Developing a water quality certification programme
SIMPLIFIED ANALYSIS FOR FAECAL COLIFORMS
This procedure tests whether or not wastewater meets the 1989 WHO Guideline of 1000 faecal coliforms per 100 ml for unrestricted irrigation.
Use normal aseptic procedures throughout. Prepare a 1 in 10 dilution by adding 1 ml of diluted sample to each of 5 tubes containing 5 ml of A -1 medium and a Durham tube. Incubate at 44.5 °C for 19-23 h, Count the number of positive tubes (those showing gas production), and read the most probable number (MPN) of
faecal coliforms per 100 ml of wastewater from the following table.
Source: Mara and Cairncross (1989)
The slightly elevated levels that show exceedances less than 2X the WHO Guideline value should remain a concern and should not be tolerated as a long- term water quality condition. Figure 12 suggests a 1-year provisional certification can be granted to areas with a faecal coliform value between 1000 and 2000 FC/100 ml. If after 1 or 2 years the sources of contamination have not been identified and controlled to < 1000 FC/100 ml, the provisional certification should be removed. Such an approach would meet the goals of the certification
programme which are to promote safe production areas and use economic incentives or disincentives to promote clean up of slightly contaminated areas. Certifying individual producers and fields
This alternative approach is to certify the water used on a specific crop or field. Water quality samples must then, as closely as economically practical, be taken to reflect the quality used on each individual farm throughout the irrigation season. Monitoring at each field attempts to improve on the disease reduction rates that can be accomplished with the area-wide approach.
The steps in the process are outlined in Figure 13. The first step is to establish the water quality conditions for the area. This includes defining primary and secondary contamination. The level of water quality sampling that occurs in Step 1 is identical to that used in certifying large irrigated areas (Figure 11). As in the previous
approach, the focus is on defining safe production areas. The financial burden for this initial assessment needs to be assumed by the public sector in order to maintain strict quality control over the data.
FIGURE 13: Certification of irrigation water quality used on individual fields for vegetable crop production
The goal of this initial step is to establish a legal basis for decisions and reduce the number of future samples that need to be taken by individual producers. By
defining in Step 1 those areas that have the greatest potential to be safe production areas, the agricultural authorities can limit the areas that should be considered for certification. This avoids the agricultural authorities having to reject a number of producers who had little chance of certification because of the extent of contamination. The agricultural authorities can then focus their resources on safe production areas.
The method used to evaluate the existence of primary contamination is identical to that used in the previous approach. The initial evaluation criteria should be <10
Number of positive tubes MPN of faecal coliforms per 100 ml
0 <100 1 220 2 510 3 920 4 1600 5 >1600
000 FC/100 ml (104) rather than the WHO Guideline of <1000 FC/100 ml (103). As discussed in the previous section, it is not the intent at this level of monitoring to certify water that is less than 104 FC/100 ml as safe for use in vegetable
production. The goal is to define on a regional basis those areas that have the greatest potential to be safe production areas.
Defining primary contamination, however, is only one part of the first step. A similar assessment must be conducted for the extent of secondary contamination (section Criteria used to select field monitoring sites).
In the alternative that focuses on a specific crop or field, all areas that show less that 104 FC/100 ml would be considered as potential safe production areas. Then it is the individual producer who must petition the Agricultural Ministry to be included in the programme (Step 2 in Figure 13). The Ministry must then decide whether to require the individual producer to conduct additional water quality testing to ensure that clean production standards are used or whether the initial monitoring
assessment conducted in Step 1 is sufficient. Any additional monitoring then becomes the responsibility of the individual producer (Step 3).
There is an exception (as noted in Step 2) to the exclusion from consideration when the initial assessment shows heavy contamination (>104 FC/100 ml). Where groundwater is being used as the only source of irrigation water within a known heavily contaminated area, this groundwater area could be considered for inclusion in the certification programme. Groundwater, even in heavily
contaminated areas, rarely shows signs of bacteriological contamination. This source of water offers a high potential for safe production; therefore, these areas should be considered for inclusion in the certification programme even if located in a heavily contaminated area (> 104). The use of groundwater, however, should not be the only criterion used for certification. The producer must be able to
demonstrate that the canal water source has been eliminated and that no secondary sources of contamination affect the groundwater supply canals. This should be a prerequisite to water quality certification for groundwater use areas. In the area-wide certification alternative described in the previous section, the health and agricultural authorities collected, analysed and assessed water quality samples and issued a certification to the irrigated area. In contrast, in this
alternative the focus is on an individual crop or field, and the health and
agricultural authorities must not only be prepared to conduct an area-wide water quality assessment but must be prepared to evaluate the water quality analyses submitted by the individual producers. Where the irrigation supply meets the WHO analyses submitted by the individual producers. Where the irrigation supply meets the WHO Guidelines of <103 FC/100 ml, the Agricultural Ministry must be prepared to authorize the producer to use a certified label. The label would state that the agricultural and or health authorities have certified that the water used in production meets health guidelines (Step 4). This label can then be applied to produce from that field if the producer has met the following series of
administrative conditions (Step 5):
information is provided to Agricultural Ministry on the type and amount of production anticipated on that field;
records are available on where produce is sold and distributed; controls were used when the produce was packed, transported and cleaned;
produce is always identified by a numerical label; and
all records are available to the agricultural and health authorities, the buyers and shippers.
