EFFECT OF ORGANIC AND INORGANIC AMENDMENTS ON THE HEAVY METAL CONTENT OF SOIL AND WHEAT CROP IRRIGATED WITH WASTEWATER

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1 Srhd J. Agric. Vol.29, No.1, ABSTRACT EFFECT OF ORGANIC AND INORGANIC AMENDMENTS ON THE HEAVY METAL CONTENT OF SOIL AND WHEAT CROP IRRIGATED WITH WASTEWATER MOHAMMAD JAMAL KHAN 1, MUHAMMAD TARIQ JAN 2 nd KHALID KHAN 3 Deprtment of Soil & Environmentl Sciences, The University of Agriculture, Peshwr Pkistn. Deprtment of Agronomy, The University of Agriculture, Peshwr Pkistn. Higher Eduction Deprtment, Peshwr Pkistn. Field experiment ws conducted to study the effect of wstewter irrigtion nd different orgnic nd inorgnic mendments on the phytovilility of metls to whet crop. Whet ws grown in (2x1 m plot) irrigted with wstewter generted from HIE (Hytd Industril Estte, Peshwr, Pkistn) nd municipl wstes during Five different mendments viz frm yrd mnure (FYM), poultry mnure (PM), dimmonium phosphte (DAP), triple super phosphte (TSP) nd humic cid (HA) were pplied nd mixed with soil prior to crop growing. In ddition, control (Tubewell irrigtion TW) nd only wstewter (WW) irrigtion plot (without mendments) ws lso set up for comprison. The FYM nd PM were pplied t the rte of 10 tons h -1. The DAP nd TSP were of 150 kg h -1 s P where s HA ws of 1.5 kg h -1. A Bsl dose of N nd of 120 nd 60 kg respectively were lso dded to ll experimentl plots except control. The results showed tht whet yield nd yield components were significntly incresed with the ddition of ll the mendments compred to control nd the higher increse ws noted in HA treted plots. The effect of different mendments pplied on AB-DTPA extrctle metls ws significnt for Cu, Fe, Mn, Ni nd Pb (P<0.05) nd non significnt for Cd, Cr nd Zn. Higher concentrtion were noted in the wstewter pplied plots with exception of Zn tht ws lowest in wstewter irrigted plots. The effect of ll the mendments on AB- DTPA extrctle metls ws comprle with exception of Pb tht ws significntly reduced by DAP. It ws concluded tht ll the metls under study were below the toxicity level in soil nd none of the essentil nutrient ws deficient. The leves metl concentrtions showed tht higher vlues of ll the metl under study were noted in leves when irrigted with WW nd TW irrigted plnts resulted minimum ccumultion of metls in leves. The effect of different mendments on the plnt uptke of metl ws vrile. Addition of HA reduced the uptke of Cd, Cr, Mn wheres DAP ws effective in reducing the phytovilility of Pb nd Zn. Key Words: uptke Wstewter, Tubewell wter, Amendments, Whet yield, Soil extrctle metls, Leves metl Cittion: Khn, M.J., M.T. Jn nd K. Khn Effect of orgnic nd inorgnic mendments on the hevy metl content of soil nd whet crop irrigted with wstewter. Srhd J. Agric. 29(1): INTRODUCTION Pkistn is extremely vulnerle to the dverse impct of climte chnge mong the developing countries. The most serious concerns identified by Tsk Force of Climte Chnge (2010) includes threts to its wter supply, besides threts to food nd energy security, vulnerility of costl re, incresed risks of extreme events (Flood, drought) lnd degrdtion due to slinity, wter logging nd dverse impct on forest, biodiversity nd humn helth. There re very limited choices to ddress the climte chnge issues. In Pkistn we need dpttion by chnging production technologies nd using wter efficiently by minimizing wter losses. Under the pressure of incresing popultion, the overll per cpit wter vilility is less thn 1800 cubic meter nd is now heding