Amendments Of Tannery Sludge Research Articles

Accumulation and Translocation of Heavy Metals in Hibiscus cannabinus Grown in Tannery Sludge Amended Soil

Digested sludge wasted by tanneries is rich in nutrients and trace elements however, the presence of toxic metals restricts their use in agriculture. The present study explores the possible application of tannery sludge amendment for the cultivation of an energy crop, Hibiscus cannabinus. The toxicity of various sludge amendments (25, 50, 75, and 100%, w/w) was examined during early seedling growth, followed by metal accumulation potential by performing pot experiments. Chemical characterization revealed the presence of Cr (709.6), Cu (366.43), Ni (74.6), Cd (132.71), Pb (454.8) μg.g-1 in tannery sludge beside N (2.1%), P 3.8 & K 316.96 (kg.hec-1.) respectively. Germination of H. cannabinus exposed to sludge extracts ranged between 80 to 95%; Relative seed germination, 81.33 to 84.43%. Relative root growth, 0.9 to 1.16 cm; and germination index, 95 to 110%. It was found that sludge extracts have not caused adverse effects on seed germination and early seedling growth. Heavy metal accumulation was observed as follows: Ni (3.37, 2.38, 1.46 & 0.90 mg.kg-1) > Pb (10.59, 10.15, 5.26, & 2.84 mg.kg-1) > Cu (2.34, 2.24, 0.97 & 0.24 mg.kg-1) > Cd (2.31, 1.19, 1.33 & 1.12 mg.kg-1) > Cr (1458, 1136.12, 601.73 & 211.6 mg.kg-1) in 100, 75, 50, & 25% sludge amended soil, respectively. The bio-concentration pattern of metals was found to be in the order of root > leaf > stem. The findings of the present study give direction for the eco-friendly and cost-effective management of tannery sludge. Further, H. cannabinus can be used for the restoration of metal-contaminated agricultural land, however, results need to be corroborated with field trials.

Effect of tannery sludge amendments on the activity of soil enzymes and phytoremediation potential of two economically important cultivars of geranium (Pelargonium graveolens)

ABSTRACTA field experiment was conducted to observe the effect of TS amendments on soil enzymes and phytoremediation potential of two economically important cultivars of geranium. Different doses of TS were applied in soil to examine threshold limit of HMs where geranium cultivars can be grown successfully in contaminated sites. Treatment variation significantly affected pH, EC, OC, N, P, K and HM content in soil after 50 days of incubation. After harvest, both cultivars were examined to assess the impact of various treatments on their fresh herb, dry matter, essential oil yield and HM accumulation. C/G ratio close to 1 was observed at 50 tha−1 sludge treatment in both cultivars. Urease and β-glucosidase activities in soil were maximum at 50 tha−1 whereas dehydrogenase and phosphatase activities were maximum at 100 tha−1 in both cultivars. β-glucosidase, acid and alkaline phosphatase, urease and dehydrogenase activities were relatively high after 85 days over 45 days in both cultivars. Maximum metal uptake was found in roots of cv. Bourbon followed by leaves. Geranium was observed to be a good candidate for phytoremediation as it mitigates metal toxicity by root absorption and cv. Bourbon is better candidate for the same.

Chemical variables influencing microbial properties in composted tannery sludge-treated soil

Repeated applications of composted tannery sludge to arable soils have the potential to greatly alter soil chemistry and thus potentially influence the soil microbial community over time. This study performed multivariate analyses using the data of soil microbial biomass, respiration, and enzymes activities obtained during 5 years (2010–2014) in a long-term experiment with composted tannery sludge amendment. The correlation between the soil microbial and chemical properties, via the analysis of similarity matrices, revealed calcium as the main single factor influencing the microbial properties, in 2010 and 2011. Afterward, chromium was the most important chemical variables driving the microbial properties in 2012, 2013, and 2014. The non-metric multidimensional scaling demonstrated that the soil microbial properties changed with composted tannery sludge application from 2010 to 2014. Multivariate analysis from soil microbial data with composted tannery sludge amendment, during 5 years, showed calcium and chromium as being the most significant variables influencing the soil microbial properties in composted tannery sludge-treated soil.

