CE 521 Environmental Biotechnology

---

Term Paper Abstracts (Fall 2000):

Review on Bacteria Pollution from Agricultural Sources

Peilin Yang

ABSTRACT

Application of swine manure to cropland, as a fertilizer or soil conditioner, is a common and economic method of manure disposal. But there is an increasing environmental concern for bacterial pollution of water bodies from animal manure applied to croplands resulting in non-point source (NPS) pollution.

Many field studies indicated that bacteria pollution of surface water from the manure applied fields and concluded that manured fields resulted in a higher bacterial concentration in the runoff water compared to non-manured fields. Some data for TC, FC, FS, and FC/FS ratio in runoff water from a variety of non-point sources can be used as the baseline data when evaluating test results from a runoff water of similar sources or when estimating a probable median value for bacteria density in runoff water. Higher concentrations were found in both surface runoff and tile-drain water after a period of high rainfall from manured soils.

High densities of FC and FS bacteria in subsurface drainage water were observed during a high precipitation period and high subsurface drainage flow. The densities were affected by the manure application rate. Disturbed soil columns become more effective at removing bacteria when channels and pores were removed by mixing part of or all of the soil in the column. Research indicated that, with moderate to high rate of water addition, suspended bacteria can rapidly move through the undisturbed profile of well-structured soil. As a result any field soil with macro pores will likely allow rapid transport of bacteria to the depth of these macro pores when receiving water. The transport and survival of bacteria were depending on the organism, its physiological state, and interactions of many factors.

Because of the water pollution resulted from manure application in agricultural lands, U.S. government has taken manure management as critical to protect water resources and the development of the agricultural industry. An appropriate manure management plan is required for certain scale of animal facilities.

Microbial water quality is commonly determined by testing for the presence and concentration of some indicator organisms. Coliform group of bacteria has been selected for microbiological water quality indicator. Bacteria die off which measured using half-life is a complex procedure and plays a very important role to the availability of pathogens and indicator organisms at the soil surface during a rainfall event.

KEY WORDS

bacteria, water pollution, manure, agricultural land, bacteria indicator

---