- Email: [email protected]
Bacteriological water quality of a multi-use catchment basin on the Avalon Peninsula, Newfoundland
Wat. Res. Vol. 23, No. 3, pp. 261-266, 1989
0043-1354/89 $3.00 +0.00
Printed in Great Britain.All rights reserved
Copyright © 1989PergamonPress pie
BACTERIOLOGICAL WATER QUALITY OF A MULTI-USE CATCHMENT BASIN ON THE AVALON PENINSULA, N E W F O U N D L A N D G. I. McT. COWAN,E. M. BAGGSand B. T. HOLLOHAN Department of Biology, Memorial University of Newfoundland, St John's, Newfoundland, Canada AIB 3X9 (First received June 1988; accepted in revisedform September 1988) Abstract--Baseline investigations of coliform bacterial populations in the Topsail-Manuels drainage system (a multiple land-use system) reveal several aquatic regions which are indicative of land usage. Seasonal fluctuations in population numbers were observed in all sample sites and appear to be related to such physical parameters as precipitation and pH. Total coliform numbers were found to be positively correlated with surface land flushing as were fecal coliform numbers but to a lesserextent. Coliform counts appeared to be most influencedby the geology and physiography of the area as well as by land occupancy and usage. Key words--aquatic systems, Escherichia cell, land usage
INTRODUCTION
This paper represents the first of a series of investigations of the aquatic resources in a multi-use catchment basin on the Avalon Peninsula, Newfoundland, Canada. It is an attempt to establish a baseline from which subsequent studies may be based. As with most ecological studies done today, some of the pristine values have been lost due to man's encroachment on the environment, but fortunately in this system the roles of industrial and socio-economic growth have remained low and parts of the system remain relatively untouched. This will no longer remain the case as the development of an oil-based industry has now arrived at a point where serious encroachment on the system is rapidly increasing. Indeed, the system is being evaluated for the development of municipal water supply for the area. The effect of land usage on bacterial water quality has been investigated by several authors with regard to numerous aspects. Geldreich (1967) studied the relationship between land usage, soil type and fecal coliforms and found that the bacterial numbers increased markedly on pasture land when compared to virgin soils. He also noted that the soil type on the pasture potentiated the possibility of contamination. Faust (1982) found fecal coliforms to be low in forests and manured cornfields and higher in pasture lands. He concluded that the number of Escherichia coli varied directly as to the amount of direct fecal contamination and that the bacteria remained relatively near or on the soil surface. Faust and Goff (1977), Faust (1982) and McFetters and Stuart (1976) all found that fecal coliforms were introduced into rural water sheds from adjacent pastures due to surface flushing.
Hollon et al. 0982) and Hendry and Toth 0982) also located point source pollution due to feed lots, watering sites, public beaches and substandard septic tank systems. The effects, however, were found to be localized. With the rapidly expanding residential-industrial use of the lower portion of the system and the ever increasing pressure on the remaining natural resources of the entire area, it is pertinent that baseline (natural) values for factors such as the extent and distribution of coliform bacteria be evaluated. It is also important to determine the extent to which human activities may accelerate eutrophic processes within the system. This may ultimately lead to losses of endemic fish species and such changes would lead to devaluation of aesthetically desired recreational and residential areas. MATERIALS AND METHODS
Sampling site The Topsail-Manuels (Topman) watershed is situated some 20 km southwest of St John's, Newfoundland (Fig. 1). It consists of a series of 26 shallow interconnected ponds varying from 3.1 to 213.0 ha and has a total catchment area of 61.1 km2 which lies across four very different geological strata (Bruckner, 1979). It is ecologically diverse in having considerable areas of coniferous forest, sphagnum bog and fen. The headwater regions contain all three ecotypes and are devoid of development of any sort. The middle sections contain a considerable amount of cattle pasture and forest while lower regions are extensively developed for commercial-industrial-residential uses. The entire watershed is drained, by two small rivers, into Conception Bay. This region is of great socio-economic significance.Due to its proximity to St John's, the major population center of the province, it is very heavily utilized for recreational purposes the entire year (camping, hunting, skiing, s n o w mohiling, boating, ice-fishing, sport-fishing). It is the m o s t
261
262
G.I. McT. COWANet al. Water samples for chemical parameters were taken in acidified (HNO3) 250 ml nalgene bottles. Samples for physical parameters (Gran alkalinity + pH) were taken in 1 liter nalgene bottles and stored in ice until analysis. The chemical analysis was carried out at the Water Analysis Laboratory at Memorial University of Newfoundland using techniques described by the Ontario Ministry of Natural Resources, Fisheries Branch, for total inflection point alkalinity (Anonymous, 1980), and pH was determined using electrometric silver/silver chloride evaluation on a Fisher Accumet model 520, pH/ion meter. Total coliform and fecal coliform values were obtained using the multiple-tube fermentation (MPN) technique (American Public Health Association, 1980). Lauryl tryptose broth was used in the presumptive phase for total coliforms and EC broth for fecal coliforms. EMB plates were used for confirmation of E. coli.
D t-m [] []
Statistical treatment The data were analyzed using SPSS-X Cluster program and the unweighted pair group method average. The data were logarithmically transformed after adding 1 to each MPN value to negate the effect of zero values [log(x + I)]. Comparison of the resultant clusters by sample date was accomplished using the Mann-Whitney U test and a significance level of P >/0.05. RESULTS AND DISCUSSION Temperature
)
Fig. I. Topsail-Manuels drainage system with distribution of land use areas and sample sites.
extensively sport-fished of any system in the province. The extensive recreational use in conjunction with the presence of cattle grazing and commercial-industrial-residential usage could thus influence the quality of the water being delivered to the lower residential-recreational areas. This lower area is presently experiencing the most rapid industrial-urban expansion in the province. The effect of the residential-industrial areas on the down-stream waters could also be especially important on the lower ends of the drainage insofar as there are resident populations of three trout species (Salmo salar, S. trutta and Salvelinus fontinalis ) as well as anadromous brown trout (Salmo trutta). This system is also being considered as a future domestic water source by the community of Conception Bay South. Sample collection and analysis Water samples for bacteriological analyses were collected at a depth of 0.3 m from the surface using sterilized evacuated 125ml bottles and a Johnson-Zobell sampler and transported to the laboratory in ice. Samples were replicated after 7 days and were collected on a bimonthly basis from the 9 sample sites (see Fig. 1). It was hoped that the results of the replications could be used as an indicator of either flushing due to the increased precipitation and runoff or as a means of detecting pointsource areas of constant input of bacterial pollution.
