Reaping bitter fruit

‘REAPING BITTER FRUIT?’ Agricultural Intensification and Farmers’ Health in the Mekong Delta NGUYEN HUU DUNG and MAX SPOOR ABSTRACT This paper analyses the impact of highly input intensive rice production in the Mekong Delta (MKD) of Vietnam on farmers’ health. This is done by using two household surveys that were undertaken with a four-year period in between (1997 and 2001), covering a similar area in the MKD, and including a sub-set of the households being present in both surveys, which provided good insights in dynamic changes of particularly fertilizer and pesticide use. Impact on health is measured through the use of health cost model. While the use of chemical inputs per hectares diminished during the period, double and triple cropping increased, hence total use still rose. With the introduction of integrated pest management (IPM), indeed a shift can be measured towards a more sustainable use of chemical inputs, while also more awareness has grown with farmers on the possible health impairments of toxic substances, with beneficial impact. INTRODUCTION In the Mekong Delta of Vietnam, the ‘rice basket’ of the country, intensification of rice production, through the increased use of chemical fertilizer and pesticides, improved seeds, and a movement towards of 2-3 rice crops per year, in some cases even in combination with one dryland crop, has provoked substantial increases in land productivity and overall output. The tendency in rice prices over the past decade has been negative, but the mentioned increase in yields has made that rice farmers saw their incomes increase. However, the intensification of rice production relies heavily on HYVs and agrochemicals, the application of which has also caused negative effects to human health. In the study, which covers a four-year period between 1997 and 2001, there was a 25 percent reduction in the use of pesticides per hectare/crop, while rice production was maintained or somewhat higher, which contributed to lower input costs. However, insecticides, fungicides and herbicides are neither entirely used by the rice crop, nor are they retained within the rice fields, but they leave the system as liquid leakages, surface runoff, spray drift, and gases. The emission of pesticides through the application on the fields, unfortunately poses potential risks to human health (both applicators and consumers), beneficial organisms, groundwater, and ecosystem integrity. These effects pose a significant cost to society and to individual rice farmers, affecting the long-term sustainability of rice production. In general, there are two possible routes of exposure of humans and wildlife to pesticides: a) to be directly exposed after spraying/granulate treatment via spray drift and gases; b) to be indirectly exposed via (residues in) food derived from crops on which pesticides are applied directly, and through drinking water originating from ground/surface water. In this paper we will focus on the first, direct effects on farmer’s health. Results of exposure to pesticides and associated effects are combined to estimate the risk to farmers’ health by using health risk models. The analysis begins with a statistical description of the direct exposure to pesticides of farmers, and the pesticide- related health effects reported by the respondents (interviewed farmers) in the study areas. These effects include both acute pesticide poisoning symptoms and chronic conditions that could be related to pesticide exposure. As a the second step, a conservative estimate of pesticide related health cost is calculated to give a lower bound estimate of the true value of reducing illness, using a health cost model. The study sites in the two surveys, 1996/97 and 2000/01 are located in the Mekong Delta of Vietnam. The 1996/97 survey we covered 6 villages in 5 districts of 4 provinces, and the 2000/01survey was conducted in 6 villages of 6 districts of the same provinces as in the 1996/1997 survey. The districts are located along the Mekong River, 120 kilometres to the west of Ho Chi Minh city, between the area near the border with Cambodia and the city of Can Tho. These areas are varied in production environment (access to irrigation system, soil fertility) and in agrochemicals application per hectare. The patterns of agrochemicals use are studied by comparing all households across the two surveys. This has been made possible as there was a group of 76 households in 4 villages which were present in both surveys, making comparisons through time possible. These 76 households provided rather complete information and are denoted as the ‘same households group’ (SHH group), which is distinct from all farm households included in the surveys, which is a substantially larger group. As in the study areas Integrated Pest Management (IPM) methods were being introduced, and during the 4-year period more farmers started implementing these, the data also distinguished between IMP and non- IPM farm households in a dynamic manner. In conclusion we show that the intensification of rice production as pursued in the Mekong Delta, and more in particular in the study sites, has had serious health impairments, which pose a significant cost to society and to rice farm households, affecting the long-term sustainability of rice production. 