Elsevier

Health & Place

Volume 15, Issue 3, September 2009, Pages 880-887
Health & Place

A relationship between environmental degradation and mental health in rural Western Australia

https://doi.org/10.1016/j.healthplace.2009.02.011Get rights and content

Abstract

Australia is currently experiencing a process of escalating ecosystem degradation. This landscape degradation is associated with many outcomes that may directly or indirectly impact on human health. This study used a Bayesian spatial method to examine the effects of environmental degradation (measured as dryland salinity) on the mental health of the resident rural population. An association was detected between dryland salinity and depression, indicating that environmental processes may be driving the degree of psychological ill-health in these populations.

Introduction

There have been very few studies examining the psychological effects of environmental degradation. The limited research has consistently found a positive correlation between environmental degradation and psychological distress (Sartore et al., 2008; Van Haaften and Van de Vijver, 1996a, Van Haaften and Van de Vijver, 1996b, Van Haaften and Van de Vijver, 1999, Van Haaften and Van de Vijver, 2003; Van Haaften et al., 2004). Furthermore, there is a strong association between many forms of psychological distress and the onset of depressive illness (Wheatley, 1994). Mental health problems associated with environmental degradation are not without precedent. Studies in Africa, Karakalpakstan and China found that such environmental processes were associated with higher levels of psychological distress (Crighton et al., 2003; Van Haaften and Van de Vijver, 1996a, Van Haaften and Van de Vijver, 1996b, Van Haaften and Van de Vijver, 1999, Van Haaften and Van de Vijver, 2003; Van Haaften et al., 2004).

Health effects of environmental change have been conceptualized along a continuum from sudden, immediate, traumatic physical and emotional impacts (such as the 2004 Indonesian earthquake and subsequent tsunami) to less acute processes (such as drought), which may be associated with gradual physical and psychological exhaustion (Cook et al., 2008; Were, 1989). Van Haaften and Van de Vijver (1999) noted that the rate of degradation was an important determinant of psychological distress.

This study examines the psychological impacts of dryland salinity in agricultural landscapes by using depression as an indicator of mental health. Dryland salinity is a slow form of degradation (depending on the soil type and level of the water table) and the manifestation of the degradation can vary from small changes in the pasture species, through to bare salt scalds (Beresford et al., 2001; Tille et al., 2001). Approximately 1 million hectares (5.5%) of the south-west agricultural zone of Western Australia is already affected by dryland salinity and this is predicted to rise to 5.4 million hectares by 2050 (NLWRA, 2001). Salinity typically leads to the loss of productive land area and subsequently agricultural production. Dryland salinity has two forms: primary and secondary. Primary salinity is the result of soils that are inherently saline as the result of a natural (non-anthropogenic) process. Secondary salinity is caused by agricultural activity, where the native vegetation is cleared and replaced with shallow-rooted crops and pastures. This shallow-rooted vegetation uses less groundwater, causing the water table to rise, bringing dissolved salts to the surface to contaminate land and surface water. Salinity often manifests itself as a visible salt scald, but may also be indicated by dead or dying trees, water-logging or the growth of more salt-tolerant species. Degradation in an affected ecosystem usually manifests as decreased biodiversity, reduced primary production and lowered resilience (Rapport, 1999). Jardine et al. (2007) suggested that there were three broad categories of human health, which could be affected by dryland salinity: dust-related illness, mosquito borne virus and mental health. Jardine et al. (2008) found that the vector for one mosquito borne virus (Aedes camptorhynchus) increased with the presence of dryland salinity, but that there was no corresponding increase in the relative risk of this infectious disease in the human population living in saline-affected areas.

Psychological quality of life has been linked to peoples sense of place (Ogunseitan, 2005) and environmental degradation influences this relationship (Rogan et al., 2005). This is captured in what Santiago-Rivera (2000) terms ‘ecopsychology’—the relationship between humans and their environment. Albrecht, 2005, Albrecht, 2006 and Albrecht et al. (2007) raises the concept of ‘solastalgia’, the pain or sadness caused by the loss or lack of solace and sense of isolation due to the present state of one's home and territory. Those who experience solastalgia can experience general distress which can escalate to serious health problems, such as depression and suicide (Albrecht, 2005; Higginbotham et al., 2006). Rogan et al. (2005) found that environmental degradation influenced the way people structured their relationship with their surroundings. Given the changes in residents surroundings due to dryland salinity, in some cases these changes can be quite rapid, there is potential for residents to experience psychological distress through such mechanisms.

Given the possible inter-related pathways that could initiate psychological distress—financial pressures due to reduced profitability, decline of social networks and solastalgia—we considered that there is potential for adverse mental health outcomes related to the environmental degradation of dryland salinity. The specific aim of this study was to determine if there were associations between areas with dryland salinity (and associated land degradation) and depression rates in the agricultural lands of south-Western Australia.

Section snippets

Study area

The study area was the largely rural south-western corner of Western Australia. This area was chosen for three main reasons: (1) it is the major agricultural zone in Western Australia and has an increasing incidence of dryland salinity, (2) it has extensive environmental data available through the Western Australian Department of Agriculture's soil and landscape mapping database, and (3) the population is encompassed by Western Australia's Data Linkage Unit (DLU) public health database.

The

Summary information

The population of the study area averaged 4,08,111 over the period 1996–2001, this was distributed across 882 census collection districts. In the period 1996–2001 there were 2669 individuals with records for depression (1016 males and 1653 females) (Table 1).

Results of Bayesian modelling/spatial analysis

The optimal model for predicting the relative risk for depression included the area level parameters for socio-economic status, percentage of the population classified as Indigenous, the proportion of the area affected by salinity, as well

Discussion

This study found the optimal predictive model for the relative risk of depression incorporated the following variables: socio-economic status (as SEIFA), percentage of the population identified as Aboriginal, and presence of dryland salinity. This finding indicates that, adjusted for other major factors, an elevated risk of hospitalisations for depression was associated with residence in areas proportionately more affected by dryland salinity. There are a range of likely explanations for these

Conclusion

In summary, dryland salinity was associated with increased relative risk for hospitalisation for depression. Although socio-economic status and the proportion of the population identified as Indigenous were important predictors of the relative risk for depression, dryland salinity also contributed to the relative risk independently. Given the changes in the surroundings due to dryland salinity, local residents could have experienced psychological distress through a range of mechanisms,

Acknowledgements

This research was funded by the Cooperative Research Centre for the Plant Based Management of Dryland Salinity. The research was approved by the University of Western Australia's ethics committee (RA/4/3/0492).

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