The great challenge for the sustainable use of excreta (urine, faeces) in agriculture is to increase the benefits of these products as resources and decrease the negative effects on human health. The risk of gastrointestinal diseases associated with the use of human excreta as natural fertilisers is well established, while information on skin problems remains largely anecdotal. The objective of this study was to evaluate the prevalence of skin problems among people involved in the handling of the urine used as fertiliser along a productive sanitation system in Ouagadougou periurban areas. A questionnaire was used for each targeted worker to collect data on sociodemographic characteristics, conditions of work and reported health symptoms such as skin burning, itching, eye irritation and paronychia. The exposure measurements were essentially based on field observations. A total of 435 people were interviewed, including 45 workers in urine storage sites, 209 farmers using urine-based fertiliser and 181 control farmers. More than 35% of site workers reported skin symptoms. For farmers using urine-based fertiliser and their controls, 17.2% and 26.0% reported skin symptoms, respectively. Overall, the associations between skin symptoms and the handling of urine used as fertiliser were almost significant ( P < 0.06). Also, the study showed that these skin symptoms reported by the urine handlers are associated with conditions of work. Effective preventive measures such as wearing suitable protective equipment and practicing good personal hygiene should be emphasized. This topic needs to be further examined using longitudinal studies.
In order to decrease reliance on chemical fertilisers, human excreta (urine, faeces) are used in agriculture around the world [
Human health risks associated with the use of wastewater and excreta in agriculture have been well shown [
Also, farmers and workers involved in handling activities (e.g. cleaners) often complain about skin problems caused by various irritants and allergens, including sun [
The skin is a considerable interface between man and his environment [
In Burkina Faso, the incidence of skin diseases associated with exposure to wastewater and agricultural inputs (fertilisers and pesticides) is not known. This incidence is probably high for the following reasons: 1) The presence in irrigated water of some hazardous agents [
Ammonia is used to produce chemical fertilisers. It also helps to preserve stored fruits [
This study was conducted among handlers of the urine used as fertiliser in Ouagadougou periurban areas, Burkina Faso. The main objective was to evaluate the prevalence of skin problems reported by people involved in the urine handling along a productive sanitation system.
The study was conducted in Ouagadougou periurban areas, where a large scale project in productive sanitation was implemented. For a period of three years (2006-2009), the project has equipped around 1000 households with eco-toilets (Urine Diversion Dry Toilets, UDDT). In each sector covered by the project, a productive sanitation system was set up, in which excreta is collected separately via UDDT and are transported and stored on a site before the use as fertilisers in the field. Urine was stored in jerry cans (20 L) and tanks (1000 L).
Each filled container was closed for at least 30 days. On average, 600 jerry cans and 15 tanks per site were used to manage the urine stocks. Our study was limited to two sites and conducted for a period of 11 months (February 2011-January 2012). Parameters of interest (pH, ammonia, heavy metals, E. coli, S. aureus, Enterococcus sp.) in urine from the studied sanitation system have been previously measured [
Two groups of workers along productive sanitation systems were targeted: 1) Handlers of the urine in storage sites, in which the main tasks were collection and transportation of the urine from households to storage sites, and the decanting, cleaning and maintenance of containers; and 2) Farmers using urine-based fertiliser. A con- trol group was integrated in this study, including non-urine using farmers, working in the same conditions as the others. All participants in this study were volunteers.
The survey on skin problems among targeted groups was preceded by the field visits in order to report the work conditions of people. To do this, forms were filled out at each visit, indicating observations concerning the hygiene practices in urine storage sites, the quality of irrigation water, and the protective measures taken during the urine handling. Data from field visits guided us to formulate relevant items for a questionnaire, which were individually administered at the workplace. The interviews were conducted face-to-face with investigators. The questionnaire was comprised of three parts: 1) The first part consists of items to collect sociodemographic characteristics of respondents; 2) The second part includes items relating to the environment and work conditions. These are the questions to find out what activities the person did, frequency of the urine handling, and about protective equipment used when working; and 3) The third part, which includes items relating to recent and/or current skin problems self-reported for the duration of work. Skin burning, itching, eye irritation and paronychia were the health symptoms examined. The location of these symptoms was also required to respondents.
