Fecal coliform bacteria continue to be the most common pollutant in Louisiana s rivers and streams, followed by low dissolved oxygen concentrations and nutrients. Sources of bacteria include sewage discharges from municipal treatment plants, subdivisions, trailer parks, and apartment complexes.
Agricultural runoff generates oxygen-depleting substances and nutrients.
In lakes, bacteria are the most common problem, followed by noxious aquatic plants, metals, dissolved oxygen, siltation, and nutrients. Leading pollutant sources include municipal point sources, septic tanks, and inflow and infiltration. In estuaries, nutrients and pathogen indicators replaced oil and grease as the most common pollutants. Nutrients and pathogens can derive from a number of sources including municipal point sources, pastureland and septic tanks, all of which ranked among the leading suspected sources of impairment. Ground Water Quality Water in the State s major aquifer systems remains of good quality.