Sources Of Water Pollution. 1  Dumping of industrial wastes, containing heavy metals, harmful chemicals, by-products, organic toxins and oils, into the nearby source of water is one of the visible causes of water pollution.  Another cause for the contamination of water is the improper disposal of human and animal wastes.
Also see audio noise. Noise is unwanted electrical or electromagnetic energy that degrades the quality of signals and data. Noise occurs in digital and analog systems, and can affect files and communications of all types, including text, programs, images, audio, and telemetry.
Noise is defined in terms of frequency spectrum (in Hz), intensity (in dB), and time duration. Noise can be steady-state, intermittent, impulsive, or explosive. Transient hearing loss may occur following exposure to loud noise, resulting in a temporary threshold shift (i.e. a shift in the audible threshold). With regard to acoustic noise associated with MR imaging, Brummett, et al.