Statistical analysis of data was performed using the STATA V12.1 (Stata Corp 4905 Lakeway Drive, Texas, USA) software. The variables were analyzed by Chi-square test or Fisher’s exact test. A P-value less than 0.05 was considered statistically significant.
In total, 435 people responded to the questionnaire, including forty-five (45) site urine handlers, two hundred and nine (209) farmers using urine-based fertiliser and one hundred eighty-one (181) as control farmers. The so- ciodemographic characteristics of the respondents are presented in
The average age of respondents was about 38 years. Male interviews predominated, with 60% and 80% for site workers and farmers respectively. The majority of those interviewed people had a low level of education (primary or uneducated). Among field workers, truck farmers were the most numerous (97%), followed by flo- wer growers (3%). For the duration of work, 53% of site urine handlers had more than 3 years and 20% had one year or less. About 87% of farmers had more than 3 years in working.
More than 35% of site urine handlers have reported skin symptoms (
In farmers, handling and non handling (control) the urine, the percentage of reported skin symptoms were 17.2% and 26.0% respectively (
Personal characteristics | Site urine handlers n = 45 | Urine handling farmers n = 209 | Control farmers n = 181 |
---|---|---|---|
Age (year) | |||
Meanδ (SD) | 37.1 (12.6) | 39.9 (9.0) | 38.6 (11.9) |
Age groups | |||
<21 n (%) | 5 (11.1) | 7 (3.3) | 22 (12.1) |
21 - 49 n (%) | 30 (66.6) | 163 (77.9) | 115 (63.5) |
>49 n (%) | 10 (22.2) | 39 (18.6) | 44 (24.3) |
Sex | |||
Male n (%) | 27 (60) | 193 (92.3) | 127 (70.1) |
Female n (%) | 18 (40) | 16 (7.6) | 54 (29.8) |
Educational level | |||
High school n (%) | 0 (0) | 1 (0.5) | 0 (0) |
Secondary school n (%) | 10 (22.2) | 25 (11.9) | 17 (9.4) |
Primary school n (%) | 20 (44.4) | 73 (34.9) | 29 (16.0) |
Uneducated n (%) | 15 (33.3) | 110 (52.6) | 135 (74.5) |
Farming type | |||
Horticultural n (%) | / | 206 (98.5) | 173 (95.5) |
Ornamental n (%) | / | 3 (1.4) | 8 (4.5) |
Duration of work (year) | |||
<1 n (%) | 9 (20) | 6 (2.8) | 6 (3.3) |
1 - 3 n (%) | 12 (26.6) | 11 (5.3) | 25 (13.8) |
>3 n (%) | 24 (53.3) | 192 (91.8) | 150 (82.8) |
δValues given as mean (SD).
Symptoms | Site urine handlers n = 45 | Urine handling farmers n = 209 | Control farmers n = 181 |
---|---|---|---|
n (%) | n (%) | n (%) | |
Overall | 16 (35.5) | 36 (17.2) | 47 (26.0) |
Burning | 4 (8.8) | 10 (4.8) | 14 (7.7) |
Itching | 10 (22.2) | 14 (6.7) | 8 (4.4) |
Paronychia | 0 (0) | 12 (5.7) | 25 (13.8) |
Eye irritation | 2 (4.4) | 0 (0) | 0 (0) |
In
Variables | Skin burning | Itching | Eye irritation |
---|---|---|---|
% | % | % | |
Duration of work (year)† | |||
<1 | 50 | 30 | 0 |
1 - 3 | 25 | 40 | 0 |
>3 | 25 | 30 | 100 |
Frequency in urine handling† | |||
≥Twice per week | 75 | 60 | 100 |
£Twice per week | 25 | 40 | 0 |
Personal protective equipment | |||
Yes | 100 | 90 | 100 |
No | 0 | 10 | 0 |
Location of skin symptoms | |||
Hand | 37.5 | 25 | 0 |
Forearm | 37.5 | 50 | 0 |
Foot | 25 | 0 | 0 |
Other | 0 | 25 | 100 |
†P = 0.06.
