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Ecological Economics 68 (2009) 28002807
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Impact of irrigation water quality on human health: A case study in India
Jeena T. Srinivasan a,, V. Ratna Reddy b
a RULNR, Centre for Economic and Social Studies, Nizamiah Observatory Campus, Begumpet, Hyderabad 500016, Indiab Livelihoods and Natural Resources Management Institute, H. No. 12-2-417/18, Sarada Nagar, Mehdipatnam, Hyderabad 500067, India
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0921-8009/$ see front matter 2009 Elsevier B.V. Adoi:10.1016/j.ecolecon.2009.04.019
a b s t r a c ta r t i c l e i n f o
Article history:Received 14 November 2008Received in revised form 23 April 2009Accepted 25 April 2009Available online 15 May 2009
Keywords:Wastewater irrigationMorbidityCost of illnessHyderabadIndia
Untreated or partially treated wastewater, which is a negative externality of urban water use, is widely usedfor irrigation in water scarce regions in several countries including India. While the nutrients contained in thewastewater is considered as beneficial to agriculture, the contaminants present in it pose environmental andhealth risks. This paper examines the morbidity status, its determinants as well as the cost of illness forhouseholds living in the areas irrigated with wastewater in comparison with those using normal qualitywater. Primary data collected from six villages irrigated with wastewater along Musi River which is fed withwastewater and one control village where normal quality water is used for irrigation has been used for theanalysis.It is seen that higher rates of morbidity exist in the wastewater irrigated villages when compared to thecontrol village. Specifically, adult and female morbidity rates are significantly higher than child and malemorbidity rates. From the logit analysis it is seen that exposure to wastewater and engagement in activitiesbased on it places the households in higher risk groups to report morbidity. Small and marginal farmers incurhigher economic cost of illness. However, it has been difficult to ascertain the cause and effect relationship asmost of the households have reported more common illnesses like fever, head ache, skin itching, stomachailments, etc. The study points out the need for a comprehensive risk assessment and adoption of riskmanagement measures including setting standards for treatment and discharge of wastewater andregulations on the type of uses etc. to prevent unplanned use of untreated or partially treated wastewaterwhile taking into account local conditions.
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Increasing scarcity of freshwater resources is driving manycountries in the arid and semi arid regions to use marginal qualitywater for agriculture and related activities. Marginal quality water orwater whose quality might pose a threat to sustainable agricultureand/or human health if used for irrigation without taking certainprecautions is of two types. They arewastewater from urban and peri-urban areas and saline and sodic agricultural drainage water andgroundwater (Cornish et al., 1999 quoted in van der Hoek et al., 2002;Qadir et al., 2007). Unlike saline and sodic water which contains saltsthat impair plant growth, wastewater comprises of both domesticsewage and industrial effluents. It therefore contains a variety ofpollutants including pathogens and heavy metals which can poten-tially harm environment as well as human and animal health. Thewastewater is, however, used for irrigation in water scarce regions indifferent parts of the world including countries from Asia, Europe,South America and the United States of America (van der Hoek, 2004).Globally around 20 million ha land is reported to be irrigated with
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wastewater and at least 10% of the world's population is thought toconsume foods produced by irrigation with wastewater (Hamilton etal., 2007; WHO, 2006a,b).