2 EFFECTS OF PESTICIDES ON THE ENVIRONMENT The risk of adverse health effects is a function of pesticide toxicity and exposure to pesticides during application. Pesticide toxicity refers to the ability to cause injury or illness. It can either be acute, causing illness that develops soon after exposure, or chronic, causing illness that develops over a long time after exposure. Chronic effects of pesticide poisoning are often irreversible, and may include reduced body weight, anaemia, kidney disorders, central nervous system disorders and cardiovascular disorders. A pesticide with high acute toxicity can be very hazardous to health, even when a very small amount is absorbed. However, in Vietnam there is neither monitoring of the health impact of pesticide use, nor are there adequate statistics available at either a local or national level in Vietnam. Frequency of pesticide application The threat to health from exposure to pesticides may also result from a frequent contact with pesticides belonging to hazardous categories. The frequency of pesticide application refers to the number of sprayings, or other forms of dissemination of pesticides during the growing season, and is an important indicator to understanding the level of pesticide exposure. Farmers decide how many times pesticides should be applied, depending on the pest conditions for the purpose of prevention, suppression or eradication of pests. Eradication of pests in open rice fields is difficult, since pests like insects, fungus, and bacteria can move from one field to surrounding ones. Therefore, most pesticide applications are to keep a pest from becoming a problem, reduce the size of a pest or hold the damage at an acceptable level. Table 1 shows that the average number of pesticide application increased from 3.71 in 1996/97 WS season to 4.06 in 2000/01 WS season, which is statistically significant at 5% level. Farmers typically applied one time herbicides, one time insecticides, and two times fungicides (PPD, 1999). All farmers sprayed fungicides at least one time to prevent their rice crops from disease, whether there were symptoms of disease or not. Although the situation varies from case to case, many factors have contributed to the relative increase in fungicide use. Numerous advertisements of fungicides have been daily broadcast via television and radio. Relatively low prices, increased marketing activities of pesticide companies and retailers, also influence farmers’ perception and serving as guidance and promotion of the use of fungicides. Table 1 Mean values of frequency of pesticides applications per crop (times per crop) Pesticides types 1996/97 WS season 2000/01 WS season t-test Non-IPM farmers (N=166) All pesticides 3.72 (1-9) 4.15 (1-7) -1.83* Categories I and II 2.70 (0-8) 1.91 (0-5) 2.75*** Categories III and IV 2.60 (1-7) 3.60 (1-7) -3.26*** IPM farmers (N=170) All pesticides 3.69 (1-8) 4.02 (1-7) -1.69* Categories I and II 2.16 (1-7) 1.75 (0-5) 1.82* Categories III and IV 2.76 (1-6) 3.50 (0-6) -2.85*** All farmers (N=336) All pesticides 3.71 (1-9) 4.06 (1-7) -2.47** Categories I and II 2.53 (0-8) 1.80 (0-5) 4.34*** Categories III and IV 2.65 (1-7) 3.53 (0-7) -4.76*** Source: 1996/97 and 2000/01 surveys In the MKD, farmers decreased their frequency of insecticides application but raised that of herbicides or fungicides spraying due to demand of their rice fields. Findings from the study of Heong et al. (1995) showed that the reduction of the number of insecticide sprays was due to farmers having stopped early season spraying for leaf-folders. According to one study, the mean number of insecticide sprays per farmer per season in fact reduced significantly from 3.4 in 1992 to 1.0 in 1997 (Huan et al., 1999). Though our surveys and the 1999 PPD survey were not conducted at the same time, location and growing season, findings on the frequency of pesticide applications in rice production seem compatible. Thus, we estimate that the results are reasonably representative for the current practices of pesticide applications of rice farmers in the MKD and indicating a change in farmers’ perception of pesticide application, especially in insecticide sprayings. Another point worth mentioning is that farmers often applied more than one pesticide in an application, especially for fungicides. In other words, farmers were exposed