Bradyrhizobium sp. inoculation ameliorates oxidative protection in cowpea subjected to long-term composted tannery sludge amendment

Oxidative stress can strongly affect biological nitrogen fixation (BNF) in nodules; therefore, the antioxidant system in nodules works to reduce the damage caused by the deleterious effects of oxidizing compounds and maintain adequate BNF. In this context, the objective of this work was to evaluate variables related to BNF and oxidative metabolism in the nodules of cowpea inoculated with Bradyrhizobium sp. and grown in soils subjected to different levels of composted tannery sludge amendment. A randomized block design was used with a 4 × 2 factorial scheme, involving four doses of composted tannery sludge (0, 5, 10, and 20 t ha−1) for uninoculated cowpea and cowpea inoculated with Bradyrhizobium sp. The cowpea inoculated with Bradyrhizobium sp. showed a better growth response than the cowpea inoculated with native rhizobia. Increases in the number of nodules, nodule dry mass, nitrogen fixation efficiency and nitrogen content were recorded in the cowpea inoculated with Bradyrhizobium sp. grown in soils with composted tannery sludge. The cowpea nodules colonized by Bradyrhizobium sp. showed lower hydrogen peroxide levels, while leghemoglobin was maintained at the highest levels. The catalase and phenol peroxidase enzymes were positively modulated in the nodules of the cowpea inoculated with Bradyrhizobium sp. We conclude that the presence of composted tannery sludge affects the establishment and development of the symbiosis between rhizobia and cowpea, mainly between native soil rhizobia and cowpea. When cowpea was inoculated with Bradyrhizobium sp., it was concluded that these plants were able to maintain better plant growth and nitrogen capture and lower oxidative stress in their nodules. Thus, inoculation with Bradyrhizobium sp. could be a useful tool for minimizing the deleterious effects of exposing plants to composted tannery sludge and for ensuring plant growth and productivity.

<b>Soil properties and cowpea yield after six years of consecutive amendment of composted tannery sludge

This study evaluated soil properties and cowpea yield after six years of consecutive amendment of composted tannery sludge. The compost was applied annually at 0, 2.5, 5, 10, and 20 Mg ha -1 and at the end of the sixth year, the chemical and physical properties of the soil were evaluated using a randomized block design. The Cr, P, K, Ca, Na and organic C contents and the pH and cation exchange capacity increased linearly after six years of compost amendment. The soil bulk density decreased linearly while the aggregate stability index increased after compost amendment. As a consequence of the changes in the chemical and physical properties of the soil, cowpea yield showed a quadratic response to the tannery rates, with an estimated maximum cowpea yield at 8.3 Mg ha -1 . In conclusion, the soil chemical and physical properties improved after six years of composted tannery sludge amendment. However, the soil pH and the Cr and Na contents increased with composted tannery sludge amendment, which influenced the cowpea yield and resulted in a quadratic response to the compost.

Comparative Study of Metal Translocation from Tannery Sludge Amended Soil to Capsicum annuum L. under the Influence of Chelants: Effect on Growth Parameters

