INTRODUCTION
Rapid industrialization has caused a financial prosperity, seemingly, however this drastic rise in living requirements followed by means of deterioration of environmental stability and as a result quality. This case isn’t always only limited to our country, but all around the world. The environment is becoming increasingly more polluted; particularly air and water pollutants has grown to be a prime hazard to the very existence of living organisms in aquatic environment. A large amount of pollutants within the form of domestic, agricultural run offs and industrial effluent are discharged without delay or circuitously into the water bodies, which have excessive effect on its biotic and abiotic surroundings due to the fact that these effluents are recognized to exhibit toxicity closer to distinctive aquatic organisms. The rate of discharge of these substances into the ecosystem is greater than the rate of their degradation by natural process, ensuing in an unwanted accumulation of such materials within the environment.

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MATERIALS AND METHODS
Before discharge of wastewater effluent into the recipient, it is essential on an obligatory basis for any commercial corporation to purify wastewater effluent discharges with respect to those pollutants with adequate treatment in a way and to an extent that doesn’t threaten the natural method and does not disqualify them from the opportunity in their multi-functional use [1]. The regulation of quality of commercial effluent discharged into the out-let water bodies is utmost essential with a purpose to maintain environmental sanctity and prevent any destructive results as a result of those effluent discharges containing poisonous materials. The physico-chemical and biological parameters used for regulatory purpose by the statutory authorities can be labeled widely as A) cause parameters and B) impact parameters. The ‘motive parameters’ are specially physico-chemical parameters, which might be prone to cause harm to the surroundings. The impact of cause parameters are normally meditated by using the ‘impact parameters’, which encompass particularly biological parameters or Bioassay [2].
RESULTS
Many developed nations toxicity assessments on commercial effluent are obligatory to make sure that discharges will no longer cause negative results on the aquatic organisms within the receiving water structures. For example, the U.S. Environmental protection agency has integrated diverse aquatic toxicity checks in national Pollutant Discharge elimination system (NPDES). However, in some nations the local governments still depend only on chemical or physical traits of effluent, including biochemical oxygen demand, pH, temperature, suspended solids, and concentration of diverse chemical substances, to monitor and modify a point source discharge. This method was proved to be irrelevant and insufficient to defend aquatic organisms [3].
The detection of physico-chemical parameters alone is not enough, because the wastewater generated from the small-scale industries may also process massive quantities of chemical substances, a lot of which may be found in such low concentrations past their detection limits and for a lot of them even the analytical strategies are insufficient [3,4]. Secondly, the physico- chemical evaluation is not only quite complex, high priced and time-consuming technique, however additionally lacks the data about additive, antagonistic or synergistic results of numerous chemicals on biotic community in aquatic environment. consequently, improvement of effective tools for the assessment of adverse effects on living organisms is what all that is required. The toxicity is one such ‘effect parameter’, which offers data about the alternative relevant parameters too and therefore, identified as ‘summary parameter’ [2]. the use of summary parameter like toxicity is drastically gaining significance everywhere in the world due to the fact, it is straightforward, smooth, and less steeply-priced when in comparison to the physico-chemical parameters and it is also ideal legally and scientifically.
In general, toxicity assessments can be i) static non-renewal, ii) static renewal, and iii) flow-through. However, the most effective is the acute static nonrenewal test, in which the test solution stays the same throughout the test. An acute toxicity test measures the deadly outcomes over a brief time frame (forty-eight hours). As per the recommendations of the Indian standards, [5] for testing of commercial water and wastewater, ‘static non-renewal toxicity test method’ has been counseled and the same is adopted.
CONCLUSION
Toxicity exams or bio-assay exams offer the impact of chemical substances on each the aquatic and terrestrial organisms. They play a critical function in presenting information on chemical toxicity, determining organism’s sensitivity and stipulate water satisfactory appropriate for consumption. The technique has been well-known right from eighteenth century. increased use of insecticides for agricultural and other functions, the toxicity exams received a significant momentum using invertebrates and fish. The toxicity exams have additionally been emphasized through organization for economic Cooperation and development (OECD) and the European economic network [6]. The OECD had even presented a bundle of test techniques covering the minimal requirement of simple ‘toxicity exams’ and more large tests like ‘bio-magnification’ and ‘bioaccumulation’ for toxicity assessment. The toxicity checking out has end up now the ‘paintings residence’ for detection, assessment and abatement of water pollutants. These assessments which can also be referred as bioassay tests are broadly used to decide the potency of physiologically active substance of unknown activity. The toxicity component as mentioned above is a critical parameter to evaluate the impact and survival of organisms to toxicants in aquatic eco-systems. The preliminary misconception that the toxicity or bioassay exams are complex, require significant infrastructure, time consuming, misguided and unreliable has been removed by the development of a consumer-friendly approach through central pollution control Board (CPCB) which has been followed by Bureau of Indian standards and this developed approach has been recognized as an Indian standard test approach. In truth the toxicity test, being simpler, less expensive, more powerful and much less time consuming is one of the essential parameters masking all above shortcomings may be used as a ‘summary parameter’. The regulatory bodies use the toxicity outcomes in terms of ‘toxicity factor’ or ‘dilution factor’. The toxicity factor is a dimensionless quantity representing variety of instances an effluent need to be diluted on log scale at which hundred per cent survival of particular test organism beneath specified conditions is ensured [7].
References

Jelena ZV, Simic V, Petrovic A (2008) On the possibility of using biological toxicity tests to monitor the work of wastewater treatment plant. Arch Biol Sci Belgrad 60: 431-436.

CPCB (Central Pollution Control Board) (2003) Effluent toxicity status in water polluting industries, Part-1: Dye & dye intermediate, bulk drugs and textile industries. Programme Objectives Series. Probes/91/2002-2003.

Tyagi VK, Chopra AK, Durgapal NC, Kumar A (2007) Evaluation of Daphnia magna as an indicator of toxicity and treatment efficacy of municipal sewage treatment plan. J Appl Sci Environ Mgt 11: 61-67.

Bureau of Indian Standard (BIS) (1971) Bio-assay methods for evaluating acute toxicity of industrial effluents and waste waters.

Bureau of Indian Standard (BIS) (2001) Bio-assay method for evaluating acute toxicity of industrial effluents and waste waters, Part 2:Using toxicity factor to zebra fish.

Mohapatra BC, Rengarnan K (1995) A manual on bio-assays in the laboratory and their techniques, Central Marine Fisheries Research Institute (CMFRI), Cochin, India

CPCB (Central Pollution Control Board) (1999) Dimensionless toxicity factor-An approach to toxicity testing for regulatory purpose.

Georg G, Heinrichsdorff (2001) Effect of age on the susceptibility of Zebra fish eggs to industrial wastewater. Water Res 35: 3754-3757.

Mitchell JAK, Burgess JE, Stuetz RM (2002) Development in eco-toxicity testing. Reviews in Environmental Science and Biotechnology 1: 169-198.