water Article Assessment of the Application of Ferrate(VI) in the Treatment of Agricultural Irrigation Water: Presence of Metals and Escherichia coli in Fresh Produce Kryss Araceli Vargas Gutiérrez 1, María Elena Rojas Meza 1, Fabricio Paredes Larroca 2,*, Erich Saettone Olschewski 2,* and Javier Quino-Favero 2,* 1 Centro Experimental La Molina, Instituto Nacional de Innovación Agraria, Ministerio de Agricultura y Riego, La Molina 15024, Peru 2 Grupo de Investigación en Soluciones Tecnológicas para el Medio Ambiente, Carrera de Ingeniería Industrial, Instituto de Investigación Científica, Universidad de Lima, Lima 15102, Peru * Correspondence: fparedes@ulima.edu.pe (F.P.L.); esaetton@ulima.edu.pe (E.S.O.); jquinof@ulima.edu.pe (J.Q.-F.) Abstract: The aim of this study is to evaluate the effects of ferrate (VI)-based treatment on sur- face water collected from the Rímac River as an irrigation water treatment model for bean (Phase- olus vulgaris), lettuce (Lactuca sativa), and radish (Raphanus sativus) plant species irrigated with treated water in the experimental field. The experimental field was divided into eight 625 m2 plots (50 m × 12.5 m) with sandy loam soil (sand 51%, silt 30%, clay 19%). The treatment system operated uninterrupted for three and a half months without deterioration in production, demonstrating that it can function continuously to improve water quality even when the effects on the parameters evaluated here did not reveal significant differences, presumably due to the prevailing effect from metal concentrations already found in the soil. This study also seeks to validate the effect of treatment on the concentration of plant tissue bacteria. Keywords: ferrate; water treatment; irrigation water; Escherichia coli Citation: Gutiérrez, K.A.V.; Meza, M.E.R.; Larroca, F.P.; Olschewski, E.S.; Quino-Favero, J. Assessment of the Application of Ferrate(VI) in the 1. Introduction Treatment of Agricultural Irrigation The consumption of fresh foods, such as salads prepared with raw vegetables, has Water: Presence of Metals and increased in recent years due to the promotion of healthy food options. However, the Escherichia coli in Fresh Produce. number of outbreaks of diseases transmitted by the consumption of fresh produce has Water 2023, 15, 748. https:// concomitantly increased [1], and the presence of bacteria resistant to several antibiotics doi.org/10.3390/w15040748 in fresh produce can only exacerbate the problem [2]. Disease outbreaks related to the Academic Editor: Christos S. Akratos consumption of fresh vegetables are commonly associated with agricultural irrigation water [3,4]. For example, in the Cajamarca valley, Peru, vegetable crops are irrigated with Received: 13 January 2023 Revised: 7 February 2023 water from rivers containing untreated wastewater. These vegetables are then sold in local Accepted: 9 February 2023 markets and consumed raw by the urban and rural population [5]. Similar scenarios have Published: 14 February 2023 also been reported in countries such as Brazil [6], England [7], and Ghana [8]. Irrigation is the controlled use of water sources in a timely manner to increase or sustained crop production [9]; irrigation includes the water that is applied by an irrigation system during the growing season, the water applied during field preparation, preirrigation, Copyright: © 2023 by the authors. weed control, harvesting, and for leaching salts from the root zone [10]. Licensee MDPI, Basel, Switzerland. Colorless and foamless water with minimum turbidity, total dissolved solids (TDS) This article is an open access article below 1000 mg/L at circumneutral pH, and specific conductance below 15 mmhos/m [11] is distributed under the terms and generally considered of good quality. However, Park et al. considers an electric conductivity conditions of the Creative Commons of up to 0.75 mmhos/cm (750 mS/cm) not to be a problem [12]. Being that irrigation is Attribution (CC BY) license (https:// the highest consumptive use of freshwater water [13] and since agricultural production creativecommons.org/licenses/by/ of food needs to be increased by around 60% by 2050 to meet the demands and provide 4.0/). Water 2023, 15, 748. https://doi.org/10.3390/w15040748 https://www.mdpi.com/journal/water Water 2023, 15, 748 2 of 15 food security [14], irrigation will have to attend the demand for water because of water scarcity. Water scarcity is the condition where water demands from agriculture and other sectors cannot be met due to low water availability [15]. Because food supply is closely related to freshwater supply and water availability is in a critical state, unconventional and substandard sources will be required [16–19] including, for example, domestic wastewater, industrial wastewater, and agricultural wastewater [20]. Surface water from rivers and lakes is considerably different from reclaimed water because elevated levels of N and P, disinfection by-products, and bacterial pathogens can remain in reclaimed water even after extensive treatment [21,22]. However, the quality of surface waters has great variation, and this occurs in waters subject to intermittent contamination events such as runoff, livestock upstream use, and uncontrolled discharges. This pollution in irrigation systems increases the risk of food crop contamination [23]. Some experiences using reclaimed water for irrigation have been positive. For example, table grapes irrigated with municipal wastewater were free of bacterial contamination [24]. A similar scenario was reported for lettuce crops [25]. However, another study considered that reclaimed water introduced contaminants in hydroponic tomatoes [26]. An additional risk associated with irrigation using reclaimed water is the introduction of heavy metals or metalloids that can accumulate in plant tissues. Studies claim that long-term irrigation with treated wastewater can cause accumulations of heavy metals at several concentrations in different aerial parts of lemon [27], rice [28], mango, and banana [29] plants. The water used for irrigation could be polluted with biological and inorganic con- taminants. Pathogens (bacteria, viruses, and protozoans) pose the greatest acute risk to human health and are a concern in freshly eaten produce; pathogen contamination is related to surface water sources [30]. The presence of heavy metals is an issue due to its potential impact on food quality and human health. Heavy metals have bioaccumulation properties; therefore, organisms will accumulate then and even convert them into more toxic substances [31]. Agricultural water treatments seek to reduce the risk of contamination of fresh produce with pathogenic organisms [32] and remove heavy metals [33] and pathogens [34] from plants. Improvement in the safety of fresh produce could require soil remediation, water remediation or both. Soil remediation techniques include containment (surface capping, encapsulation, and landfilling), removal (soil washing, soil flushing, electrokinetic extraction, and phytore- mediation) and stabilization (solidification, vitrification, and chemical stabilization) [35]. Among these methods, adsorption has been considered one of the most effective methods due to its low cost and high efficiency when in use [36], the simultaneous adsorption of inorganic and organic pollutants such as Cr (VI) and phenol [37], or even incorporate a heterogeneous catalyst for the removal of atrazine (ATZ) from soil [38]. Irrigation water treatment technologies have been sought to decontaminate irrigation waters with food-borne bacterial pathogens: slow-bed sand filtration, membrane filtration, ultraviolet (UV) radiation, ozone disinfection, peroxyacetic acid treatment, chlorine dioxide treatment, and chlorination with sodium hypochlorite [39]. Potential irrigation water treatment techniques include hydrodynamic cavitation, electrolyzed oxidizing water (EO), and electrochemical treatment [32]. One of the water treatment agents used is ferrate(VI); it is an iron species with a high oxidation state that acts as a powerful oxidizing agent and whose remnants are harmless ferric cations; therefore, it is deemed a green treatment agent [40,41]. Proposals to use ferrate as a multivalent agent have been described to remove inorganic contaminants, pathogens, and endocrine disruptors without the formation of chlorinated by-products [42]. The ferrate removal efficiency of copper, manganese, zinc, and natural organic matter (NOM) from river water with ferrate reached 86% for NOM, 99% for copper, 73% for Mn, and 100% for Zn [43]. The use of a low dose of ferrate improved the reduction of the chemical oxygen demand measured with permanganate (CODMn) by iron-manganese co-oxide films. Using 0.1 mg/L potassium ferrate, the removal of a CODMn of 20.0 mg/L Water 2023, 15, x FOR PEER REVIEW 3 of 15 Water 2023, 15, 748 3 of 15 ferrate, the removal of a CODMn of 20.0 mg/L reached a removal efficiency of 92.5% [44]. Fer- reaatec haesd aalsroe bmeeonv alpepflfiiecdie enffceyctoivfe9ly2 .t5o% re[d4u4c].e Fhuermratne fhecaasl aploslolubtieoenn inadpipclaiteodrse ifnfe scetwivaeglye btoy remduocveinhgu DmNaAn ,f decaamlapgoinllgu vtiioranl icnadpiscidatso arnsdi nbascetweraiagl eceblly mremborvainegs D[4N5]A, a,nda amlsaog rienmgoviirnagl ctraapcseisd osfa mndicrboapcotellruiatalnctesl linm neamtubrraal nweast[e4r5s ][,4a6n].d also removing traces of micropollutants in naturIanl twhiast esrtus d[4y6 a].n irrigation water treatment plant was built based on ferrate and ferric ions Ianbitlhitiys sttou dimyparnoivreri gthaeti ownawteart eqrutarleitaytm thernotupglahn