The study comparatively assess the enhancement of metal translocation to shoot edible part and overall growth effect in Capsicum annuum L. grown on tannery sludge ammended with three different chelants. A comparison between the effects of application of three chelants on the growth and metal accumulation in C. annuum L. grown on tannery sludge amended soil was conducted to assess the enhancement of the metal translocation to the shoots, edible part and the overall effect on the growth. The analysis of the results revealed that all the morphological parameters (except number of leaves), chlorophyll and protein contents increased in the plants by the addition of chelants in 25% tannery sludge (TS) after 120 d as compared to the plants grown on T (garden soil). The plants treated with nitriloacetic acid (NTA) have shown better growth than ethylediamine tetraacetic acid (EDTA) and citric acid (CA) as compared with no addition of chelants. The accumulation of Cr in the leaves increased (72.03±6.03) by the addition of CA in 25% TS, in contrast to Ni and Cd after 120 d. Similarly, translocation of Cr and Zn increased in the edible part by the addition of EDTA, compared plants chelants. Comparison of Cr accumulation level in the leaves among three chelants, showed higher level in CA treated plants, whereas, Ni proved otherwise. However, in view of the higher translocation of Cr and Zn, it is advisable to grow plants on NTA alongwith 25% TS amended soil.

Short communication. Growth and nodulation of cowpea after 5 years of consecutive composted tannery sludge amendment

Tannery industry releases high amounts of tannery sludge which are currently composted and used in agricultural soils. The consecutive amendment of such composted tannery sludge (CTS) may affect soil microrganisms, such as rhizobia. In this study, we evaluated the effects of 5-year repeated CTS amendment on growth, nodulation, and yield of cowpea (Vigna unguiculata L.) CTS was applied in different amounts (0, 2.5, 5, 10 and 20 Mg/ha) to a sandy soil. Amendment of CTS increased soil pH, electrical conductivity (EC), sodium and chromium content. Plant growth, nodulation, N accumulation, and cowpea yield increased up to 10 Mg/ha; however, above this rate, these variables decreased. After 5 years of CTS amendment, the increase in soil chemical properties, particularly EC and Na content, exerted negative effects on the growth, nodulation, and yield of cowpea.

Soil Microbial Biomass After Three-Year Consecutive Composted Tannery Sludge Amendment

Brazilian industry produces huge amounts of tannery sludge as residues, which is often disposed by landfilling or land application. However, consecutive amendment of such composted industrial wastes may cause shifts in soil microbial biomass (SMB) and enzyme activity. This study aimed to evaluate SMB and enzyme activity after 3-year consecutive composted tannery sludge (CTS) amendment in tropical sandy soils. Different amounts of CTS (0.0, 2.5, 5.0, 10.0, and 20.0 t ha−1) were applied to a sandy soil. The C and N contents of SMB, basal and substrate-induced respiration, respiratory quotient (qCO2), and enzyme activities were determined in the soil samples collected after CTS amendment for 60 d at the third year. After 3 years, significant changes were found in soil microbial properties in response to different CTS amounts applied. The organic matter and Cr contents significantly increased with increasing CTS amounts. SMB and soil respiration peaked following amendment with 10.0 and 20.0 t ha−1 of CTS, respectively, while qCO2 was not significantly affected by CTS amendment. However, soil enzyme activity decreased significantly with increasing CTS amounts. Consecutive CTS amendment for 3 years showed inconsistent and contrasting effects on SMB and enzyme activities. The decrease in soil enzyme activities was proportional to a substantial increase in soil Cr concentration, with the latter exceeding the permitted concentrations by more than twofold. Thus, our results suggest that a maximum CTS quantity of 5.0 t ha−1 can be applied annually to tropical sandy soil, without causing potential risks to SMB and enzyme activity.

<b>Heavy metals and yield of cowpea cultivated under composted tannery sludge amendment

The study aimed to evaluate the phytoavailability of heavy metals (Cr, Cd, Ni and Pb) concentrations in leaves and grains, and yield of cowpea (Vigna unguiculata L) grown in soil amended with composted tannery sludge (CTS) for two consecutive years. The experiments were carried out in 2009 and 2010 in soil amended with CTS at 0, 5, 10, 20, and 40 Mg ha -1 . The CTS amendment rates applied were above 10 Mg ha -1 , increased Cr concentrations in cowpea leaves. There were not increases in the heavy metals concentrations in cowpea grains after two years. In 2009, the application of CTS amendment did not promote increase in plant yield. However, in 2010, CTS amendment at 10 and 20 Mg ha -1 increased cowpea yield. The amendment of composted tannery sludge linearly increased linearly the concentration of Cr in the leaves of cowpea after two years. Composted tannery sludge promoted increases in cowpea yield.

