Water Quality of East Texas Streams: Forested Versus Pastured Watersheds Receiving Poultry Litter Applications

摘要

Water quality and stream discharge were monitored at six sites on two Nacogdoches County, Texas streams over a nine month period (March - November 1995). Three sites were located in forested watersheds and the other three sites were downstream of pastured watersheds surface-applied with poultry litter, a potential nonpoint source of pollution. Stream water samples were analyzed for Ca, K, Mg, Na, 03-N ,TKN, P04-P, TP, TSS, pH, and dissolved oxygen. A rapid bioassessment was conducted to assess aquatic life stream conditions. Half of the 273 stream samples had nitrate-nitrogen concentrations greater than 0.30 mg L-1 high enough to support excessive aquatic plant growth, but were below the USEPA drinking water standard (10.0 mg L-1). However, almost 90% of samples had extremely low phosphate-phosphorus concentrations (u3c0.008 mg L-1), which may act as the limiting factor to prevent eutrophic conditions. Other parameters analyzed were within standards recommended by state and federal agencies. Benthic macroinvertebrate species intolerant of stressful conditions were plentiful, indicating good water quality in these streams. Current land management practices appear to have no adverse effects on water quality in the study watersheds.