to become wter scrce country. As popultions continue to grow nd more freshwter is diverted to cities for domestic use of which out 70% lter returns s wstewter thus mking the use of wstewter incresed both in terms of the res irrigted nd in the volumes pplied (Scott et. l., 2004). It is estimted tht more thn 20 million hectres in 50 countries re currently irrigted with urbn wstewter (Ensink et l. 2004). Untreted wstewter is used for irrigtion in over 80% of ll Pkistni communities with popultion of over 10,000 inhitnts. The sence of suitle lterntive wter source, wstewter s high nutrient vlue, reliility, nd its proximity to urbn mrkets re the min resons for its use (Ensink et l. 2004). The findings of Ensink et l, from country-wide survey in the four min provinces of Pkistn showed tht untreted wstewter ws used in 50 out of 60 visited cities. The three min resons for the use of wstewter were the high slinity of groundwter, recent droughts tht hve led to decline in groundwter tles, nd the nutrient vlue of wstewter. Other importnt resons were the proximity of urbn mrkets nd the reliility of wstewter, which unlike regulr irrigtion wter is not subjected to rottionl schedule The use of untreted wste wter in the immedite surroundings for the growing of crops nd vegetles is common prctice. When such wter is used for growing of crops for long period, being consider s rich source of nutrients lso become source of hevy metls build up in soil nd tht my be toxic to the plnts nd lso cuse

2 M. Jml Khn, et l. Effect of orgnic nd inorgnic mendments on the hevy metl of soil 50 deteriortion of soil (Kirkhm, 1983). The disposed wste wters re contminted with trce elements like led (Pb), copper (Cu), zinc (Zn), boron (B), coblt (Co) chromium (Cr), rsenic (As), molybdenum (Mo), mngnese (Mn) etc. mny of which re non essentil nd over time toxic to plnts, nimls nd humn beings. This cusing undesirle chnge in the physicl, chemicl nd biologicl chrcteristics of ir, wter nd soil nd ffects humn life, lives of nimls nd plnts. Pre-tretment of wstewter is lwys recommended before griculturl ppliction but due to the high costs involved, in most plces round the globe nd more specificlly in the developing countries, wstewter, irrespective of its origin is pplied to the crops untreted. Therefore, wys needs to be found out to decrese the mobility of toxic hevy metls, rendering them less mobile nd more stle, thereby decresing their vilility to the plnt. One such method is the phytostiliztion of hevy metls. Soil mendments re the mjor requirement for the successful estlishment of vegettion in the metl-contminted soils. The ddition of mendment such s fly sh, sewge sludge, pig mnure, is effective in lowering the metl toxicity of the soil nd provide slow relese of nutrient sources such s N, P, K to support plnt growth (Chiu et l., 2006). Cow mnure, poultry mnure nd pig mnure were found to be effective in reducing led vilility to plnts, leding to lower uptke of led (Scildone et l., 1980, Wong nd Lu, 1985). In ddition, fertilizers re n essentil ingredient for successful restortion of mine wstes (Brdshw nd Chdwick, 1980). Trnsmission of Cd, Pb, nd Zn through the food chin is ffected by the soil-plnt brrier (Chney nd Giordno, 1977). The brrier limits trnsmission of metls through the food chin either by soil chemicl processes tht limit the solubility or by the plnt senescence from phytotoxicity. Phosphte mendments tht cn immobilize Pb in contminted soils include hydroxyptite (Boisson et l., 1999, Lperche et l., 1997, Khn