otxwidaastbiounil tabnads ecdoaognufleartiroante parnodcefessrerisc. iSoondsiuambi lfietyrrtaotei mwpasro pvreodthuecewda etelercqtruoaclhiteymtihcraolluyg ihn osxitiud aatniodn aapnpdliecdo atgougelathtieorn wpirtohc efesrsreisc. Sioondsi utom trfeeartr asuterfwacaes wpraotedru ccoeldlecetledct rfroocmhe tmheic Ralílmyainc Rsitvuera nasd aanp iprrliegdattionge wthaetrerw tritehatfmerernict imonosdetol ftorera btesaunr,f alectetuwcaet,e arncdo lrleacdtiesdh fcrroomp tphreoRduímctaiocnR. iTvehre aRsíamnaicr rRigivaetiro rnewceaivteers tdreoamtmesetnict manodd ienldfuorstbrieaaln d,ilsecthtuarcgee, sa,n wdhriacdhi isnhcrceroaspep itrso cdounccteionntr.aTtihoensR oímf macetRailv aenrdr emceicivroeosrdgoamniesmstisc, and icnodnussidtreirailndgi stchhea ergffeesc,twivhenicehssin ocfr eaa csoenittsincuoonuces nttrreaattimonesnot fsmysetetaml afnodr imrriicgraotoiorgna wniastmers,, aand aucotonmsidateerdin sgytshteemef ffeocrt tivheen ceosnstoinfuaocuosn ptirnoudouucstitorena otmf feenrrtastyes itse mdefsoigrnirerdig aantido ndewvaetleorp, eadn aount soimtea ttoe dcosnytsinteumoufoslryt pherocdounctein fueorruastep troo dimucptrioovneo ifrrfeigrraatitoenis wdaetseirg qnuedaliatnyd. Tdheev setluodpyed alosno ssieteektso toco vnatliinduaoteu tshlye epfrfoedctus coef ftererraatmteetnot iomnp trhoev ceoinrcriegnattriaotniown oatfe mr eqtuaalsli itny. leTahfye svteugdeytaabllseos s(leeetktuscteo),v laelgiduamteesth (ebeeaffnesc)t,s aonfdt rpelaatnmt etnistsoune tbhaectceorniac e(rnatdraistihoens)o. f metals in leafy vegetables (lettuce), legumes (beans), and plant tissue bacteria (radishes). 2. Materials and Methods 2. Materials and Methods 22..11.. FFeerrrraattee((VVII)) PPrroodduuccttiioonn TThhee ffeerrrraattee((VVII)) iioonn iiss pprroodduucceedd tthhrroouugghh eelleeccttrroocchheemmicicaallo oxxididaatitoionno offa a2 200c cmm× × 2200 ccmm iirroonn aannooddee aanndd aa 2200 ccmm ×× 2200 ccmm ssttaaiinnlleessss sstteeeell ccaatthhooddee sseeppaarraatteedd bbyy aa ccaattiioonn eexxcchhaannggee mmeemmbbrraannee ((22..33 ww c 2 cmm2; ;CCTTIIEEMM-1-1, ,ZZibiboo CCaanntitaiann, ,SShhananddonong,g ,CChihnian)a, )w, whihcihc hjojionitnlytl yfofromrm a areraecatoctro. rT.hTreher ereearcetaocrtso orfs tohfe tshaemsea dmime denimsioennssi coonnsnceocntende ctote ad 5t Vo aan5dV 0.a72n dA 0p.o72wAer psoouwrceer sfooru arc ceufrorrenat cduernresintyt doef n8s0i tAy/om2f 8 w0oArk/emd2 awlteorrnkaetdelayl tdeurnriantge ltyhed u5 rhin egletchtero5lyhsies.l eAct sryoslytesmis. Aof sByTs1t0e1mS poferBisTt1al0t1icS ppuemripstsa (lLtiecapduFmlupids, (BLaeoaddinFglu, iCdh, iBnaao) cdoinngtr,oCllhedin bay) ac oSn7t 1ro20ll0e dprboygraamS7- 1m2a0b0lep rlooggirca cmomntarobllleerl o(PgiLcCc)o (nStireomlleenrs(,P BLeCrl)in( S, iGemeremnasn, yB)e frillilne,dG eearcmh raenayc)tofirl lcehdameabcehr wreiatch- t5o0r%c hNaamObHer (wQuitihm5p0a%c, NCaaOllaHo, (PQeuriúm) paancd, Cdiaslclhaoar, gPeedr út)hea nfderrdaitsec hoanrcgee dthteh seyfnetrhraesteis owncaes tchoemspylnetteh.e Esiaschw raesaccotomr plreotde.ucEeadc h12r3e.a5c mtoLr pofr o0d.2u2c4e dmo12l/3L. 5somluLtiofn 0(.2262.49 mg foelr/rLateso/Llu) tiino n5 (h2.6 F.9ergrafter prartoed/uLc)tiionn5 wha.sF aeurtroamteapterdo dbuyc tthioen sewqausenatuiatol mwaotrekdinbgy otfh tehes ethqureeen rteialctwoorsr.k Tinhge orefstuhletinthgr eferraeatec tworass. sTtohreedre isnu alt itnagnkfe arnradt elawtear susteodr efdori ndaailtya ntrkeaatnmdenlattse. rFuersreadtef ocor ndcaeinly- treaatitomnesn wtse. rFee rmraetaescuornecde nsptreacttiroonpshwoetoremmeteraicsaulrleyd astp 5e0c5tr onpmh outsoimnge tari cUaVlly26a0t05 0s5pencmtroupshinog- atoUmVe2te6r0 0(Sshpiemcatrdozpuh,o Ktoymoteot e,r J(aSphainm)a adnzdu ,aK myotloa,r Jeaxptainc)taionnd caomefofilcaireenxt toinf c1ti0o5n0 cLo/emffiocli ecnmt o[4f71]0. 5T0heL /femrroaltec(mVI[)4 7p]r.oTdhuectfieornra dteia(VgrIa)mpr iosd suhcotwion idni aFgigraumre i1s,s ahnodw tnhein pFroigduurceti1o,na nudnitth ies pshrodwunc tiino nFiugnuirtei s2.s hown in Figure 2. FFiigguurree 11.. FFeerrrraattee((VVII)) pprroodduuccttiioonn ssyysstteemm.. Water 2023, 15, x FOR PEER REVIEW 4 of 15 WWaatetrer2 2002233, ,1 155, ,7 x4 8FOR PEER REVIEW 44 ooff 1155 Figure 2. The ferrate(VI) reactor installed in th e treatment plant. FFiigguurre 2. The ferrate(VI) reacTe h2.eT shuepfeerrrvaitseo(VryI) croeanctt toorri innssttalled in the treatment plant. rol andal ldedatian athcequtriesaittmioenn t(SpClaAntD. A) system manages and moni- tors fTeThrhreaes tseuu pppereorrvdviusisocortiyroycn oc ionnnt trthorelo alr neaadncdto adrtsa.t aWc aqhcueqinus iaitsi foietniror(naSt C(eS A(CVDAIA)D d)Aossy)e ss toyefsm t1e.1m2a mnagagn/eLas giase nusd saemndd,o unmnitodonersir- fttehorer sas ftaemrprear otoedp puerrcoatditoiunncgti incoontnh ideni rttiehoaenc rsteo, arthcst.eo Wfreshr. rWeantheae(Vnfe Iar) rfeaelrteercat(trVeo