Locally produced hydrogen sulphide detecting water quality test kits increase household level monitoring in rural Tanzania

In developing countries, rural water sources have the highest levels of faecal contamination but are the least monitored. Affordable field-based water quality tests are needed. The presence of faecal indicator bacteria can be determined with hydrogen sulphide (H2S) detecting tests, that are inexpensive and simple to make locally. In rural Tanzania, a non-governmental organisation (NGO) designed, produced and evaluated a new H2S water quality test kit. The H2S test results correlated with log10 Escherichia coli densities from conventional water quality tests. The production cost was US$ 1.10 and the test retailed for US$ 1.37. In total, 433 tests were sold through local pharmacies and NGOs. Additionally, 165 WaSH education meetings, reaching 3,408 community members, were conducted with the H2S test demonstrated in over half the meetings. Preand post-surveys of 294 meeting participants saw an increased reporting of household level water treatment by 24%. The H2S test was widely accepted, with 94% of those surveyed willing to buy the test in the future. International and national guidelines for drinking water monitoring need to be amended to include locally produced H2S water quality tests. This will enable households to monitor their own water sources and make informed choices about water safety and treatment. This is an Open Access article distributed under the terms of the Creative Commons Attribution Licence (CC BY 4.0), which permits copying, adaptation and redistribution, provided the original work is properly cited (http://creativecommons.org/licenses/by/4.0/). doi: 10.2166/wh.2018.220 s://iwaponline.com/jwh/article-pdf/16/3/359/245891/jwh0160359.pdf Fatuma Matwewe Jacqueline Thomas (corresponding author) Environmental Health and Ecological Sciences, Ifakara Health Institute, P.O. Box 53, Ifakara, Morogoro, Tanzania E-mail: jmthomas@ihi.or.tz Kate Hyland Maji Safi kwa Afya Bora (MSABI), P.O. Box 284, Ifakara, Morogoro, Tanzania Jacqueline Thomas Pollution Research Group, Chemical Engineering, University of KwaZulu-Natal, Durban 4041, South Africa; Water Research Centre, The University of New South Wales, Kensington, NSW 2052, Australia; and School of Civil Engineering, The University of Sydney, Darlington, NSW 2008, Australia


INTRODUCTION
Inadequate water, sanitation and hygiene (WaSH) is estimated to cause 842,000 diarrhoeal deaths annually (Prüss-Ustün et al. ). This represents 58% of all deaths due to diarrhoea and equivalent to 1.5% of the global disease burden (Prüss-Ustün et al. ). In sub-Saharan Africa (SSA), nearly 68% of the population use unimproved water sources for drinking water (UNICEF & WHO ) and the clustered burden of inadequate WaSH is estimated to contribute to 61% of all diarrhoeal deaths (Prüss-Ustün et al. ). In SSA, a review of 72 institutions from ten countries, reveals that monitoring is predominately conducted in urban areas by institutions with higher water quality budgets (Peletz et al. ). Further, improved water sources, as defined by the Joint Monitoring Program (UNICEF & WHO ), were monitored up to three times more frequently than unimproved sources (Crocker & Bartram ; Kumpel et al. ). In the SSA study, the most highly monitored water sources are urban piped water systems (64% of samples) by water utilities, which had the lowest levels of contamination (4% of samples) (Kumpel et al. ). Unimproved water sources are more frequently contaminated with faecal indicator bacteria (FIB) at higher risk levels, especially in rural areas and poorer countries (Bain et al. ).
One of the main barriers to increased testing is the cost of water quality tests and the technical skills and laboratories to conduct the tests. Escherichia coli and thermotolerant coliforms (TTC) are the only FIB for contamination in water recommended by the World Health Organization (WHO) Drinking Water Guidelines, 2011.
There are a range of laboratory and field-based commercial water quality tests that identify E. coli and TTC. Water quality tests range in price from US$ 0.50 to US$ 7.50 for reagents, plus there are costs for consumables, specialist equipment and training (Bain et al. ). The estimated total cost of a water quality test is estimated between US$ 7.09 and US$ 7.44 per sample, with labour and transportation costs the largest fractions (Crocker & Bartram ). For disadvantaged rural communities, the costs are prohibitive. More affordable and accessible field-based drinking water quality testing is needed for the world's population, who rely on unimproved water sources.
The hydrogen sulphide (H 2 S) bacteria detecting test was first developed in India as a simple and inexpensive field water quality test with incubation at ambient temperatures (Manja et al.  Dar es Salaam study also raised questions about the costeffectiveness of using commercial water quality tests in interventions (Davis et al. ). Affordable water quality testing combined with appropriate WaSH education is a potential tool to trigger community-driven demand and behaviour change, however further evaluation is needed.
Interestingly, the role and effectiveness of H 2 S tests for household level water quality testing and WaSH education programmes has not been explored to date.
The main aim of this research was to improve WaSH awareness and behaviour through community use of H 2 S water quality tests. This was achieved through the following four objectives: (1) to produce H 2 S tests locally in rural Tanzania for the first time, (2) to validate the effectiveness of the H 2 S tests used in the hands of the community testing local drinking water sources, (3) to design a marketing and WaSH education programme that included H 2 S tests, and (4) to determine if the inclusion of the H 2 S tests improved WaSH education outcomes.