Temperatures recorded at the time of sampling are shown in Table 1. They show a relative uniformity throughout the system on any given sample collection date and indicate a maximum during late August and a minimum occurring in January. Permanent ice cover occurs from mid-January until mid-March. Thermal stratification has not been demonstrated and the ponds are considered to be isothermal due to their shallow physiography,
pH The pH values of the samples obtained for the system are presented in Table 2. The values tended to fluctuate considerably during the study period. There were notable depressions after heavy rains but these quickly recovered (within a week), indicating some degree of buffering of the system as a whole. In general, the pH values were lowest at sites in the upper portion of the system (sites 7 and 8) and became progressively higher towards the bottom (outflows, sites 1 and 9). A general decrease in pH values was not evident throughout the system from August through January, possibly due to the decomposition of aquatic vegetation. Values then tended to increase through the spring and summer months (March-August). The ability of aquatic systems to recover from acid precipitation has been documented by several authors, and it is generally agreed that carbonate systems and biological processes changing carbon dioxide concentrations control the background pH of natural waters (Rippley and Gibson, 1984; Faust, 1983).
263
Bacteriological water quality Table 1. Water temperatures (°C) at sample sites Site number Sample date
1
2
3
4
5
6
25/09/81 02/10/81 11/11/81 22/11/81 27/01/81 08/02/82 07/04/82
13 13 5 5 -1 -0.5 1.5 2 13 13 18 18 6 4
12 14 8 6 --I --0.5 3 4 14 17 17 18 6 6
12 13 8 6 -1 -0.5 2 3 16 13 16 16 5 4.5
13 14 7 6 -I -0.5 I 3 17 19 18 18 5 5.5
12 14 7 6.5 -0.5 -0,5 2 3 17 14 19 18 7 4
10 12 6 5 0 - 1 0.5 0.5 13 14 18 17 6 4
14/04/82 07/06/82 16/06/82 24/08/82 30/08/82 15/11/82 24/11/82
Total coliform counts Two standard methods for the analysis of water samples for total coliforms~ are the multiple-tube fermentation (MPN) technique and the membrane filter technique (American Ptlblic Health Association, 1980). For the present study the membrane filter method was not used since it'has limitations in testing waters high in turbidity and;noncoliform bacteria. In particular, the latter may result in low coliform estimates, which is also a common criticism of the MPN technique. Additionally, the water system under study was being tested for coliform levels for the first time. Therefore, to demonstrate the applicability of the membrane filter technique in studying the system would require that parallel tests with the multiple-tube fermentation technique be conducted (American Public Health Association, 1980). Since
7 10 9 4 4 --I --0 1 1 14 15 15 16 5 3
8
9
12 12 4.5 5 -I -0.5 I 1 19 21 18 18 5 5
13 12 3 4.5 -I 1.5 0 2 14 17 19 19 6 4
there were 9 sites to be sampled bimonthly over a 14-month period it was decided to use the multipletube fermentation technique only. A problem commonly encountered with this method is the interference caused by Aeromonas hydrophila. However, according to yon Graevonitz (1985), only a minority of strains yield lactose-fermenting colonies on enteric differential agars. The results of the analyses of samples for total coliforms (MPN) are presented in Table 3. These data indicate extreme variability in numbers both between sample locations for a given date and for each sample site over the sampling period. Nevertheless, there is a general trend towards maximum numbers in the late summer-fall (August-November), then decreasing to a low in the winter-late spring months (January-June).
Table 2. Bimonthly pH values at sample sites Site number Sample date
1
2
3
4
5
6
7
8
9
12/11/81 27/01/82 07/04/82 14/06/82 30/08/82 24/11/82
6.32 5.48 5.62 5.84 5.79 4.86
5.98 5.66 6.21 6.35 6.40 6.78
5.55 5.27 5.47 5.80 5.57 6.23
6.47 6,13 6.33 6.56 6.56 6.90
5.63 4.89 5.33 6.30 5.70 5.53
5.18 4.49 4.88 5.41 5.31 5.23
5.06 4.65 4.13 5.10 4.68 5.20
5.30 4.99 4.91 5.56 5.28 5.35
6.52 5.99 5.66 7.79 6.84 6.99
Table 3. MPN values for total coliforms Site number Sample dates
l
2
3
4
5
6
7
8
9
Rainfallt
25/09/81 02/10/81 12/11/81 22/11/81 27/01/82 08/02/82 07/04/82 07/06/82 14/06/82 24/08/82 30/08/82 15/11/82 24/11/82
2400 920 540 920 1600 350 920 II0 280 94 1600 2400 130
--* 1600 2400 1600 140 140 350 920 2400 2400 2400 2400 2400
-26 170 350 79 79 130 31 I1 I1 170 220 540
-350 2400 2400 240 240 130 170 170 170 920 34 1600
--130 130 49 23 33 130 8 33 8 23 79
49 33 350 79 33 13 33 79 33 31 33 70 79
130 4 170 170 49 49 49 220 49 23 31 31 180
33 5 110 280 350 49 130 180 17 43 33 34 170
920 79 920 540 1600 350 350 110 13 540 220 170 21
72.0 17.6 77.1 59,0 53.2 33.0 44.9 2.2 0.0 30.3 60.2 8.2 16.7
*No data. ?Rainfall (ram) for 7 days prior to sample.
264
G.I. McT. COWANet al.