nd Jones, 2008 nd 2009). A rpidly growing popultion, sline groundwter, poorly performing irrigtion distribution system, nd recurrent droughts hve led to incresed wter shortges in Pkistn. Under these conditions, the use of untreted urbn wstewter for griculture hs become common nd widespred prctice. This experiment ims t investigting the wstewter use looking t environmentl nd helth risks together with the nutritive vlue of wstewter. In ddition to this, the effectiveness of different chemicl nd orgnic mendments to immobilize hevy metls nd decrese the potentil entry of hevy metls into food chin, in n effort to find sfe nd chep wy for using untreted wstewter for griculturl crops. MATERIAL AND METHODS The mini plots experiments were estlished on the west side of the min building of The University of Agriculture, Peshwr, Pkistn with the objective to see the long term effect of wstewter irrigtion nd see the soil build up of hevy metls if ny. Whet crop ws grown in November19, 2008 nd irrigted with wste wter generted from Hytd Industril Estte (HIE) mixed with municipl wstes. The plots were fenced with wire nd 4 tnks of 500 L cpcity were plced for storing wste wter. The soil ws ploughed nd good seed bed ws prepred mnully. Five different mendments viz FYM, PM, DAP, TSP nd HA were pplied nd mixed with soil prior to crop growing. In ddition to the tretments plots, control (Tubewell irrigtion) nd only WW irrigtion plot (without mendments) ws lso set up for comprison. The FYM nd PM (collected from the diry nd poultry frm of Khyber Pkhtunkhw Agriculturl University Peshwr) were pplied t the rte of 10 tons h -1. The DAP nd TSP were dded t the rte of 150 kg h -1 s P wheres HA ws dded t the rte of 1.5 kg h -1. Humic cid ws procured from the Deprtment of Soil nd Environmentl Sciences, The University of Agriculture, Peshwr, Pkistn. Bsl dose of N nd K t the rte of 120 nd 60 kg respectively were lso dded to ll experimentl plots except control. Whet crop cv Ghznvi ws grown in rows 25 cm prt. Prior to the crop growing, the field ws irrigted uniformly with wstewter collected from Mlkndhere Khwr tht drins the effluent from HIE dmix with municipl nd household wste wter. The wste wter ws stored in tnks for subsequent irrigtion when needed throughout the experimentl period. The experiment ws lid out in RCB design with three replictions. The wstewter smple ws nlyzed for metl content using tomic sorption spectrophotometer (Tle 1). Soil nd Plnt Anlysis A composite soil smple (0-15 cm depth) from experimentl plot ws collected ir dried, crushed nd pssed through < 2 mm sieve nd nlyzed for vrious metls using AB-DTPA extrctnt (Hvlin nd Soltnpour (1981). Prticle size nlysis ws determined (Tle I) using hydrometer method (Gee nd Buder, 1986). Soil ph nd electricl conductivity (EC) were determined (Tle 1) in 1:1 (w/v) soil: wter extrcts (Smith nd Dorn, 1996). Lime content ws determined by cid neutrliztion method (Richrd, (1954) wheres orgnic mtter content ws determined by Nelson nd Sommer (1982) method. Leves smples of whet (third lef from the bottom fully mtured t heding stge) were collected, dried in oven, grinded nd metl content ws determined by using tomic sorption spectrophotometer following wet digestion procedure s given by Zrcins et l., (1987). Whet ws grown up to mturity nd the yield nd yield component dt including fresh nd dry biomss, plnt height nd grin yield dt ws recorded. At hrvest, soil smples from ech tretment plot were collected to ssess the effect of mendments on immobiliztion of metls.

