Contribution of the co-authors
AA designed the study and analyzed the data. EM conducted sampling
design, field and lab work. AA wrote the first draft of the manuscript,
and EM contributed to the revision of the manuscript. The
authors declare that they have no conflict of interest.
Acknowledgements
This work was supported by the Swedish Energy Agency (Grant No.
35586-1) and the Gothenburg Centre for Global Development (GCGD).
The authors would like thank Janaka Withanage and Thusitha
Madurande Geeganage for logistical support and the farmers in the villages
who assisted the project. Constructive comments from two anonymous
reviewers helped to substantially improve an earlier version of
this manuscript.
Appendix A. Supplementary data
Dataset used for analyses accompanies this paper as supplementary
file (Appendix S1). More information about dataset are available upon
request to the authors. Supplementary data associated with this article
can be found in the online version, at doi:http://dx.doi.org/10.1016/j.
scitotenv.2016.10.022.