Cluster analysis revealed the presence of two natural groupings which appear to reflect the intensity and type of land utilization in the areas immediately adjacent to the sample sites. The first group contains sites 1, 2, 4 and 9 which all exhibit relatively high total coliform values and are all located in heavy residential-industrial areas which are also extensively used for recreational purposes. The second group is composed of sites 3, 5, 6, 7 and 8. Sites 6, 7 and 8 represent the upper portion of the system and together with site 3 (which is in the lower portion) represent areas having no residential-industrial usage and moderate recreational utilization. Site 5 is located on the fringe of the industrial-residential area but is well used for recreation. Sites 1, 2, 4 and 9, which all exhibit relatively high total coliform counts, are all located in heavy residential-industrial areas which are also extensively used for recreational purposes. This situation would indicate that the total coliform count is, for the most part, due to the influence of residential-industrial activities. These increased values may also be due to increased runoff in the lower reaches which in turn adds to the surface flushing. Flushing effects can vary due to soil type, usage and water table as well as the duration and intensity of the precipitation leading to different lag times for flushing effects. The correlation between log total coliform values and precipitation for the weeks previous to sampling was examined and found to be low but significant (0.2305). This would thus explain at least part of the increased values. Nevertheless, the lower sites have more ecological diversity and are more suitable for a greater spectrum of organisms which could be responsible for total coliform values. The values for the upper part of the system indicate a minimal effect of both recreational and agricultural usage. The input from endemic wildlife would also seem to be minimal.
Fecal coliform counts
The results obtained from the analyses for fecal coliforms are presented in Table 4. Cluster analysis of
this data again resulted in the formation of the same two groups as was found for the total coliform data. The first group is composed of sites 3, 5, 6, 7 and 8, which are characterized by generally having low fecal coliform counts throughout the period of study. The second group consists of sites 1, 2, 4 and 9, which exhibit generally high but extremely variable values. Both assemblages appear to form natural groups based on land usage criteria. The first group consists of sites in areas with no residential component and mainly light to moderate recreational or agricultural usage. The sites comprising the second group are all in predominantly residential and industrialized areas. It would appear that human habitation and/or industrialization is causal for the input of the majority of the fecal coliforms. This could be expected as much of the lower area contains many substandard septic systems, and buildings and disposal fields are located in some cases as close as 15 m to ponds and streams. In addition, surface flushing due to precipitation is also partly causal and evidenced by a significant but low correlation coefficient with log fecal coliform values. In areas of low fecal coliform counts it is most likely that wildlife usage of the areas is responsible for the majority of the fecal coliform input including the spike values observed. This would also suggest that the recreational and/or agricultural (cattle) usage contribute little to the system. However, identification of isolates would be required to definitely rule out such factors as Klebsiella from land runoff. The primary agricultural areas in the middle of the system (above site 6) are seasonally used for pasturing cattle (late May--October). The area is characterized by low hills and rolling grassland frequently interrupted by bands of trees, shrubs and occasional wet bogs. The low counts of both total and fecal coliforms observed in this site may be due to land physiography which acts as vegetation buffer zones which have been found to be effective in substantially reducing pollution from feed lots (Young et al., 1980).
Table 4. MPN values for fecal coliibrms Site number Sample dates 25/09/81 02/10/81 12/11/81 22/11/81 27/01/82 08/02/82 07/04/82 14/04/82 07/06/82 14/06/82 24/08/82 30/08/82 15/11/82 24/11/82
I 1600 70 240 170 70 79 920 130 4 <2
5 2 360 2
2 --* 33 180 22 8 2 21 13 110 I1 17 460 1600 2400
3 -2 33 <2 <2 4 2 8 <2 <2 <2 <2 <2 2
*No data.
tRainfall (ram) for 7 days prior to sample.
4 -33 180 <2 13 8 79 1600 8 <2 2 7 <2 920
5 -<2 11 2 5 2 8 5 <2 <2 5 5 2 <2
6 17 23 8 8 <2 <2 7 7 <2 <2 2 8 <2 2
7 <2 4 8 2 <2 <2 2 <2 <2 <2 <2 <2 <2 <2
8 8 <2 11 2 <2 <2 130 11 <2 <2 2 2 <2 2
9 I10 4 79 79 70 13 350 17 8 <2 33 33 13 <2
Rainfallt 72.0 17.6 77.1 59.0 53.2 33.0 44.9 38.4 2.2 0.0 30.3 60.2 8.2 16.7
Bacteriological water quality In this part of the system under study, the density of cattle is low and feces are dispersed over a wide area. Furthermore it has been reported that where stream contact with cattle has occurred, the shallow turbulent waters have eliminated much of the pollution potential (Hollon et al., 1982). In addition to this, the water from these areas flows into a large, shallow pond (103 ha, mean depth 4.1 m) which acts as a settlement basin thereby further reducing the fecal coliform counts. Boylen et al. (1983) found that in oligotrophic lakes the bacteria found in circumneutral lakes (pH > 6) grew less favorably at lower pH values. This would infer that acidic conditions are deleterious to such bacterial populations. This contention is further supported by the works of Fjerdingstad and Nilssen (1982). Our findings also support this in that there is a significant correlation between the pH and log fecal coliform values (0.2851). The pH values generally increase downstream (except for site 1) from the top to the bottom of the system, as do the coliform numbers. Additional evidence of this may be derived from a comparison of sites 1 and 9, both having elevated coliform counts. In the case of site 1, elevated coliform populations are more likely to be due to increased residential input, whereas the counts from site 9 may be due to raised pH values as well as residential usage and the physiography of the area immediately above the sample site. This point is further supported when looking at the pH and coliform numbers for site 4 which has raised bacterial counts and elevated pH values. Examination of the nature of the industrial-commercial activities reveals no potential for contributing to the heightened coliform values. It must be inferred that the residential and, to a smaller extent, the agricultural components in these lower regions of the system are responsible for the higher coliform levels observed. The residences in this area have been wholly reliant on septic tanks and percolation fields for the disposal of human wastes. Hagedorn et al. (1978, 1981) and Rahe et al. (1978) have found that fecal contamination of water may result from lateral movement of organisms through different soil type interfaces. Soil saturation and seasonal variability in the height of the water table may also be contributing factors. The area under investigation has a complex geology being comprised of four geological groups with a major fault line transversing the watershed. The area has also been heavily glaciated, leaving a porous overburden and only shallow soils. This has also produced a considerable number of substrate interfaces, which frequently reach the surface on exposed hillsides and stream banks. The direct relationship of fecal coliform numbers with seasonal fluctuations in the water table would suggest a situation similar to that described by Hagcdorn et al. (1981) and Rahc et al. (1978).