3 Srhd J. Agric. Vol.29, No.1, Sttisticl Anlysis Replicted dt were nlyzed using Genstt Discovery Edition 3, pckge. Mens were compred by using lest significnt difference (LSD) test (Steel nd Torrie, 1980). RESULTS AND DISCUSSION Soil nd Wter Properties The soil of the experimentl site ws silt lom with ph vlue slightly lkline nd modertely clcreous (CCO 3 = 12.5 %). The EC ws 0.54 d Sm -1 with the orgnic mtter content of 1.02 % (totl orgnic nitrogen less then 0.2 g kg -1 ) tht my not sustin crops without fertilizers ddition (Tle 1). According to the Ntionl Environmentl Qulity Stndrds (NEQS)- EPA (1998) for liquid industril effluents nd municipl wstes, the level of Cr, Cd, Cu, Fe, Ni nd Pb were ove the permissible limits in HIE wstewter wheres the tubewell wter is of good qulity. The ph of the wstewter ws slightly lkline with EC of 1.01 d Sm -1 tht is considered mrginl for irrigtion (Tle I). Tle 1. Physicochemicl chrcteristics of soil of experimentl site nd wste/tube-well wter used for irrigtion Prmeters Soil Wstewter Tubewell wter Texture Silt Lom - - ph EC d Sm OM (%) CCO 3 (%) Cd (mg L -1 ) ND * 0.19 ND Cr (mg L -1 ) ND Cu (mg L -1 ) Fe (mg L -1 ) Mn (mg L -1 ) Ni (mg L -1 ) ND Pb (mg L -1 ) Zn (mg L -1 ) ND = Not detected Effect of Amendments on Yield nd Yield Component of Whet Irrigted with Wstewter The yield nd yield component of whet s ffected by vrious orgnic nd inorgnic mendments were significntly ffected by the ddition of vrious mendments. Minimum yield (0.84 kg plot -1 ) of fresh biomss ws hrvested from plots receiving only tube well wter wheres the higher yield (2.21 kg) ws obtined from plots supplied with humic cid (HA) followed by poultry mnure (Fig.1). The fresh biomss produced by fertilizers (DAP nd TSP) nd wstewter irrigtion ws non significnt (mong themselves) indicting the nutritive vlue of wstewter irrigtion. The dry biomss followed similr trend s ws noted for fresh mtter yield being mximum (1.44 kg) in HA treted plot nd minimum (0.41 kg) in plots irrigted with tube well wter (Fig. 2). The vritions in dry biomss with respect to different tretments were significnt (p < 0.05). Hroon (2009) reported 27 % yield increse of whet due to the ddition of 1.0 kg h -1 HA ddition. Humic Acid is thought to improve yield due to its cpility of supplying N nd P to plnts but the totl mount of HA dded is generlly 1 or 2 kg h -1 which will hrdly supply 0.04 to 0.08 kg N nd kg h -1 P to soil. This mount is fr below the overll nutrient requirements (Khttk nd Mohmmd, 2008; nd Shrif et l., 2002 b). However, the beneficil effect of HA ddition my be ssocited with improvement in the physico-chemicl nd biologicl environment of soil (Brnnon nd Sommers, 1985). Plnt height (Fig. 3) lso followed similr trend s ws recorded for biomss (both fresh nd dry) production. Shorter plnts (60 cm) were recorded in tube well irrigted plots without ny fertilizers nd tller plnts (90 cm) being mximum with humic cid dditions in ddition to wstewter irrigtion. Khn et l. (2009) reported higher biomss nd tller plnts of tomto when irrigted with effluents with or without supplementl NP nd K dditions. Grin yield ws significntly incresed by the ddition of orgnic nd inorgnic mendments. Significntly higher yield ws noted in HA treted plot irrigted with wstewter followed by PM mended plot wheres minimum yield ws recorded in control (TW irrigted plot). The results of the FYM, DAP nd TSP on grin yield production were comprle. Segur et l. (2004) dvocted the re-use of wste wter in rid nd semirid region of the world nd reported tht significntly higher yield of melon nd tomto were obtined when the crops were irrigted with effluents in the greenhouse crops. The positive effect of the effluents (ozone treted wste wter) ws due to its significntly higher mount of N, P nd K. In nother study, Akitk et l. (2002) reported tht tomto growth, yield nd qulity were not effected by the ddition of treted wstewter compred to tpe wter. The effect of both phosphtic fertilizers (DAP nd TSP) in the present study ws comprle with FYM or PM indicting tht P ws not yield limiting fctor. Khn nd Jones (2008) reported the dverse effect of DAP on yield of tomto but this ws minly due to the initilly cidic ph (3.35) in their study nd very high dose of DAP (23 g kg -1 soil).

