Chemical investigation of water from a 21 ha lake with a maximum depth of 32 m formed in a former limestone quarry south of Kraków, Poland was carried out. The lake is meromictic, with maximum values of O₂ in mixolimnion, and water homothermy noted in December. The important influence of the polluted Vistula River, flowing only in 600m distance that mainly infiltrates the quarry, resulted in high chloride content and conductivity value. Low chlorophyll a concentration and TSISD value show that the lake is oligotrophic, whereas the nutrient concentrations indicate slightly higher trophy.
Samples of orange juices were evaluated according to standard criteria in Code of Practice and compared with standard RSK values (Richtwerte und Schwankungsbreiten bestimmter Kennzahlen). In 15 orange juices, the content of chlorides, total acidity, volatile acids and ammonia did not exceed values in Code of Practice. It was found that samples F and K (66.30 g/dm3 and 57.65 g/dm3) contained more glucose than is allowed by Code of Practice. Juices G and K did not exceed RSK values for the D-isocitric acid content (103.68 g/dm3 and 109.96 g/dm3). Criterion according to citric and D-isocitric acid ratio corresponded to the normal values in 100% orange juice in samples G, K, L and also in 12% orange nectar P (69.3; 118.6; 51.4 and 72.3).