265
Sinton (1982) found that intermittent contamination of wells occurred in areas of septic tank usage but could find no direct evidence that the tanks in the area were directly involved. Sinton (1982) also noted a subsequent decrease of bacterial populations with an increase in water table but offers no explanation other than dilution and dispersion effects to explain this phenomenon. In this situation at Yadhurst, Sinton (1982) infers that the deep aquifers may be carrying contaminants of septic tank origin to the wells. That system uses deep drainage fields whereas here they are in the top 1.5 m of soil and this allows for leaking out into surface waters. Comparison of the total coliform and fecal coliform numbers reveals much greater values of the former. There also appears to be little relationship between the two. This indicates that in all probability there is a comparatively large though variable density of coliforms of nonmammalian origin. Geldreich (1967) found that only a small percentage of coliforms were contributed by plants and terrestrial insects. Geldreich and Clarke (1966) found that freshwater fish do not have a permanent coliform flora in the digestive tract unless they are living in polluted areas and then may even harbour mammalian fecal coliforms. Thus the nonmammalian coliforms must in large part be of both aquatic and terrestrial invertebrate origin. Evidence presented suggests that a positive relationship exists between total coliform populations and precipitation. Therefore, a significant portion of the coliforms are introduced by land flushing, which is directly influenced by land usage. This investigation has revealed that a natural system may exist in such a way as to confuse one's classification of what may constitute a polluted system. Based on local Department of Health regulations and standards the entire system would appear to be bacterially contaminated if one uses strict coliform count criteria. However, as can be seen from the site descriptions, the upper areas receive only "natural" inputs and man and his endeavours are not the cause of any of the measured data. This can then be considered to be a baseline system and subsequent differences or changes may then be attributed to any site usage downstream from these upper sites. The evidence presented does show elevations in counts downstream regardless of the system's built-in ability to regulate and cleanse itself, and these increased counts relate positively with land occupancy and usage. Other mitigating circumstances which aid and abet pollution are seen in the geology and physiography of the area as well as physical parameters such as precipitation, pH and temperature. Acknowledgements--This study was funded by a grant
from the President's Fund Memorial University of Newfoundland. The authors wish to express their appreciation to S. Power, W. Sparkes and L. Green for preparation of the manuscript.
266
G . I . McT. COWAY et al.
REFERENCES Anon. (1980) Determination of Total Inflection Point Alka-
linity. Ontario Ministry of Natural Resources, Fisheries Branch, Toronto, Ontario. APHA (1980) Standard Methods for the Examination of Water and Wastewater, 15th edition. American Public Health Association, Washington, D.C. Boylen C. W., Shick M. O., Roberts D. A. and Singer R. (1983) Microbiological survey of Adirondack lakes with various pH values. Appl. envir. Microbiol. 45, 1538-1544. Bruckner W. D. (1979) Geomorphology of the Avalon Peninsula, Newfoundland. Mineral Development Division, Dept. of Mines and Energy, Government of Newfoundland and Labrador. Faust L. M. (1983) Total alkalinity versus buffer value (capacity) as a sensitivity indicator for freshwaters receiving acid rain. J. envir. Sci. Hlth 18, 701-711. Faust M. A. (1982) Relationship between land-use practices and fecal bacteria in soils. J. envir. Qual. 11, 141-146. Faust M. A. and GoffN. M. (1977) Basin size, water flow, and land use effects of fecal coliform pollution from a rural watershed. In Watershed Research in Eastern North America Vol. 2 (Edited by Correl D. L.), pp. 611~34. Chesapeake Bay Center for Environmental Studies, Smithsonian Institution, Edgewater, Md. Fjerdingstad E. and Nilssen J. P. (1982) Bacteriological hydrological studies on acid lakes in Southern Norway. Arch. Hydrobiol. Suppl. 64, 443-483. Geldreich E. E. (1967) Fecal coliform concepts in stream pollution. Water Swge Wks 114, R-98. Geldreieh E. E. and Clarke N. A. (1966) Bacterial pollution indicators in the intestinal tract of freshwater fish. Appl. Microbiol. 14, 429-437.
von Graevenitz A. (1985) Aeromonas and Plesiomonas. In Manual o f Clinical Microbiology (Edited by Lennette E. H., Balows A., Hausler W. H. and Shadomy H. J.), 4th edition, pp. 278-281. American Society for Microbiology, Washington, D.C. Hagedorn C., Hansen D. T. and Simmonson G. H. (1978) Survival and movement of fecal indicator bacteria in soil under conditions of saturated flow. J. envir. Qual. 7, 55-59. Hagedorn C., McCoy E. L. and Rahe T. M. (1981) The potential for ground water contamination from septic effluents. J. envir. Qual. 10, 1-8, Hendry G. S. and Toth A. (1982) Some effects of land use on bacteriological water quality in a recreational lake. Wat. Res. 16, 105-112. Hollon B. F., Owen J. R. and Sewell J. I. (1982) Water quality in a stream receiving dairy feedlot effluent. J. envir. Qual. 11, 5 4 . McFetters G. A. and Stuart S. A. (1976) Impact of horses on the bacterial water quality of Cottonwood Creek, Grand Teton National Park. J. envir. Hlth 39, 123-125. Rahe T. M., Hagedorn C., McCoy E. L. and Kling G. F. (1978) Transport of antibiotic coli through Western Oregon hillslope soils under conditions of saturated flow. J. envir. Qual. 7, 487-494. Rippley B. and Gibson C. E. (1984) The variation of calcium, magnesium, sodium and potassium concentration, pH and conductivity in lakes in Northern Ireland. Arch. Hydrobiol. 101, 345-360. Sinton L. W. (1982) A groundwater quality survey of an unsewered semi-rural area. N.Z. J. Mar. Freshwat. Res. 16, 317-326. Young R. A., Huntrods T. and Anderson W. (1980) Effectiveness of vegetated buffer strips in controlling pollution from feedlot runoff. J. envir. Qual. 9, 483-487.
