I bought the Phoslock because I don't want to put alum in my pond. I have dogs that stir up the bottom and drink the water so I was concerned about alum.
"All forms of alum can cause irritation of the skin and mucous membranes. Breathing alum can cause lung damage. Aluminum also may attack lung tissue. Because it's a salt, eating massive amounts of alum can make you sick. Usually ingesting alum will make you vomit, but if you could keep it down, the alum could upset the ionic equilibrium in your bloodstream, just like overdosing on any other electrolyte. However, the primary concern with alum is longterm exposure to low levels of the chemical. Aluminum, from your diet or healthcare product, can cause degeneration of nervous system tissue. It is possible exposure to aluminum could lead to an increased risk of certain cancers, brain plaques or Alzheimer's Disease."
Loretta...that quote sounds like it is from some of the fear mongers out there. Alum (AlSO4) is a GCS chemical, generally considered safe. Toxicity in a pond can only occur if the pH drops to 5.4 or below to allow the aluminum to become soluable. Alum has/had been used as an anti-perspirant for decades as well as being used in virtually every public water supply until more effective polymers were created to clarify and remove solids.
The "claims" made in your fear quote are what could happen in a concentrated setting, and not because of the aluminum, but because it is a mildly corrosive acid only. In a pond, heavily diluted, it is VERY safe.
