Most of the environmental studies make use of the naturally occurring isotopes with the advantage that they need not be injected in the system for a particular study Stable isotopes such as isotopes of light elements (hydrogen, carbon, nitrogen, oxygen, sulphur, chlorine) are most commonly used in combination with conventional techniques in the environmental studies. Isotope like C-13, N-15, and S-34 are used to study the origin, type, fate, behavior of pollutants in a system. In this study, stable isotopes have been applied in combination with conventional techniques to investigate Karachi...

Metals are non-biodegradable and are considered as major environmental pollutants causing cytotoxic, mutagenic and carcinogenic effects in animals. Aquatic organisms have the ability to accumulate heavy metals from various sources including sediments, soil erosion and runoff, air depositions of dust and aerosol, and discharges of waste water. Therefore, accumulation of heavy metals in aquatic organisms can pose a long lasting effect on biogeochemical cycling in the ecosphere.The rapid growth of population in the catchment areas may lead to deterioration of lake water quality...