The study used the risk matrix adapted from Davison et al. (2006) and Bartram et al. (2009) to measure the risks, using scores from 1 to 4, and to explain the consequence of each score. The hazards analysis, hazards events and control measure were adapted from Pérez-Vida et al. (2013). Table 1 was constructed to distinguish between hazard assessment and risk analysis whereas Table 2 suggests risk control matrix based on the outcomes of the study. Identification of a team, hazard analysis, critical control limit and control measures were conducted using the risk matrix score of 1 to 4. The risk matrix scores used were no impact (1), tolerable (2), peripheral (3) and not tolerable (4), adapted from Davison et al. (2006). Consequences include no health impact (1), minimal impact causing dissatisfaction and health concern (2), marginal impact which can cause health risk (3) and major impact with serious health consequences (4). Risk estimation was shown with and without control measures. The use of these criteria aimed at identifying the systematic risk assessment procedure used to determine critical control points.
Hazard analysis of drinking water from pre-requisite assessment to the point of use, adapted from Pérez-Vida et al. (2013)
| Risk analysis criteria . | Activity and procedure of risk assessment . | Hazard event . | Critical limits . | Type of hazard . | |||
|---|---|---|---|---|---|---|---|
| (DWA 1994) . | Water quantity . | Water quality . | Hygiene . | Structural design . | |||
| Pre-requisite hazard analysis | 1. Accessibility | Distance travelled to improved water source less than 200 m; Unimproved water sources closer to households and the furthest at more than 5 km | Distance travelled to the source should not exceed 200 m | X | X | X | |
| 2. Availability | Communal water sources not available for up to 6 months | 25 L/c/d water should be available to each person | X | X | X | ||
| Unimproved water sources used as secondary source and are reliable | X | X | |||||
| 3. Potability | Contaminated communal water used for consumption | Total coliform counts should not exceed 10/100 mL; E. coli should not be found in water (<1/100 mL) | X | X | |||
| Contaminated secondary sources used for consumption | X | X | |||||
| Use of unimproved sources | X | X | |||||
| Use of contaminated water stored in containers | X | X | X | ||||
| Private boreholes located next to sanitary facilities (septic tanks, cowshed, toilets, etc.) | X | X | |||||
| On-site risk assessment from collection point to the point of use | 4. Collection point | Water accessed from taps, springs, tanks and private drilled wells | Not determined | X | X | XX | |
| Dirty containers used for water collection (showing scratches, biofilm and moving particles) | X | X | X | ||||
| Hands dipped inside drinking water during collection | |||||||
| 5. Transportation | Dirty wheelbarrow load used for water transportation | Not determined | X | X | X | ||
| Water transported in dirty containers without lids in dusty roads | X | X | X | ||||
| Water transported by head with hands dipped inside | X | X | X | ||||
| 6. Storage | Water stored in dirty containers | Not determined | X | X | |||
| Soil mixed with soap is used to clean containers | X | X | X | ||||
| Water stored in containers without the lids and exposed to dust | X | X | X | ||||
| Water stored in dusty house | X | X | |||||
| 7. Point of use | Dirty scooping vessels used to scoop water from the storage container | Not determined | X | X | X | ||
| Dipping hands in drinking water | |||||||
| Risk analysis criteria . | Activity and procedure of risk assessment . | Hazard event . | Critical limits . | Type of hazard . | |||
|---|---|---|---|---|---|---|---|
| (DWA 1994) . | Water quantity . | Water quality . | Hygiene . | Structural design . | |||
| Pre-requisite hazard analysis | 1. Accessibility | Distance travelled to improved water source less than 200 m; Unimproved water sources closer to households and the furthest at more than 5 km | Distance travelled to the source should not exceed 200 m | X | X | X | |
| 2. Availability | Communal water sources not available for up to 6 months | 25 L/c/d water should be available to each person | X | X | X | ||
| Unimproved water sources used as secondary source and are reliable | X | X | |||||
| 3. Potability | Contaminated communal water used for consumption | Total coliform counts should not exceed 10/100 mL; E. coli should not be found in water (<1/100 mL) | X | X | |||
| Contaminated secondary sources used for consumption | X | X | |||||
| Use of unimproved sources | X | X | |||||
| Use of contaminated water stored in containers | X | X | X | ||||
| Private boreholes located next to sanitary facilities (septic tanks, cowshed, toilets, etc.) | X | X | |||||
| On-site risk assessment from collection point to the point of use | 4. Collection point | Water accessed from taps, springs, tanks and private drilled wells | Not determined | X | X | XX | |
