8,255
edits
Changes
Jump to navigation
Jump to search
mLine 1:
Line 1: − +
no edit summary
__NOTOC__
__NOTOC__
Cationic exchange capacity (CEC) is an indicator of the capability of the soil, [[filter media]] or [[green roof media]], to retain dissolved, positively charged elements such as [[heavy metals|metals]], which are a common pollutant in stormwater runoff. Soil has the ability to retain dissolved metals due to the negative charge of clay and organic [[matter]](OM).
Cationic exchange capacity (CEC) is an indicator of the capability of the soil, [[filter media]] or [[green roof media]], to retain dissolved, positively charged elements such as [[heavy metals|metals]], which are a common pollutant in stormwater runoff. Soil has the ability to retain dissolved metals due to the negative charge of clay and [[organic matter]](OM).
Positively charged dissolved metal ions (i.e. cations) are attracted to the negatively charged particles which can cause them to be removed from solution and retained in the soil. CEC is influenced by soil texture (higher in fine textured soil), OM content (higher in organic soil), and [[pH]] (lower in acidic soil). Soils with high CEC are able to retain a larger proportion of dissolved metals and other positively charged pollutants, while soils with low CEC will retain less. The CEC of a soil sample is the sum of the exchangeable cations in the sample and expressed in milliequivalents (meq) of positive charge per 100 grams (g) of soil.
Positively charged dissolved metal ions (i.e. cations) are attracted to the negatively charged particles which can cause them to be removed from solution and retained in the soil. CEC is influenced by soil texture (higher in fine textured soil), OM content (higher in organic soil), and [[pH]] (lower in acidic soil). Soils with high CEC are able to retain a larger proportion of dissolved metals and other positively charged pollutants, while soils with low CEC will retain less. The CEC of a soil sample is the sum of the exchangeable cations in the sample and expressed in milliequivalents (meq) of positive charge per 100 grams (g) of soil.