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Helminth eggs in marine and river sediments
Volume 20/Number
6/June
1989 0025-326X/89 $3.00 + 0.00 O 1989 Pergamon Press plc
Marine Pollution Bulletin, Volume 20, No. 6, pp. 269-271, 1989. printed in Great Britain.
Helminth Eggs in Marine and River Sediments J. SCHWARTZBROD, M. T. THEVENOT and J. L. STIEN Ddpartement de Microbiologie, Facultd de Pharmacie, 5 rue Albert Lebrun, 54000 Nancy, France
This investigation examines the sources of parasite contamination and their effect on the contamination of three types of marine sediments of a specific coastal region: marine sediments, river sediments, and sewage sludge. In the sludge, concentrations varied between 2 X101 to 3.4 ×102 eggs kg -~ with 30% of samples containing at least four different types of eggs (nematode and cestode eggs). In the river sediment, helminths eggs were found in 90% of samples (sector Besos) and in 80% of samples (sector Liobregat). Only 20% of the littoral marine sediments from the Besos were positive for helminth eggs but in the sludge effluent zone all the samples were positive. At 7 0 0 0 m offshore no samples contained helminth eggs. In the Llobregat sector, 35% of samples contained heiminth eggs; there was no apparent difference in the degree of parasite contamination between the littoral (200 m offshore) and the intermediate zones (1000 m offshore). At 4000 and 12 000 m offshore no samples contained helminth eggs. The viability of Ascaris eggs was studied. Globally the percentage of viable eggs was always higher in Besos sector than in Llobregat. If all sediment river samples contained viable eggs we have recognized in some sediment marine sample viable Ascaris eggs: in Besos sector 14% of viable Ascaris eggs were still found at 3000 m and 4 0 0 0 m offshore while only samples collected from littoral zone in Liobregat sector contained 5% of viable Ascaris eggs.
highly polluted rivers (the Besos river and the Llobregat river), treated and raw wastewater. Sewage sludge is transported offshore from Barcelona through a deep conduit. Three sample types were studied: marine sediments, river sediments, and sewage sludge.
Marine sediment sampling Marine sediments were collected from 50 m to 7 km offshore of metropolitan Barcelona at depths varying from 6 to 150 m. Samples obtained from the oceanographic vessel Garcia del Cid required use of a Van Veen double spoon. River sediment sampling These came from the two rivers that empty into the sea at Barcelona: the Besos river and the Llobregat river. Samples were taken from the upper layer of mud (23 cm thick) with a raking shovel fixed to a pole. The Besos river samples were collected 1500 m upstream of its mouth; the Llobregat river ones, 3500 m upstream of its mouth. Sewage sludge sampling Raw sludge was collected after primary decantation from the San Adrian wastewater treatment plant which treats 300 000 m 3 of wastewater daily. Figure 1 shows the location and characteristics of the sampling points. Methods
Microbiological pollution of the marine environment is often the result of human activities in the coastal zone such as offshore dumping of sewage sludge or effluents from raw or treated wastewater. Although many studies have been done on viral and bacteriological pollution of the marine environment, very little is known about parasitological contamination of this important resource (Bitton et al., 1983; Feachem et al., 1983; Schwartzbrod et al., 1986). This investigation addresses the problem of parasitological contamination in examining its sources and their effect on the contamination of sediments of a specific coastal region.
Parasite density was too low for direct microscopic examination, thus all the samples underwent an enrichment procedure. A preliminary study (Stien & Schwartzbrod, 1986) had shown that, out of all the various concentration methods available, the one described by Janeckso-Urbanyi (1931) was best adapted to the sample types investigated here. This method uses a high density (d--1.44) potassium iodomercurate solution with low viscosity so that the eggs rise rapidly to the surface. The slides are read at 400× magnification. The viability determination of Ascaris eggs was studied after n-butanol treatment (Stien & Schwartzbrod, 1988).
Sampling
Results
Barcelona was selected as the study site because of the many effluents into the sea. These consist of two
The results are expressed as number of eggs kg-1 sample and are presented by geographic sector with two 269
Marine PollutionBulletin
k
Treatment ptant ~ San a d r i a n ~
Borcetono
Trichurs) with only 14% of viable Ascaris eggs. Sediment samples from 7000 m offshore did not contain any helminth eggs.