Test production
The original composition of the H 2 S test was selected

Test validation in the laboratory
The effectiveness of the H 2 S test was determined against 47 water sources including treated water, protected and unpro-

Test validation in the community
An initial trial was conducted with 16 households recruited from the villages of Idete and Namawala, Kilombero Valley, Tanzania. The households received training on how to use the tests and then conducted the tests themselves on two water sources: the primary drinking water source and an alternative poorer water source. A negative control (bottled water) was also tested. The tests were left with the household to incubate over 24 h in a warm safe place, such as a window sill. At the time of sampling comparative water samples were taken and tested in the laboratory using H 2 S test and for E. coli/total coliforms (as previously described).
The households also answered some questions on their water source, water treatment, demand for water quality testing, ability to use the H 2 S test and willingness to use and pay for the H 2 S tests.

Development and marketing of H 2 S tests
For the commercial test kit, a smaller water volume of 20 mL with a disposable plastic tube was the most suitable.
H 2 S medium was delivered via infusing an absorbent cotton pad with 1 mL of medium then drying it, as described previously (Mosley & Sharp ). An instruction booklet in kiSwahili language was also developed for the test that included a sanitary survey guide to determine the health risk of the tested water.
A comprehensive marketing campaign for the tests was developed that included print materials and radio presenta-

Inclusion of H 2 S tests in a WaSH education programme
The H 2 S test was introduced as in intervention for randomly selected villages as part of a WaSH education programme run by MSABI. The programme was based on participatory community awareness, delivered via participatory community meetings, demonstration visits and house-to-house visits. The H 2 S test kit was added to the programme and a local or household level water source was tested. Participants returned the following day to view the results of the water quality test. In total, 94 out of 165 WaSH education meetings were conducted with the addition of the H 2 S test kit. Each meeting had approximately 20 participants. Surveys were conducted with approximately 119 community members before they participated in the standard WaSH education meetings and another 175 who participated in the H 2 S test kit in addition to the WaSH education meetings. A tablet-based survey tool was used to gather information on demographics, WaSH behaviours (including hand washing with soap), WaSH infrastructure (including toilet type) and any plans to change WaSH practices (Table S1, available with the online version of this paper).
The survey was conducted again two months after the WaSH education sessions.

Statistical analysis
All statistical analysis and graphs were produced using the statistical software program Prism ® (GraphPad Software, La Jolla, CA, USA). E. coli cfu/100 mL data were transformed to log 10 and tests for correlation were performed using the Spearman's test. WaSH education survey results were compared in 2 × 2 contingency tables of responses from pre-and post-education intervention. Chi-square tests with one degree of freedom and Yate's correction were used to compare the final proportions of the two WaSH education groups post-intervention. All results were considered statistically significant at the significance level of p 0.05.

Ethical approval
Free and informed consent of the participants or their legal representatives was obtained and the study protocol was

Test production
Reagents were sourced from suppliers in Dar es Salaam and order times for imported reagents were less than two months. The reagent cost per H 2 S test pair was only US$ 0.41 per 100 mL test (Table S2, Figure 1(a)). The larger volume, 5 mL of media compared to 2.5 mL, produced a more distinct black colour when positive.

Test validation in the laboratory
Efficacy studies in the laboratory determined the limit of detection for spiked S. enterica to be 5 bacteria/100 mL for 100 mL bottles and 20 bacteria/100 mL for 5 mL bottles.
The optimal incubation time at ambient temperature was 24 h, for distinct colour change (Figure 1 and Figure S1).
From the laboratory S. enterica spiking results in three risk categories were developed: low, medium and high ( Figure 2 and Table S3). If both tests (100 mL and 5 mL) were negative, the limit of detection values estimate that less than 20 H 2 S producing bacteria were present per 100 mL of water sample (Table S4). This was determined as low risk. When the 100 mL test was positive and the 5 mL test negative then there is an estimated range of greater than 20 bacteria but less than 100 bacteria/100 mL, thus medium risk category. A high risk category was estimated when both bottles were positive, with an estimated density of greater than 100 bacteria/100 mL. (Tables S3 and S4 are available  between the H 2 S risk categories and log 10 E. coli densities. Non-linear regression described the relationship with log 10 E. coli with a hyperbolic function but goodness of fit was low (R 2 ¼ 0.51). The low risk category detected E. coli densities from 0 to 9 cfu/100 mL, which would be considered low risk by WHO standards. The high risk category also consistently detected concentrations of E. coli that would be considered a risk, 50 to 7.2 × 10 5 cfu/100 mL. However, the moderate risk category was more variable detecting between 3.5 and 1.0 × 10 3 cfu/100 mL.
Overall, the H 2 S test accurately described the risk for the water sources, both with respect to the type of water source (improved and unimproved) and the corresponding E. coli densities.

