water quality 48 health hazards 21 wastewater irrigation 19 wastewater treatment 19 sanitation 16 water reuse 16 water pollution 13 public health 12 irrigation water 8 case studies 7 farmers 7 irrigated farming 7 risk reduction 7 urban agriculture 7 wastewater 7 agriculture 6 developing countries 6 guidelines 6 nutrients 6 water use 6 aquaculture 5 drinking water 5 heavy metals 5 monitoring 5 risk management 5 salinity 5 crop production 4 economic aspects 4 environmental effects 4 food security 4