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One of the most industrial fields that pose great concern to the ecosystem is the textile industry. About 2 million of solid wastes, 7 million cubic meters of waste waters as well as 3 million of carbon dioxide was registered globally (Protectia mediului in Romania. nd).
The textile industries use minimum 3000 meters cube per day and utilizes products that are toxic throughout the chain of production. Toxic materials are solvents, metals, dyes and surfactants that basically constitute the massive volume of effluents which need proper treatment before they are spread in the nature.( Dellamatrice & Monteiro. 2006a b; Rodrigues & Pawlowsky, 2007; Arslan-Alaton & Alaton, 2007; Mathur et al., 2007 Sharma et al., 2007; Abreu et al. 2008). In addition, textile wastewater involves in a wide arrays of chemical consumption and dyes substances along the production patterns that threaten the environment not simply because its liquid state but due to its chemical composition.(Venceslau et al., 1994)
Conventionally, biological treatment of textile wastewaters has been the first priority for many industries so far (Kunz et al. 2002). On the other hand, sludge is being produced in a large volume during this process (Kunz et al., 2002). Sludge is surplus compounds and biomass that resist the biodegradable process. Approximately 1-10 ton of sludge in moist state is derived from every 50 meters cube of water from a textile industry daily (Balan & Monteiro, 2001).
Typically, the finish product of textile sludge is being directed to landfill or destroy through expensive incineration program. Since, sludge contains huge amounts of fertilizer compound such as Nitrogen, Phosphorus, Potassium, and micronutrients; recycling of sludge were made easily by enriching the soil in agricultural process (Rosa et al., 2007) or can be use to upgrade soil contents ( Araujo & Monteiro, 2005 ; Araujo et al., 2007). The adverse effect pertaining this recycling method therefore poses great concern to the ecosystem as well as for human being since sludge contain toxic materials like dyes, heavy metals and other materials that cannot be easily controlled. In addition, products from both biotic and abiotic transformation that can results in soil destruction.(Hewitt & Marvin 2005; Sharma et al., 2007; Rosa et al. 2007). The ecosystem that comprises of both terrestrial and aquatic organisms is prone to contamination and results in adverse effects due to sludge.
Research was made in the characterization of textile industries' effluent in Kaduna, Nigeria and results revealed that from five major textile industries, seven measurable variables were detected as beyond the range limit set by the Federal Ministry of Environment. The parameters were namely, coloured effluent containing dyes, chemical oxygen demand (COD), biochemical oxygen demand (BOD), suspended solid (SS), NH3, Sulphur, Cu, and TDS. Excessive Colour was found in all the five industries and fall 350 times the average. Cu was recorded as 80% which is 3 times the acceptable limit. Whereas COD, SS, NH3, BOD and S were 24, 13, 8, 7 and 3 times the permissible limit. Critical disease burden is connected with the air, soil and water contaminated by effluent from the industrial process in Kaduna, Nigeria (WHO, 2002) however, current shorter life expectancy is being recorded according to such textile waste disposal within developing countries as compared to developed nations(WHO, 2003).
Waste such as sludge, water, solids or gas can be defined as hazardous waste since they can exist as a mixture of waste and present a high risk to the ecosystem due to their resistance to biological treatment, toxic and possess cumulative harmful effects within the living organisms.
About 10- 20% of the textile waste is classified as hazardous waste and heavy metals associated with solvents comprise of the major part in the textile factory.
Certain heavy metals that constitute the textile industries wastewaters are carcinogens and can be found attached to suspended solids or exist freely( not chemically bind) in the effluent ( Tamburlini et al. 2002) consequently the dose and exposure duration determine the other chemicals that derived from the textile effluent (Kupchella and Hyland, 1989). Typically chemicals in the textile effluent do not simply act as toxins to terrestrial organisms, however it poses a threat to the aquatic organisms as well (Novick, 1999).