Certifying individual fields gives the health and agricultural authorities close control of labelling and distribution of produce. The Agricultural Ministry in return must be prepared to make quick administrative decisions to ensure the availability and timely distribution of produce. Closer control means continuous financial resource needs for the Agricultural Ministry especially if they certify areas in remote regions. The key element in an effective programme is strong water quality monitoring. All the water quality sampling in Step 1 of Figure 13 should be used until experience is gained about the water quality within an irrigated area. The goal should be to repeat a similar area-wide assessment at least once every two to three years. Where monitoring is conducted at the field level by individual producers (Step 3), this should also be repeated every two years. After experience is gained, the monitoring in Step 3 can be reduced. A description of the process for repeating the analysis by individual producers (Step 6) is given in Figure 14. The procedure in Figure 14 is similar in concept to that described for the area-wide assessment. Repeated sampling for certification of water used on a specific crop or field will be faced with the dilemma of how to handle areas that have previously shown
compliance with the WHO bacterial guideline but now slightly exceed the WHO Guideline value (<2X the guideline value). Water quality samples are being collected near the field after the water has travelled many kilometres through earthen lined canals in rural areas. The sources of contamination under such circumstances can be many, including non-human sources (animals, wildlife, etc.). While this water presents a disease transmission risk, that risk is significantly below that seen closer to urban areas where the level of contamination often exceeds 104 FC/100 ml. For the areas that were initially below the WHO bacterial guideline but now have faecal coliform levels from 1000 to 2000 FC/100 ml, the emphasis should not be on exclusion but should be directed at trying to identify the sources of contamination to make this a safe production area.
A provisional certification can be used for areas that only slightly exceed the WHO Guideline. Provisional certification is not to promote these areas as safe
production areas but to promote these areas as having significant potential to become safe production areas. Use of a 1-2 year provisional certification assumes a risk but that risk is far less than the unrestricted use of contaminated water for vegetable crop production in other areas. Strict adherence to the limited time period will diminish the future need to utilize the provisional certification. As sufficient safe production areas are identified, use of the provisional certification could eventually be abandoned as a step in the certification process.
FIGURE 14: Routine analysis for faecal coliforms (FC) in the irrigation water used at the field level in areas certified as safe production zones
With increased consumer awareness of the need for hygienically clean produce, there may be an informal labelling of produce. This would be an effort by growers to ensure the consumers of their product safety. There is a high potential for fraud with any informal system. The Agricultural Ministry needs to standardize the use of certification labels to ensure consumer protection and place a high degree of credibility in the labels being used.
The proposal described in Figure 13 also has the potential for fraud. The potential for fraud, however, should not diminish the desire of the agricultural and health authorities to use a standard certification label. The economic advantages of using the label should be an incentive by the users to avoid fraud. Likely sources of fraud are:
not taking the required water analyses or utilizing for analysis water sources other than those used in production;
utilization of products from outside the certified area; altering or omitting data used for certification;
handling, packing and processing the produce in unsanitary conditions; and
using irrigation water that is not certified.
There is no way to avoid fraud but, when found, the agricultural and health authorities should take swift and firm action. This will strengthen the role of the Agricultural Ministry in its efforts to promote safe production areas and reduce the possibility of fraud in the future.
The two alternative approaches presented in this and the previous section emphasize promoting safe production areas but each requires a different level of resources and administrative backing. Both proposals should only be considered as concepts. The actual development of a certification programme must consider several other factors. A detailed discussion of such factors can be found in a report on a water quality certification project in Chile (FAO, 1993). There are three factors that this report concluded were important to the success of any programme:
that all public agencies agree that only one label will be recognized as certifying production in safe areas. Decisive and quick action must be taken to prohibit the use of alternative labels;
that the Agricultural Ministry is prepared to apply the programme uniformly and nationwide as producers from all zones of the country will want the same economic advantages in selling their produce; and
that the Agricultural Ministry is prepared to fully operate the
programme in order to maintain a high level of credibility with both the producer and the consumer.
resources to be done with high standards and a high degree of credibility. In developing countries it may be necessary to structure and implement a pilot programme in water quality certification for safe vegetable production. This pilot programme would give the initial programme high visibility. Seeking international assistance in structuring and implementing a pilot programme or in conducting the nationwide water quality assessment would also give the programme the needed credibility with the affected farmers as well as the consumers, both national and international.
