Res. Environ. Life Sci. 2(1) 41-48 (2009)
[email protected]
ISSN: 0974-4908 http : //www.geocities.com/rel_sci/
Amelioration of tannery effluent toxicity in radish (Raphanus sativus) based on nutrient application Kamlesh Nath*, Dharam Singh, Aditya Verma and Y.K. Sharma Laboratory of Environmental Sciences, Department of Botany, University of Lucknow, Lucknow -226 007, India *email-
[email protected] (Received: September 28, 2008 ; Revised received: January 18, 2009 ; Accepted: January 24, 2009) Abstract: In the pot culture experiment different dilutions of treated tannery effluent (T.E.) i.e. 10, 25, 50, 100 % were selected to study the toxic effect on radish (Raphanus sativus L.) plant. For the recovery of plant damage, protective value of 10 and 25 ppm of certain macro (potassium) and micro nutrient (Iron and zinc) were also used in the form of zinc sulphate (ZnSO4), potassium sulphate (K2SO4) and iron sulphate (FeSO4) and added in 50% T.E. in separate pots. Finally the experiment was setup with the various treatments i.e. Control (distilled water), 10% T.E., 25% T.E., 50% T.E., 100% T.E., 50% T.E.+10 ppm ZnSO4, 50% T.E.+25 ppm ZnSO4, 50% T.E.+10 ppm K2SO4, 50% T.E.+25 ppm K2SO4, 50% T.E.+10 ppm FeSO4 and 50% T.E.+25 ppm FeSO4. The various growth parameters, pigments, enzymes’ activity, total protein, total sugar and metals’ accumulation were analyzed in each treatment at the end of 90th day while pigments, enzymes’ activity, total protein and total sugar contents were also observed at 45th day. The different concentrations of T.E. showed significant increase in leaf area, fresh and dry weights at lower concentration (< 25%) while they decreased at 50% concentration of T.E. The pigments (chlorophyll, pheophytin and carotenoids) were decreased with increase in concentration of T.E. The lower doses of T.E. (10% at 45 days) slightly increased chlorophyll b, pheophytin a and total carotenoid pigments content. The total sugar and protein contents were also significantly decreased while catalase and peroxidase activity showed significant increase with rise in concentrations of T.E. The concentration of chromium was increased with increase in T.E.t concentration in plant leaf and root, while the other elements i.e. Zn, K, Fe were decreased with increase in T.E. concentration in both parts. The zinc, potassium and iron sulphate treatments led to recover the damage caused by T.E. in all parameters. The concentration of chromium was also found to be decreased in recovery treatments in comparision to 50% T.E. treatment. Overall, in recovery treatments Zinc showed highest and significant recovery in most of the parameters. Iron also showed almost similar effects to the zinc while potassium showed minimum recovery. Key words: Tannery effluent, Chromium (VI), Pigments, Amylase, Catalase, Peroxidase, Sugar, Protein, Metal accumulation, Raphanus sativus L.
great damage to the soil when they are discharged. The presence of heavy metal ions such as chromium in industrial waste water is a potential hazard to aquatic, animal and human life. Chromium compounds are widely used in a number of industries such as leather, textile, chemical printing dye-ink manufacturing metal electroplating industries etc. (Trivedi, 1989; Trivedi and Goel, 1985). Chromium trioxide (CrO3) is used in chrome plating, copper stripping, aluminium anodizing, as a catalyst, refractories, in organic synthesis and photography (Sittig, 1979), galvanizing and tanning industries in river (Weijden and Middelburg, 1989). All these processes add chromium into the environment through the effluents. Trace amount of chromium is considered to be essential for normal metabolic process (Beatjer et al., 1974). However intake at higher level has been found to produce adverse and hazardous effects on human beings, plants and aquatic life (Tondon et al., 1978). Hexavalent chromium is 100 to 1000 times more toxic than the most common trivalent compounds (Gaugthafar et al., 1991). Thus it becomes imperative to remove chromium from the effluents before the discharging into water or on to land / soil. In the environment chromium exist in several oxidation states but Cr6+ and Cr3+ are the prevalent species. Among the two species Cr6+ is more toxic than Cr3+ (Sinha et al., 2005). Chromium is used in metal plating industries, tanneries and oil well drilling (Abbassi et al., 1998). Cr6+ compounds are highly water soluble and toxic compared to Cr3+ (chromium III) compounds. The health effects of