Heavy metals are essential to biological metabolism, however, the absence or excess heavy metals in the biological system could cause detrimental adverse effects to the living organisms (Ward, 1995). Copper, chromium and cadmium are heavy metals that pose great concern due to their high concentration in the textile and tannery industries effluent. Regular increased in the use of large scale of metals in the textile industries becomes a critical issue as far as the environment is exposed to pollution from metallic compounds. Since metallic compounds have the ability to shift from one organism to another within the food chain, food contamination by metallic compounds remains a critical awareness as far as they can easily penetrate the biosystems via the soil, water and air ( Lokhande and kelkar, 1999). Moreover, contamination from toxic metallic components is a burning issue considering the facts that landfill disposal of textile effluents may travel deeper in the soil and contamination of ground water is inevitably. Heavy metals not only pose problem to the terrestrial components, besides the aquatic ecosystem is also at stake ( Aghor, 2007; Patil, 2009). Accumulation of harmful metallic components lead to a series of well documented challenge for the ecosystem since the heavy metals tolerates the biodegradation process (Malarkodi et. al. 2007). Furthermore, researches conducted by (Lokhande and kelkar, 1999) prove that productivity decreases within the sediments, biota and water due to the increase in deposit of heavy metals and pose an increase in health risk within human being as whole ( Kazi et al. 2009, Gbaruko et al. 2008; Ember, 1975 ; sunderman, 1959; Cai, 2009; Pokhrel, 2009). According to (Sharma et al., 2004), nowadays, contamination from residual heavy metals in sediments and water as well as their possible sources and cumulative effects can be determine thoroughly with the aid of risk assessment.
Today great concern is based on the improper disposal of textile effluent, specially, in the soil and into water. This is because the alarming health risks issues and the destruction of the proper flow components within the food chain that lay emphasis on textile and tannery industry effluent. Textile industries have been commercially challenge by the consumer consumption and in order to meet the demand various heavy metals with different toxic effects are being employed. Established study should be conducted to identify the toxicity of metals in textile effluent and the current condition of both the soil and ground water.
However, it is difficult to use chemical analysis to determine the toxicity of the textile sludge since textile waste is classified on a large scale of various chemicals. Therefore, toxicity tests are more explicit to obtain information about the hazards associated with the textile sludge.
Since only twelve articles that propose the eco-toxicity of textile sludge from effluent worldwide, Wilke et al. (2008) mentioned that efforts made to employ the eco-toxicity test were not deeply taken into consideration. As a result, from a study made in Brazil, by (L.S. Gomes, F.A. Silva S. Barbosa & F.Kummrow., 2012) different state of matter from the textile sludge were tested on several organisms such as, algae, bacteria, micro crustaceans, fishes, bacteria, earth worms, common constituents of fresh water planktons, plants and mammals. It is also been viewed that samples extracted from sludge was compared according to the suitability of the test before they are employed since previous results were obtained and outcomes were difficult to compare among authors. However, it can be deduced that different extraction procedures have specific effects in the toxicity response curve. Hence, according to the EN 14735 (2005) international standards, Koci et al. (2010) states that comparison in the field of toxicity can be easily conducted parallel to the compatibility of the sample sludge.
Moreover, sample extraction from textile sludge determine the phototoxicity when toxic substances accumulated in the vicinity of growth medium for living plants cause tissue destruction. That is, when plants absorb hazardous material directly in their tissues. Some host tissues were Avena sativa, Brassica campestris and Latuca sativa (Parvez et al., 2006). Moreover, phototoxicity among living plants were observed in the germination process, where seeds that contain the highest amount of nutrients is less affected than those which possess little nutrients. Results where noted in the root cell elongation and wheat seeds (T. aestivum) is more prone to toxicity of textile sludge as compared to soy bean seeds (G. max).
An evaluation made on the phototoxicity of seedlings in wheat seeds and soy bean seeds by Araujo et al. (2005) explain the fact that aqueous extracts from sludge inhibit the growth of seedlings in the aerial part, decrease in biomass, clear effects in the leaves, chlorophyll content, root length and the action of the enzyme peroxidase in both the roots and leaves. The sample extracted was in concentration ranges from 0.19 to 152 g/L-1. Above the concentration of 0.19 g/L-1, adverse effects were observed that results in considerable decrease of total dry mass, root length and inhibition in the height of the seedlings. These hazardous effects typically relate to the presence of toxic heavy metals such as Zn and Cu.
