Ключевые слова: billboards, brazil, chemical, cityscape, clean, danger, day, dirty, drain, drainage, dump, ecology, environment, environmental, environmental pollution, factory, fern, floating, flow, flowing, fluid, garbage, green, hazardous, health hazard, industrial, industrial waste, industry, liquid, natural, nature, pines river, pipeline, plant, polluted, polluting, pollution, river, sewage, sewer, so paulo, south america, stream, substance, toxic, unhygienic, urban, waste, water,