4 M. Jml Khn, et l. Effect of orgnic nd inorgnic mendments on the hevy metl of soil 52 ) b TW WW FYM DAP HA PM TSP Tretments Fig.1. Fresh biomss (kg plot -1 ) of whet s influenced by different tretments nd wstewter irrigtion ) b 0.20 TW WW FYM DAP HA PM TSP Tretments Fig.2. Dry biomss of whet (kg plot -1 ) of whet s influenced by tretments nd wstewter irrigtion

5 Srhd J. Agric. Vol.29, No.1, b TW WW FYM DAP HA PM TSP Tretments Fig.3. Plnt height (cm) of whet s influenced by different tretments nd wstewter irrigtion ) 0.60 b 0.50 bc c bc c d 0.20 TW WW FYM DAP HA PM TSP Tretments Fig.4 Grin yield of whet (kg plot-1) s influenced by different tretments nd wstewter irrigtions Effect of Amendments on AB-DTPA Extrctle Metl Content of Soil Irrigted with HIE Wstewter The effect of different mendments pplied on AB-DTPA extrctle metl content ws significnt for Cu, Fe, Mn, Ni nd Pb (P<0.05) nd non significnt for Cd, Cr nd Zn. Averge AB-DTPA Cd concentrtion rnged from 0.84 mg kg -1 in the wstewter pplied soil to 0.11 mg kg -1, in the FYM mended soil, decrese of out 86 % in extrctle

6 M. Jml Khn, et l. Effect of orgnic nd inorgnic mendments on the hevy metl of soil 54 Cd (Tle 2) compred to control. Although non significnt (compred to other mendments), the ddition of FYM ws more effective in reducing the extrctility of Cd followed by DAP ppliction. The effectiveness of FYM on reducing Cd vilility my be due to the formtion of insoluble Cd nd orgnic mtter complexes tht might hve reduced its extrctility. Krc (2004) reported decrese in extrctle Cd in soil when mended with compost nd this decrese ws ttributed to the formtion of orgnic mtter complex with Cd in soil. The AB-DTPA extrctle Cr followed similr trend s ws noted for Cd concentrtion (Tle 2). The effect of the mendments ppliction (within) ws not significnt (P < 0.05). However, higher concentrtion of Cr (0.24 mg kg -1 ws noted in wstewter irrigted soil. According to the criticl soil test vlues reported by Kt-Pendis nd Pendis (1995), it ws noted tht both Cd nd Cr were below the level considered to be toxic in soil for plnt growth. Boln nd Durismy (2003) in their review indicted tht phosphte compounds re effective in reducing the phytovilility of Cd wheres orgnic mendments re effective for phytostilizing Cr nd Cu in soil. Averge AB-DTPA extrctle Cu concentrtion rnged from 3.53 mg kg -1 in the wstewter irrigted soil to 2.62 mg kg -1 in the FYM mended soil, decrese of 26 % in extrctle Cu (Tle 2). Overll, the mximum AB- DTPA extrctle Cu reduction ws by the ddition of FYM nd HA nd the lowest reduction ws from TSP nd DAP. Khn nd Jones (2008) reported the superiority of liming on the reduction in phytovilility of Cu tht ws ttributed to the significnt increse in soil ph by liming in their study. This pprent contrdiction with the present study is minly becuse the soil used in their experiment ws cidic (ph 3.39) while in the present study the ph ws ove 7. Sir et.l (2008) reported n increse in extrctle Cu by the ddition of FYM nd press mud wheres ctivted crbon reduced the Cu extrctility. In the present study, there were no significnt differences between the mendments with respect to extrctle Cu but were significntly different from plots receiving wstewter or tubewell wter. Iron, one of the essentil micronutrients nd usully less studied s pollutnt ws significntly (p<0.05) ffected by the different mendments. Like Cu, the ddition of mendments reduced the extrctility of Fe by ll the mendments nd HA ws more effective compred to ll other tretments. The mximum Fe concentrtion ws noted in soil irrigted with wstewter. All the mendments were non significnt (P >. 