Turun Vesi Oy käyttää PAC (polyalumiinicloridia) Kokemäenjoen veden ”puhdistamiseen”
Pelätään, että alumiini (pääkomponentti PAC:ista) voi aiheuttaa Alzheimerin tautia.
Lisäksi ne ovat syöpää aiheuttavia (karsinogeenisiä aineita)
Jotkut kotitaoudessa käytettävät graanavedet sisältävät suuria pitoisuuksia alumiiniyhdistettä, koska sitä lisätään koagulantiksi puhdistusprosessissa.Se voi olla vaarallista ihmisille, koska alumiini-ionit on todettu myrkyllisiksi em. munuaistautisille yksilöille.
An inorganic polymer ‘PAC’ (polyaluminium
chloride) is the most widely used coagulant in water
treatment (Van Benchosten and Edzwald, 1990; Boisvert et al.,
1997; Najm et al., 1998; Okuda, et al., 1999, 2001).
Though aluminium-based coagulants are frequently used in
water treatment there are fears that aluminium (the major component
of PAC and alum) may induce Alzheimer’s disease (Crapper et al.,
1973; Miller et al., 1984; Martyn, et al., 1989) and that they exhibit
strong carcinogenic properties (Dearfield et al., 1964; McCollister
et al., 1964; Mallevialle et al., 1984). Some domestic tap waters
may contain aluminium in relatively high concentrations because
aluminium has been added as a flocculant during the purification
process (DWAF, 1996). The implication of this may be serious
since aluminium ions have been demonstrated to be toxic especially
in individuals with impaired renal function (Savory and Wills,
1991).
Coagulation or chemical precipitation has been known since
the previous century when it became widely used in England where
lime was used as coagulant alone or with calcium chloride or
magnesium (Genovese and Gonzale, 1998). Removal of turbidity
by coagulants however, depends on the type of colloids in suspension,
pH, chemical composition of the water, the type of coagulant and
coagulant aid, and the degree and time of mixing provided for
chemical dispersion and floc formation (Rossi and Ward, 1993).
Furthermore, Cheng et al. (1995) studied the coagulation mechanism
by using Al2(SO4)3, a cationic polymer and FeCl3. They found two
main mechanisms of coagulation: At a relatively high coagulant
dosage and higher pH, the adsorption of particles onto a floc of
aluminium hydroxide or ferric hydroxide predominates, while the
formation of insoluble complexes in a way that is analogous to that
of charge neutralisation predominates at low coagulation dosage
and lower pH values
Pelätään, että alumiini (pääkomponentti PAC:ista) voi aiheuttaa Alzheimerin tautia.
Lisäksi ne ovat syöpää aiheuttavia (karsinogeenisiä aineita)
Jotkut kotitaoudessa käytettävät graanavedet sisältävät suuria pitoisuuksia alumiiniyhdistettä, koska sitä lisätään koagulantiksi puhdistusprosessissa.Se voi olla vaarallista ihmisille, koska alumiini-ionit on todettu myrkyllisiksi em. munuaistautisille yksilöille.
An inorganic polymer ‘PAC’ (polyaluminium
chloride) is the most widely used coagulant in water
treatment (Van Benchosten and Edzwald, 1990; Boisvert et al.,
1997; Najm et al., 1998; Okuda, et al., 1999, 2001).
Though aluminium-based coagulants are frequently used in
water treatment there are fears that aluminium (the major component
of PAC and alum) may induce Alzheimer’s disease (Crapper et al.,
1973; Miller et al., 1984; Martyn, et al., 1989) and that they exhibit
strong carcinogenic properties (Dearfield et al., 1964; McCollister
et al., 1964; Mallevialle et al., 1984). Some domestic tap waters
may contain aluminium in relatively high concentrations because
aluminium has been added as a flocculant during the purification
process (DWAF, 1996). The implication of this may be serious
since aluminium ions have been demonstrated to be toxic especially
in individuals with impaired renal function (Savory and Wills,
1991).
Coagulation or chemical precipitation has been known since
the previous century when it became widely used in England where
lime was used as coagulant alone or with calcium chloride or
magnesium (Genovese and Gonzale, 1998). Removal of turbidity
by coagulants however, depends on the type of colloids in suspension,
pH, chemical composition of the water, the type of coagulant and
coagulant aid, and the degree and time of mixing provided for
chemical dispersion and floc formation (Rossi and Ward, 1993).
Furthermore, Cheng et al. (1995) studied the coagulation mechanism
by using Al2(SO4)3, a cationic polymer and FeCl3. They found two
main mechanisms of coagulation: At a relatively high coagulant
dosage and higher pH, the adsorption of particles onto a floc of
aluminium hydroxide or ferric hydroxide predominates, while the
formation of insoluble complexes in a way that is analogous to that
of charge neutralisation predominates at low coagulation dosage
and lower pH values
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