Badabna/ //~
/~3~4'5
River Besos
Llobregat sector results Continental sources: In this sector, the Llobregat fiver
• IO •ll 12
R / ~
4
•7
Sampl.ingpo,ntsecretSesos • Sornptingpolnt setterC l o S e , a t • t ScaLeI 9 a O 0 0
~o kms
I
Fig. 1 Locationof samplingpoints. well-defined sample zones: the Besos sector and the Llobregat sector.
Besos sector results Continental sources: In this sector, there are major coastal sources of contamination: the waters and sediment of the Besos river, wastewater and sewage sludge from the wastewater treatment plant. Besos river sediment." Helminth eggs were found in 90% of the samples analysed with levels ranging from 2 X 101 to 1X 10 z eggs kg-1. The mean was 4.2 X 101 eggs kg-1. These eggs were either nematode or cestode families (Table 1). All the samples with nematode eggs contained, in decreasing amounts, Ascaris, Enterobius, Toxocara, and Trichuris; only Hymenolepis was found for cestodes. All Ascaris eggs were viable. San Adrian treatment plant sludge: All the sludge samples contained helminth eggs (nematodes and/or cestodes) with numbers varying from 2 x 101 to 3.4 x 102 eggs kg-L The nematode eggs were Trichuris and Enterobius in 12 out of 17 samples. The cestodes were predominantly Hymenolepis (12/17) with one sample containing Tenia eggs. There was great variety in the eggs recovered from most of the samples as certain ones contained as many as 6 different genera (Table 1). Marine sediments: Analysis of the results leads to classification of the samples into four categories according to the sampling points (Table 2). The littoral sediments include the samples taken along the coast (points 1, 2, 3, 4, and 5) except for the mouth of the Besos river. Only one of these samples contained helminth eggs (Hymenolepis). The sediments sampled at the Besos river mouth (points 6, 7, 8, and 9) all contained nematode eggs, Ascaris, Trichuris, and Toxocara in decreasing amounts but no Enterobius and only one sample had cestode eggs present (Hymenolepis). 50% of Ascaris eggs were viable. The samples from the sludge effluent zone (points 10 and 11), at 3000 and 4000 m offshore, contained nematode eggs (Ascaris and 270
water and sediment and raw wastewater from several collectors are possible sources of helminth eggs. Only the fiver sediment was analysed. Llobregat river sediment: Helminth eggs were found in 80% (8/10) of these samples with quantities varying from 2X101 to 1.4X102 eggs kg-1 and a mean of 4.8 x 102 eggs kg-~ (Table 1). Nematode eggs were found in 7 of the 8 positive samples with Trichuris, Toxocara, Ascaris, and Enterobius in order of decreasing amount. The percentage of viable Ascaris eggs was 40%. Cestode eggs (Hymenolepis) were found in only 3 samples. Marine sediments: The marine sediment results are classified into 3 groups according to their sampling points (Table 3). Littoral zone sediments: This includes samples taken from the Llobregat river mouth to 200 m offshore (points 1, 2, 3, and 4). Both nematode (Ascaris and Trichuris) and cestode (Tenia) eggs were found in 2 out of 4 samples in low quantities (2x10~-4X101 eggs kg-1). The percentage of viable Ascaris eggs was very low 5%. Intermediate zone sediments: This consists of the samples taken from points 5 and 6 at 1000 m offshore. Only nematode eggs (Trichuris, Toxocara) were found in 1 of 2 samples. Offshore sediments: The samples taken at 4000 and 12 000 m offshore (points 7 and 8) did not contain any helminth eggs.