0.05) mong themselves. Reduction of extrctle Fe by different tretments is plusible due to binding of Fe (s well s Cu, Pb nd Zn) on orgnic mtter in the compost tretment nd the precipittion of metls with CCO 3 s the soil ws modertely clcreous. The concentrtion of extrctle Mn lso vried significntly (P < 0.05) nd the higher vlue (22.86 mg kg -1 ) ws noted in soil irrigted with wstewter with no ddition of mendments nd the lowest vlue (3.94 mg kg -1 ) ws recorded in TSP mended plot. The ddition of HA enhnced the extrctility of Mn. According to the criticl test vlues reported by Hvlin nd Soltnpour (1981) the concentrtion of Mn ws in the dequte rnge nd ccording to the USEPA (1999) stndrd of irrigtion, the wstewter hd much lower concentrtion of Mn to be problem for irrigtion. Sir, et l. (2008) in their incubtion studies reported reduction of Mn with ddition of ctivted crbon but AB-DTPA extrctle Mn incresed with FYM nd poultry mnure (PM). In the present study, PM increse the Mn content in soil compred to FYM indicting enrichment of Mn in poultry mnure wheres the ddition of TSP reduced its extrctility. The AB-DTPA extrctle Ni content in soil ws significntly ffected by the ddition of different mendments. According to the NEQS (1998), the wstewter irrigted plots hd higher Ni concentrtion (below the permissible limits) compred to ll other tretments nd tubewell irrigted plots showing its build up in soil. The ddition of mendments significntly reduced the Ni concentrtion nd the lowest vlues were recorded in plots treted with TSP nd poultry mnure. Sir, et l. (2008) reported decrese in Ni concentrtion with the ddition of FYM nd ctivted crbon nd this decrese in Ni were ttributed to its immobiliztion with humified OM in soil. The significnt reduction in Ni by TSP my be due to presence of C tht hs reduced its biovilility. Robinson et l. (1999) reported significnt reduction in both coblt nd Ni by the ddition of CCO 3. Led is one of the most widely studied nd most frequent polluting metl. Unlike Cr nd Cd, AB-DTPA extrctle Pb ws significntly (P < 0.05) ffected by the ddition of different mendments. DAP showed the gretest reduction compred to unmended wstewter nd tubewell irrigted plots, while the ddition of FYM nd HA incresed the extrctility of Pb. The effect of P contining mendments on Pb stiliztion is well documented in the literture (M et l., 1995; Hettirchchi nd Pierzynski, 2002). The ppliction of soluble phosphte (DAP) nd its effect on immobilizing Pb nd Cd is reported by McGowen et l. (2001). Ruby et l. (1994) indicted tht dequte levels of phosphte were responsible for the formtion of insoluble complexes nd the reduction in potentilly phytoville Pb. Bst nd McGowen, (2004) while compring lime, rock phosphte nd DAP reported tht DAP ws most effective in immobilizing Cd, Pb nd Zn nd lime ws the lest. Unlike Pb, the AB-DTPA extrctle Zn concentrtion ws not ffected significntly by either tretment. Interestingly, the wstewter irrigted plots hd lower vlues thn the plots irrigted with tubewell wter. This ws becuse the concentrtion of Zn ws much lower in the wstewter to be considered toxic ccording to NEQS (1998) for irrigtion. All the mendments enhnced the extrctle Zn compred to control nd wstewter irrigted plots. Unlike Sir, et l. (2008), the non significnt vritions in Zn content of soil my be due to the low level of Zn present in soil s well s in wter. Shumn (1999) observed tht Zn retention by soil incresed in the presence of orgnic mteril.