According to Rosa et al. (2007), samples derived from textile sludge are in different composition, stabilized sludge( treated at tertiary level through anaerobic degradation) creates an increase in the biomass production and germination rate up to 12.5% but exercises inhibitory effects in the biomass production at the same concentration for the fresh sludge. Seed germination slow down at 50% of the concentration from fresh sludge, however, the amount of seed nutrients is also affected by the fresh and stabilized sludge during germination process. As a result, compost from stabilized sludge can be therefore employed (Rosa et al., 2007).
Moreover, experiment has been conducted within the aquatic ecosystem where aqueous sample of sludge from dyeing process (grouped as II A which classified as non-inert for Brazilian standard NBR 10004) and a specimen from treatment plant of effluent in textile mills( grouped as II B which is classified as inert; NBR 10004 (ABNT,2004). The toxicity factor (TF) is the tool employed to determine the result and limit to 10% of the inactivity within the organisms when exposed to lower concentration per meters cube of the samples. Compared to the toxicity factor results, sample from the dyeing treatment shows no toxic effects for D. magna as guinea pig, besides, TF for sample sludge from textile mills shows considerable acute toxicity to the D. magna (Rodriguez & Pawlowsky., 2007)
From the above statements, aqueous stabilized sludge does not possesses any toxic effect on D. magna as compared to fresh sludge. The same experiment does not affect fishes since stabilized sludge shows any dose response curve (24hr exposure), on the other hand, fresh sludge shows toxicity (Rosa et al. 2007)
As per Girotti et al., 2008, the progress in using bacteria for toxicity test is more cost-effective and less time consuming for the experiment. In this experiment Girotti et al. uses V.fischeri since it is regarded as more sensitive to various chemicals compared to other types of bacteria. The test aimed at determining the restriction within the respiration, nitrification, enzymatic production of ATP (adenosine tri phosphate) and lumininescence. Stabilized sludge shows no significant effects on the V. fisheri whereas fresh sludge at 50% effective concentration values( EC50) shows low effect of toxicity which is greater than 80% in composition ( Rosa et al. 2007)
According to Soni et al. (2008), an experiment of samples sludge was conducted on pregnant Swiss albino mice as bio assay within mammals. Sludge sample from biological and chemical treatment which is diluted in water (solubilized samples) gives rise to maternal toxicity with no lethal effects. Furthermore, a tetratogenic and embryotoxic effects in fetuses and it is critically observed at higher dose of sludge concentration.
The assessment of wastes is being conducted via the toxicity test by various authors ( Pandard et al., 2006; Wilke et al., 2008 Koci et al., 2010), unfortunately, it is difficult to establish a proper test battery as far as small quantity of data is being gathered. Standardize steps for processing the test is not yet established as compared to the extraction procedure. However, from the limited experiments undergone by authors, proof of toxicity is clearly expressed according to the samples extracted from textile sludge but still remain burning issues.
In addition to the ecotoxicity of sludge, heavy metals need continuous awareness as far as a study was conducted in quantifying the toxic metal pollutants in sediments from the Kasardi River that travels within the Taloja industrial sector of Mumbai, India. Mumbai is situated in the Maharashtra state which is the second most populous and wealthiest state in India. As per the Central Pollution Control Board (CPCB), Maharashtra state consists of huge number of polluted rivers that spread throughout the country.
