controllers.js

var pollutants = [];

var findPollutant = function(point) {
	for (var i in pollutants) {
		if (pollutants[i].latitude == point[1] && pollutants[i].longitude == point[0]) {
			return i;
		}
	}

	return -1;
}

for (var i in waterbodies) {
	var wb = waterbodies[i];
	var points = waterbodies[i].points;
	if (points && points.length) {
		for (var j in points) {
			var index = findPollutant(points[j]);

			if (index === -1) {
				pollutants.push({
					latitude: points[j][1],
					longitude: points[j][0],
					causes: [wb.LW_DETAILED_CAUSE_NAME],
					waterbody: wb.LISTED_WATER_NAME
				});
			} else {
				pollutants[index].causes.push(wb.LW_DETAILED_CAUSE_NAME);
			}
		}
	}
}