Is()VydnI)ot hdseeossoiesf o1pf.i l1o2.1tm 2p mgla/gnL/tL ci saisnu u stsereedda,t,u uunnpdd eteorr t2thh8e8e smsaa3m/deea oyop.p eerraattiinngg ccoonnddiittiioonss,, tthhee ffeerrrraattee((VII)) eelleeccttrroossynttheessiiss piillott pllaantt ccaan ttrreeaatt uupp ttoo 228888 m33/daay. 2.2. Irrigation Water Treatment 22..22.. IIrOrrriuiggraa tptiioiolnno tW waatateterer rTT rtrereaeatamttmmeennetnt t plant was installed at the La Molina Experimental Center of theO Nuurar ptpiioillonotat lw Ianatsteetrirt tutrrteeeaa totmf eAenngttr pipclluaanlnttut rwaala ssIn iinnsosttvaalalllteeidodn aa t(tI tNthheIeA LL)a a( FMigooluliinrneaa 3 EE)x xipnpe eLrriiimeaen,n tPtaaellr CuCe.e nTnthteeerr ocoeffn tththeeer NNcoaamttiioponnraiaslle IsInn sastgtiitrtuiucttueel otouffrA aAglg rlriaicncuudllt tudureradalli IcInanntneoodvv ataotti ioornens (e(IIaNrcIIAhA ))b ((yFF iitgghuuerr ePe 3e3)r)u iinvni LaLinim gaao,,vP Peeerrnruum.. TeTnhhtee. cCceernnotpteer ricr orciomgmaptprioirsines sewsa agatrgeicrru iiclsut ueltrxuatrrlaalalc ntleaddnd dfer dodmiecda tihecadet etRodímr etoase cra eRrsciehvaebrrcy htht hrbeoyuP tgehrheu avPniae nirrurgviogivaanetir ongnmo vceaennrtna. mlC arenondpt. isCrtroriogrepadt ii orirni gawa rateitoseenrr ivwsoeaixrtet. rrTa ihcste ee drxitvfrreaorcm twetdaht efrrRo dmíme vathicaetR iRoivníme rpatochi nrRoti uvisge har ptahpnrroioruxriggmha ataitonenl yirc r7ai ngkaamltia ofnrndo cmsat notharel d aenixnd- apsteroerrismeedrev niontia ral. cTrrehoseepr ravivroeiarr. awTnhadte e rrreicdveeeirv iweasta idoteonrm pdeoesivtniicta tieisfofanlpu ppeonroitnsx tia minsda at pienlpydruo7sxktirmmiaalft rdeolimysc 7ht hakermgee xfsrp ouemprism ttrheena temaxl.- cTprhoeerpi mraereseenartavanlo dcirr roiespc efairlvleeads a dtnowdmi creees ctaei ciwveefeflse udke oanmntsdeas itntiscd ewinffadltuueersn tirtsisa ulasdnedids ci nhtoad ruigrsretisrgiuaaptle ds tairs ec1ah4ma-hr.geTcehtsae urrepe ssptelrroevtao moirf. icTsrhofiepll erodewstenwrevidcoe ibray i wsth efeiel kcleeadnn ttdewri.it cTsehw eaa etwexrpeeieskrui masneeddn ttiaotsl i frwerriagrtaettre (iaVs 1Iu)4-s-behades cettoda r iterrrepiagltoamtteoe fnact r1po4lp-ahnoetwc itsna derede spbigylontthe odef ctcoer notrtpe rao.tw T2nh4e eLde/ mxbpyine tr hfioem rce aenn dttaaelirlf.y eT rthroaetta eelx( oVpfIe 1)r-5ibm maes3en, dtaantlr dfee airttr miast eeun(sVteIpd)l -tabona itsreirsdigd tareteseai gatm nheeadnlft-t hopeltacrnteaatr ties2 cd4reoLsp/ig mpnlieondt fftoorr t atrhedi 3 asat is2lty4u tdLoy/tma. lino ffo15r am da, ialny dtoittails oufs 1e5d mto3,i rarnigda itte isa uhsaeldf- htoe citrarirgeactreo ap hpalloft-hfoecrttahries csrtoupd yp.lot for this study. (a) (b) (a) (b) (c) (d) Figure 3. Cont. (c) (d) Water 2023, 15, x FOR PEER REVIEW 5 of 15 (e) (f) Figure 3. (a) Aerial image of the experimental area at INIA. The color of the reservoir water is an indicator of the concentration of algae. Water treatment plant images: (b) pumping system of the Rímac River water reservoir; (c) dosing pumps, (d) serpentine mixer, (e) treated water reservoir, (f) geotube. WaWtera t2e0r2230,2 135, ,1 x5 ,F7O4R8 PEER REVIEW The pilot plant (Figure 4) consists of a centrifugal pump that drives t5h eof 5 w1o5fa 1t5er for treatment, a water return system that manages the incoming water flow of the treatment plant, a rotameter, two static mixers, and a built-in serpentine mixer with 1.5-inch PVC pipes with a total length of 22 m. Ferric chloride 40% (Quimpac, Callao, Perú) was dosed at the inlet of the serpentine mixer at a rate of 29 mg/L using a peristaltic pump; a couple of meters further on, ferrate(VI) was dosed at a rate of 1.12 mg/L using a diaphragm dosing pump; and at two more meters, the SIFLOC 13,980 flocculant (MERCK ,Barcelona, Spain) was injected through another peri- staltic pump at a rate of 1.0 mg/L. The outgoing flocs from the serpentine mixer were retained in a 3 m × 2 m Tencate GT500 geotube (Tencate Geosynthetics, Pendergrass, GA, USA), and the outlet water was pumped into a reservoir to irrigate the experimental area. The dosing of the ferrate(VI) alkaline solution increased the pH to a value close to the target value of 6.50. After starting th(ee) operation of the treatment plant and co(nf)t rolling both the pH values aFnigdFu igtrheu er3e . f(3lao.) (cAa )peArioearld iiaumlciamtgieoa gnoef, othfete he eqxpueexarpliemitryeimn oteafnl ttarrleaar teaeatd IaN taIInNAd.I A Tuh.nTe thcreoelcaootrl eodrf otwhfeta hrteesrree rwsveoraivsro weirvawtaealrut eiasr taiesnd a nfor 13 cionndiniscdeacitcouartt ooivrf eoth fdet haceoyncsoc entnocte rnvatterioraintfi oyon f toahlfgeaa lecg.oa Wer.raeWtceatrt etorreptaretemraatetmniote nptl aopnlfta ntimht eiam gtearsge:e a(sbt:m)( bpe)unpmtu pmpinlpgai nsgyt.s stTyesmhte mo fi nothlfet ht ewater wRaímRs íamsca aRmcivRpeirlv ewedra twoeran