to more hazardous pesticides in one application. Therefore, the total number of times getting in touch with pesticide hazardous categories is somewhat different from the number of applications of pesticides. The frequencies of exposure to pesticide categories I and II (NA1) and pesticide categories III and IV (NA2) were defined as the number of times that farmers had contact with a certain kind of pesticide. Therefore, each farmer could be exposed to more than one type of pesticide during one application. This means that the sum of NA1 and NA2 would be at least equal to or larger than the number of applications per season. This separation was expected to more explicitly reflect the impact of pesticide on farmers’ health impairments. A ‘vertical’ comparison between seasons shows a substantial change in the application of pesticides categories. Data in Table 1 show that during a four-year period, surveyed farmers reduced the frequency of application of pesticides in categories I and II from 2.53 to 1.80 times per crop, but raised that of pesticides in categories III and IV from 2.65 to 3.53 times per crop. All these changes are statistically significant (‘all farmers’). IPM farmers through participation in Farmer Field Schools, training courses, or the use of experimental fields have partly changed their perception on insecticide sprayings, thereby helped to reduce the overall number of applications. Within one season, the average frequencies of total pesticides application and pesticides categories NA1 and NA2, applied by IPM farmers were lower than those by non-IPM farmers, except for the application of NA2 in 1996/97 WS season. However, the differences were not statistically significant (See Annex Table 2), except for the frequency of pesticide categories NA1 applied in 1996/97 WS season. Though the average number of pesticide application per crop of IPM farmers was lower than that of non-IPM farmers, data in Table 2 show that both groups increased the number of pesticide applications during a four-year period. In 2000/01 WS season, about 46.8% (all households) to 54.5% (SHH group) percent of non-IPM farmers group respectively sprayed from and more than 5 times per season, while only around 34.8% (all households) to 33.3% (SHH group) percent of IPM farmers sprayed at those levels. In a survey of PPD (1999), IPM farmers also had a lower number of pesticide applications than that of non-IPM farmers. In addition, farmers with higher education tended to reduce the number of pesticides application, implying that those farmers had better access to IPM practices and innovation (Annex Tables 1). How farmers’ health related to this pesticide exposure characteristics is examined in the second section of this paper. Table 2 Frequency of pesticides applications in rice production of surveyed households (Share of farm households) Frequency 1996/97 WS season 2000/01 WS season (Times/crop) Non-IPM IPM All Non-IPM IPM All All farm households 0-2 19.3 15.5 18.1 19.1 12.5 14.5 3-4 57.1 67.2 60.5 34.0 52.7 47.2 >=5 23.5 17.2 21.5 46.8 34.8 38.4 SHH-group 0-2 19.1 20.7 19.7 13.6 13.0 13.2 3-4 57.4 72.4 63.2 31.8 53.7 47.4 >=5 23.4 6.9 17.1 54.5 33.3 39.5 Source: 1996/97 and 2000/01 surveys Farmers’ perception on the effects of pesticide to personal health The perception that long term use of pesticides can contribute to health ailments was relatively common amongst the respondents. During the two surveys, most of the farmers interviewed said that their spouses, children and other family members participated in rice growing. Field activities include planting, weeding, applying fertilizer, spraying pesticides and harvesting of rice crops. However, no farmer reported that they allowed their children (not in labour force) and women to directly apply the pesticides. Some children could participate in pesticide application in terms of helping to bring pesticide product bottles/boxes, sprayers, and water supply for applicators. Though pesticide drifts and pesticide are diluted in the water of rice fields, they may cause indirect effects to women workers and children during weeding. Almost all the farmers interviewed (Table 3) believed that pesticides could have some bad effects on their health. The more experienced farmers thought that pesticides had a stronger negative effect on health, compared to those farmers who had been using pesticides for a shorter time. Data in Table 3 show how low or high farmers in the two surveys rated the effect of pesticides on their health. In 1996/97 survey, 18.6% and 10.7% said the effects were ‘very much’ and ‘extremely large’, compared to 14.1% and 29.4% believing it was ‘very little’ or ‘little’ (respectively). 