| Dirty containers used for water collection (showing scratches, biofilm and moving particles) | X | X | X | ||||
| Hands dipped inside drinking water during collection | |||||||
| 5. Transportation | Dirty wheelbarrow load used for water transportation | Not determined | X | X | X | ||
| Water transported in dirty containers without lids in dusty roads | X | X | X | ||||
| Water transported by head with hands dipped inside | X | X | X | ||||
| 6. Storage | Water stored in dirty containers | Not determined | X | X | |||
| Soil mixed with soap is used to clean containers | X | X | X | ||||
| Water stored in containers without the lids and exposed to dust | X | X | X | ||||
| Water stored in dusty house | X | X | |||||
| 7. Point of use | Dirty scooping vessels used to scoop water from the storage container | Not determined | X | X | X | ||
| Dipping hands in drinking water | |||||||
Risk assessment matrix in household water, adapted from Pérez-Vida et al. (2013)
| Activity and risk assessment no. . | Risk estimation without control measure . | Corrective measures . | Risk estimation with control measure . | ||
|---|---|---|---|---|---|
| Hazard no. . | Consequence . | Risk score . | Consequence . | Risk score . | |
| 1. Accessibility | Major impact with serious health consequence | Not tolerable (4) | Provision of safe water to reduce distance, prolonged waiting time and use of unimproved water sources | Marginal impact which can cause health risk | Peripheral (3) |
| 2. Availability | Major impact with serious health consequence | Not tolerable (4) | Disinfection of water obtained from unsafe sources; Health education and awareness | Minimal impact causing dissatisfaction and health concern | Peripheral (2) |
| 3. Potability | Major impact with serious health consequence | Not tolerable (4) | Health education on good water storage and hygiene practice at home; Conduct environmental impact assessment before construction of sanitary or water system | Minimal impact causing dissatisfaction and health concern | Tolerable (2) |
| 4. Collection point | Major impact with serious health consequence | Peripheral (3) | Health education on good water storage, hygiene and treatment | Minimal impact causing dissatisfaction and health concern | Tolerable (2) |
| 5. Transportation | Major impact with serious health consequence | Not tolerable (4) | Clean and disinfect transport used for transporting water; Health education and awareness on hygiene practices at home | Minimal impact causing dissatisfaction and health concern | Tolerable (2) |
| 6. Storage | Major impact with serious health consequence | Not tolerable (4) | Health education on good water storage, hygiene and treatment | Minimal impact causing dissatisfaction and health concern | Tolerable (2) |
| 7. Point of use | Marginal impact which can cause health risk | Peripheral (3) | Health education and awareness on good hygiene practices at the point of use | Minimal impact causing dissatisfaction and health concern | Tolerable (2) |
| Activity and risk assessment no. . | Risk estimation without control measure . | Corrective measures . | Risk estimation with control measure . | ||
|---|---|---|---|---|---|
| Hazard no. . | Consequence . | Risk score . | Consequence . | Risk score . | |
| 1. Accessibility | Major impact with serious health consequence | Not tolerable (4) | Provision of safe water to reduce distance, prolonged waiting time and use of unimproved water sources | Marginal impact which can cause health risk | Peripheral (3) |
| 2. Availability | Major impact with serious health consequence | Not tolerable (4) | Disinfection of water obtained from unsafe sources; Health education and awareness | Minimal impact causing dissatisfaction and health concern | Peripheral (2) |
| 3. Potability | Major impact with serious health consequence | Not tolerable (4) | Health education on good water storage and hygiene practice at home; Conduct environmental impact assessment before construction of sanitary or water system | Minimal impact causing dissatisfaction and health concern | Tolerable (2) |
| 4. Collection point | Major impact with serious health consequence | Peripheral (3) | Health education on good water storage, hygiene and treatment | Minimal impact causing dissatisfaction and health concern | Tolerable (2) |
| 5. Transportation | Major impact with serious health consequence | Not tolerable (4) | Clean and disinfect transport used for transporting water; Health education and awareness on hygiene practices at home | Minimal impact causing dissatisfaction and health concern | Tolerable (2) |
| 6. Storage | Major impact with serious health consequence | Not tolerable (4) | Health education on good water storage, hygiene and treatment | Minimal impact causing dissatisfaction and health concern | Tolerable (2) |
| 7. Point of use | Marginal impact which can cause health risk | Peripheral (3) | Health education and awareness on good hygiene practices at the point of use | Minimal impact causing dissatisfaction and health concern | Tolerable (2) |