trceeerse rarevts oetrihrv; eo(ci r)b; de(ocg)siindnongs ipinugm popusfm, t(hdp)se ,s e(ddrap)yesne taripnneedn m tianixfeteerm,r (iexth)e rte,r e(raeet)estdere rwavtaeotdeirrw rweastaeersrv rofeiislrel, er(vfd)o ior,n the dgaeyo(fts)u gibtee o.w tuabse .refilled previously to the beginning of the treatment. An hourly composite of 5 samTphlee sp oilof t1 pLla onft w(Faigteurr ew 4a)s c monasdi e in the morning and afternoon for a total ofThe pilot plant (Figure 4) consstiss tosf oaf caencetrnitfruigfuagl aplupmupm tphatht adtridvreisv etsheth we awteart ef two sam-ples an r orf or tretartematemanlety,n zate ,wda.aw teart erretruertnu rsnysstyesmte mthatht amtamnaangaesg ethseth inecionmcoimngin wgawteart eflroflwo wof othf eth teretartematemnet nt plapnlatA,n tat , trahoitrsao mtsateamtgeeret,,e trpw, Htow , sottuastrtiabct iimdciimtxyei,xr sbe,ri osa,ncahdn eadm baiucbialult -ioilntx- iysnegrsepenrep ndetiennmtein amenimdxe i(rxB ewOr iwDthi5 t)1h,. 5c1-o.i5n-cdinhuc PchtViPvCVi tCy, and tpoitpapeli psm ewseitwtahil t ahv taaoltutaoelt sale lwnlegentrhge t ohrfe o2cf2o2 rm2d.me d. . Ferric chloride 40% (Quimpac, Callao, Perú) was dosed at the inlet of the serpentine mixer at a rate of 29 mg/L using a peristaltic pump; a couple of meters further on, ferrate(VI) was dosed at a rate of 1.12 mg/L using a diaphragm dosing pump; and at two more meters, the SIFLOC 13,980 flocculant (MERCK ,Barcelona, Spain) was injected through another peri- staltic pump at a rate of 1.0 mg/L. The outgoing flocs from the serpentine mixer were retained in a 3 m × 2 m Tencate GT500 geotube (Tencate Geosynthetics, Pendergrass, GA, USA), and the outlet water was pumped into a reservoir to irrigate the experimental area. The dosing of the ferrate(VI) alkaline solution increased the pH to a value close to the target value of 6.50. After starting the operation of the treatment plant and controlling both the pH v alues and the floc production, the quality of treated and untreated water was evaluated for 13 FciognFuisrgeeuc 4rue.t Wi4v. eaW tdeartae ytrrste rateotam tvmeeenrnitft pyp llatahnnett ddcioiaarggrreraacmmt .o. peration of the treatment plant. The inlet water was samFeprlreidc cohnloceri date t4h0e% b(eQgiuninminpga co, fC tahlel day and after the reservoir was filled on the damysiO xiten rw aaat sad rraeaiftlieylloe bdf a2 p9srimse,vg it/ohLuesu ltysri entoag ttamhpeee nbreits gtpianl aaon,tP ceorún)suwmas dosed at the inlet of the serpentineltnicinpgu omf pth; ae ctoreeusap talmeneo nfatmv. eAertnear ghseof uuorrftlh y2e c.r2oo5mn ,Lpfo eosrirfta e4t eo0(f%V I )ferric c5h slwoamraisdpdeleo, ss0 eo.d6f 21a5 tL aL or oaf tfwe 2ao6tfe.91r. 1wg2/aLms fgme/raLrdauet seiin(nV gthIa)e sdmoialouprhtnirioanngg,m annddod sa i1fnt5eg rLpn uomof nfpl f;ooacrnc adu ltaaotnttawtl 1oo0fm 0tw0o rome smga/meLte-. rs, pleths eanSaIFlyLzOedC. 13,980 flocculant (MERCK, Barcelona, Spain) was injected through another 2.3p. EerAxisptt eatrhlitimisc espntautgamel p,C parHot pa, tFruairtebeldiodsf it1y.0, bmiogc/hLe.mTihcaelo ouxtyggoeinng dfleomcsanfrdo m(BOthDe5s)e, rcpoenndtuincetivmitiyxe, ranwde re totraelt Tamhineeet adel vivnaallauu3aestm iwo×ne r2oe fmr etcrToeerandtceeaddt.e wGaTt5e0r0 igne octruobpes (Tweansc actearGrieeodsy onutht eotincs ,aPne nexdperegrriamsse,nGtaAl, half- hecUtaSrAe) ,aarnead wthietho ustalentdwya ltoeramwa ssopilu (msapnedd i5n1to%a, sreilste 3rv0o%ir, tcolairyr i1g9a%te)t,h we hexicphe rwimaesn dtailvaidreead. into The dosing of the ferrate(VI) alkaline solution increased the pH to a value close to the target value of 6.50. After starting the operation of the treatment plant and controlling both the pH values and the floc production, the quality of treated and untreated water was evaluated for 13 consecutive days to verify the correct operation of the treatment plant. The inlet water was sampled once at the beginning of the day and after the reservoir was filled on the days it was refilled previously to the beginning of the treatment. An hourly composite of 5 samples of 1 L of water was made in the morning and afternoon fo r a total of two Figsuarme p4.l eWsaatnera tlryezaetmd.ent plant diagram. At this stage, pH, turbidity, biochemical oxygen demand (BOD5), conductivity, and totOalnm ae tdaal ivlya lbuaessiws, etrheer terceoartdmeedn. t plant consumes an average of 2.25 L of 40% ferric chloridOe, n0.a62d5a Lil yofb 2a6s.i9s ,gt/hLe fetrrreaattem(VenI)t spollauntitocno, nasnudm 1e5s La onf aflvoecrcaugleanotf 120.0205 mLgo/fL4. 