According to expert, lack of awareness and monitoring of the proper waste disposal due to rapid urbanization had led such challenge to the ecosystem and the pollution of water as a whole (Zingde and Govindan, 2001; Modak et al., 1990; Rajaram and Das 2008; Khurshid et al., 1998; Pachpande and Ingle, 2004; Prabha and Selvapathy, 1997; Singare et al., 2010; Singare et al., 2011a; Singare et al., 2011b; MPCB; 2004)
Apart from other pollutants discharged in the river, toxic heavy metals is detrimental to the environment as, it is non-biodegradable, have cumulative effects and time frame for half lives is longer. Toxic metals remain a problematic to the environment since they continue to cause nuisance even if they are removed from the source. Toxic metals undergo biomagnificatication, bioaccumulation and geoaccumulation when they enter the ecosystem. As results, toxic metals may turn into more dangerous substances through bio transformation. Heavy metals can be taken up by biological organisms through contamination of particulate matter or intake in the form of free metal ions (Salomons and Forstner, 1984).
Experiment where done in collecting separates samples from sediments in the upstream and downstream of the Kasardi River near Taloja industrial sector and specimen were taken in depth centimeter of 0-15cm and 15-30cm respectively. 2g of the samples were mixed with 8ml of aqua regia and exposed to near dryness with the absence of stones and roots for 2hrs. Samples were dissolved in a volume of 10% of nitric acid at 2% concentration to give an acidic medium and filtered via Whatman's No.1 filter paper with de-ionized water to give finalized volume. The volume depends on the level of metals present (Chen and Ma. 2001). The specimens were directed to Nitric acid for digestion using microwave-assisted procedure. Pressure is kept at 30 bars and power at 700 watts (Clesceri, 1998; Paar, 1998). By the aid of Perkin Elmer ASS-280 Flame Atomic Absorption Spectrometer and calibration were made differently according to the metal present provide results from the majority of elements such as Nickel (Ni), copper (Cu), Zinc (Zn), lead (Pb), cadmium (Cd) , Manganese (Mn) and Iron (Fe) respectively. Chromium (VI) concentration was obtained colorimetrically from the use of spectrometer at 540 nm by diphenyl cabazide (DPC) approach (APHA 1998, Deepali, K. K Gangwar, 2010).
Moreover, studies were conducted to find the concentration of metals in the textile effluents, the related soil and ground water from a textile industry located at Delhi-Dehradun highway, near Bahadarabad, Haridwar, India. Experiment was similar to the one performed at Taloja industrial sectors, instead for soil sample, aqua regia that is, a ratio of 1:3 of HCL and HNO3 were added together with HCIO4 solution and heated for dryness. Distilled water is added to make a volume of 100ml and Whatman No.42 is employed for filtration. Atomic absorption spectrophotometer is used to translate metals found in samples ( Berrow and Mitchell, 1993; Buckley and Cranston, 1993, Deepali, K.K Gangwar, 2010)
From the above results, Cr, Cu, Pb, Mn , Fe amd Cd come from the textile effluent that produce hazardous health effects and impact on the ecosystem. Metals listed above are classified as heavy metals since their metallic form have densities greater than 4g/cc.
The expected limit of metal level in both the soil and water were standardized by the safe limit provided by World Health Organization (WHO).
Chromium (Cr) compounds in textile effluents from a textile industry situated in Delhi-Dehhradun were recorded at 2.38 mg/l which was viewed as 89.30% more than the lower amount of 0.255ml/l recorded for Nigeria textile industries in Lagos metropolis ( Ugoji and Aboaba, 2004, Deepali, k.k . Gangwar, 2010)
The major routes of entry for Chromium (Cr) are typically through absorption, ingestion, through the skin and by inhalation of particles containing chromium. According to the National Institute of Occupational Safety Hazard, NIOSH (1992), the lethal oral dose of sodium chromate is estimated at 50 ppm for human (LD50). Acute health effects of chromium liquid or solid compounds result mainly to the acute toxicity of clinical symptoms such as skin ulcers, inflammation of nasal membrane allergic contact dermatitis, vomiting, diarrhea, cardiovascular shock due to loss of blood in gastrointestinal tract and haemorrhagic diathesis. Moreover, skin ulcers, necrosis in the liver, aortic plagues, necrosis of epitheliums in the kidney and gastric ulcers (Morton Lippman, 1991)
On the other hand, Long-term effects of chromium exposure are septum perforations of the nasal, damage of the liver, ulceration of skin surfaces, rhinitis, edema, cancer in the intestinal lung and stomach. Respiratory effects and chronic rhinitis is observed. Lung inflammation, emphysema, lung tumors and congestion of polyps in the upper respiratory tract is also observed from chronic exposure to chromium. (Morton Lippman, 1991). Textile and tannery industries record the highest amount chromium in their waste water effluents ( Pachpande and Ingle, 2004). Pollution from chromium derives from agents like mordents, pigments and dyes in the textile industry. Moreover, at high temperature chromium become more toxic to health and cancer to human is basically due to chromium contamination ( Ember, 1975)
Besides, chromium have toxicological effects on the ecosystem as it is viewed by the Centre for Ecological Sciences (2001) where plants express growth restriction in the aerial part and the roots.