7 Srhd J. Agric. Vol.29, No.1, Tle 2. Effect of orgnic nd inorgnic mendments on the AB-DTPA extrctle metl content (mg kg -1 ) of soil irrigted with HIE wstewter Tretments Cd Cr Cu Fe Mn Ni Pb Zn TW Wstewter FYM DAP HA PM TSP LSD NS NS NS Effect of Amendments on Phyto-vilility of Metl Irrigted with HIE Wstewter The results of hevy metl concentrtion of plnts s ffected by vrious mendments (Tle 3) were significntly (P <0.05) vrile. The overll results suggest tht higher concentrtions of ll the metl under study were noted in leves when irrigted with wstewter while tube well irrigted plnts resulted minimum ccumultion of metls in leves. Higher vlues in the wstewter my be due to the fct tht wstewter ws composed of vrious types of industril, municipl nd domestic effluents tht contined vrieties of chemicls nd suspended solid hving vriety of metls. This cn be confirmed from the wter nlysis given in Tle I. These results re in line with the results obtined by Knsl nd Singh (1983), Schirdo et l. (1986) nd Lone et. (2003) who studied the effect of wste wter on mize, berseem, culiflower, spinch nd okr nd found considerle higher concentrtion of hevy metls compred to soil receiving tubewell irrigtion. The effect of different mendments on the plnt uptke of metl ws vrile (Tle 3). Addition of HA reduced the uptke of Cd, Cr, Mn wheres DAP ws effective in reducing the phytovilility of Pb nd Zn. The reson of lower concentrtion of Cd, Cr nd Mn my be due to dilution effect s significntly higher biomss ws produced when HA ws pplied. Addition of TSP significntly reduced the phytovilility of Fe nd Cu vilility ws reduced by the ddition of poultry mnure. The ddition of FYM with exception of Ni enhnced the phytovilility of metls (due to the binding of metls on orgnic mtter nd its subsequent relese to plnt s reported by Geebelen et l. (2002). This seems contrdictory when viewed in light of the extrctle metls reported in Tle 2, suggesting tht the extrctle metls not necessrily men phytoville s phytovilility is governed by other soil fctors like soil ph nd lime content. The superiority of DAP or TSP s Pb nd Zn stilizing gent s reported by Hettirchchi nd Pierzynski (2002) nd McGowen et l. (2001). From the Tle 3, it cn be further seen tht plnt ccumulted higher concentrtion of Cd, Cr, Fe, Ni nd Pb in plots irrigted with wstewter nd these vlues re considered to be excessive or toxic in mture lef tissues generlized for vrious species (Kt-Pendis nd Pendis, 1995). However, the vlues for ll the metls were within the permissible rnge in tubewell irrigted plots or in mny cses the ddition of mendments reduced the phytovilility. The concentrtion of Mn nd Zn ws within the sfe limits (Kt-Pendis nd Pendis, 1995) regrdless of the irrigtion wter supply nd mendments used. Tle 3. Effect of orgnic nd inorgnic mendments on the hevy metl content (mg kg -1 ) of plnts irrigted with HIE wstewter Tretments Cd Cr Cu Fe Mn Ni Pb Zn TW Wstewter FYM DAP HA PM TSP LSD CONCLUSIONS AND RECOMMENDATION Whet yield nd yield components were significntly ffected by the ddition of vrious mendments. Minimum yield ws hrvested from plots receiving only tube well wter wheres the higher yield ws hrvested from plots supplied with humic cid (HA). Tissue hevy metls results reveled tht higher concentrtions of ll the metl under study were noted in leves when irrigted with wstewter. Addition of HA reduced the uptke of Cd, Cr, Mn wheres DAP ws effective in reducing the phytovilility of Pb nd Zn. The need for wys to reduce helth nd environmentl risks while t the sme time sfegurding positive impcts of using wstewter cn be chieved by using mendments such s HA, DAP or FYM to reduce the hevy metl uptke of metls.

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