0% ferric chloride, 0.625 L of 26.9 g/L ferrate(VI) solution, and 15 L of flocculant 1000 mg/L. 2.3. Experimental Crop Fields The evaluation of treated water in crops was carried out on an experimental half- hectare area with sandy loam soil (sand 51%, silt 30%, clay 19%), which was divided into Water 2023, 15, 748 6 of 15 Water 2023, 15, x FOR PEER REVIEW 6 of 15 2.3. Experimental Crop Fields The evaluation of treated water in crops was carried out on an experimental half- heeicgthatr e62a5r ema 2w piltohtss (a5n0d my l×o a12m.5 smoi)l. (Tshaen dlan51d% w, assi lpt r3e0p%ar,ecdla fyor1 p9%lan),tiwngh,i cahndw saosild siavmidpeldes inwtoerei gahntal6y2z5edm t2op dloettesr(m50inme t×hei1r2 i.5nimtia)l. mTheteall acnodntwenats. Fpirneaplalyre, dirrfiograptiloann ttianpge,sa wnderseo iinl - sastmalpleleds, swpearceedan 7a5l ycmze daptaordt.e termine their initial metal content. Finally, irrigation tapes were iInns ttahlilse de,xsppearcimeden75tacl mfiealpda, rwt.e planted beans (Phaseolus vulgaris), lettuce (Lactuca sa- tiva)I,n atnhdis reaxdpiesrhiemse (nRtapl hfiaenldu,s wsaetipvluasn)t eind tbheraenes d(Pifhfeasreonlut scavmulgpariigs)n,sl.e tFtouucer (pLlaocttsu cwaesraeti virar)i,- agnadteradd wisihtehs t(rReaptehdan wusatseart iavnusd) tihnet horteheedr iffofeurre wntitcha munptariegantse.dF wouarteprl oetxstrwaecrtedir driigraetcetdlyw friothm trtehaet erdesweravtoerira. nTdheth peloth learyfoouutrs wiethreu rnatnredaotmedlyw saetleercteexdtr, aacst esdhodwirenc tilny Ffriogmureth 5e. rTehser vpoloirt.s Twhe rpel oirtrliagyaoteudts inw 3e rme orannthdso fmorly bseealnesc t(egdr,eaesn sphoodw hnairnveFsitg)u, 1re m5o. nTthhe fpolro ltesttwuecere, airnrdig 1a tmedoninth 3fmoro rnatdhishfoers.b eans (green pod harvest), 1 month for lettuce, and 1 month for radishes. FFigiguurere5 .5D. Disitsrtirbiubtuiotinono fo(fa ()al)e tlteuttcuecaen adn(db )(bra) driasdhischro cprsoipns tihne tehxep exripmeerinmtaelnptlaolt sp.loWtsa.t eWr afltoewr sfloinwtsh ein dtihreec tdioirnecotfioanrr oowf sa,rproipwins,g pinipbinluge .inY eblllouwe. pYleoltlso:wir rpigloattiso: nirwriigtahttiorena tweditwh atrteera;tpedu rwplaeteprlo; tpsu: irrprlieg aptiloonts: wiirtrhiguantitornea wteidthw uantterre. ated water. 22.4.4. .W WaatetrerQ QuuaaliltiytyA Annalaylysissis ppHHl elevveelsl,s,e elelectcrtirciacal lc oconndduuctcitvivitiyty, B, BOODD5,5,t uturbrbididitiytya annddc oconncecenntrtaratitoionnsso of fm meetatalslsa anndd mmeetatallloloididss( A(As,s,A Al,l,C Cdd, ,C Coo, ,F Fee, ,H Hgg, ,P Pbb, ,N Naa, ,a annddZ Znn))m meeaassuurreeddb byya aS Shhimimaaddzzuu2 2003300( (SShhiim-- ddaazzuuC Coroproproartaiotino,nK, yKoytot,oJa, pJapna)nin) dinudctuivcetilvyeclyou cpoluedplpedla spmlaasma sms sapsesc strpoemctertoemr (eItCerP -(MICSP)- wMerSe) rweceorred redcoarsdperde vasio purselvyioduesclyri bdedsc[r4ib8]e.dp [H48, ]e.l pecHtr, ieclaelcctorincdalu cotinvdituy,ctainvditytu, arbnid ittuyrbwideriety rewceored erdeconrd-seidte ,opn-Hsitaen, dpHel eacntrdic ealecotrnicdaul cctoivnidtyuc(EtiCvi)tyu s(iEnCg) HuascinhgH HQa4c0hD H(QH4a0cDh, (LHoavceh-, laLnodv,eClaOnd, ,U CSOA,) UmSuAlt)i pmaurlatmipeatrearmeeqtuerip emqueinptm, aenndt, taunrdb itduirtbyiduistiyn gusainLgo av iLbovnidboTnBd- 2T1B1-2IR11 tuIRrb tiduirmbiedtiemr e(Lteorv i(bLonvdib, oSnchdl,e Sefcshtlreaeßfes,trDaoßrem, Dunodrm, Guenrdm, aGneyr)m. BaOnyD)5. wBOasDd5 ewtearsm dineetedrumsiinegd auHsiancgh aB OHDacThr aBkOIIDiTnrsatrku ImI einsttirnumthenlta bino rtahteo rlyabuosriantgorsya muspilnegs csoalmlepcltesd cloesllsetchteadn laenssh tohuarn baenfo hreoumre baesfuorreem meenat.surement. 22.5.5. .S SooililA Annaalylysissis SSooilils asmamplpinligngw wasapse prfeorrfmoremderda nrdaonmdolymilny eianc heaocfht hoef 1t6hep l1o6t spolfotths eoef xtpheer iemxpeenrtiaml cernotpal acreroap. T ahreease. Tshamespe lseasmwpelrees awnearley zaendalbyyzeadc beryt iafi ceedrtliafbieodr alatobroyra(Gtoernye (rGael nAenraall yAtincaallySteicravli cSeesr- (SvAicGes) ,(SLAimGa),, LPiemrua), Puesirnug) uthsienEgP tAhe/ ESPWA-8/S4W6 m-8e4t6h mode.thTohde. rTehseu rltessuarltes laisrtee ldisitnedT ianb lTeaAbl1e oAf1 Aopf pAepnpdeixndAi.x A. 2.6. Microbiological Analysis for Escherichia coli Detection in Radishes 2.6. Microbiological Analysis for Escherichia coli Detection in Radishes Fresh items without damage were rinsed with water and decontaminated by immer- sion inFr9e5s%h eittehmanso wl aitnhdourut bdbaemdafgoer w60esr;e arfitnesretdh iws istthe pwtahteeyr awnedre diemcomnetrasmedinaanteddr ubbyb iemdmfoerr- 6s0iosnin in2 .955%%s eotdhiaunmolh aynpdo cruhblobreitde ,fowra 6s0h esd; atfhterer ethtiims setsepw tithheyst wereilree wimatmere,rasnedd aalnldow ruedbbteod dfroyr i6n0a s cilne a2n.5b%e nsochdifuomr 1 hhy.pToecnh-lgorraitme, swamasphleeds wtherreee ttriamnessf ewrriethd stotesrtileer iwlea0te.5r,L asntdo malalocwheerd btaog sdcryo nitna ian icnlega1n0 0bemnLcho ffo0r. 11% hb. uTfefner-egdrapmep staomnepalensd wheorme otrgaennsizfeerdrefdor t6o0 ssteartil2e5 00.r5p Lm s[t4o9m].