摘要：Coastal area of Semarang City is susceptible to water pollution and one of which is due to sea water intrusion. Diarrhea is an infectious disease that causes more than 26,93% of mortality in children under five years old and cases average over 30% in coastal area of Semarang City. The aim of this study was to evaluate assotiation between Water Pollution Index (WPI) and incidence of diarrhea in children under five years old. This type of research is an observational analytic study with a cross sectional study design. Sampel consisted of 18 respondens from 7 districts in coastal area of Semarang City. Independent variable is water pollution index which is calculated based on parameters of pH, salinity, TDS, and E.coli . Dependent variable is incidence of diarrhea under five years old. Data analysis used univariate and bivariate analysis using rank spearman correlation and Geographical Information System (GIS). Result found moderate category of water pollution index in Mangkang Kulon, Mangunharjo, Mangkang Wetan, and Bandarharjo. We identified associations between water pollution index (p 0,014, r: 0,857), E.coli in water (p 0,017, r: 0,842), salinity in water (p 0,013, r: 0,860), TDS in water (p 0,011, r: 0,871) and incidence of diarrhea. There is no relationship significantly between pH in water (p 0,782, r: -0,130) and incidence of diarrhea. WPI provides information on water quality and contaminants in water has potential trigger to digestive disorders. Cases of diarrhea occured by pathogenic microbiological, material, and chemical compounds. Conclussion, there is assotiation between water pollution index and incidence of diarrhea in coastal area of Semarang City.