Small necrotic blotches and reddish brown staining on the leaves was also recorded. A study was made in Delhi-Dehradun, Haridwar district where chromium concentration detected in the groundwater was at 0.935 mg/l in the absence of hexavalent chromium ( Deepali and k.k Gangwar., 2010) but, chromium was observed at 0.05 ppm in the ground water sample at Karur district, Tamil Nadu due to dyeing process effluent contamination( Kannan et al. 2005)
According to ground water contamination of chromium, it can be deduced that effluents containing dyes agent pose great concern in the contamination of the ecosystem.
Cadmium was found in high level of pollution due to dyeing process since result from a study of metal concentration in textile effluents, associated with soils and ground water reveals that the concentration of cadmium in the textile industry effluent was 0.018 mg/l and in the dyeing process was 10% times in the dye house effluent ( Dubey et al. 2003). Chronic exposure to few amount of cadmium in water, air or in contaminated food results in cumulative effects which cause kidney disease. Bones weakness and lung destruction arise from long-term exposure is also recorded (ATSDR, 2005).
On the other hand, cadmium interferes in the bio system and penetrates the fishes' tissues within the food chain. It is less viewed as toxic to plants as compare to Cu, but same phototoxic in relation to Cr and Pb.
Cadmium is toxic to both invertebrates and vertebrates (Moore and Ramamoorthy, 1984).
An experiment was conducted on the contamination of ground water by Cadmium by Deepali and k.k Gangwar (2010) and the value recorded was higher than the permissible limit (0.04 mg/l) lay by the WHO (1958). Few contamination of human due to consumption of fishes was recorded (Moore and Ramamoorthy, 1984), but it was also registered as 0.29 ppm in ground water Panipat which also exceed the limit value presented by (ISI, 1991).
A study was conducted in Taloja River, India for the presence of heavy metals in sediment ,reveals that the concentration of Copper from textile effluents is regarded as varying between 121.5 mg/kg in the downstream of the river and 133.7 mg/kg in the upstream.( new York science journal,2011).
Among all the heavy metals present in the textile effluent, copper is deemed to be extremely poisonous to most fishes, aquatic plants and invertebrates. Copper inhibit growth and reduces reproduction rate in both animals and plants. The chronic dose exposure limit for copper is 0.02-0.2 mg/L (Moore and Ramamoorthy, 1984). Besides, copper is absorbed by aquatic plants three time more than terrestrial plants (Science for Ecological Sciences, 2001). Excess concentration of copper affects the roots, by targeting the proper function of cell membrane and cause destruction of the membrane design. Copper prevent the root growth and exhibit tiny brown secondary roots.
Since copper initiate cumulative effect in the plant and human body, copper have a larger half-life.
Another burning issue for copper contamination of 0.05 mg/l is viewed as high concentration above the permissible limit set by the IS (ISI, 1991) in ground water for textile industry situated in Haridwar district, India. Another study is conducted by Sharma et al. (1999) who state that in Sanganer, jaipur a textile unit within the perimeter of Haridwar is higher with a concentration of 0.75 mg/l.
