In effetti, a ben pensarci, anche per me la colonna d'acqua è sempre in contatto, pur non essendo in movimento. Io credo che comunque sciogliere l'alluminio in acqua, seppur in parti piccolissime, è difficilissimo e potrebbe avvenire solo per presenza di altri minerali che potrebbero interagire, ma non sono un esperto e mi astengo da giudizi. Comunque waterblock rivestiti non ve ne sono, poichè tutto quello che utilizziamo è fatto per dissipare le CPU dei PC, per cui nessuno si interessa alla qualità del materiale. Se ti preoccupa, puoi farti costruire un waterblok in acciaio inox da una ditta specializzata (tipo weerg.com) che accetta file tipo .stl per stampanti 3D. Altrimenti si può fare come ha fatto ElettronicaIn nell'articolo apparso sul numero 135, che ha creato una piastra di rame con tubi in acciaio inox saldati: soluzione semplice, efficace ed economica, forse poco performante, ma sicuramente da provare.
page0041.pdf
Aggiunto dopo 24 minuti 58 secondi:
Per completezza, ho scaricato gli articoli scientifici citati, e ora mi occorrerà del tempo per studiarli,
ma in prima battuta ho trovato che tutti dicono lo stesso concetto: la tossicità è elevata per bassi valori del pH.
Acid water containing aluminium has been known for several years to be highly
toxic to fish. Accordingly, it is probable that most of the fish kills in southern
Norway are a consequence of the aluminium released from the ground by the acid
precipitation rather than an effect of acid itself (Muniz & Leivestad, 1980a, b).
Aluminium is most toxic at a pH around 5 (Muniz & Leivestad, 1980a, b) which
is known to be easily tolerated by brown trout (Muniz & Leivestad, 1980a, b) and
rainbow trout (Graham & Wood, 1981). Aluminium toxicity has been considered
to be due to ion-regulatory collapse, as judged from a rapid loss of plasma sodium
and chloride before death of the fish (Muniz & Leivestad, 1980b). However, signs
of respiratory stress, such as elevation of ventilation frequency, increased standard
oxygen uptake rate and lowered venous oxygen tension, have been observed in
non-cannulated specimens (Muniz & Leivestad, 1980a; Rosseland, 1980). Ion loss
invariably occurs at acutely toxic pH values, and seems to be the primary cause of
death, except at extremely low pH values (< 3.5) where respiratory stress plays an
important role (Packer & Dunson, 1972; Wood & McDonald, 1982; McDonald &
Wood, 1981). The concentration of calcium in the water has a profound effect
upon the survival in, and the physiological response to, acid water. High calcium
concentrations improve survival (Graham & Wood, 1981), diminish the ionregulatory disturbance, and compound the acid-base disturbance (McDonald et
al., 1980). These changes are a result of the effect of Ca+ + on ion permeability and
active transport in the gill membranes (McWilliams, 1982; McDonald, 1983;
McDonald et al., 1983).
Previous experiments on the effects of aluminium in acid water have been
performed in ' soft water ' with very low calcium levels (0-0141 mmol 1- '), and
have indicated that increased calcium concentrations improve survival and slow
down ion loss (Brown, 1983; Muniz & Leivestad, 1980b). This study was undertaken in order to extend the narrow range of calcium concentrations so far used in
acid-aluminium studies to levels at which calcium exerts its maximal influence on
aluminium toxicity and mode of toxic action. At these calcium concentrations
acidification is unlikely to occur in nature, since accompanying increases in
bicarbonate and carbonate concentrations will increase the buffering capacity of
the water.
da H. Malte, Effects of aluminium in hard, acid water on metabolic rate,
blood gas tensions and ionic status in the rainbow trout