- acher bags containing 100 mL of 0.1% buffered peptone and homogenized for 60 s at 250 rpm [49]. Serial dilutions were performed, and one milliliter of each dilution was placed Water 2023, 15, x FOR PEER REVIEW 7 of 15 in a petri dish adding 20 mL of molten RAPID’E.coli 2 medium (BioRad, Hercules, CA, USA). Plates were incubated at 37 °C for 24 h and the results were expressed as CFU/g. 2.7. Plant Tissue Metal Analysis Elemental analysis of the samples were performed by ICP-MS. The samples were Water 2023o, 1v5e, 7n4 8dried at 60 °C for 24 h. Then, to determine metal concentrations by ICP- MS, 0.50 g7 of 15 of these samples were digested using 3 mL of a nitric acid–perchloric acid mixture in a 3:1 ratio [50]. The bioaccumSuerliaatlidoinlu ftiaocntsowr e(BreApFe)r foorfm thede, manedtaonlse wmailsli lcitaelrcoufleaatcehdd ailsu tfioolnlowwass palcacceodrdininagp etri to [51]. dish adding 20 mL of molten RAPID’E.coli 2 medium (BioRad, Hercules, CA, USA). Plateswere incubated at 37 ◦C fo𝐵r 𝐴24𝐹h=an𝐶d𝐶the results were expressed as CFU/g.2.7. Plant Tissue Metal Analysis (1) Elemental analysis of the samples were performed by ICP-MS. The samples were oven where Cplant is the cdorinedceant t6r0a◦tCiofnor i2n4 thh.eT heedni,btoled petaerrmt oinfe tmheet avlecgoentcaenbtlrea taionnds bCysoIiCl rPe-pMrSe,s0e.5n0tsg tohf eth ese metal concentratiosnam inp ltehs ew seoreild (igTeasbtelde uAsi1n go3f mALppofeannditirxic Aac)i,d b–optehrc helxopric acid mixture in a 3:1 ratio [50].The bioaccumulation factor (BAF) of the metals was craelcsuseladte idna ms fgol/lkowg soafc dcorryd ing matter. to [51]. C BAF plant= (1) 2.8. Statistical Analysis Csoil Comparison owfh EersecCheplraincthisiat hceolcio CncFeUnt rpateior ngirnatmhe oefd ipblleanpta rttisosfuthee wveagse tpaebrlefoarnmd eCdso ilwreitphre ase nts Welch two-sampleth te-tmesett aul scoinngce nRt r[a5t2io]n. in the soil (Table A1 of Appendix A), both expressed in mg/kg ofdry matter. 3. Results 2.8. Statistical Analysis The results of theC coommpabriinsoend otfrEeascthmereicnhita ocfo lifeCrFrUatep(eVr gI)r aamndof Fpela(InItIt)i sisruriegwataisopne rwfoartmeerd awreit h a Welch two-sample t-test using R [52]. as follows: 3. Results 3.1. Variation in pH, EleTchtreicreaslu Cltosnodfuthceticvoimtyb, iBnOedDtr,e antmd eTnut robf ifdeirtrya te(VI) and Fe(III) irrigation water are The average ianscfoolmloiwnsg: pH during the 13 treatment days was 10.48 ± 0.39 (average ± SD); water has diu3.r1n. aVla rviaatiroinaitniopnHs, Edleucetr itcoal Cthoned udcrtaivwityi,nBgO oDf, atnhdeT uwrbaitdeitry to irrigate the other fields and because theT rheesaevrevroagier insc ormepinlegnpiHshdeudri nwg iththe 1w3 atrteeartm. Aenfttdeary tsrweastm10e.4n8t±, t0h.3e9 p(aHve roafg eth±e SD); water decreased two aatenr haavsedraiugren aol fv a6r.i6a3ti o±n s0d.4u7e, taoctheiedvrianwgi nag soifgtnheifwicaatnert troeidrruigcatitoe nth eino tBheOrDfie lds from 7.5 ± 4 to 2.1 a±n d0.b8e7c aaunsde tah esirgesneirfviociarnist rreepdleuncisthioend winit htuwrbatiedr.itAyf tferrotmrea 3tm7 e±n t4,.t5h etop H6.5o f±t h2e.0w. ater The average incomdecreased to7i.5ng± e4letoct2r.1ic a ±a nl caovnerdague0.87 andcat oifv6it.63 ±signyifi ocafn 7 03.47, at re0d ±u c5 c5h iμevsi/ncgma significant reduction in BODtion in turbiindcitryeafrsoemd3 t7o± 7747.5 ±to 462.5 μ±s/2c.m fr 0. om The after treatment. Thavee irnagcereinacsoem iin gceolnecdtruiccatlivcointyd uicst iavtittyriobfu7t3e0d± to55 tµhse/ ccmomincbrienaesedd ttroe7a7t7m±en42t µosf/ cm ferric chloride anda fNteraOtreHat msoelnut.tiTohne cinocnretasieningco tnhdeu cstyivnithyeis iaztterdib ufeterdrattoet(hVeIc)o. mThbien eddatirleya tvmael-nt of ues obtained of pHfe,r erilcecchtlroirciadle caonnddNuacOtHivsiotylu, tBioOn Dco,n atanindin tgutrhbeidsyintyth aesriez esdhfoerwrante i(nV IF).iTghuerdea 6il.y values obtained of pH, electrical conductivity, BOD, and turbidity are shown in Figure 6. 12 50 11 40 10 9 30 8 20 Inlet 7 Outlet 10 6 Inlet Outlet 5 0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Day of treatment Day of treatment Figure 6. Cont. pH Turbidity (NTU) Water 20W2a3t,e r1 520, 2x3 F, 1O5R, x P FEOERR P REEVR IREEWV IEW 8 of 81 5o f 15 Water 2023, 15, 748 8 of 15 900 20 900 20 18 InletInlet 850 18 Outlet 850 16 Outlet 16 800 14 800 1412 750 1102 750 180 700 8 700 6 650 46 650 24 600 Inlet Outlet 02 600 550 Inlet 0 0 Ou1tlet 2 3 4 5 6 7 8 9 10 11 12 13 14 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 550 Day of treatment Day of treatment 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Figure 6. pH, turbidDaityy of, terelaetmcternitcal conductivity, and BOD5 variations thrDoauy gofh troeautmt etnht e 13 days of treat- Figumreen 6t. (pmHea, ntu vrabliudeist yw, ietlhe csttarincdard deviations). Figure 6. pHa,l tcuorbniduityc,tievleictytr,i caanl dco BnOduDct5i viatyr,iantidonBsO tDh5rovuargiahtioounts tthreo 1u3g hdoauytst hoef 1tr3edaat-ys of men3t. 2(m. Veaarnia vtiaolnuse sin wt rMeitaehttm aselt naatnn(ddm aMeradne tvdaalellvuoeiidas twCioiotnhnscs)et.an ntdraartdiodnesv iations). 