0043-1354/89 $3.00 +0.00
Printed in Great Britain.All rights reserved
Copyright © 1989PergamonPress pie
BACTERIOLOGICAL WATER QUALITY OF A MULTI-USE CATCHMENT BASIN ON THE AVALON PENINSULA, N E W F O U N D L A N D G. I. McT. COWAN,E. M. BAGGSand B. T. HOLLOHAN Department of Biology, Memorial University of Newfoundland, St John's, Newfoundland, Canada AIB 3X9 (First received June 1988; accepted in revisedform September 1988) Abstract--Baseline investigations of coliform bacterial populations in the Topsail-Manuels drainage system (a multiple land-use system) reveal several aquatic regions which are indicative of land usage. Seasonal fluctuations in population numbers were observed in all sample sites and appear to be related to such physical parameters as precipitation and pH. Total coliform numbers were found to be positively correlated with surface land flushing as were fecal coliform numbers but to a lesserextent. Coliform counts appeared to be most influencedby the geology and physiography of the area as well as by land occupancy and usage. Key words--aquatic systems, Escherichia cell, land usage
INTRODUCTION
This paper represents the first of a series of investigations of the aquatic resources in a multi-use catchment basin on the Avalon Peninsula, Newfoundland, Canada. It is an attempt to establish a baseline from which subsequent studies may be based. As with most ecological studies done today, some of the pristine values have been lost due to man's encroachment on the environment, but fortunately in this system the roles of industrial and socio-economic growth have remained low and parts of the system remain relatively untouched. This will no longer remain the case as the development of an oil-based industry has now arrived at a point where serious encroachment on the system is rapidly increasing. Indeed, the system is being evaluated for the development of municipal water supply for the area. The effect of land usage on bacterial water quality has been investigated by several authors with regard to numerous aspects. Geldreich (1967) studied the relationship between land usage, soil type and fecal coliforms and found that the bacterial numbers increased markedly on pasture land when compared to virgin soils. He also noted that the soil type on the pasture potentiated the possibility of contamination. Faust (1982) found fecal coliforms to be low in forests and manured cornfields and higher in pasture lands. He concluded that the number of Escherichia coli varied directly as to the amount of direct fecal contamination and that the bacteria remained relatively near or on the soil surface. Faust and Goff (1977), Faust (1982) and McFetters and Stuart (1976) all found that fecal coliforms were introduced into rural water sheds from adjacent pastures due to surface flushing.
Hollon et al. 0982) and Hendry and Toth 0982) also located point source pollution due to feed lots, watering sites, public beaches and substandard septic tank systems. The effects, however, were found to be localized. With the rapidly expanding residential-industrial use of the lower portion of the system and the ever increasing pressure on the remaining natural resources of the entire area, it is pertinent that baseline (natural) values for factors such as the extent and distribution of coliform bacteria be evaluated. It is also important to determine the extent to which human activities may accelerate eutrophic processes within the system. This may ultimately lead to losses of endemic fish species and such changes would lead to devaluation of aesthetically desired recreational and residential areas. MATERIALS AND METHODS
Sampling site The Topsail-Manuels (Topman) watershed is situated some 20 km southwest of St John's, Newfoundland (Fig. 1). It consists of a series of 26 shallow interconnected ponds varying from 3.1 to 213.0 ha and has a total catchment area of 61.1 km2 which lies across four very different geological strata (Bruckner, 1979). It is ecologically diverse in having considerable areas of coniferous forest, sphagnum bog and fen. The headwater regions contain all three ecotypes and are devoid of development of any sort. The middle sections contain a considerable amount of cattle pasture and forest while lower regions are extensively developed for commercial-industrial-residential uses. The entire watershed is drained, by two small rivers, into Conception Bay. This region is of great socio-economic significance.Due to its proximity to St John's, the major population center of the province, it is very heavily utilized for recreational purposes the entire year (camping, hunting, skiing, s n o w mohiling, boating, ice-fishing, sport-fishing). It is the m o s t
261
262
G.I. McT. COWANet al. Water samples for chemical parameters were taken in acidified (HNO3) 250 ml nalgene bottles. Samples for physical parameters (Gran alkalinity + pH) were taken in 1 liter nalgene bottles and stored in ice until analysis. The chemical analysis was carried out at the Water Analysis Laboratory at Memorial University of Newfoundland using techniques described by the Ontario Ministry of Natural Resources, Fisheries Branch, for total inflection point alkalinity (Anonymous, 1980), and pH was determined using electrometric silver/silver chloride evaluation on a Fisher Accumet model 520, pH/ion meter. Total coliform and fecal coliform values were obtained using the multiple-tube fermentation (MPN) technique (American Public Health Association, 1980). Lauryl tryptose broth was used in the presumptive phase for total coliforms and EC broth for fecal coliforms. EMB plates were used for confirmation of E. coli.
D t-m [] []
Statistical treatment The data were analyzed using SPSS-X Cluster program and the unweighted pair group method average. The data were logarithmically transformed after adding 1 to each MPN value to negate the effect of zero values [log(x + I)]. Comparison of the resultant clusters by sample date was accomplished using the Mann-Whitney U test and a significance level of P >/0.05. RESULTS AND DISCUSSION Temperature
)
Fig. I. Topsail-Manuels drainage system with distribution of land use areas and sample sites.
extensively sport-fished of any system in the province. The extensive recreational use in conjunction with the presence of cattle grazing and commercial-industrial-residential usage could thus influence the quality of the water being delivered to the lower residential-recreational areas. This lower area is presently experiencing the most rapid industrial-urban expansion in the province. The effect of the residential-industrial areas on the down-stream waters could also be especially important on the lower ends of the drainage insofar as there are resident populations of three trout species (Salmo salar, S. trutta and Salvelinus fontinalis ) as well as anadromous brown trout (Salmo trutta). This system is also being considered as a future domestic water source by the community of Conception Bay South. Sample collection and analysis Water samples for bacteriological analyses were collected at a depth of 0.3 m from the surface using sterilized evacuated 125ml bottles and a Johnson-Zobell sampler and transported to the laboratory in ice. Samples were replicated after 7 days and were collected on a bimonthly basis from the 9 sample sites (see Fig. 1). It was hoped that the results of the replications could be used as an indicator of either flushing due to the increased precipitation and runoff or as a means of detecting pointsource areas of constant input of bacterial pollution.
