<P> Children age 8 and under are only allowed entry with the use of arm floaters, provided free of charge . The lagoon is not suitable for children under the age of 2 years . </P> <P> The Blue Lagoon is accessible for wheelchair users with a ramp that extends into the water and a shower chair . There is also a private changing room available for those with special needs, complete with a roll - in shower . </P> <P> The rich mineral content is provided by the underground geological layers and pushed up to the surface by the hot water (at about 1.2 MPa (170 psi) pressure and 240 ° C (464 ° F) temperature) used by the plant . Because of its mineral concentration, water cannot be recycled and must be disposed of in the nearby landscape, a permeable lava field that varies in thickness from 50 cm (20 in) to 1 m (3.3 ft). The silicate minerals is the primary cause of that water's milky blue shade . After the minerals have formed a deposit, the water reinfiltrates the ground, but the deposit renders it impermeable over time, hence the necessity for the plant to continuously dig new ponds in the nearby lava field . </P> <P> A small experimental facility is still visible near the plant, where the engineers made decantation tests to evaluate the speed of mineral deposition, which is clearly a limiting factor both to the plant's rentability and sustainability . Hence, geothermal energy exploitation at this location is not without environmental impact . </P>

What makes the blue lagoon in iceland blue