The supply of water to the city ensures the supply of wastewaterbecause the depleted fraction of domestic and residential water use istypically only 1525% with the remainder returning as wastewater(Scott et al., 2004). In a semi-arid area, a city of 1million people wouldproduce enough water to irrigate approximately 15003500 ha(WHO, 2006a). Irrigation with wastewater is said to have bothbeneficial and harmful effects (Chen et al., 2005; Singh et al., 2004).WHO (2006a) reports that at an irrigation rate of 1.5 m3 of irrigationwater per m2 of field area per year in a typical semi arid climate,treatedmunicipal wastewater can supply 225 kg of nitrogen and 45 kgof phosphorous per hectare per year which reduces or eliminates theneed for supplementary fertilization needs. However, excessiveaccumulation of contaminants like heavy metals in soils lead toelevated heavy metal uptake by crops and thus affect food quality andsafety (Muchuweti et al., 2006). Consumption of food cropscontaminated with heavy metals is one of the important pathwaysfor intake of toxic substances into the human body of which somebecome apparent only after several years of exposure (Bahemuka andMubofu, 1999; Ikeda et al., 2000). This apart, the microbial quality ofwastewater also poses a major threat to the health of those who are
2801J.T. Srinivasan, V.R. Reddy / Ecological Economics 68 (2009) 28002807
directly as well as indirectly exposed to it, of which, the greatestconcern are pathogenic viruses, bacteria, protozoa, and helminths. Asis evident from Section 2, a study on the health effects of wastewaterirrigation on theworkers and others is complex, as awhole lot of socioeconomic as well as hygienic and behavioural aspects also influencetheir health conditions. This is especially true in developing countrieslike India where wastewater use is mostly unplanned and unregu-lated. Over all, the health impacts of poor water quality translate intohigh morbidity and mortality rates, malnutrition, reduced lifeexpectancy, etc followed by high economic cost of illness.
Against this background, the major objective of the paper is toassess the morbidity status of the households living in the wastewaterirrigated villages in the peri urban areas of Hyderabad city in India incomparison with those who use normal quality water for irrigation.The study further identifies the determinants of morbidity and as wellestimates the economic cost of illness for the households in the studyarea. Primary data at the household levels have been collected fromsix villages irrigating with wastewater in the peri urban areas ofHyderabad and one village using normal quality water for irrigation.Overall, the study points out to the prevalence of higher morbidityrates among the households in wastewater irrigated villages. It isidentified that the type and extent of exposure to wastewater eitherdirectly or indirectly are important determinants of morbidity.Therefore, the study highlights the need for further research toexplore the dose response relationships so that appropriate riskmanagement strategies to prevent exposures to pathogens and toxicchemicals by a combination of measures such as wastewatertreatment, produce restriction, methods of application and otherexposure control methods etc can be adopted to minimise the healthrisks of wastewater irrigation while utilising its benefits, especially inthe dry water scarce regions.
2. Wastewater irrigation and health risks: an overview
In this section, we present a brief overview of types of wastewaterirrigation and health risks. Asano (1998) identifies three types ofirrigation use of wastewater. They are (1) direct use of untreatedwater (2) direct use of treated wastewater and (3) indirect use ofwastewater. The application of wastewater to land directly from asewerage system or other purpose-built wastewater conveyance isgenerally referred to as the direct use of untreated wastewater. Thistype of use exists in countries like Pakistan and Kenya. On the otherhand, the direct use of treated wastewater is where control exists overthe conveyance of the wastewater from the point of discharge to atreatment plant and to a controlled area where it is used for irrigation.Many countries in Middle East, which makes use of wastewaterstabilization ponds to remove pathogens, widely adopt this method.Indirect use happens when municipal and industrial wastewater isdischarged without treatment or monitoring into the watercoursesdraining an urban area from where farmers draw water for irrigationlike in the case of Musi River in Hyderabad in India which has becomea de facto sewer.
Contamination of soils and crops due to wastewater irrigation arewidely reported from different parts of the world. It has been reportedthat 45% of wastewater irrigated areas in China are contaminated withheavymetals at themost serious level. Not only in China, this has been aproblem in several other countries like Germany, France and India aswell (Ingwersen and Streck, 2006; Dere et al., 2006; Singh and Kumar,2006). The chemical contaminants like cadmium and lead aresequestered in the soils and its uptakebycrops serve as the transmissionroute in the human chain (Jeyabaskaran and Sree Ramulu, 1996;Mendoza et al 1996; Mitra and Gupta 1999). Evidence of heavy metaltransmission through milk produced by cattle fed with wastewaterirrigated fodder is reported in South Asia where per capita milkconsumption is the highest in the developingworld (Delgado et al 1999;Swarup et al 1997). The con