Complex sentence: Nitrates, if a factor in a specific case, would most often be ingested by infants in high nitrate drinking water, however, nitrate exposure also may occur if eating, for instance, vegetables containing high levels of nitrate.
Split into simpler sentences: Nitrates, if a factor in a specific case, would most often be ingested by infants in high nitrate drinking water. However, nitrate exposure may also occur if eating, for instance, vegetables containing high levels of nitrate.