Introduction In the tanning industry about 25% of the weight of raw hide results in the finished leather where as the remaining 75% becomes a solid waste; of the solid waste about 50% is utilized by the manufacturers of poultry feed, gelatin, glue, fish meal and soap, and remaining 50% is dumped indiscriminately. In the rawhides or skins processing, of the offered quantity of chemicals (except Cr) about 15% are consumed and the unconsumed chemicals are either discharged into tannery effluent or as solid waste. In case of chromium about 70% of the offered amount is taken up by the hides/skins and about 30% remains unexhausted and goes into effluent waste water as well as into solid waste. The tannery effluents reaching to the canals, river or ponds, when used for irrigation, cause severe skin infection in the farmers. During last year the problem was so serious that it came under focus of the media. Tannery industries let out 2540 litres of effluents and 40 grams of chrome salt for every kilogram of processed hides and skins and about 4-5 litter chrome waste water is produced per kg hide and skin. Spent chrome tan liquor is acidic and greenish in nature with a pH 2.6 to 3.8. It contains about 500 to 5500 mg L-1trivalent chromium. Total suspended solids and BOD ranges were reported to be 1500 to 2400 mg L-1 and 800 to 3500 mg L-1 respectively (Chakraborty et al., 1965). Leaching of tannery effluent contaminated ground water sources also causes human and cattle health hazards when used as drinking water. Unproportionate heavy metals of tannery effluents are also causing Research in Environment and Life Sciences
41
February, 2009
Nath et al. these are very well documented (WHO, 1988). Cr6+ compounds are highly soluble and easily bio-available than the sparingly soluble Cr3+. Chromium greater than 2 ppm has been reported to be inhibitory for plant growth resulting in stunted growth, poor development of roots and discoloring of leaves (Pratt, 1966). Transport of chromium in the root from the soil is very slow (skeffington et al., 1976), but once it enters, it can be rapidly transported. Toxic heavy metals are mostly absorbed and get accumulated in various plant parts as free metals which may adversely affect the plant growth and metabolism (Barman and Lal, 1994) and their accumulation is biomagnified at different trophic levels through food chains (Rai et al., 2002).
Arnon (1949), as amended by Lichtenthaler (1987) was used for the pigments estimation. The estimation of enzymes viz. catalase and peroxidase was done by using the method of Euller and Josephson (1927) and Luck (1963) respectively. Protein and total sugar was estimated by the method of Lowry et al. (1951) and Dubais et al. (1956) respectively. Metal accumulation in plant and soil samples was estimated by the method of Piper (1942) and Lindsay and Norvell (1978) respectively. In soil samples calcium carbonate was estimated by the method of Piper (1942). Organic matter of soil was estimated by Walkley and Black (1934) method, modified by Nelson and Sommer (1982). The data observed in the experiment were statistically analyzed for the calculation of standard error (S.E.) and student ‘t’ test was administered for testing the hypothesis.
Present study is performed to explore the toxic effect of tannery effluent on plants growth, metals accumulation, and metabolism. Study also aims at studying remedial approach through zinc, potassium and iron sulphate.
Results Table 1 shows the physico-chemical characteristics of treated tannery effluent. After treatment the tannery effluent is turned light yellow in colour. Odor of tannery effluent was foul and pH - 7.89. Dissolve oxygen (DO) was found nil. The EC, BOD, COD, total hardness, total solids (TS), total dissolved solids (TDS) and total suspended solids (TSS) were found higher than permissible limits. The chromium, zinc, potassium and iron were found 25.10, 2.34, 31.2 and 28.10 ppm respectively.
Materials and Methods In the Pot culture experiments different dilutions of treated tannery effluent (T.E.) i.e. 10, 25, 50, 100 % (10% means, 10 ml effluent and 90 ml distilled water) were selected to see the toxic effect on radish (Raphanus sativus L.) plants. For the recovery of plant damage 10 and 25 ppm of zinc sulphate (ZnSO4), potassium sulphate (K2SO4) and iron sulphate (FeSO4) were also prepared and added in 50% T.E. in separate pots. Finally the experiment was setup with the various treatments i.e. Control (distilled water), 10% T.E., 25% T.E., 50% T.E., 100% T.E., 50% T.E.+10 ppm ZnSO4, 50% T.E.+25 ppm ZnSO4, 50% T.E.+10 ppm K2SO4, 50% T.E.+25 ppm K2SO4, 50% T.E.+10 ppm FeSO4 and 50% T.E.+25 ppm FeSO4. The higher concentration of recovery elements were used to produce more free ions for increase availability to plants roots. The chromium presented in T.E. reduces the absorption capability of various nutrients in plants, while the amount of recovery elements already present in effluent may be presented as binding form (with other elements present in effluent) or non ionic form which is not suitable for absorption by plant roots (Pandey et al., 2003). At the level of 50% T.E. the significant damage were observed so these levels are chosen for recovery purpose (Nath et al., 2005, 2009).