Temperatures recorded at the time of sampling are shown in Table 1. They show a relative uniformity throughout the system on any given sample collection date and indicate a maximum during late August and a minimum occurring in January. Permanent ice cover occurs from mid-January until mid-March. Thermal stratification has not been demonstrated and the ponds are considered to be isothermal due to their shallow physiography,
pH The pH values of the samples obtained for the system are presented in Table 2. The values tended to fluctuate considerably during the study period. There were notable depressions after heavy rains but these quickly recovered (within a week), indicating some degree of buffering of the system as a whole. In general, the pH values were lowest at sites in the upper portion of the system (sites 7 and 8) and became progressively higher towards the bottom (outflows, sites 1 and 9). A general decrease in pH values was not evident throughout the system from August through January, possibly due to the decomposition of aquatic vegetation. Values then tended to increase through the spring and summer months (March-August). The ability of aquatic systems to recover from acid precipitation has been documented by several authors, and it is generally agreed that carbonate systems and biological processes changing carbon dioxide concentrations control the background pH of natural waters (Rippley and Gibson, 1984; Faust, 1983).
263
Bacteriological water quality Table 1. Water temperatures (°C) at sample sites Site number Sample date
1
2
3
4
5
6
25/09/81 02/10/81 11/11/81 22/11/81 27/01/81 08/02/82 07/04/82
13 13 5 5 -1 -0.5 1.5 2 13 13 18 18 6 4
12 14 8 6 --I --0.5 3 4 14 17 17 18 6 6
12 13 8 6 -1 -0.5 2 3 16 13 16 16 5 4.5
13 14 7 6 -I -0.5 I 3 17 19 18 18 5 5.5
12 14 7 6.5 -0.5 -0,5 2 3 17 14 19 18 7 4
10 12 6 5 0 - 1 0.5 0.5 13 14 18 17 6 4
14/04/82 07/06/82 16/06/82 24/08/82 30/08/82 15/11/82 24/11/82
Total coliform counts Two standard methods for the analysis of water samples for total coliforms~ are the multiple-tube fermentation (MPN) technique and the membrane filter technique (American Ptlblic Health Association, 1980). For the present study the membrane filter method was not used since it'has limitations in testing waters high in turbidity and;noncoliform bacteria. In particular, the latter may result in low coliform estimates, which is also a common criticism of the MPN technique. Additionally, the water system under study was being tested for coliform levels for the first time. Therefore, to demonstrate the applicability of the membrane filter technique in studying the system would require that parallel tests with the multiple-tube fermentation technique be conducted (American Public Health Association, 1980). Since
7 10 9 4 4 --I --0 1 1 14 15 15 16 5 3
8
9
12 12 4.5 5 -I -0.5 I 1 19 21 18 18 5 5
13 12 3 4.5 -I 1.5 0 2 14 17 19 19 6 4
there were 9 sites to be sampled bimonthly over a 14-month period it was decided to use the multipletube fermentation technique only. A problem commonly encountered with this method is the interference caused by Aeromonas hydrophila. However, according to yon Graevonitz (1985), only a minority of strains yield lactose-fermenting colonies on enteric differential agars. The results of the analyses of samples for total coliforms (MPN) are presented in Table 3. These data indicate extreme variability in numbers both between sample locations for a given date and for each sample site over the sampling period. Nevertheless, there is a general trend towards maximum numbers in the late summer-fall (August-November), then decreasing to a low in the winter-late spring months (January-June).
Table 2. Bimonthly pH values at sample sites Site number Sample date
1
2
3
4
5
6
7
8
9
12/11/81 27/01/82 07/04/82 14/06/82 30/08/82 24/11/82
6.32 5.48 5.62 5.84 5.79 4.86
5.98 5.66 6.21 6.35 6.40 6.78
5.55 5.27 5.47 5.80 5.57 6.23
6.47 6,13 6.33 6.56 6.56 6.90
5.63 4.89 5.33 6.30 5.70 5.53
5.18 4.49 4.88 5.41 5.31 5.23
5.06 4.65 4.13 5.10 4.68 5.20
5.30 4.99 4.91 5.56 5.28 5.35
6.52 5.99 5.66 7.79 6.84 6.99
Table 3. MPN values for total coliforms Site number Sample dates
l
2
3
4
5
6
7
8
9
Rainfallt
25/09/81 02/10/81 12/11/81 22/11/81 27/01/82 08/02/82 07/04/82 07/06/82 14/06/82 24/08/82 30/08/82 15/11/82 24/11/82
2400 920 540 920 1600 350 920 II0 280 94 1600 2400 130
--* 1600 2400 1600 140 140 350 920 2400 2400 2400 2400 2400
-26 170 350 79 79 130 31 I1 I1 170 220 540
-350 2400 2400 240 240 130 170 170 170 920 34 1600
--130 130 49 23 33 130 8 33 8 23 79
49 33 350 79 33 13 33 79 33 31 33 70 79
130 4 170 170 49 49 49 220 49 23 31 31 180
33 5 110 280 350 49 130 180 17 43 33 34 170
920 79 920 540 1600 350 350 110 13 540 220 170 21
72.0 17.6 77.1 59,0 53.2 33.0 44.9 2.2 0.0 30.3 60.2 8.2 16.7
*No data. ?Rainfall (ram) for 7 days prior to sample.
264
G.I. McT. COWANet al.