Discussion and Conclusions Coastal sources of parasite contamination are numerous and varied. It is necessary to underline the great diversity of helminth eggs found in most of the samples from sediments and treatment plant sludge. In the sludge, 30% of the samples contained at least four different types of eggs with more or less the same distributions of nematode and cestode eggs. The concentrations found here are in agreement with those reported in the literature, with levels varying from 1×102 to 5.4×103 eggs kg-~ (Kabrick & Jewell, 1982; Graham, 1981; Stien & Schwartzbrod, 1987). The frequent presence of Enterobius eggs in the sludge samples should be emphasized, indicating a certain level of enterobiasis infestation in the local population. This type of nematode egg, in contrast to the others identified in this study (Ascaris, Trichuris and Toxocara) has been found only sporadically in these kinds of samples (Shephard, 1971i Knaack & Ritschell, 1975; Bergstrom, 1981). Only 10% of the fiver sediment samples contained three types of eggs with the nematode eggs being predominant in all the sectors studied. Only 20% of the littoral marine sediments from the Besos sector were positive for helminth eggs. All the river mouth samples contained nematode eggs (Ascaris, Trichuris and Toxocara). The sludge effluent zone samples also were
Volume 20/Number 6/June 1989 TABLE 1 Parasite contamination of sediments from the Besos and Llobregat Rivers and of wastewater treatment plant sludge.
River Besos sediment San Adrian treatment plant sludge Llobregat River sediment
Number of eggs kg-~ Extreme value Mean value
Littoral sediments Point 1 Point 2 Point 3 Point 4 Point 5
10
9
2 x 10~-1 x 102
4.2 x 10 ~
9
3
5
1
17
17
2 x 101-3.4 x 102
1.1 x 10 a
15
5
5
2
10
8
2 x 10~-1.4 x 102
4.8 x 102
7
5
2
1
Distance from shore
Helminths eggs kg-t (mean value)
250 400 250 400 500
ND* ND 2 x 10 ~ ND ND
m m m m m
Sediments sampled at the river Besos mouth Point 6 50 m Point 7 400 m Point 8 400 m Point 9 1500 m
4 4 6 8
Samples from the sludge effluent zone Point 10 3000 m Point 11 4500m
8 x 10 ~ 4 X 10 ~
Samples from offshore Point 12
Number of samples a type of eggs 1 2 3 4 5 6
Number of samples positive
TABLE 2 Parasite contamination of the marine sediments in the Besos sector. Sampling point location
Number of samples with nematode eggs
Number of samples tested
7000 m
x 101 X 10 ~ X 10 t x 10 ~
ND
*Not detected. a l w a y s p o s i t i v e f o r n e m a t o d e eggs. Finally, at 7 0 0 0 m o f f s h o r e , n o s a m p l e s c o n t a i n e d h e l m i n t h eggs. T h e v i a b i l i t y o f A s c a r i s eggs w a s d i f f e r e n t f r o m t h e k i n d a n d the geographic origin of the samples. Globally the p e r c e n t a g e o f v i a b l e A s c a r i s eggs w a s a l w a y s h i g h e r in B e s o s s e c t o r t h a n in L l o b r e g a t s e c t o r ; t h e r e was also m o r e v i a b l e A s c a r i s e g g s in r i v e r s e d i m e n t s a m p l e s t h a n in m a r i n e s e d i m e n t s a m p l e s . I n B e s o s s e c t o r 1 4 % o f v i a b l e A s c a r i s e g g s w e r e still f o u n d at 3 0 0 0 m a n d 4 0 0 0 m offshore while only samples collected from littoral z o n e in L l o b r e g a t s e c t o r c o n t a i n e d 5 % o f v i a b l e A s c a r i s eggs. In c o n c l u s i o n , this s t u d y p r e s e n t s an i n v e n t o r y o f d i f f e r e n t p a r a s i t o l o g i c a l c o n t a m i n a t i o n f o u n d in r i v e r w a t e r a n d s e d i m e n t s a n d in s e w a g e s l u d g e r e l e a s e d offshore. We have shown the proportion of helminth eggs in m a r i n e s e d i m e n t s m i c r o b i o l o g i c a l c o n t a m i n a t i o n a n d u n d e r l i n e d t h e d i f f e r e n c e in b e h a v i o u r b e t w e e n n e m a t o d e a n d c e s t o d e eggs, t h e l a t t e r b e i n g m u c h less f r e q u e n t , p r o b a b l y d u e to t h e g r e a t e r fragility o f c e s t o d e s in a m a r i n e e n v i r o n m e n t . W e h a v e also s h o w n t h e e x t r e m e liability o f p i n w o r m eggs in s e a w a t e r as t h e y w e r e f r e q u e n t l y f o u n d in c o a s t a l s o u r c e s b u t n e v e r in other samples. We have always found viable Ascaris eggs in s e d i m e n t r i v e r s a m p l e s . S o m e s e d i m e n t m a r i n e s a m p l e s c o n t a i n e d v i a b l e A s c a r i s eggs. T h e s e results
3
1
1
TABLE 3 Parasite contamination of the marine sediments in the Llobregat sector. Sampling point location
Distance from shore
Littoral sediments Point 1 Point 2 Point 3 Point 4 Intermediate zone sediments Point 5 Point 6 Offshore sediments Point 7 Point 8
Helminths eggs kg(mean value)
200 m 100 m 200 m 200 m
4 X 101 2 x 10 ~ ND* ND
1000 m 1000 m
ND 6 x 10 ~
4000 m 12 000 m
ND ND
*Not detected. obtained from seawater underline the necessity of f u r t h e r i n v e s t i g a t i o n i n t o t h e full i m p a c t o f o f f s h o r e dumping of treatment plant sludge on marine parasitol o g i c a l p o l l u t i o n , p a y i n g p a r t i c u l a r a t t e n t i o n to t h e viability a n d t h e i n f e c t i v i t y o f t h e h e l m i n t h eggs f o u n d .
