Table 4. Summary statistics: a. Extracted Studies (n = 55), b. Extracted Records (n = 102), c. Extracted records associated with confirmed enteric pathogen presence (n = 74), d. Sampled well numbers (n = 52) and analysed groundwater sample numbers (n = 39).
| Variable | Canada | United States | ||
| Total | Pathogen Present | Total | Pathogen Present | |
| N (%) | N (%) | N (%) | N (%) | |
| a. | ||||
| Supply Type (n = 54) | ||||
| Municipal | 4 (7.4) | 3 (75) | 11 (20.3) | 9 (81.8) |
| Private | 9 (16.6) | 3 (33.3) | 24 (44.4) | 15 (62.5) |
| Community | 0 (0) | - | 5 (9.2) | 4 (80) |
| Mixed | 0 (0) | - | 1 (1.8) | 1 (100) |
| Fecal Indicator Organisms (n = 39) | ||||
| Total Coliforms | 7 (17.9) | n/a | 25 (54.1) | n/a |
| E. coli | 10 (25.6) | n/a | 24 (51.5) | n/a |
| Intestinal enterococci | 5 (12.8) | n/a | 11 (28.2) | n/a |
| Coliphage | 2 (7.5) | n/a | 6 (15.3) | n/a |
| C. perfringens | 0 (0) | n/a | 5 (12.8) | n/a |
| Heterotrophic Plate Counts | 0 (0) | n/a | 2 (7.5) | n/a |
| Sample Season (n = 31) | ||||
| Spring | 0 (0) | - | 4 (12.9) | 2 (50) |
| Summer | 2 (6.4) | 1 (50) | 8 (25.9) | 2 (25) |
| Autumn | 2 (6.4) | 2 (100) | 9 (29) | 6 (66.7) |
| Winter | 1 (3.2) | 0 (0) | 0 (0) | - |
| Year Round | 0 (0) | - | 5 (16.1) | 4 (80) |
| Pathogen Detection Method (n = 40) | ||||
| Molecular Techniques | 7 (17.5) | 7 (100) | 22 (55) | 18 (81.8) |
| Microscopy | 1 (2.5) | 0 (0) | 3 (7.5) | 2 (66.7) |
| Culture-based | 0 (0) | - | 7 (17.5) | 5 (71.4) |
| b. | ||||
| Aquifer/Bedrock Type (n = 61) | ||||
| Karstified | 0 (0) | - | 13 (21.3) | 12 (92.3) |
| Unconsolidated | 0 (0) | - | 17 (27.8) | 15 (88.2) |
| Fractured Bedrock | 1 (1.6) | 1 (100) | 9 (14.7) | 4 (44.4) |
| Un-fractured Bedrock | 4 (6.5) | 2 (50) | 9 (14.7) | 7 (77.7) |
| Diverse (Large Area) | 0 (0) | - | 8 (13.1) | 7 (87.5) |
| Study Design (n = 102) | ||||
| Repeat Sampling | 7 (6.8) | 3 (42.8) | 25 (24.5) | 21 (84) |
| Snapshot Sampling | 4 (3.9) | 2 (50) | 18 (17.6) | 18 (100) |
| Outbreak Investigation | 1 (1) | 1 (100) | 41 (40.2) | 24 (58.5) |
| Laboratory-based | 0 (0) | - | 6 (5.8) | 5 (83.3) |
| c. | ||||
| Pathogen Type (n = 102) | ||||
| Bacterial | 2 (2) | 2 (100) | 20 (19.6) | 12 (60) |
| Protozoan | 6 (5.8) | 2 (33) | 15 (14.7) | 9 (60) |
| Viral | 4 (3.9) | 2 (50) | 55 (53.9) | 46 (88.5) |
| Pathogen Source (n = 74) | ||||
| Agriculture/Livestock | n/a | 4 (5.4) | n/a | 5 (6.7) |
| Wild Animals | n/a | 1 (1.3) | n/a | 2 (2.7) |
| Septic tank/Sewage system | n/a | 2 (2.7) | n/a | 43 (58.1) |
| Surface Water Body | n/a | 2 (2.7) | n/a | 33 (44.6) |
| Contamination Pathway (n = 74) | ||||
| Precipitation | n/a | 3 | n/a | 14 (18.9) |
| Geological | n/a | 1 | n/a | 43 (58.1) |
| Source-specific | n/a | 2 | n/a | 23 (31.1) |
| Canada | United States | |||
| Mean | Range | Mean | Range | |
| d. | ||||
| Well Number | 15 | 1–1,208 | 160 | 1–5,520 |
| Sample Number | 41 | 1–1,208 | 225 | 1–5,520 |
| Samples/well | 2.73 | 1.4 | ||