By handling the urine on storage site, with a frequency of more than twice per week, had given incidence rates of 75%, 60% and 100% respectively for skin burning, itching and eye irritation (
In
In farmers handling urine-based fertiliser which reported skin symptoms (26 among 209 in total), about 85% had at least two years in the work. For these farmers, the frequency of handling urine averaged once per week. More than half of farmers (59%) did not use a personal protective equipment (
In this study, we evaluated the possible links between skin problems and the handling of urine among people
Variables | Skin burning | Itching | Paronychia |
---|---|---|---|
% | % | % | |
Duration of work (year)† | |||
<1 | 10 | 0 | 8.3 |
1 - 3 | 30 | 40 | 25 |
>3 | 60 | 60 | 66.7 |
Frequency in urine handling† | |||
≥Twice per week | 0 | 0 | 0 |
£Twice per week | 100 | 100 | 100 |
Personal protective equipment | |||
Yes | 50 | 29 | 41.7 |
No | 50 | 71 | 58.3 |
Farming type | |||
Horticultural | 100 | 100 | 83.3 |
Ornamental | 0 | 0 | 16.7 |
Location of skin symptoms | |||
Hand | 36.3 | 35.7 | 100 |
Forearm | 27.2 | 50 | 0 |
Foot | 36.3 | 14.3 | 0 |
Other | 0 | 0 | 0 |
†P = 0.06.
involved within productive sanitation systems in Ouagadougou periurban areas. The health symptoms examined were essentially skin burning, itching, eye irritation and paronychia, which can be caused by various agents potentially existing in the work environment. Exposure measurements were based mainly on observations made at any moment by the urine handlers on the workplace (storage site and farm field). We also considered as indicators of risk, data from a previous study on the characterization of chemical (pH, ammonia, heavy metals) and bacteriological (E. coli, S. aureus, Enterococcus sp.) parameters in the urine of the studied sanitation system [
Overall, the results of this study indicate skin symptoms reported by respondents were associated with the work they do. The prevalence of skin problems in the urine site urine handlers was almost the double of that found in farmers handling urine-based fertiliser (
We observed that farmers not handling urine-based fertiliser also reported skin symptoms. Further investiga- tions on the risks faced by farmers in the fields are needed. It is likely that the causes of skin diseases among farmworkers are many. However, some studies suggested that exposure to chemical inputs, e.g. pesticides and fertilisers [
In addition, we observed significant associations between examined skin symptoms and work conditions, particularly the frequency of the urine handling and the duration of work (
Previous studies have shown that the handling of products with high alkalinity (pH ˃ 12), exposed people to the risk of skin burning [
Other associations found in this study are difficult to explain. This is the case of the connection between the occurrence of a paronychia and exposure to the urine-based fertiliser, in the sense that the causative agent is often carried by the subject himself [
Few limits to this study can be mentioned. First, respondents were asked to recall the experienced skin symp- toms, since the beginning of their work. It is possible that subjective responses have been provided by the sur- veyed population. In order to minimize these errors due to oversight, Vallejos and et al. [
Having a better understanding of factors associated with the occurrence of skin problems can help in efforts to prevent and to treat [
This study suggests the existence of associations between health symptoms such as skin burning, itching, eye irritation and the handling of the urine used as fertiliser. The harmful effect of ammonia on the skin seems predominant compared to other measurable parameters in the handled urine. However, skin symptoms examined in this study could not be exclusively attributed to the urine exposure; other factors inherent to the workplace can be implicated. Based on the data obtained, it is necessary that people involved in the handling of the urine used as fertiliser, have to maintain personal good hygiene practices and wear protective equipment while working to reduce the health risks. In order to make our data more incisive and better explore the topic, additional studies are needed. For example, longitudinal studies by monitoring regularly some parameters (e.g. diagnosis, severity and duration of health symptoms) within cohorts, should better assess the effects of ailments due to some expo- sure. Thus, data from such studies can guide health policy makers, especially in the agricultural sector where the effects associated with exposure to chemical inputs are not well established.
The authors acknowledge the collaboration of the managers of excreta storage sites along productive sanitation systems in Ouagadougou. Furthermore, we wish to give our special thanks to Dr. Marylise Mbakop for the help in the preparation of this study. Finally, we are grateful to the International Foundation for Science (IFS) for the funding source.