Basically, Cu was recorded as high dose concentration of 109.54 ug/gm from soil sample within the vicinity of Rishabh Valvaleen textile factory located in Delhi-Dehradun, Haridar district, india ( Deepali &k.k. Gangwar, 2010). However, soil sample tested around textile dyeing industry revealed another alarming concentration of 148.6 mg/l of copper in Bangladesh.(Kashem and Singh, 1999).
As aresult, both statements explain the fact that textile industry involving dyeing is a burning issue for the ecosystem as a whole.
The presence of manganese in textile effluent is suggested to be 0.570 mg/l in a study conducted in the Haridwar district, India, but it was seen at higher concentration of 1.65mg/l manganese by authors in textile industries effluent in Nigeria, which was 65.46% more than the study carried in Haridwar district ( Yusuff and Sonibare, 2004). As compared to the different routes of entry, manganese intake by ingestion stimulates lower health effects in relation to other metals but if intake is by respiratory tract it can penetrate in to the brain by two ways; through the nasal cavity which is a shortcut to the brain tissue known as olfactory or by the lung uptake to provide a source for long-term exposure (Weiss, 2006).
Iron concentration was high enough (2.95mg/l) in the ground water of the Haridwar district as it was ranged above the acceptable limit (0.3-1.0)mg/l interpret by the ISI, 1991( Deepali & Gangwar. 2010). Beyond the limit iron bacteria is propagated and defect in the water supply is observed. Problem encountered in domestic use as well as appearance and taste is affected.
Heavy metals in the coastal marine sediment behave differently due to their ability to mix with organic matter in their ionized formed, colloidal and macro particulate phases.
As regard to a study made in Pali (Rajasthan), textile factories within the district is one the main pillar of the economic since it consist of 989 sectors that are deeply engaged in the printing and dyeing of cotton and synthetic textile. However, most of the textile industries operate in that area generates their effluents directly into the nearby river called Bandi. These dye stuff containing effluents possess the characteristics of dissolved matter or suspended state in waste water. Dye components are complex structure of long chain of monomers and are strongly non- biodegrable. Since the de-colorization of textile industry and manufacturing of dye stuff waste waters is complicated, effluent containing dyes remain great concern for the ecosystem. As a result, only 47% of the 87 dye items remain unchanged to bio degradable process.
Since colour continues to remain intact and stable, dye is obviously regarded as persisting in nature. On the other hand, it is resistant to degradation, toxic and renders clear water useless for operations. Colour from dye stuff is difficult to treat with conventional biological and chemical process. Since acceptable treatment cannot successfully remove the azo and other dyes, the remaining effluents may interfere with the aquatic life in the form of ionized components and suspension of solids in water. The dye effluents comprise of compounds or split organic groups (moieties) that may be carcinogenic, mutagenic and toxic to aquatic organisms.(Suzuki, T., Timofei.S., Kurunczi, L. Dietze, U. and Schuurmann., 2001; Mathur et. al. 2005).
The effluents from dyeing process in textile industries remain an alarming issues since the ecological and toxicological effects were due to disposal of textile waste waters in the natural water, thus, contribute to the massive water pollution in the Pali district.
Benzidine as a form of dye is classified by the International Agency for Research on Cancer to be related as cancer in human. Carcinogenic effect of benzidine is found to be popular in mammals including human being.
Moreover, Direct Blue 6 and Direct Black 38 are regarded as powerful carcinogens since they may cause neoplastic liver nodules and hepatocellular in rats after a limited time of 12 days exposure only. Both the Direct Blue 6 and Direct Black 38 is derived from the benzidine dyes( Robens, J.F., Dill, G.S., Ward, J.M. Joiner, J.R., GriesemerR.A, and Douglas, J.F ., 1980; Mathur et al., 2005)
Moreover, the mutagenic test of sludge samples was conducted by Umbuzeiro et al (2004) from six different samples of textile factory having dyeing department. The evaluation was carried out by using Ames test with TA98 and TA100 strains derived from Salmonella .Ames test is based on the fact that material expressing mutagenic effects in bacterium probably cause carcinogenic effects in laboratory animals and if prolonged research is undertaken may basically cause cancer in human. Solutions of both the strains were prepared in the presence and absence of S9. With the aid of an extractor solvent, which is methanol, is employed efficiently to remove mutagenic compounds from sludge. The results were recorded and mutagenic effects result in both the absence and presence of S9. Suggestion was made by the author and TA98 strain express mutagenic effects due to the presence of high concentration of dye in sludge, which is classified as aromatic amines and aminobenzenes.
