ABSTRACT
H ea v y m eta l co n tam in a tio n in soil and g ro u n d w a te r is am o n g th e la rg e r th re a ts to en v iro n m en ta l and hum an h ea lth th a t has resu lted fro m th e industria l an d p o p u la tio n ex p an sio n o f th e 2 0 th cen tury . So lub le sa lts o f th e heavy m etals (A s, B a , C d , C r, C u , Pb, N i, and Zn, am o n g o th e rs) h ave en te red soil and g ro u n d w a te r fro m ac tiv ities such as m etal-p la ting and finishing, tann ing , dyeing, ap p lica tio n o f p estic ides, d e te rio ra tio n o f pain ts and o th e r coa tin g s , and fro m th e c o m b u s tio n o f au to m o b ile fuels; in sho rt, from m any o f o u r m o re im p o rtan t e co n o m ic and cu ltu ra l activ ities. T h e leach ing po ten tia l o f heavy m etals from th e u n sa tu ra te d zo n e , th e ir m obility in g ro u n d w a te r , and th e ir e ffec tive rem e d ia tio n d ep en d on several fac to rs . T hese fac to rs inc lude th e s ite ’s h y d ro lo g ic an d g eo lo g ic characteris tics , solubility and spec ia tio n o f th e heavy m etals , a tten u a tio n and im m obilization p ro cesses, and th e ex ten t to w h ich th e heavy m eta ls m ay b e d ispersed b o th ho rizon tally and vertically as th ey m ig ra te
[1]. S ta te en v iro n m en ta l p ro tec tio n agencies, such as th e C o n n ec ticu t D ep a rtm en t
o f E n v iro n m en ta l P ro te c tio n (C T D E P ) have d eve loped reg u la tio n s th a t estab lish c lean u p s ta n d a rd s fo r h aza rd o u s w aste sites. C T D E P estab lished b o th D irec t E x p o su re C lean u p C rite ria as w ell as P o llu tan t M obility Soil C leanup C riteria . T h e fo rm e r p ro te c ts hum an hea lth and th e env ironm en t from risks asso c ia ted w ith d irec t ex p o su re to con tam in ated soil, w h ereas th e la tte r p ro te c ts g ro u n d w a te r fro m b eco m in g con tam in ated w ith m obile p o llu tan ts leached th ro u g h th e co n tam in a te d u n sa tu ra te d zone. C T D E P R em ed iation S tan d a rd s R eg u la tio n , S ec tio n 2 2 a - 13 3 k - 1, 1997 requ ires th a t th e "po llu tan t soil cleanup c rite ria .... be se t a t a level such th a t soil w ate r, as it en ters th e g ro u n d w ate r, d o es n o t exceed th e d rink ing w a te r p ro tec tio n criteria ."