Fractionation and availability of heavy metals in tannery sludge-amended soil and toxicity assessment on the fully–grown Phaseolus vulgaris cultivars

This study was conducted to assess the effect of tannery sludge on the bush bean (Phaseolus vulgaris) cultivars fully–grown on a culture sandy soil, as tannery sludge is valuable to improve soil fertility but long term studies evaluating the effect on fully grown plants are scarce. Tannery sludge amendments (0, 0.77, 1.54, 3.08 and 6.16 g tannery sludge kg−1 soil) were characterized and the main heavy metals identified (Cr, Mn, Fe, K, and Zn) later on sequentially and singly extracted, for soil fractionation and availability determination, respectively. Metals showed different fractionation and availability patterns, being the most toxic metal (Cr) found to primarily bind to the carbonate fraction in soil, while almost 10% of the total Cr was available for plant uptake. In the green house experiments, bush bean cultivars exposed to increasing tannery sludge amendments were evaluated at different plant stages. Metal accumulation and physiological parameters (chlorophyll, carotenoids, nitrate reductase activity and dry weight) were determined. Toxicity was primarily due to Cr, stimulating or affecting the response of physiological parameters and suppressing seed formation at the highest tannery sludge ratio. Metals were mainly accumulated in the roots of bush beans, diminishing in the upper part of the plants with minimal translocation to seeds, supposing little risk for human consumption. Additionally, important correlations, antagonistic and synergistic relationships were observed between the extracted metals and metal accumulation in plant tissues.

Dosage-dependent shift in the spore community of arbuscular mycorrhizal fungi following application of tannery sludge

The controlled disposal of tannery sludge in agricultural soils is a viable alternative for recycling such waste; however, the impact of this practice on the arbuscular mycorrhizal fungi (AMF) communities is not well understood. We studied the effects of low-chromium tannery sludge amendment in soils on AMF spore density, species richness and diversity, and root colonization levels. Sludge was applied at four doses to an agricultural field in Rolândia, Paraná state, Brazil. The sludge was left undisturbed on the soil surface and then the area was harrowed and planted with corn. The soil was sampled at four intervals and corn roots once within a year (2007/2008). AMF spore density was low (1 to 49 spores per 50cm(3) of soil) and decreased as doses of tannery sludge increased. AMF root colonization was high (64%) and unaffected by tannery sludge. Eighteen AMF species belonging to six genera (Acaulospora, Glomus, Gigaspora, Scutellospora, Paraglomus, and Ambispora) were recorded. At the sludge doses of 9.0 and 22.6Mgha(-1), we observed a decrease in AMF species richness and diversity, and changes in their relative frequencies. Hierarchical grouping analysis showed that adding tannery waste to the soil altered AMF spore community in relation to the control, modifying the mycorrhizal status of soil and selectively favoring the sporulation of certain species.

Metal Accumulation and Growth Response in Vigna radiata L. Inoculated with Chromate Tolerant Rhizobacteria and Grown on Tannery Sludge Amended Soil

The effects of inoculation of four chromate tolerant rhizobacterial strains previously isolated from rhizosphere of plants from chromium contaminated area in mung plant Vigna radiata grown on tannery sludge amended soil were evaluated. An increase of 138%, 88%, 256% and 54.14% in root length, shoot length, biomass and total chlorophyll, respectively was observed after 60 days of treatments by consortium. Similarly, a significant enhancement in Fe, Mn, Zn, Ni, Pb, Cr, Cu and Cd accumulation was observed in consortium inoculated plants as compared to non-inoculated plants. Results showed that rhizobacterial strain helps in ameliorating metal induced phytotoxicity, acquiring higher biomass and metal uptake in the plant may be useful in decontamination of metal from polluted soil.

