410 likes | 606 Views
The SODISWATER PROJECT - Solar Disinfection (SODIS) of Drinking Water. Dr Kevin McGuigan Dept. of Physiology & Medical Physics Royal College of Surgeons in Ireland Dublin 2, IRELAND Email: kmcguigan@rcsi.ie. Salgaa, Nakuru, Kenya.
E N D
The SODISWATER PROJECT- Solar Disinfection (SODIS) of Drinking Water Dr Kevin McGuiganDept. of Physiology & Medical Physics Royal College of Surgeons in IrelandDublin 2, IRELAND Email: kmcguigan@rcsi.ie
Salgaa, Nakuru, Kenya More than 1 billion people have no access to safe drinking water. More than 1 million children die from waterborne disease annually SODISWATER Project, RCSI
SODIS Process - Fetch the water SODISWATER Project, RCSI
Wash an ordinary plastic Bottle (supervised by husband) SODISWATER Project, RCSI
Fill the Bottle(supervised by cat and dog) SODISWATER Project, RCSI
Expose the water in the bottle for 6 hours - (supervised by foreman) SODISWATER Project, RCSI
After 6 hrs in the sun, drink the water(supervised by the rest of the village) SODISWATER Project, RCSI
RCSI group working on Solar Disinfection since 1992 SODISWATER Project, RCSI
2004 Indian Ocean Tsunami Despite >10 years research & > 30 papers, it became obvious that Aid Agencies were reluctant to promote SODIS as a method of water treatment in aftermath of humanitarian disasters. SODISWATER Project, RCSI
In 2006 obtained €2.7M funding (€1.9M EU, €0.3M Irish Govt. & €0.5M others) for the 3 year SODISWATER Project to expand knowledge of solar disinfection (SODIS) and help promote technology. SODISWATER Project, RCSI
Health Impact Assessment study model • Children under age of 5 Years • 14 month trial • Control group maintained usual practices. • All test group families given two 2-L bottles per child • Test group placed bottles in sun for 6h • Drink today what was treated yesterday SODISWATER Project, RCSI
Diarrhoeal disease rates recorded using “Smiley-Face Diary” SODISWATER Project, RCSI
Health Impact Assessment - A Tale of Four Studies: “it was the best of studies, it was the worst of studies” SODISWATER Project, RCSI
Zimbabwe Study Total = 839 children Control group = 547 Test group = 292 SODISWATER Project, RCSI
Results No Significant Effect Observed • Political tension. • Pre- & post-election (3-4 months) suspension of all foreign funded projects. • Economic hyper-inflation. • Cholera epidemic. • Fear of interference with bottle by neighbours. SODISWATER Project, RCSI
South Africa Study A total of 649 households were recruited with 386 children in the control group and 438 in the test group. Of the total of 824 children 402 were male and 421 female SODISWATER Project, RCSI
Typical S. African brick houses SODISWATER Project, RCSI
S. Africa Results • Incidence rates were lower in those drinking solar disinfected water (incidence rate ratio* 0.64, 95% CI 0.39-1.0, P ) 0.071) but not statistically significant • Solar disinfection was not significantly associated with non-dysentery diarrhea risk overall (P = 0.419). * IRR = Incident rate in test group / Incident rate in control group SODISWATER Project, RCSI
S. Africa Results – cont’d • Incidence of dysentery was significantly associated with higher motivation, defined as 75% or better completion of diarrhea data. • Compared with the control, participants with higher motivation achieved a significant reduction in dysentery (incidence rate ratio (IRR = 0.36, 95% CI 0.16-0.81, P = 0.014). However, there was no significant reduction in risk at lower levels of motivation. SODISWATER Project, RCSI
S. Africa Results – cont’d • A statistically significant reduction in dysentery was achieved only in households with higher motivation, showing that motivation is a significant determinant for measurable health gains. • SODIS works but only if you use it! SODISWATER Project, RCSI
Other problems • Overall compliance rate was poor (~35%). Many S. African users feared SODIS use would release local govt. from responsibility to provide clean water (S.A.) so they stopped using it! doi: 10.1021/es103328j.
Kenya Study SODISWATER Project, RCSI
Bondena Urban Slums in Nakuru SODISWATER Project, RCSI
Rural Maasailand, Kenya SODISWATER Project, RCSI
Test Group = 555 children in 404 households using SODIS. Control Group = 534 children in 361 households with no intervention. Post-election violence, disruption, interruption. SODISWATER Project, RCSI
Kenya Results Dysentery and non-dysentery diarrhea were significantly (P<0.001) reduced by use of solar disinfection: dysentery days IRR = 0.56 (95% CI 0.40 to 0.79); dysentery episodes IRR = 0.55 (95% CI 0.42 to 0.73); non-dysentery days IRR = 0.70 (95% CI 0.59 to 0.84); non-dysentery episodes IRR = 0.73 (95% CI 0.63 to 0.84). SODISWATER Project, RCSI
Anthropometry – height & weight SODISWATER Project, RCSI
Effect of SODIS on child development? • Median height-for-age was significantly increased in those on SODIS, corresponding to an average of 1.3 cm taller over a 1-year period over the group as a whole (95% CI 0.54 to 2.2 cm, P=0.001). • Median weight-for-age was similarly higher in those on SODIS, corresponding to a 0.4 kg heavier difference in weight after a year on SODIS (95% CI 0.16 to 0.64 kg, P<0.001). SODISWATER Project, RCSI 29
Comment • Anthropometric benefit only observed in Kenyan study. Probably because only area where we saw significant malnutrition. • This is the first trial to show evidence of the effects of SODIS on childhood anthropometry & should alleviate concerns that the lower disease rates associated with household water treatment are the product of biased reporting rather than genuinely decreased incidence. SODISWATER Project, RCSI 30
Cambodia - results Children drinking SODIS water were at lower risk of dysentery (IRR = 0.40, 95% CI 0.18 to 0.92, P=0.032). Incidence was low, hence wide C.I. Children drinking SODIS water were at lower risk of non- dysentery diarrhoea (IRR = 0.40, 95% CI 0.31 to 0.50, P < 0.001). SODISWATER Project, RCSI
General SODISWATER Conclusions: • SODIS significantly reduces incidence of dysentery (0.36<IRR<0.56) in most study communities (S Africa, Kenya, Cambodia). • SODIS associated with height & weight benefit in child development for Kenyan children. • No genotoxic risk observed for standard SODIS method over 6 months (Recommend replace bottles every 6 months). SODISWATER Project, RCSI
33 countries where SODIS is currently in daily use by > 4.5 million people SODISWATER Project, RCSI
Acknowledgements • Health Research Board (NS/2003/007) • Irish Aid and Health Research Board (GHRA/06/01) • European Science Foundation COST Action P9 • European Commission (FP6-INCO-CT-2006-031650 - SODISWATER) SODISWATER Project, RCSI