Bergstrrm, K. (1981). Recovery of parasite eggs from sewage sludge from sewage plants and septic tanks in Norway. Norsk. Vet. 93, 323330. Bitton, G., Damron, B. L., Edds, G. T. & Davidson, J. M. (1980). Sludge Health Risks of Land Application. Ann Arbor Science, Ann Arbor. Feachem, R. G., Bradley, D. J., Garelick & Mara, D. D. (1983). Sanitation and Disease: Health Aspects of Excreta and Wastewater Management. John Wiley, New York. Graham, H. J. (1981). Parasites and the land application of sewage sludge. Rapport Ontario Ministery of the Environment no. 110. Janeckso, A. & Urbanyi, L. (1931). Mrthode d'enrichissement coprologique. Rev. Gen. Med. Vet. 42,496-497. Kabrick, R. M. & Jewell, W. J. (1982). Fate of pathogens in thermophilic aerobic sludge digestion. Wat. Res. 16, 1051-1060. Knaack, J. & Ritschel, M. (1975). Zur Eliminierung von exogenen Helminthen Stadien aus dem kommenalen Abwasser durch verschiedene Abwasserreinigungverfahren. Z. Ges. Hyg. 21,746-750. Schwartzbrod, J., Thevenot, M. T., Collomb, J. & Baradel, J. M. (1986). Parasitological study of wastewater sludge. Environ. techn, letters 7, 155-162. Shephard, M. R. N. (1971). The role of sewage treatment in the control of human helminthiases. Helminth Abst. 40, 1-16. Stien, J. L. & Schwartzbrod, J. (1986). Techniques de concentration des oeufs d'helminthes: valeurs et limites. Proceedings Colloque Fes: Eaux continentales ressources et assainissement 48. Stien, J. L. & Schwartzbrod, J. (1987). Devenir des oeufs d'helminthes au cours d'un cycle d'rpuration des eaux usres urbaines. Reu. Int. Sc. Eau 3, 77-82. Stien, J. L. & Schwartzbrod, J. (1988). Viability determination of Ascaris eggs recovered from wastewater. Environ. Techn. Letters 9,401-406.
271
6/June
1989 0025-326X/89 $3.00 + 0.00 O 1989 Pergamon Press plc
Marine Pollution Bulletin, Volume 20, No. 6, pp. 269-271, 1989. printed in Great Britain.
Helminth Eggs in Marine and River Sediments J. SCHWARTZBROD, M. T. THEVENOT and J. L. STIEN Ddpartement de Microbiologie, Facultd de Pharmacie, 5 rue Albert Lebrun, 54000 Nancy, France
This investigation examines the sources of parasite contamination and their effect on the contamination of three types of marine sediments of a specific coastal region: marine sediments, river sediments, and sewage sludge. In the sludge, concentrations varied between 2 X101 to 3.4 ×102 eggs kg -~ with 30% of samples containing at least four different types of eggs (nematode and cestode eggs). In the river sediment, helminths eggs were found in 90% of samples (sector Besos) and in 80% of samples (sector Liobregat). Only 20% of the littoral marine sediments from the Besos were positive for helminth eggs but in the sludge effluent zone all the samples were positive. At 7 0 0 0 m offshore no samples contained helminth eggs. In the Llobregat sector, 35% of samples contained heiminth eggs; there was no apparent difference in the degree of parasite contamination between the littoral (200 m offshore) and the intermediate zones (1000 m offshore). At 4000 and 12 000 m offshore no samples contained helminth eggs. The viability of Ascaris eggs was studied. Globally the percentage of viable eggs was always higher in Besos sector than in Llobregat. If all sediment river samples contained viable eggs we have recognized in some sediment marine sample viable Ascaris eggs: in Besos sector 14% of viable Ascaris eggs were still found at 3000 m and 4 0 0 0 m offshore while only samples collected from littoral zone in Liobregat sector contained 5% of viable Ascaris eggs.
