Does the manner of making artificially carbonated water raise any health concerns for example contaminants in water?

No. In fact, naturally carbonated water has had far more health issues than man-made, with even the Perrier works having had at least one well-publicized recall due to Benzene contamination (1990). The man-made process is the same one used to provide you bottled water, and is similar to the processes used to deliver tap water to you. The only extra step required is dissolving CO2 in water by delivering it to the flat water at high pressure. Because natural sources of sparkling mineral water must be natural, they are less subject to process control and thus harder to assure quality.