In this graduate work will be explained the concept of pesticides, their division and properties. Pesticides are persistent organic pollutants and organic compounds resistant to photolytic, chemical and biological degradation. They have the characteristic of low solubility in water and high solubility in fats causing accumulate in fatty tissues of living organisms. In a few chapters will be explained their effect on the human body due to direct exposure to the environment. They are found in the environment at low amounts, but they are transported over long distances by air and water, and are so widespread throughout the world, including in regions where they have never been used. An analysis of a sample from Vela Rika is made , river on the Island Krk, and the results are attached, explained and compared with a maximum allowable amounts. The results will be described in the discussion and further developed in the conclusion. In the past decade the use of pesticides has become an unavoidable topic of discussion on sustainable food production, considering the intensive agricultural production and increasing the population's needs for food, their use can be expected in the future.