highly polluted rivers (the Besos river and the Llobregat river), treated and raw wastewater. Sewage sludge is transported offshore from Barcelona through a deep conduit. Three sample types were studied: marine sediments, river sediments, and sewage sludge.
Marine sediment sampling Marine sediments were collected from 50 m to 7 km offshore of metropolitan Barcelona at depths varying from 6 to 150 m. Samples obtained from the oceanographic vessel Garcia del Cid required use of a Van Veen double spoon. River sediment sampling These came from the two rivers that empty into the sea at Barcelona: the Besos river and the Llobregat river. Samples were taken from the upper layer of mud (23 cm thick) with a raking shovel fixed to a pole. The Besos river samples were collected 1500 m upstream of its mouth; the Llobregat river ones, 3500 m upstream of its mouth. Sewage sludge sampling Raw sludge was collected after primary decantation from the San Adrian wastewater treatment plant which treats 300 000 m 3 of wastewater daily. Figure 1 shows the location and characteristics of the sampling points. Methods
Microbiological pollution of the marine environment is often the result of human activities in the coastal zone such as offshore dumping of sewage sludge or effluents from raw or treated wastewater. Although many studies have been done on viral and bacteriological pollution of the marine environment, very little is known about parasitological contamination of this important resource (Bitton et al., 1983; Feachem et al., 1983; Schwartzbrod et al., 1986). This investigation addresses the problem of parasitological contamination in examining its sources and their effect on the contamination of sediments of a specific coastal region.
Parasite density was too low for direct microscopic examination, thus all the samples underwent an enrichment procedure. A preliminary study (Stien & Schwartzbrod, 1986) had shown that, out of all the various concentration methods available, the one described by Janeckso-Urbanyi (1931) was best adapted to the sample types investigated here. This method uses a high density (d--1.44) potassium iodomercurate solution with low viscosity so that the eggs rise rapidly to the surface. The slides are read at 400× magnification. The viability determination of Ascaris eggs was studied after n-butanol treatment (Stien & Schwartzbrod, 1988).
Sampling
Results
Barcelona was selected as the study site because of the many effluents into the sea. These consist of two
The results are expressed as number of eggs kg-1 sample and are presented by geographic sector with two 269
Marine PollutionBulletin
k
Treatment ptant ~ San a d r i a n ~
Borcetono
Trichurs) with only 14% of viable Ascaris eggs. Sediment samples from 7000 m offshore did not contain any helminth eggs.
Badabna/ //~
/~3~4'5
River Besos
Llobregat sector results Continental sources: In this sector, the Llobregat fiver
• IO •ll 12
R / ~
4
•7
Sampl.ingpo,ntsecretSesos • Sornptingpolnt setterC l o S e , a t • t ScaLeI 9 a O 0 0
~o kms
I
Fig. 1 Locationof samplingpoints. well-defined sample zones: the Besos sector and the Llobregat sector.
