysed by flame (Pb and Zn) and graphite furnace (Cu) atomic absorption spectrometry (Fernandez et al., 1991 ). The fluvial particulates were collected by filtration
A.J. Ramirez, A.J. Fernandez C. arid R. Fraile
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Lead, copper and zinc in atmospheric and fluvial ,particulates from the Caracas Valley, Venezuela Armando J. Ramirez i, Alberto J. Fernfindez C. 2 and Rebeca Fraile 3 l lnstituto de Ciencias de la Tierra, Facultad de Ciencias, Universidad Central de Venezuela P.O. Box 3895, Caracas IOIO-A, Venezuela 2Centro de Quimica Analitica, Facultad de Ciencias, Universidad Central de Venezuela P.O. Box 47102, Caracas 1041-A, Venezuela 3Centro de Quimica, Instituto Venezolano de Investigaciones Cientfficas, P.O. Box 21827, Caracas 1020-A, Venezuela
Abstract
The atmospheric particulates from the Caracus Valley in Venezuela and the fluvial particulates transported by the Tuy River into the Caribbean sea have been evaluated for Pb, Cu and Zn with the purpose of determining the contamination levels in the study area. The atmospheric particulate samples were collected in the city of Caracas using a low volume sampler whereas the fluvial particulate were collected at the mouth of the Tuy River. The particulate samples were analysed by flame or graphite furnace atomic absorption spectrometry depending upon the concentration levels of the heavy metal under study. The results obtained for the fluvial particulates enabled estimates to be made of the total anthropogenic flux of Cu (383 ton year-l), Pb (528 ton year -1) and Zn (865 ton year-l). These results yield annual per capita inputs for Cu (96 g),Pb (132 g) and Zn (216 g) which greatly exceed those from global anthropogenic emissions. The weighted average concentration of Pb (1.13 %) found in the atmospheric particulates was much higher than those for Cu (140 mg kg 1) and Zn (200 mg kg -1) and reflects the high motor car traffic in the Caracas Valley. The anthropogenic/natural ratios estimated in this study were as follows: 2.6 for Pb; 1.5 for Cu and 1.5 for Zn. This indicates that anthropogenic inputs for Cu, Pb, and Zn in the study area exceed those from natural sources, cars being the major source for Pb and industrial activities the major sources for Cu and Zn.
Introductiion
The quantity and distribution of heavy metals in air, water, sediments, soils and biological materials have notably increased in the last decades due to human activities (F6rstner and Wittmann, 1983; Salomons and F 6 r s t n e r , 1984; Warren, 1981). This a n t h r o p o g e n i c input of heavy metals tothe enviromnent may surpass the natural fluxes and p r o d u c e .significant c h a n g e in global biogeochemical cycles. The urban d e v e l o p m e n t , g r o w i n g industrialisation and the discharge of gaseous, liquid and solid wastes into the environment without treatment, have been the main reasons for the degree of contamination that exists in the developing countries (Ajmal et al., 1987; Kouadio and Trefry, 1987; De Lacerda et al., 1987; Romieu et al., 1991). Venezuela has also e x p e r i e n c e d a high demographic expansion, especially in the north where a high degree of pollution has been reported for Lake Maracaibo (Parra, 1979), Lake Valencia
(Lewis and Weibezhan, 1983; Mogoll6n et al., 1988), Tuy River (Humphreys, 1975; Mogoll6n et al.,] 987, 1990; Ramirez, 1991 ; Ramirez et al., 1988; Taboada and Garcia, 1978), Coastal areas (Gamboa and Bonilla, 1983; Mogoll6n, 1989) and Caracas City (Ishizaki and Sanhueza, 1979; Sanhueza et al., 1979; Lara et al.,1984) Caracas, the capital and largest Venezuelan city, is locatcd in the northwestern part of the Tuy River basin and it is the major source of pollutants into the Tuy River. This study is mainly concerned with the atmospheric particulates in the Caracas Valley and the fluvial particulates transported by the Tuy River into the Caribbean sea. The objectives of this study are: (1) to evaluate the concentrations of Pb, Cu and Zn in the atmospheric particulates; (2) to estimate the annual anthropogenic fluxes of Pb, Cu and Zn out of the basin; (3) to compare the anthropogenic to the natural sources and in addition, to compare the influence of cars to other identified anthropogenic sources.
130
Atmospheric and fluvial particulates
) ~ ~ S/ ~ ~
k,
) .
"~ '.,. . I ~L.r
LAKE'~
VALENCIA
~'x,.,^ . . . . . . . .
,"
/--
"--
i-"
ATLANTIC OCEAN
tSAN JUAN
. . . . .
ORINOCO
~
Riuoc
"
I /RIO CU' I I 0
\
ORINOCO
\
RiO \ NEGRO
0 [
,)
\.../
SCALE IOO 200 I I Kms.
500 I
Figure 1 Map of Venezuelan hydrographic basins.
Study Area and Methodology The Venezuelan fluvial system (Figure 1) has been divi~led into three groups: contributors to the Atlantic Ocean, The Caribbean Sea and Lake Valencia (Zinck,1982: Ramirez et al., 1992). The rivers d r a i n i n g into the C a r i b b e a n Sea are subdivided into those rivers draining directly into sea (Caribbean Sea basin) and those draining through Lake Maracaibo. The Tuy River has the highest stream flow amongst those rivers entering the Caribbean Sea basin (Figure 1). The Tuy R i v e r B a s i n , l o c a t e d in the northcentral part of Venezuela (Figure 2), has an area of 6,600 km 2, a population of 4.3 • 106 inhabitants and the highest population and car densities for any of the Venezuelan catchments draining directly into the Caribbean Sea (Grunwald et al., 1989). The annual average temperature, rainfall and runoff are 27~ 140 cm and 36 cm r e s p e c t i v e l y . The a n n u a l p r e c i p i t a t i o n is characterised by two seasons, dry and wet, with March and April being the driest months of the year, and July and August the wettest ones (Ramirez, 1991; Zambrano, 1970; Zinck, 1982). The northern area of the Tuy River basin experiences lower precipitation and runoff and has
Table 1 Weighted averages (mg kg -1) for Pb, Cu and Zn in the atmospheric and fluvial particulate. Fluvial Total Pb Cu Zn
144 125 288
Natural 40 51 115
Atmospheric Total 11,300 140 200
much higher population and car densities than the southern area. The northern lithology is mostly low-grade metasediments with a relatively high carbonate content whereas the southern lithology is a combination of metavolcanic and maficultramafic rocks (Dengo, 1953; Picard and Pimentel, 1968; Seiders, 1965, Smith, 1952,1953). The atmospheric particulates were collected in the Caracas downtown area over a one-week period, from January to July of 1988, using a low volume sampler with cellulose acetate filters. The acid extracts of the airborne particulate were analysed by flame (Pb and Zn) and graphite furnace (Cu) atomic absorption spectrometry (Fernandez et al., 1991 ). The fluvial particulates were collected by filtration
A.J. Ramirez, A.J. Fernandez C. arid R. Fraile
67" 00'
66" 30'
CARIBBEAN
~0'
~"
./ ~
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~
66" 00'
SEA
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