no, its not safe to dispose nuclear waste in water,rather it would be safe to dispose it in common salt trenches.
water
Two disadvantages of nuclear waste are: disposal of nuclear waste is very expensive and takes a long time, and nuclear waste is radioactive. The advantages are: nuclear power plants are usually built on a coast, so the risk of contaminating drinking water is low; nuclear waste does not emit carbon into the air.
If you put nuclear waste in a situation where groundwater can flow over it on the way to a water course, you will obviously get contamination. Nuclear waste stores have to be very carefully considered to find locations that are safe from water access.
I assume you mean how does nuclear radiation affect the human body. Nuclear energy as used in nuclear power plants has no effect normally as the radiation is well contained. However if you want to know about the effect of radiation on the body, see the link below
because nuclear waste is toxic causing water to become just as toxic in the environment
The reason it isn't safe to jump in water that is contaminated with nuclear waste material is because it can make you sick or even kill you.
nuclear waste is worst
Yes, there is nuclear waste in space.
nuclear waste
nuclear waste is a by product of nuclear power plants, or in the creation of nuclear weapons.
nuclear waste contains about 90 % of nuclear fuel but it is much harmful then nuclear itself.