As per Mathur (2007) and Gomes et. al. (2011) , the Ames test is also employed to evaluate the sample sludge. But samples were taken from biologically treated sludge and chemically treated sludge separately. Findings were obtained and chemically treated sludge is viewed as mutagenic to TA98 and TA100 but the sludge from biological treatment represents potent risk for mutagenic effects. Suggestion is made by the author as mutagenic effect is associated with the existence of dyes from dyeing process.
From the above statement it is imperative to treat textile effluents containing dyes differently before it is generated into the nature, since most of the textile containing dye effluent and/or sludge remains an issue to be considered in the carcinogenic effects of dyes. Conventional treatment of effluents: biological and chemical treatment is limited on the removal of azo and other dyes.
The Ames test is classified as best tools to investigate the mutagen effects of dye effluents and analysis of data from is based on the "two fold rule" where test chemical give positive results on consecutive chemical concentrations.
-Positive effects occur when mutant derived from the former cell (revertant) provide a multiplication effect in relation to increase in dosage.
-Negative effects occur when no multiplication effect is observed when mutant from former cell is exposed in relation to increase in dosage.
-Inconclusive effects occur when no compound is identified as mutagen.
Mathur et al. (2005) conduct an experiment from a total of seven dye specimens gathered from Pali local market which were randomly chosen to produce solution of different concentration ( 2u/l, 5u/l, 10u/l, 50u/l and 100u/l respectively) in order to obtain analysis on mutagenic effects of those dyes.
However, the Ames test derived from the five concentrations reveals that, Congo red and Royal blue dyes which were both classified as Direct dye shows positive but moderate mutagenic effect i.e, at 100u/l of dye generate 700-1200 revertants.
Besides, Bordeaux which is also a Direct dye produce a huge multiplication effects of revertants associated with a 100u/l dose and classified as tremendously mutagenic as compared to other Direct dyes mentioned before. Bordeaux generates 12000 revertants.
Violet shows a minor change as mutagenic effect ratio was 2.0 enough to produce insignificant result.
Further, the remaining dyes were classified as Processing dye or namely Orange 3R, Brown GR and Blue SI. They were also known as Cremzoles. From the results obtained, Orange3R and Brown GR express moderate mutagenic effect where 1200-1400 mutants from the former salmonella strains were produce. On the other hand, extremely mutagenic effect was recorded on the side of Blue SI dye, since reproducible revertants were screened at 15000 in 100u/l of the dye.
Since most of the textile factory dyes are carcinogens as per the International Agency for Research on Cancer and as well as tetratogens (Beck, S.L., 1983), there are various facts regarded to triple primary cancers in urinary Bladder, liver and kidney associated to dyes were reported by workers in dyeing textile and dye manufacturing industries ( Morikawa, Y.K. Shiomi, Y. Ishihara and N. Matsuura., 1997; Mathur et al. 2005)
The finishing and dyeing process constitute the main pollution in textile industries as far as the processes employ various dye components and chemicals of ambiguous structure. Dye and chemicals remain a critical issue as far as they not usually contained in the production pattern, and are discharged as effluent causing problem to the ecosystem. Moreover, in certain countries, especially in Pali, India, where dyes are being sold for textile industries with only their brand names and without any toxicological aspect: biological hazards and chemical nature.
Chemical oxygen demand (COD), bio-chemical demand (BOD), strong suspended solids, colour, heat, acidity and other soluble compounds are of serious concern in the textile effluent ( Dae-Hee et al., 1999).
