Add anti-freeze to the water so you are able to cool the water close to 0 oC to get better vacuum.
If you are going to utilise anti freeze, I suggest you use an enclosed system that minimises the inhalation and contact with any "misting" that may occur.
Pharmacology:
Ethylene glycol is rapidly absorbed once it is ingested and is then widely distributed into body tissues. Peak blood levels are generally seen in 1-4 hours. Exposure to the skin and lungs may cause irritation but does not cause the systemic toxicity in the way that methanol does. Lethal quantities in adults are considered to be 100 ml, but in children much less may cause serious cardiac, renal, and CNS toxicity.
Ethylene glycol itself is relatively nontoxic. After absorption the unchanged compound undergoes glomerular filtration and passive reabsorption. It is then broken down into metabolites that are highly toxic and cause the associated findings of ethylene glycol toxicity. Ethylene glycol is converted to glycoaldehyde by alcohol dehydrogenase. This is the rate limiting step of a reaction in the liver that continues to breakdown the glycoaldehyde into glycolate, glyoxylate, and oxylate (see below).
Inhalation:
Vapor inhalation is generally not a problem unless heated or misted. Exposure to vapors over an extended time period has caused throat irritation and headache. May cause nausea, vomiting, dizziness and drowsiness. Pulmonary edema and central nervous system depression may also develop. When heated or misted, has produced rapid, involuntary eye movement and coma.
http://www.embbs.com/cr/alc/alc7.html (http://www.embbs.com/cr/alc/alc7.html)