Figure 1 showing burning of younger leaves which started after 45 days, yellowing of leaves (lower chlorophyll) in plants treated with T.E.. Roots showed stunted growth and transverse section of radish root showed black pigmentation because of higher chromium concentration. Plant growth parameters of radish in different dilutions of tannery effluent are given in Table 2 ,Fig. 2 to 6, 9 and 10. Leaf area and fresh weight increased with increase in concentration of effluents, and showed decrease from 50% tannery effluent onwards. The dry weight was found to be decreased in 10% tannery effluent which increased in 25% T.E. and further decreased in 50 and 100% T.E.. Leaf area, fresh weight and dry Table - 1: Analysis of treated tannery effluent (T.E.)
Radish (Raphanus sativus L., c.v. -V .R. Japani) seeds were used for the experiment. T.E. samples were taken from common effluent treatment plant, Unnao, U.P and the effluent was analyzed for various physico-chemical properties (APHA, 2005). Seeds were sown in each pot and treatments were supplied as and when required basis. The experiment was performed in triplicate. At the end of experiment (90th Day) fresh weight was taken with the help of digital balance and dry weight was measured after by placing plants in hot air oven at 80±1oC for 24 hours. The various growth parameters, pigments, enzymes activity, total protein, total sugar and metals accumulation were observed in each treatment at the end of 90th day while pigments, enzymes activity, total protein and total sugar contents were also observed at 45th day. The method of
Research in Environment and Life Sciences
42
Parameters
Concentration
Colour Odour Ec pH Dissolved oxygen (DO) Biological oxygen demand (BOD) Chemical oxygen demand (COD) Total hardness Total solids (TS) Total dissolved solids (TSS) Total suspended solids (TSS) Chromium (Cr) Zinc (Zn) Potassium (K) Iron (Fe)
Light yellow Foul 17.57 dsm-1 7.89 NIL 200 ppm 300 ppm 2.0 mg L-1 20.43 mg L-1 19.66 mg L-1 1.1 mg L-1 25.10 ppm 2.34 ppm 31.2 ppm 28.10 ppm
February, 2009
Effect of tannery effluent on radish plants Table - 2: Effect of tannery effluent (T.E.) and its combination with Zn, K and Fe on plant growth in radish (Raphanus sativus L.) plant at harvest Leaf
Root
Treatments
Fresh weight (g)
Dry weight (g)
Moisture (%)
Fresh weight (g)
Dry weight (g)
Moisture (%)
Control 10% T.E. 25% T.E. 50% T.E. 100% T.E. 50% T.E.+10 ppm ZnSO4 50% T.E.+25 ppm ZnSO4 50% T.E.+10 ppm K2SO 4 50% T.E.+25 ppm K2SO 4 50% T.E.+10 ppm FeSO4 50% T.E.+25 ppm FeSO4
14.48±0.63 18.33±1.24 38.13±2.01* 31.86±2.35* 11.92±0.85 39.53±0.92* 49.60±2.06* 45.74±0.68* 50.90±1.86* 34.27±1.95* 37.02±0.72*
1.18±0.14 0.94±0.07 1.85±0.05* 1.45±0.14 0.97±0.02 2.35±0.21* 3.13±0.13* 2.66±0.07* 2.94±0.03* 2.24±0.31* 2.59±0.05*
91.88±0.66 94.84±0.06* 95.12±0.12* 95.43±0.27* 91.72±0.83 94.04±0.57* 93.64±0.54 94.17±0.15* 94.21±0.20* 93.50±0.62 92.99±0.09
69.79±3.14 63.64±1.12 42.84±2.95* 17.38±2.86* 1.90±0.02* 32.34±2.89* 54.61±1.93* 34.74±2.82* 24.58±3.23* 20.93±0.94* 22.23±0.24*
5.19±0.66 4.03±0.35 3.69±0.07* 1.56±0.29* 0.31±0.08* 2.82±0.26* 4.13±0.36 2.77±0.13* 1.99±0.28* 1.50±0.05* 1.96±0.42*
92.59±0.82 93.68±0.44 91.34±0.41 91.10±0.24 89.43±0.20* 91.27±0.33 92.47±0.40 92.63±0.18 91.88±0.65 92.83±1.95 91.18±0.04
Values are mean of three replicates ± SE, * = Statistically significant at p