Role of antioxidants in Cr tolerance of three crop plants: Metal accumulation in seeds

Pot experiments were conducted on three crop plants ( Vigna radiata cv. PDM54, V. radiata cv. NM1, Brassica juncea cv. vaibhav) which were grown on six different tannery sludge (TS) amendments. The translocation of Cr to the seeds was found to be higher in B. juncea than the two cultivars of V. radiata, and their levels were below detectable limits in all the three plants grown on lower amendments of tannery sludge (T10 and T25). There was a gradual increase in protein content and antioxidant levels in all the plants grown on lower sludge amendments. However, the levels of all the antioxidants were higher in B. juncea than the two cultivars of V. radiata. The increase in malondialdehyde content of B. juncea was lower than the two cultivars of V. radiata as compared to their respective controls. Overall, the plants of B. juncea have shown better tolerance than both the cultivars of V. radiata.

Comparative growth response of two varieties of Vigna radiata L. (var. PDM 54 and var. NM 1) grown on different tannery sludge applications: effects of treated wastewater and ground water used for irrigation

This study evaluates the possibility of using contaminated soil by treated tannery wastewater and the use of tannery sludge in agriculture. The plants of Vigna radiata var. PDM 54 grown on contaminated soil and irrigated with ground water have not shown the translocation of toxic metal (Cr) in the upper part. The biomass of the plant increased when irrigated with treated tannery wastewater compared to ground water, whereas no significant change was observed in chlorophyll and protein contents. In both the varieties (var. PDM 54 and var. NM 1) of V. radiata grown on tannery sludge amendments, the growth parameters exhibited a pronounced positive growth response up to 35% tannery sludge amendments compared with the plants grown on garden soil. Despite the Cr accumulation at lower amendments, no toxicity symptoms were observed in both the varieties of the plants. Higher amendments affected various growth parameters, NR activity, and carbohydrate content of the plants. The results suggest that the plants of V. radiata (var. PDM 54) may be grown on contaminated soil or lower sludge amendments and irrigated with ground water. No translocation of toxic metal Cr was found in the seeds of the plants grown in up to 25% tannery sludge. However, periodical monitoring is required before the consumption of seeds. Overall, the results showed that plant growth patterns were influenced to some extent by the level of soil contamination and the water used for irrigation.

Uptake and translocation of metals in Spinacia oleracea L. grown on tannery sludge-amended and contaminated soils: Effect on lipid peroxidation, morpho-anatomical changes and antioxidants

The plants of Spinacia oleracea L. grown on contaminated soil (CS) and different amendments of tannery sludge (TS) have shown high accumulation of metals in its edible part. The accumulation of toxic metal (Cr) in the leaves of the plants grown on CS was recorded as 40.67 μg g −1 dw. However, the leaves of the plants grown on 100% TS have accumulated about two times (70.80 μg g −1 dw) higher Cr than the 10% TS (31.21 μg g −1 dw). Among growth parameters, the root length was more affected at 90 d than the shoot length, number of leaves and leaf area. The study of scanning electron micrographs showed 29.31% increase in stomatal length in the leaves of the plants grown on CS as compared to garden soil (GS), which served as control, however it decreased in the plants grown on higher amendments of TS. The decrease in MDA content at initial period of exposure and lower amendment was recorded in the leaves, whereas, significant increase (>10% TS onward) was observed with increase in tannery sludge ratio at 90 d as compared to GS. A coordinated increase in all the studied antioxidants (cysteine, non-protein thiol, ascorbic acid, carotenoid contents) was found up to 75 d of growth. At 90 d, most of the antioxidant decreased as compared to 75 d causing oxidative stress as evidenced by increased level of lipid peroxidation and decreased chlorophyll and protein contents. Maximum increase of 181.43% in MDA content and maximum decrease of 53.69% in total chlorophyll content was recorded in the leaves of the plants grown on 100% TS after 90 d of growth. The plants grown on CS have shown an increase in shoot length, number of leaves, leaf area, photosynthetic pigments and protein contents and in all the studied antioxidants. Thus, these plants are able to combat stress involving defense mechanism, resulting in healthy growth of the plants. The results are well coordinated as there is no change in the MDA content as compared to the plants grown on GS. In view of high Cr accumulation in edible part of S. oleracea grown on CS after irrigation with tap water, it is not advisable to use these plants for edible purposes. Summing up, it is recommended that the level of metals in the edible part should be checked instead of healthy growth as deciding parameter for consumption. It is demonstrated through this study that metal enriched plants have detoxification mechanism and grow well on organic matter enriched contaminated soil.

