Definitions and units. (i) The ‘‘cation exchange capacity’’ (CEC) is the sum total of exchangeable cations that a sediment or soil can adsorb. The CEC is expressed in milliequivalents of negative charge per 100 grams (meq/ 100g) or milliequivalents of negative charge per gram (meq/g) of soil or sedi- ment.
Definitions and units. (i) ‘‘Hydrol- ysis’’ is defined as the reaction of an organic chemical with water, such that one or more bonds are broken and the reaction products of the trans- formation incorporate the elements of water (H2O).
Definitions and units. The UV-VIS absorption spectrum of a solution is a function of the concentration, c1, ex- pressed in mol/L, of all absorbing spe- cies present; the path length, d, of the spectrophotometer cell, expressed in cm; and the molar absorption (extinc- tion) coefficient,ei, of each species. The absorbance (optical density) A of the solution is then given by: A = d∑εici i For a resolvable absorbance peak, the band width λ is the wavelength range, expressed in nm=10¥9 m, of the peak at half the absorbance maximum.
Definitions and units. (i) ‘‘Desorption efficiency’’ of a particular compound applied to a sorbent and sub- sequently extracted with a solvent is the weight of the compound which can be recovered from the sorbent divided by the weight of the compound origi- xxxxx sorbed.
Definitions and units. ( i) ‘‘D eso r p- t io n efficie n c y’’ of a p a r t ic u l a r co m - po un d a pplied t o a so r be n t a n d s u bse- q u e n t l y ex t r a c t ed wi t h a solve n t i s t h e weig h t of t h e co m po un d w h ic h c a n be r ecove r ed f r o m t h e so r be n t divided b y t h e weig h t of t h e co m po un d o r igi n a ll y so r bed.
Definitions and units. ( i) T h e ‘‘c a t io n exc h a n ge c a p a ci t y’’ (CEC) i s t h e s u m t o t a l of exc h a n ge a ble c a t io n s t h a t a sedi m e n t o r soil c a n a dso r b. T h e CEC i s exp r essed i n m illieq u iv a le n t s of n eg a t ive c h a r ge pe r 100 g r a m s ( m eq/ 100g) o r m illieq u iv a le n t s of n eg a t ive c h a r ge pe r g r a m ( m eq/g) of soil o r sedi- m e n t .
Definitions and units. (i) ‘‘Desorp- tion efficiency’’ of a particular com- pound applied to a sorbent and subse- quently extracted with a solvent is the weight of the compound which can be recovered from the sorbent divided by the weight of the compound originally sorbed.
Definitions and units. T h e UV–VIS absorption spectrum of a sol u t io n i s a fun c t io n of t h e co n ce n t r a t io n , c1, ex- p r essed i n m ol/L , of a ll a bso r bi n g spe- cies p r ese n t ; t h e p a t h le n g t h , d, of t h e spec t r op h o t o m e t e r cell, exp r essed i n c m ; a n d t h e m ol a r a bso r p t io n ( ex t i n c- t io n) coefficie n t , εi, of e a c h species. T h e a bso r b a n ce ( op t ic a l de n s i t y) A of t h e sol u t io n i s t h e n give n b y: A = d∑εici i F o r a r esolv a ble a bso r b a n ce pe a k , t h e b a n d wid t h λ i s t h e w a vele n g t h r a n ge, exp r essed i n n m =10¥9 m , of t h e pe a k a t h a lf t h e a bso r b a n ce m a xi m u m .
Definitions and units. The UV-VIS absorption spectrum of a solution is a function of the concentration, c1, ex- pressed in mol/L, of all absorbing spe- cies present; the path length, d, of the spectrophotometer cell, expressed in cm; and the molar absorption (extinc- tion) coefficient,ei, of each species. The Environmental Protection Agency § 796.1050 absorbance (optical density) A of the solution is then given by: A = d∑εici i For a resolvable absorbance peak, the band width λ is the wavelength range, expressed in nm=10¥9 m, of the peak at half the absorbance maximum.