Cluster analysis revealed the presence of two natural groupings which appear to reflect the intensity and type of land utilization in the areas immediately adjacent to the sample sites. The first group contains sites 1, 2, 4 and 9 which all exhibit relatively high total coliform values and are all located in heavy residential-industrial areas which are also extensively used for recreational purposes. The second group is composed of sites 3, 5, 6, 7 and 8. Sites 6, 7 and 8 represent the upper portion of the system and together with site 3 (which is in the lower portion) represent areas having no residential-industrial usage and moderate recreational utilization. Site 5 is located on the fringe of the industrial-residential area but is well used for recreation. Sites 1, 2, 4 and 9, which all exhibit relatively high total coliform counts, are all located in heavy residential-industrial areas which are also extensively used for recreational purposes. This situation would indicate that the total coliform count is, for the most part, due to the influence of residential-industrial activities. These increased values may also be due to increased runoff in the lower reaches which in turn adds to the surface flushing. Flushing effects can vary due to soil type, usage and water table as well as the duration and intensity of the precipitation leading to different lag times for flushing effects. The correlation between log total coliform values and precipitation for the weeks previous to sampling was examined and found to be low but significant (0.2305). This would thus explain at least part of the increased values. Nevertheless, the lower sites have more ecological diversity and are more suitable for a greater spectrum of organisms which could be responsible for total coliform values. The values for the upper part of the system indicate a minimal effect of both recreational and agricultural usage. The input from endemic wildlife would also seem to be minimal.
Fecal coliform counts
The results obtained from the analyses for fecal coliforms are presented in Table 4. Cluster analysis of
this data again resulted in the formation of the same two groups as was found for the total coliform data. The first group is composed of sites 3, 5, 6, 7 and 8, which are characterized by generally having low fecal coliform counts throughout the period of study. The second group consists of sites 1, 2, 4 and 9, which exhibit generally high but extremely variable values. Both assemblages appear to form natural groups based on land usage criteria. The first group consists of sites in areas with no residential component and mainly light to moderate recreational or agricultural usage. The sites comprising the second group are all in predominantly residential and industrialized areas. It would appear that human habitation and/or industrialization is causal for the input of the majority of the fecal coliforms. This could be expected as much of the lower area contains many substandard septic systems, and buildings and disposal fields are located in some cases as close as 15 m to ponds and streams. In addition, surface flushing due to precipitation is also partly causal and evidenced by a significant but low correlation coefficient with log fecal coliform values. In areas of low fecal coliform counts it is most likely that wildlife usage of the areas is responsible for the majority of the fecal coliform input including the spike values observed. This would also suggest that the recreational and/or agricultural (cattle) usage contribute little to the system. However, identification of isolates would be required to definitely rule out such factors as Klebsiella from land runoff. The primary agricultural areas in the middle of the system (above site 6) are seasonally used for pasturing cattle (late May--October). The area is characterized by low hills and rolling grassland frequently interrupted by bands of trees, shrubs and occasional wet bogs. The low counts of both total and fecal coliforms observed in this site may be due to land physiography which acts as vegetation buffer zones which have been found to be effective in substantially reducing pollution from feed lots (Young et al., 1980).
Table 4. MPN values for fecal coliibrms Site number Sample dates 25/09/81 02/10/81 12/11/81 22/11/81 27/01/82 08/02/82 07/04/82 14/04/82 07/06/82 14/06/82 24/08/82 30/08/82 15/11/82 24/11/82
I 1600 70 240 170 70 79 920 130 4 <2
5 2 360 2
2 --* 33 180 22 8 2 21 13 110 I1 17 460 1600 2400
3 -2 33 <2 <2 4 2 8 <2 <2 <2 <2 <2 2
*No data.
tRainfall (ram) for 7 days prior to sample.
4 -33 180 <2 13 8 79 1600 8 <2 2 7 <2 920
5 -<2 11 2 5 2 8 5 <2 <2 5 5 2 <2
6 17 23 8 8 <2 <2 7 7 <2 <2 2 8 <2 2
7 <2 4 8 2 <2 <2 2 <2 <2 <2 <2 <2 <2 <2
8 8 <2 11 2 <2 <2 130 11 <2 <2 2 2 <2 2
9 I10 4 79 79 70 13 350 17 8 <2 33 33 13 <2
Rainfallt 72.0 17.6 77.1 59.0 53.2 33.0 44.9 38.4 2.2 0.0 30.3 60.2 8.2 16.7
Bacteriological water quality In this part of the system under study, the density of cattle is low and feces are dispersed over a wide area. Furthermore it has been reported that where stream contact with cattle has occurred, the shallow turbulent waters have eliminated much of the pollution potential (Hollon et al., 1982). In addition to this, the water from these areas flows into a large, shallow pond (103 ha, mean depth 4.1 m) which acts as a settlement basin thereby further reducing the fecal coliform counts. Boylen et al. (1983) found that in oligotrophic lakes the bacteria found in circumneutral lakes (pH > 6) grew less favorably at lower pH values. This would infer that acidic conditions are deleterious to such bacterial populations. This contention is further supported by the works of Fjerdingstad and Nilssen (1982). Our findings also support this in that there is a significant correlation between the pH and log fecal coliform values (0.2851). The pH values generally increase downstream (except for site 1) from the top to the bottom of the system, as do the coliform numbers. Additional evidence of this may be derived from a comparison of sites 1 and 9, both having elevated coliform counts. In the case of site 1, elevated coliform populations are more likely to be due to increased residential input, whereas the counts from site 9 may be due to raised pH values as well as residential usage and the physiography of the area immediately above the sample site. This point is further supported when looking at the pH and coliform numbers for site 4 which has raised bacterial counts and elevated pH values. Examination of the nature of the industrial-commercial activities reveals no potential for contributing to the heightened coliform values. It must be inferred that the residential and, to a smaller extent, the agricultural components in these lower regions of the system are responsible for the higher coliform levels observed. The residences in this area have been wholly reliant on septic tanks and percolation fields for the disposal of human wastes. Hagedorn et al. (1978, 1981) and Rahe et al. (1978) have found that fecal contamination of water may result from lateral movement of organisms through different soil type interfaces. Soil saturation and seasonal variability in the height of the water table may also be contributing factors. The area under investigation has a complex geology being comprised of four geological groups with a major fault line transversing the watershed. The area has also been heavily glaciated, leaving a porous overburden and only shallow soils. This has also produced a considerable number of substrate interfaces, which frequently reach the surface on exposed hillsides and stream banks. The direct relationship of fecal coliform numbers with seasonal fluctuations in the water table would suggest a situation similar to that described by Hagcdorn et al. (1981) and Rahc et al. (1978).