Role of public service
A primary role of public service in food supply is consumer protection. This includes establishing national policies and programmes that promote and provide a safe and readily available food supply. The use of contaminated water to irrigate vegetables and certain fruits in Santiago, Chile, was identified as one of the chief means of spreading certain diseases including cholera (Shuval, 1993). Therefore efforts in the public sector must be strengthened to develop a safe food supply that meets national needs. Some of the considerations that are needed by the public service are:
establishing consumer protection standards; regulating health standards;
promoting safe production by developing plans to meet national production needs;
promoting national interests in international markets; minimizing negative or non-productive expenditures; and public education.
A programme to certify the bacterial quality of water used in production of high-risk crops such as vegetables focuses on controlling a public health problem. As such, the Health Ministry has the primary role for public health. The health authorities should set the boundaries and limitations for acceptability such as the WHO Guidelines (WHO, 1989) and the role of Agricultural Ministry should only be to implement programmes which promote safe agricultural production within the limitations established by the health specialists.
The health authorities carry the primary role in setting the health standards for water utilized for irrigation. The present standard as described in the WHO
Guidelines should remain the goal of Agricultural Ministry. The Agricultural Ministry should evaluate, however, whether national production goals can be met while meeting this standard. If clear evidence is available that national production goals cannot be met or that negative economic conditions will result, the Agricultural Ministry needs to consult with the health authorities regarding a temporary modification to the regulation. It is strongly felt that the regulation may be very restrictive for existing conditions in many developing countries and that the Health and Agricultural Ministries will need to evaluate closely the data collected during a water quality monitoring programme (see discussion in the section Alternate irrigation methods later in this chapter).
A coordinated programme among the agricultural, irrigation and health authorities can make a crop or water quality certification programme much more effective. The focus of the agricultural and irrigation authorities must remain on production
and supply issues while the health specialists need to focus on consumer protection. The agricultural authorities should emphasize certification of safe production areas or safe production techniques to enhance the ability of the
producers to respond to health restrictions. This emphasis would also enhance the ability of the health authorities to restrict cropping in non-certified areas or control the distribution of non-certified produce. Controlling or restricting cropping for health reasons should remain with the health authorities as the restriction is being done for a public health reason.
The health specialists should take the lead in developing and maintaining a bacteriological laboratory quality control programme for private laboratories since this is outside the expertise of agricultural specialists. The choice, timing and frequency of water quality sampling, however, should remain with the agricultural authorities since they have the expertise to define representative sites within an irrigated zone.
The agricultural and health authorities could jointly strengthen the role of the certification programme by using public education techniques to emphasize to consumers and vendors the need to buy only certified produce. In addition, the use of fraudulent labels could be reduced if the health authorities strengthen their regulations against false advertisement or health protection claims on labels. An important new role for the national and regional agricultural and irrigation authorities is ensuring that the needs of production agriculture are thoroughly considered in plans to treat and dispose of urban wastewater. It is only under a coordinated plan that the agricultural sector can proceed to make long-term safe production areas without such a programme becoming a financial drain on public resources.
There is another level of the public sector that is important to the success of a national water quality certification programme: the local service agencies that serve the irrigation water user. Their role is to ensure a steady flow of the resources (financial, water, seed, etc.) needed to produce a food supply. These local agencies, especially those that supply water, must focus on ensuring that the resource they supply does not affect the safety of the food being produced. An important local group is the canal or irrigation association. They control how water is diverted, distributed and often what other water enters the irrigation supply canals. Because of the importance of contamination that occurs in the irrigation canal network, these associations hold a major key to ensuring a safe water supply. Often those discharging into the irrigation system are also water users or are directly connected with the agricultural system in the area. Each holds a stake in ensuring a safe water supply but often the results of their joint or individual actions are not well understood. These local agencies could act as a focal point for national health and agricultural authorities which are attempting to clean up or promote safe production areas. The local agencies are an important factor in the area-wide certification alternative described above.
Role of the private sector (producer, packer and shipper) in certification The private sector growers hold the key to the success of a water quality
certification programme. The programme to label safe produce must be voluntary to be effective. The public service agencies have limited resources for regulation. Structuring the programme must be done with the view of minimizing the burden
on the public service agencies and the producers and stress that compliance with the programme will bring the producers economic advantages. Informal
programmes are likely to occur in the future and these will be driven by economic incentives. In any formal programme, the private sector must be willing to self- regulate itself with the punishment for failure being a loss of economic advantage. To promote self-regulation, the programme must have several checks and
balances built in but rely heavily upon economic incentives. This process must be driven by the consumer. The alternative and more difficult approach is for the