Phytoextraction capacity of the Chenopodium album L. grown on soil amended with tannery sludge

The metal accumulation potential of Chenopodium album L. grown on various amendments of tannery sludge (TS) was studied after 60 days of sapling planted. The analysis of the results showed that the levels of pH, cation exchange capacity, organic carbon, organic matter and DTPA extractable metals (except Mn) of amendments increased by the addition of tannery sludge ratio. Shoot length of the plant increased by the addition of sludge, whereas, no marked change was observed in root length, fresh and dry weight of the plant. Accumulation of the metals in the plants was found in the order; Fe > Mn > Zn > Cr > Cu > Pb > Ni > Cd. Translocation of toxic metals (Cr, Pb, Cd) in different parts of the tested plant was found in the order; leaves > stems > roots. An increase in the photosynthetic pigments, carotenoid and leaf protein contents of the plants were found to increase with increase in sludge amendments. Correlation analysis between metal accumulation in the plants with DTPA extractable metals emphasized that Mn, Ni, Cr, Pb and Cd showed positive correlation ( p < 0.05), whereas, Fe, Zn and Cu showed negative correlation. Transfer factor analysis emphasized that 10% TS amendments were suitable for phytoextraction of Cr. Overall analysis of the data exhibited that the plants may be used for phytoextraction of Cr from tannery waste contaminated soil as most of the metal was accumulated in harvestable part which is a matter of serious concern, whenever used for edible purposes.

Chemical fractionation and heavy metal accumulation in the plant of Sesamum indicum (L.) var. T55 grown on soil amended with tannery sludge: Selection of single extractants

A pot experiment was carried out to study the single and sequential extractions of metals in different tannery sludge amendment and the potential of the plant of Sesamum indicum L. var. T55 (sesame) for the removal of metals from tannery waste contaminated site. The metal extraction efficiency obtained with each extractants was slightly different and follow the order; EDTA > DTPA > NH 4NO 3 > NaNO 3 > CaCl 2. The correlation analysis between extractable metals in the different amendments of sludge and metal accumulation in the plant (lower and upper parts) showed better correlation for most of the tested metals with EDTA extraction. In this study, a sequential extraction technique was applied on different amendments of tannery sludge. The results showed that Mn, Zn, Cr and Cd were mostly associated with Fe–Mn oxide fraction in most of the amendments, K and Ni was found in residual (RES) fraction, Fe and Cu was bound with organic matter (OM) and RES fractions and Na was associated with carbonate (CAR) fraction. The metal accumulation after 60 d of growth of the plant was found in the order of K > Na > Fe > Zn > Cr > Mn > Cu > Pb > Ni > Cd and its translocation was found less in upper part. The accumulation of toxic metals (Cr, Ni and Cd) in the plants was found to increase with increase in sludge ratio, in contrast, the accumulation of Pb decreased. In view of growth parameters and metal accumulation in the plant, it was observed that lower amendments (25%) of tannery sludge were found suitable for the phytoremediation of most of the studied metals.

