This part of ISO 5667 provides guidance on the principles to be applied to the design of sampling programmes, sampling techniques and the handling and preservation of samples of sea water from tidal waters (for example, estuaries and tidal inlets, coastal regions and the open sea). It does not apply to the collection of samples for microbiological or biological examination. General guidance on sampling for microbiological purposes is given in ISO 8199. The main objectives of this part of ISO 5667 are specified in 1.1 to 1.4. 1.1 Quality characterization measurement Measurement of variations in spatial distribution and temporal trends in water quality to establish the effects of climate, biological activity, water movements and the influences of man, and also to assist in determining the magnitude and consequences of future changes. 1.2 Quality control measurement Measurement of water quality over a long period of time at one or more defined places to establish whether water quality, once characterized, remains suitable for defined uses such as bathing, protection of aquatic life, demineralization or cooling purposes, and to establish whether observed changes are unacceptable. 1.3 Measurements for specific reasons Assessment of the cause, magnitude and effect of significant variations in water quality and investigation of the sources and subsequent fate of pollutants discharged into marine waters. Identification of pollution, for example invertebrate, fish or bird mortality, or other conspicuous phenomena such as colour or turbidity development, or formation of floating layers of dirt or oil, which can be ascribed to discharges, spillages or even plankton blooms. However, it must be stressed that this objective is often very difficult to achieve. Mortalities may be caused by natural phenomena and cumulative pollutants may often remain largely unseen. 1.4 Examination of the effects of man-made structures Assessment of water quality variations caused by engineering developments such as barrages, jetties, bridges, breakwaters or ports, and resulting from the extensive use of marine waters for waste disposal.