Besos sector results Continental sources: In this sector, there are major coastal sources of contamination: the waters and sediment of the Besos river, wastewater and sewage sludge from the wastewater treatment plant. Besos river sediment." Helminth eggs were found in 90% of the samples analysed with levels ranging from 2 X 101 to 1X 10 z eggs kg-1. The mean was 4.2 X 101 eggs kg-1. These eggs were either nematode or cestode families (Table 1). All the samples with nematode eggs contained, in decreasing amounts, Ascaris, Enterobius, Toxocara, and Trichuris; only Hymenolepis was found for cestodes. All Ascaris eggs were viable. San Adrian treatment plant sludge: All the sludge samples contained helminth eggs (nematodes and/or cestodes) with numbers varying from 2 x 101 to 3.4 x 102 eggs kg-L The nematode eggs were Trichuris and Enterobius in 12 out of 17 samples. The cestodes were predominantly Hymenolepis (12/17) with one sample containing Tenia eggs. There was great variety in the eggs recovered from most of the samples as certain ones contained as many as 6 different genera (Table 1). Marine sediments: Analysis of the results leads to classification of the samples into four categories according to the sampling points (Table 2). The littoral sediments include the samples taken along the coast (points 1, 2, 3, 4, and 5) except for the mouth of the Besos river. Only one of these samples contained helminth eggs (Hymenolepis). The sediments sampled at the Besos river mouth (points 6, 7, 8, and 9) all contained nematode eggs, Ascaris, Trichuris, and Toxocara in decreasing amounts but no Enterobius and only one sample had cestode eggs present (Hymenolepis). 50% of Ascaris eggs were viable. The samples from the sludge effluent zone (points 10 and 11), at 3000 and 4000 m offshore, contained nematode eggs (Ascaris and 270
water and sediment and raw wastewater from several collectors are possible sources of helminth eggs. Only the fiver sediment was analysed. Llobregat river sediment: Helminth eggs were found in 80% (8/10) of these samples with quantities varying from 2X101 to 1.4X102 eggs kg-1 and a mean of 4.8 x 102 eggs kg-~ (Table 1). Nematode eggs were found in 7 of the 8 positive samples with Trichuris, Toxocara, Ascaris, and Enterobius in order of decreasing amount. The percentage of viable Ascaris eggs was 40%. Cestode eggs (Hymenolepis) were found in only 3 samples. Marine sediments: The marine sediment results are classified into 3 groups according to their sampling points (Table 3). Littoral zone sediments: This includes samples taken from the Llobregat river mouth to 200 m offshore (points 1, 2, 3, and 4). Both nematode (Ascaris and Trichuris) and cestode (Tenia) eggs were found in 2 out of 4 samples in low quantities (2x10~-4X101 eggs kg-1). The percentage of viable Ascaris eggs was very low 5%. Intermediate zone sediments: This consists of the samples taken from points 5 and 6 at 1000 m offshore. Only nematode eggs (Trichuris, Toxocara) were found in 1 of 2 samples. Offshore sediments: The samples taken at 4000 and 12 000 m offshore (points 7 and 8) did not contain any helminth eggs.
Discussion and Conclusions Coastal sources of parasite contamination are numerous and varied. It is necessary to underline the great diversity of helminth eggs found in most of the samples from sediments and treatment plant sludge. In the sludge, 30% of the samples contained at least four different types of eggs with more or less the same distributions of nematode and cestode eggs. The concentrations found here are in agreement with those reported in the literature, with levels varying from 1×102 to 5.4×103 eggs kg-~ (Kabrick & Jewell, 1982; Graham, 1981; Stien & Schwartzbrod, 1987). The frequent presence of Enterobius eggs in the sludge samples should be emphasized, indicating a certain level of enterobiasis infestation in the local population. This type of nematode egg, in contrast to the others identified in this study (Ascaris, Trichuris and Toxocara) has been found only sporadically in these kinds of samples (Shephard, 1971i Knaack & Ritschell, 1975; Bergstrom, 1981). Only 10% of the fiver sediment samples contained three types of eggs with the nematode eggs being predominant in all the sectors studied. Only 20% of the littoral marine sediments from the Besos sector were positive for helminth eggs. All the river mouth samples contained nematode eggs (Ascaris, Trichuris and Toxocara). The sludge effluent zone samples also were
Volume 20/Number 6/June 1989 TABLE 1 Parasite contamination of sediments from the Besos and Llobregat Rivers and of wastewater treatment plant sludge.
