摘要：This paper deals with the review of harmful effect of discharging ballast water on marine environment. These effects are grouped into harmful effects on echo system, economy and human health. There have been provided the examples of negative effects of discharging ballast water in certain areas and organisms responsible for causing unrecovered changes in echo systems. The conditions have been explained which should be fulfilled for the organisms to enter by ballast water and consequently to threaten marine environment. There have been described coming of organisms into the ballast tanks when ballasting the ship, conditions in ballast tanks influencing on their survival and also other ship's areas where organisms can persist by water ballast.
