Monday, August 27, 2012

Environmental pollution: the case of Xenobiotics


Xenobiotics are chemical substances that are foreign to the biological system. They include naturally occurring compounds, drugs, and environmental agents (Mondofacto online medical dictionary at www.mondofacto.com).The classes of xenobiotics include: pesticides, polyaromatic hydrocarbons (PAHs), polychlorinated aromatics, solvents, hydrocarbons, and others (surfactants, silicones, and plastics).

Xenobiotics levels in soils are generally low (less than 100 ppm) unless they are concentrated by application as in the case of pesticides, by spills or by waste disposal. They can occur in soils in solid, dissolved and gaseous phases and all undergo microbial and abiotic (chemical) transformations (Logan, 2000).
Photo source: www.cleanwaterfund.com


Pesticides are the most important xenobiotic pollutants because of their widespread use in agriculture. In many developing countries, unregulated use of pesticides by poor farmers contributes not only to environmental pollution but to health problems as well.

In the soil, pesticides can be temporarily fixed through adsorption by soil particles. The persistence or decomposition of pesticides in the soil is influenced by soil moisture, organic matter content, redox potential, soil acidity, soil temperature, texture, adsorption potential and clay minerals (Schactschabel et al., 1998; Sonon and Schwab, 2004).

References

Logan, T.J. 2000. Soils and environmental quality. In: Handbook of Soil Science (M.E. Sumner, ed.). CRC Press, Boca Raton, pp: G155-G169.

Schactschabel P., H.P. Blume, G. Brümmer, K.H. Hartge and U. Schwertmann. 1998. Lehrbuch der Bodenkunde (14th ed.). Ferdinand Enke Verlag, Stuttgart.

Sonon, L.S. and P.A. Scwab. 2004. Transport and persistence of nitrate, atrazine and alachlor in large intact soil columns under two levels of moisture contents. Soil Science 169: 541-553.


5 comments:

Martin Bacon said...

I think Soil pollution is defined as the build-up in soils of persistent toxic compounds, chemicals, salts,
radioactive materials, or disease causing agents, which have adverse effects on plant growth and animal
health.

am i right?

Victor B. Asio said...

Thanks for leaving a comment.Yes, you are right although we could also add "human health" (...on plant growth, animal and human health).

Pharmajobs-India said...

Hi! Dr. what is the average time span required for pesticide degradation in the soil. And it seems pesticide use has become inevitable for better yield.

Ross Taylor said...

Nice article, it i very useful information. The xenobiotic is one essential substance for detoxing procedure of soil and plant. Insect fumigations are the most essential xenobiotic pollutants because of their comprehensive use in gardening. Xenobiotics are ingredients that are international to the scientific system. They consist of normally sourced ingredients, medication, and ecological providers .The sessions of xenobiotics include: bug fumigations, polyaromatic hydrocarbons , polychlorinated aromatics, chemicals, hydrocarbons, etc. Xenobiotic stage in oil are generally low. Environment

Derek Patterson said...

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