Accumulation of metals and its effects in Brassica juncea (L.) Czern. (cv. Rohini) grown on various amendments of tannery waste

The metal accumulation potential and its tolerance in the plants of Brassica juncea (L.) Czern. (cv. Rohini) grown on various amendments of tannery sludge (10%, 25%, 35%, 50%, 75%, 100%) were studied after 30, 60, and 90 days after sowing. These plants were found to be effective accumulators of metals (Cr, Fe, Zn, and Mn); however, the seeds accumulated the least quantities of all the metals tested. The oil content of the seeds was found to increase up to 35% tannery sludge followed by a decrease. An increase in the photosynthetic pigments, protein, and sugar contents was recorded at the lower amendments of tannery sludge at initial exposure periods followed by a decrease compared to their respective controls. However, the malondialdehyde, proline, and ascorbic acid contents of the roots and leaves of the plant increased at all the sludge amendments and exposure periods, compared to their respective controls. The levels of cysteine and nonprotein thiol contents in the roots and leaves of the treated plant were found higher at all the sludge amendments and exposure periods except at 90 days, where a decrease was observed in the leaves at 100% tannery sludge as compared to their respective controls. The tolerance exhibited by the sludge-grown plants of B. juncea in the present study may be attributed to the enhanced level of the antioxidants induced under stress conditions.

Response of antioxidants in sunflower ( Helianthus annuus L.) grown on different amendments of tannery sludge: its metal accumulation potential

The interaction of metals present in tannery waste and their tolerance in the plants of sunflower ( Helianthus annuus L.) was studied in the present paper under field conditions. Effects of 100% tannery sludge and various amendments of tannery sludge (10%, 25%, 35%, 50%, 75%) along with one set of control were studied on the physiological and biochemical parameters of the plant along with their metal accumulation potential after 30, 60 and 90 d after sowing. The plants of H. annuus were found effective in the accumulation of metals (Cr, Fe, Zn and Mn) in roots, shoots and leaves, however, the level of toxic metal, Cr was found below detection limit in the seeds of the plant. The oil was extracted from the seeds of the plant and the level of oil content was increased up to 35% tannery sludge as compared to control followed by decrease at higher tannery sludge ratio. An increase in the chlorophyll, protein, cysteine, non-protein thiol and sugar contents was observed at the lower amendment of tannery sludge at initial exposure periods followed by decrease than their respective controls. Malondialdehyde content in the roots and leaves was increased beyond 50% sludge amendments at all the exposure periods as compared to control. However, proline and ascorbic acid contents of the roots and leaves of the plant increased at all the exposure periods and sludge amendments, compared to their respective controls.

Translocation of metals and its effects in the tomato plants grown on various amendments of tannery waste: evidence for involvement of antioxidants

A field experiment was conducted to study the effect of different amendments of tannery sludge on physiological and biochemical parameters of tomato plant ( Lycopersicon esculentum L. Mill). The accumulation of metals (Cr, Fe) in different parts of tomato plants grown on tannery sludge amended soil increased in a concentration and duration-dependent manner. The accumulation of both the metals was found lowest in the fruits of the plant. The statistical analysis of the results showed an increase in chlorophyll and protein contents in lower sludge amendment ratio at all exposures followed by a decrease at highest (100%) sludge amendment ratio. Lipid peroxidation enhanced in both root and leaves of sludge grown plants of tomato at all the sludge amendments and exposure periods, which is evidenced by increased malondialdehyde content, however the maximum increase was found in the roots (43.63%) and leaves (56.66%) of the plant grown on 100% tannery sludge at 60 d, over respective controls. The level of antioxidants, cysteine, non-protein thiol and ascorbic acid increased in the sludge grown plants of tomato to cope up with stress induced by the excess amount of the heavy metals present in the tannery sludge. The maximum increase was found in cysteine content (75.53% in the leaves), non-protein thiol content (92.68% in the roots) and ascorbic acid content (29.66% in the roots) of the plant at 75% tannery sludge after 30 d. The tomato plants were found well adopted for minimizing damage induced by reactive oxygen species, when grown on tannery sludge amendments in the present study.