265
Sinton (1982) found that intermittent contamination of wells occurred in areas of septic tank usage but could find no direct evidence that the tanks in the area were directly involved. Sinton (1982) also noted a subsequent decrease of bacterial populations with an increase in water table but offers no explanation other than dilution and dispersion effects to explain this phenomenon. In this situation at Yadhurst, Sinton (1982) infers that the deep aquifers may be carrying contaminants of septic tank origin to the wells. That system uses deep drainage fields whereas here they are in the top 1.5 m of soil and this allows for leaking out into surface waters. Comparison of the total coliform and fecal coliform numbers reveals much greater values of the former. There also appears to be little relationship between the two. This indicates that in all probability there is a comparatively large though variable density of coliforms of nonmammalian origin. Geldreich (1967) found that only a small percentage of coliforms were contributed by plants and terrestrial insects. Geldreich and Clarke (1966) found that freshwater fish do not have a permanent coliform flora in the digestive tract unless they are living in polluted areas and then may even harbour mammalian fecal coliforms. Thus the nonmammalian coliforms must in large part be of both aquatic and terrestrial invertebrate origin. Evidence presented suggests that a positive relationship exists between total coliform populations and precipitation. Therefore, a significant portion of the coliforms are introduced by land flushing, which is directly influenced by land usage. This investigation has revealed that a natural system may exist in such a way as to confuse one's classification of what may constitute a polluted system. Based on local Department of Health regulations and standards the entire system would appear to be bacterially contaminated if one uses strict coliform count criteria. However, as can be seen from the site descriptions, the upper areas receive only "natural" inputs and man and his endeavours are not the cause of any of the measured data. This can then be considered to be a baseline system and subsequent differences or changes may then be attributed to any site usage downstream from these upper sites. The evidence presented does show elevations in counts downstream regardless of the system's built-in ability to regulate and cleanse itself, and these increased counts relate positively with land occupancy and usage. Other mitigating circumstances which aid and abet pollution are seen in the geology and physiography of the area as well as physical parameters such as precipitation, pH and temperature. Acknowledgements--This study was funded by a grant
from the President's Fund Memorial University of Newfoundland. The authors wish to express their appreciation to S. Power, W. Sparkes and L. Green for preparation of the manuscript.
266
G . I . McT. COWAY et al.
REFERENCES Anon. (1980) Determination of Total Inflection Point Alka-
linity. Ontario Ministry of Natural Resources, Fisheries Branch, Toronto, Ontario. APHA (1980) Standard Methods for the Examination of Water and Wastewater, 15th edition. American Public Health Association, Washington, D.C. Boylen C. W., Shick M. O., Roberts D. A. and Singer R. (1983) Microbiological survey of Adirondack lakes with various pH values. Appl. envir. Microbiol. 45, 1538-1544. Bruckner W. D. (1979) Geomorphology of the Avalon Peninsula, Newfoundland. Mineral Development Division, Dept. of Mines and Energy, Government of Newfoundland and Labrador. Faust L. M. (1983) Total alkalinity versus buffer value (capacity) as a sensitivity indicator for freshwaters receiving acid rain. J. envir. Sci. Hlth 18, 701-711. Faust M. A. (1982) Relationship between land-use practices and fecal bacteria in soils. J. envir. Qual. 11, 141-146. Faust M. A. and GoffN. M. (1977) Basin size, water flow, and land use effects of fecal coliform pollution from a rural watershed. In Watershed Research in Eastern North America Vol. 2 (Edited by Correl D. L.), pp. 611~34. Chesapeake Bay Center for Environmental Studies, Smithsonian Institution, Edgewater, Md. Fjerdingstad E. and Nilssen J. P. (1982) Bacteriological hydrological studies on acid lakes in Southern Norway. Arch. Hydrobiol. Suppl. 64, 443-483. Geldreich E. E. (1967) Fecal coliform concepts in stream pollution. Water Swge Wks 114, R-98. Geldreieh E. E. and Clarke N. A. (1966) Bacterial pollution indicators in the intestinal tract of freshwater fish. Appl. Microbiol. 14, 429-437.
von Graevenitz A. (1985) Aeromonas and Plesiomonas. In Manual o f Clinical Microbiology (Edited by Lennette E. H., Balows A., Hausler W. H. and Shadomy H. J.), 4th edition, pp. 278-281. American Society for Microbiology, Washington, D.C. Hagedorn C., Hansen D. T. and Simmonson G. H. (1978) Survival and movement of fecal indicator bacteria in soil under conditions of saturated flow. J. envir. Qual. 7, 55-59. Hagedorn C., McCoy E. L. and Rahe T. M. (1981) The potential for ground water contamination from septic effluents. J. envir. Qual. 10, 1-8, Hendry G. S. and Toth A. (1982) Some effects of land use on bacteriological water quality in a recreational lake. Wat. Res. 16, 105-112. Hollon B. F., Owen J. R. and Sewell J. I. (1982) Water quality in a stream receiving dairy feedlot effluent. J. envir. Qual. 11, 5 4 . McFetters G. A. and Stuart S. A. (1976) Impact of horses on the bacterial water quality of Cottonwood Creek, Grand Teton National Park. J. envir. Hlth 39, 123-125. Rahe T. M., Hagedorn C., McCoy E. L. and Kling G. F. (1978) Transport of antibiotic coli through Western Oregon hillslope soils under conditions of saturated flow. J. envir. Qual. 7, 487-494. Rippley B. and Gibson C. E. (1984) The variation of calcium, magnesium, sodium and potassium concentration, pH and conductivity in lakes in Northern Ireland. Arch. Hydrobiol. 101, 345-360. Sinton L. W. (1982) A groundwater quality survey of an unsewered semi-rural area. N.Z. J. Mar. Freshwat. Res. 16, 317-326. Young R. A., Huntrods T. and Anderson W. (1980) Effectiveness of vegetated buffer strips in controlling pollution from feedlot runoff. J. envir. Qual. 9, 483-487.