River Besos sediment San Adrian treatment plant sludge Llobregat River sediment
Number of eggs kg-~ Extreme value Mean value
Littoral sediments Point 1 Point 2 Point 3 Point 4 Point 5
10
9
2 x 10~-1 x 102
4.2 x 10 ~
9
3
5
1
17
17
2 x 101-3.4 x 102
1.1 x 10 a
15
5
5
2
10
8
2 x 10~-1.4 x 102
4.8 x 102
7
5
2
1
Distance from shore
Helminths eggs kg-t (mean value)
250 400 250 400 500
ND* ND 2 x 10 ~ ND ND
m m m m m
Sediments sampled at the river Besos mouth Point 6 50 m Point 7 400 m Point 8 400 m Point 9 1500 m
4 4 6 8
Samples from the sludge effluent zone Point 10 3000 m Point 11 4500m
8 x 10 ~ 4 X 10 ~
Samples from offshore Point 12
Number of samples a type of eggs 1 2 3 4 5 6
Number of samples positive
TABLE 2 Parasite contamination of the marine sediments in the Besos sector. Sampling point location
Number of samples with nematode eggs
Number of samples tested
7000 m
x 101 X 10 ~ X 10 t x 10 ~
ND
*Not detected. a l w a y s p o s i t i v e f o r n e m a t o d e eggs. Finally, at 7 0 0 0 m o f f s h o r e , n o s a m p l e s c o n t a i n e d h e l m i n t h eggs. T h e v i a b i l i t y o f A s c a r i s eggs w a s d i f f e r e n t f r o m t h e k i n d a n d the geographic origin of the samples. Globally the p e r c e n t a g e o f v i a b l e A s c a r i s eggs w a s a l w a y s h i g h e r in B e s o s s e c t o r t h a n in L l o b r e g a t s e c t o r ; t h e r e was also m o r e v i a b l e A s c a r i s e g g s in r i v e r s e d i m e n t s a m p l e s t h a n in m a r i n e s e d i m e n t s a m p l e s . I n B e s o s s e c t o r 1 4 % o f v i a b l e A s c a r i s e g g s w e r e still f o u n d at 3 0 0 0 m a n d 4 0 0 0 m offshore while only samples collected from littoral z o n e in L l o b r e g a t s e c t o r c o n t a i n e d 5 % o f v i a b l e A s c a r i s eggs. In c o n c l u s i o n , this s t u d y p r e s e n t s an i n v e n t o r y o f d i f f e r e n t p a r a s i t o l o g i c a l c o n t a m i n a t i o n f o u n d in r i v e r w a t e r a n d s e d i m e n t s a n d in s e w a g e s l u d g e r e l e a s e d offshore. We have shown the proportion of helminth eggs in m a r i n e s e d i m e n t s m i c r o b i o l o g i c a l c o n t a m i n a t i o n a n d u n d e r l i n e d t h e d i f f e r e n c e in b e h a v i o u r b e t w e e n n e m a t o d e a n d c e s t o d e eggs, t h e l a t t e r b e i n g m u c h less f r e q u e n t , p r o b a b l y d u e to t h e g r e a t e r fragility o f c e s t o d e s in a m a r i n e e n v i r o n m e n t . W e h a v e also s h o w n t h e e x t r e m e liability o f p i n w o r m eggs in s e a w a t e r as t h e y w e r e f r e q u e n t l y f o u n d in c o a s t a l s o u r c e s b u t n e v e r in other samples. We have always found viable Ascaris eggs in s e d i m e n t r i v e r s a m p l e s . S o m e s e d i m e n t m a r i n e s a m p l e s c o n t a i n e d v i a b l e A s c a r i s eggs. T h e s e results
3
1
1
TABLE 3 Parasite contamination of the marine sediments in the Llobregat sector. Sampling point location
Distance from shore
Littoral sediments Point 1 Point 2 Point 3 Point 4 Intermediate zone sediments Point 5 Point 6 Offshore sediments Point 7 Point 8
Helminths eggs kg(mean value)
200 m 100 m 200 m 200 m
4 X 101 2 x 10 ~ ND* ND
1000 m 1000 m
ND 6 x 10 ~
4000 m 12 000 m
ND ND
*Not detected. obtained from seawater underline the necessity of f u r t h e r i n v e s t i g a t i o n i n t o t h e full i m p a c t o f o f f s h o r e dumping of treatment plant sludge on marine parasitol o g i c a l p o l l u t i o n , p a y i n g p a r t i c u l a r a t t e n t i o n to t h e viability a n d t h e i n f e c t i v i t y o f t h e h e l m i n t h eggs f o u n d .
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