Polluted river running through natural riverbed

polluted river natural riverbed contamination pollution environmental health hazards ecosystem impurities toxins chemicals waste unhealthy unfit discharge sediments debris runoff filthy muddy unpleasant algae sewage effluents damaged unsightly unsustainable adverse unsanitary neglected unsuitable unwholesome harming aquatic life erosion industrial agriculture urban natural habitat degraded poor quality discoloration foul odorous unappealing unbalanced deterioration