Arsenic is present in the Waikato river (Robinson et al, 1995)1, and the maximum allowed concentration of arsenic in water according to NZ regulation is 10 µg L−1

.

a. Convert this measure into a weight percentage by assuming that one litre of water weighs one kilogram and then express this limit in parts per billion.

b. By looking at the data in Fig 1.3

, determine whether or not there was too much arsenic in the Waikato river in 1994.