22.6% of farmers thought pesticide application affected much to their health. These respondents perceived that if they used pesticides for a long time it might cause their body to become weaker, reduce their life span, and other ‘unknown’ health problems. Approximately, 4.5% said that pesticides had ‘no effect’ on their health. These were predominantly the young ones who had recently begun rice growing, and did not perceive pesticide exposure as a health hazard because they had never experienced from ‘clear’ poisoning. In their perception, acute poisoning signs such as fatigue, headaches, and skin itching were normal and short- lived, and these signs normally disappeared after bathing. They said that the poisoning from spraying could happen more to an older applicators compared with a younger one, and to those with a weak physical condition. Table 3 Farmers’ perception of effects on health of prolonged pesticide use 1996/97 survey 2000/01 survey Measurement scale No. of farmers % of farmers No. of farmers % of farmers No effect 8 4.5 4 2.5 Very little effect 25 14.1 48.0 20 12.6 34.0 Little effect 52 29.4 30 18.9 Much effect 40 22.6 54 34.0 Very much effect 33 18.6 52.0 29 18.2 66.0 Extremely large effect 19 10.7 22 13.8 177 100.0 159 100.0 Source: 1996/97 and 2000/01 surveys In the 2000/01 survey, farmers were more aware of health hazards resulting from pesticide application. Only 2.5% of respondents said pesticides spraying had no effects on their health. From Table 3 its shows that 66% of the respondents considered that pesticides had much effect (or more) compared to 52% in the 1996/97 survey. This change in farmers’ perception seems to imply a significant improvement of farmers’ knowledge gained from activities of the national IPM program. Health impairment evidence from rice farmers Given the direct exposure to pesticides, farmers reported many visible symptoms of pesticide poisoning. Since signs or symptoms of pesticide poisoning can be confused with other health ailments (e.g., the flu, food poisoning etc.), the interviewers have given respondents a question to confirm that those symptoms appeared right after or within 24 hours after spraying. Therefore, reported symptoms in this study are those cases with ‘actually poisoned’ observations. Researchers often used visible health impairments as evidence of the effects of pesticide use on farmers’ health (Huang et al., 2001). Table 4 Farmers’ confirmation of pesticide poisoning symptoms after application 1996/97 survey (n=177) 2000/01 survey (n=159) Assessment scale No. of farmers* % farmers No. of farmers % farmers No opinion 3 2.3 4 4.6 May be 9 7.0 5 5.7 Sure 9 7.0 14 15.9 Very sure 85 65.9 90.7 56 63.6 89.8 Completely sure 23 17.8 9 10.2 No. respondents had symptoms 129 100.0 88 100.00 Source: 1996/97 and 2000/01 surveys Note: * based on respondents who got poisoning signs/symptoms only). In addition, medical research should be conducted to verify these and reflect invisible/chronic symptoms that accumulate in the human body. In this study, no medical tests were conducted, therefore visible health impairments here may be underestimated, but they are consistently being observed among farmers. Results of the 1996/97 and 2000/01 surveys show that farmers who directly applied pesticides experienced a host of complaints after spraying compared to how they felt before spraying. To identify reporting bias all respondents were asked if they believed pesticides could cause such health ailments. Respectively 90.7% and 89.8% of sample farmers in 1996/97 and 2000/01 surveys noted that they were sure of the poisoning symptoms, as these did not happen in other field activities (e.g. fertilizer application) (Table 4). Post-spraying symptoms such as blurred vision, body tremors, muscle fasciculation (eyelid twitching), skin itching and irritation, or even vomiting, were considered to happen due to pesticide exposure. Data in Table 4 show that 72.9% (129/177) and 55.3% (88/159) farmers have had experience with poisoning from pesticides in 1996/97 and 2000/01 seasons respectively. A lower rate of farmers that reported poisoning symptoms in 2000/01 WS season may be a result from a reduction of pesticide dose applied, better knowledge of safe use, and a shift from pesticides categories I and II to pesticides categories III and IV. However, it should be noted that each farmer can get simultaneously more than one acute poisoning symptom. Farmers reported during or shortly after applying pesticides symptoms to include headache, eye irritation, fatigue, shortness of breath, vomiting, skin irritation, coughing, diarrhoea, convulsion, and others (stomach cramps, body tremors, dry throat, chest pains, and dizziness) Signs and symptoms of pesticide poisoning reported by all farmers are presented in Table 5. Table 5 Signs and symptoms of pesticide poisoning reported by all farmers Sign/symptoms 1996/97 WS season 2000/01 WS season No. of farmers % farmers No. of farmers % farmers