Test validation in the community
In total, 16 households successfully completed the H 2 S training and conducted the tests independently. There was an even gender representation. All participants had a positive H 2 S sample for at least one of their chosen water sources, as the majority (11 households) primary sources were unimproved, unprotected dug wells. All the bottled water controls were negative, indicating that there was no contamination introduced due to incorrect technique during testing. Community members were easily able to identify the positive black colour change for the H 2 S tests (Figure 1(c)) from water  sources that were faecally contaminated, such as shallow open wells. The risk recommendations were translated into kiSwahili and clearly understood and interpreted by community members. All households indicated that the results changed their opinion about their water quality and that they would be willing to purchase the H 2 S test in the future.

Development and marketing of H 2 S tests
The H 2 S test kit was produced for US$ 1.10 (Table S7, available online). The retail sale price was set at US$ 1.37 (TZS 3,000) and the wholesale price at US$ 1.25 (TZS 2,500).
This was consistent with the price bracket indicated in the initial community trial.

An eight-page instruction booklet was produced in both
English and kiSwahili. The booklet covered the risk of contaminated water, how to use the H2S test (Figure 3), how to conduct a sanitary survey and how to treat water in the household.
Out of the 713 tests distributed for sale, the majority (300 tests) were sold by other NGOs in Tanzania (Table S8, available online). The sales by local pharmacies were less than had been expected. This was potentially due to the fact that the tests are a new product. This result highlights that more marketing and support to the points of sale was needed.
In total, 31 customers (22 male and nine female) were contacted and surveyed after purchasing and using the test themselves. The majority (22 people) bought the test out of curiosity and the remainder out of concern for their water quality (nine people). Nearly all (30 people) reported that the test results had motivated them to start using household water treatment. Further, all customers surveyed reported that they successfully conducted the test independently and all but one said they would purchase the test again in the future.

Inclusion of H 2 S tests in a WaSH education programme
The use of H 2 S tests was evaluated through 165 meetings with 3,408 participants (Table S4). In the education meetings that demonstrated the H 2 S test, the majority of participants (77%) returned the next day to view the test results (Table S9). The majority of water sources tested were dug-wells (48%). Most of the H 2 S test water quality results were in the high to very high range (62%), indicating the overall poor water quality present (Table S10). (Tables   S9 and S10 are available online.) To determine the impact of the H 2 S inclusion in the education programme, a follow-up survey was asked of 175 participants in the H 2 S education programme and 119 in Figure 3 | A two-page exert from the instruction booklet for the H 2 S test kit detailing how to conduct the water quality test. The final risk level is based on the degree of colour change from yellow to black. The booklet that was included in the H 2 S test kit for sale was produced in the local language, kiSwahili. the standard education programme (Table 1). Overall, the participant responses were very similar between the education groups. The only variation to this was the response to if they had improved their latrine since the education, where improvement was generally increasing cleanliness or adding a cover over the drop hole. For the H 2 S group, only 48 of the participants (29%) had improved compared to 41 participants (43%) for the standard education, however this difference was not significant (p ¼ 0.06). Both WaSH education programmes increased the number of participants who reported that their water was not safe to drink.
For the H 2 S group the percentage was comparable (33 people, 20.1%) to the standard group (14 people, 15.4%), with no significant difference (p ¼ 0.87). Consequently, there was an increase in the proportion of participants who reported treating their drinking water prior to drinking.
The increase was comparable between groups, with the H 2 S test group increasing by 24.4% (40 people) and the standard group by 24.5% (23 people). For the remainder of the questions there were minimal differences between the groups.
The loss to follow-up of 31 participants (26%) in the standard education group reduced the ability to detect some of the changes between groups.
In the pre-survey, all of the H 2 S education group (175 respondents), reported that they would like to have their water tested to gauge its safety. When asked how much they would pay for a water quality test, the majority 58% selected the lower price of US$ 0.45, with the remainder willing to pay US$ 1.37 or greater for the test. In the posteducation survey, nearly all (94%, 154 respondents) reported that that they would buy the H 2 S test in the future.

Validation in the laboratory and community
The H 2 S was successfully produced for the first time in rural Tanzania in a simple laboratory setting using easily sourced   The pre-survey was conducted before WaSH education and post-survey was conducted after the WaSH education. The Chi-squared (χ 2 ) test (with 1 degree of freedom) compares the post-survey response percentages between both WaSH education groups. c The probability (p) is recorded with significance set at p 0.05.
bottles. Restrictions for other organisations to make the tests are the requirement for some basic equipment and knowledge of sterile handling; although successful production of the tests using a simple cooking oven (for sterilisation of strips at 55 C until dry) has been well described (Mosley & Sharp ).

CONCLUSIONS
The H 2 S test has proven to be an affordable, locally producible water quality test in rural Tanzania. Further, it is an empowering tool in WaSH education programmes. The H 2 S test should be advocated for inclusion in international guidelines as a preliminary water quality test at household level and in community WaSH education programmes.
Tools such as this are critical so that communities can be informed of their water quality and takes steps to improve household WaSH practices, which will ultimately reduce illness and protect environmental water sources.