During the wet processing, textile industries employ large amount of water and chemicals. However, waste water treatment systems as well as the generation of effluents from textile industries into nearby water bodies pose considerable problem to the ecosystem. According to E.K. Mahmoud (2009), textile effluent can be effectively managed via the Chemically Enhanced Primary Treatment (CEPT). In this method of treatment, both ferric chloride ( FeCl3) and aluminum sulphate(alum) were compared in jar test to identify the acceptable coagulant before proceeding into an effective way of treating textile effluent. Coagulation and flocculation of wastewater particles were observed during this experiment. In the experiment both coagulant were tested separately and Aluminium sulphate(alum) produce positive result at 300ppm where the removal of colour was at 75%, chemical oxygen demand (COD) at 69% and turbidity at 64%. The result was obtained after the pH range was at 7.2. Beside, another experiment was conducted using a mixture of alum and cation polymer concentration at 300mg/l and 1 mg/l respectively. The results were as follow; removal of colour =95%, chemical oxygen demand (COD) =76%, turbidity =75% and phosphorus = 90%.
According to this research, CEPT is an important tool of microbial de-colorization system for a total removal of colour. The treatment program was able to remove 95% of colour as well as heavy metal. Thus, CEPT can be used for de-colourizing purposes in textile dye effluents and it is a straightforward procedure with low-cost technology.
On the other hand, S.A.Abo-farha (2010), proposed another treatment method concerning the degradation of azo dyes with reference to their molecular structure. In this experiment removal of two particular dyes structures were compared by using Fenton, Fenton-like, photo-Fenton and Fenton-like treatment methods. C.I Acid Orange 8 (AO8) and C.I Acid Red 17(AR17) were chosen as the two acid dyes since they are known as organic contaminants. Proper concentrations of Fenton reagent (H2O2 and Fe2+), Fenton's-like Reagent (H2O2 and Fe3+), hydrogen peroxide and the two acid dyes were established with adequate pH solution medium. Continuous application of U.V irradiation, increases the degradation degree of both acid dye .The reaction undergo positive result in the degradation (de-colourization) of the two acid dyes while following the steps i.e Photo-Fenton>photo-Fenton-like>Fenton>Fenton-like. However, the degradation from the four advanced oxidation process (AOP) reveals that mono sulphonic azo dye (AO8) degrades more rapidly as compared to disulphonic azo dye (AR17). Moreover, the author suggests that the reaction is efficient at optimum condition.
Following the advanced oxidation treatment, S.A. Abo-Farha (2010) employed another method known as homogenous photo-catalytic degradation of Monoazo and Diazo dyes with UV/H2O2. In this process, the degradation of monoazo dye Acid Orange 10(A010) and diazo dye Acid Red 114 (AR114) where investigated. The utilization of a spectrophotometer helps to observe the disappearance rate of the two acid dyes at the absorption of maximum visible wavelength. From the experiment, an increase from the initial concentration of H2O2 causes a boost in the de-colourization rate until a critical (maximum) value is obtained and beyond the range at which result is restricted due to saturation. The speed of reaction responds a pseudo-first-order reaction since H202 was in excess. K= [acid dye].
The process undergo heterogeneous photo-catalytic as well, where titanium dioxide (TiO2) was employed. The photo-catalytic degradation process depends on the TiO2 concentration, the dye structure, dye concentration and the pH medium used. UV lights cause the release of highly energetic oxygenated species due to the electron excitation into conduction band of the TiO2 semiconductor. As a result, the active oxygenated species attack the dye component leading to photo-degradation. Proper concentration of H2O2 increase the rate of photo-degradation since, H2O2 is an essential electron acceptor that led to rapid formation of active oxygenated species. The author suggests that monoazo dye (A010) degrades more rapidly as compared to diazo dye (AR114) .
From both research made by S.A. Abo-Farha, it is clearly viewed that the determination of the dye structure is primordial in order to proceed further in the treatment. Since degradation affects is more persistent in monoazo as compared to diazo dyes.