3.2. VariTatrieoantsm ienn Mt r3ee.2tda.ulV caaerndiad t tiMhonese ctiaonlnMlociedtna tlCraaontndiocMennestt aorlaflo tAiidosnC, soA nlc,e nPtbra, taionnds Zn. In contrast, the concen- trations of Fe, Co, anTdre Natam iennctrreeadsuecde.d Tthe cinoncrceanstrea tinio nFse ocfaAns b, Ae le,xPpbl,aaindedZ nb.yI nthceo natdrdasit,iothne concen- ofT freeraratmte eanntd r feedtrruaictci eocndhsl otohrfiedF ec,o. CTnohc,eea nnintdrcaNretaiosinnec sir neo afCs eAod sm. ,T aAhyel ,bi nPec bre, alaasnteedidn ZtFone t.ch aIenn cbcoeomenxptproalassiitnti,eo tdnh beoy fc ttohneeca ednd-ition tratiiroonns aonfo Fdee, uCseod, o affonfred rf reNartreaa atien dcgrefenraersirceacdtih.ol onTr.hi dTeeh .ienT ichnreceiranescaerse eai nsien F iNne Cac oaisnm d bauyee b eteoxr pierloatnien daentdoo dtbheye octoxhmied paaotdisoditnio tinoonf the of feinr raa 2te0 amnodl/ Lfe NrraiicrOo cHnha lsnoorlduidetieuo.sn eT,d hffoeor r iffneecrrrrraaettaees(gVee nIi)ne rs aCytniootn hm.eTsahiyse, biinnecj rereceatlseaedti enddiNr teaoci tstlhyd ueine cttoom tirhopeno iansnilteoitdo.e nTo hoxeifd tahtieo n in ironr easnuoltds eo butsaeinde fdoa fro2 f0re mCrrdoal t/aenL dgN eHanOgeH rwasteoiroleun tn.i ooTnth ,cfeoo nrincflecurrrseaiavtese(e.V DIi)nas iyNlyna tvh iaesls uidse,usi neoj eft comt eiedrtoadnli r aeancntdloy mdinet tooaxltlhiodeidain tlieotn. T he concentrations orbestauilntseodb atarien esd for Cd and Hg were not conclusive. Daily values of metal and metalloidin a 20 mol/L NaOcHon scoenlutrtaitoionn,s fhooobrwt afeinnr eirnda tFaeri(egVushIr)oe ws7y.n nitnhFeigsiusr,e i7n.jected directly into the inlet. The results obtained for Cd and Hg were not conclusive. Daily values of metal and metalloid concen0.0t30rations obtained are shown in Figure 70..30 Inlet 0.25 Outlet 0.025 0.030 00.2.300 0.020 Inlet 00.1.255 Outlet 0.025 0.015 00.1.200 0.020 0.010 Inlet Outlet 0.050.15 0.015 0.005 0.00 0.10 0.010 0.000 Inlet -0.05 0 Ou1tlet 2 3 4 5 6 7 8 9 10 11 12 13 14 15 0.050 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Day of treatment Day of treatment 0.005 0.00 0.000 0.0005 0-.000.0152 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Inlet Outlet 0.0004 Day of treatment 0.0010 Day of treatment 0.0003 0.0008 0.0005 0.0012 0.0002 Inlet 0.0006 Outlet 0.0004 0.0010 0.0001 0.0004 0.0003 0.0008 0.0000 0.0002 Inlet Outlet 0.0002 0.0006 -0.0001 0.0000 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 0.0001 Day of treatment 0.0004 Day of treatment 0.0000 Figure 7. Cont. 0.0002 Inlet Outlet -0.0001 0.0000 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Day of treatment Day of treatment Cd mg/L As mg/L Conductivity (μS/cm) Cd mg/L As mg/L Conductivity (μS/cm) Co mg/L Co mg/L Al mg/L Al mg/L BODBO (Dm5g (/mL)g/L)5 Water 2023, 15, x FOR PEER REVIEW 9 of 15 Water 2023, 15, 748 9 of 15 3.0 0.012 Inlet 2.5 Outlet Inlet 0.010 Outlet 2.0 0.008 1.5 0.006 1.0 0.004 0.5 0.002 0.0 0.000 -0.002 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Day of treatment Day of treatment 80 0.008 Inlet Outlet 70 0.006 60 0.004 50 0.002 40 0.000 30 Inlet Outlet -0.002 20 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Day of treatment Day of treatment 0.008 Inlet Outlet 0.006 0.004 0.002 0.000 -0.002 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Day of treatment Figure 7. Metal anFdi gmureeta7l.loMidet acloanncdenmtreatatilolonid vcaorniacteinotnrast i(omnevaanr ivataioluness( mweiathn svtaalunedsawrdit hdesvtainadtiaorndsd).e viations). 3.3. Heavy Metal 3C.3o.nHteenatvsy iMn eBteaal nCso natnedn tLseinttuBceae ns and Lettuce The results for bTheaenress ualntsdf olertbtueacnes wanedrele totbutcaeiwneedre forbotmain aedn farovmeraangea voefr aegieghoft esiagmhtpsalemsp les each each and are listaendd inar Tealibstleeds 1in aTnadb l2e,s r1easnpdec2t,ivreeslpye. ctively. Table 1. Heavy metal content in beans (Phaseolus vulgaris). Table 1. Heavy metal content in beans (Phaseolus vulgaris). Metal (mg/kg) Irrigation with Irrigation with UntreatedMetal Irrigation with TreatedT Wreaat-ed WIartreirg(aBtAioF)n with UnW-ater (BAF) Significance * (mg/kg) teCru (BAF) Significance * 2.897t(r0e.0a4t5e)d Water (BA2F.7) 19 (0.042) ns Cu 2.8C97r (0.045) 0.4249 (0.0223.)719 (0.042) 0.3663 (0.020) ns ns Ni 0.1813 (0.039) 0.1783 (0.039) ns Cr 0.42P4b9 (0.023) 0.5502 (0.000.43)663 (0.020) 0.54 (0.004) ns ns Ni 0.18Z1n3 (0.039) 11.98 (0.0306.1) 783 (0.039) 11.01 (0.033) ns ns Pb Note: * n0o.t5s5ig0n2ifi (c0a.n0t.04) 0.54 (0.004) ns Zn 11.98 (0.036) 11.01 (0.033) ns Note: * not significant. Zn mg/L Pb mg/L Fe mg/L Na mg/L Hg mg/L Water 2023, 15, x FOR PEER REVIEW 10 of 15 Water 2023, 15, 748 10 of 15 Table 2. Heavy metal content in lettuce (Lactuca sativa). Table 2. Heavy metal content in lettuce (Lactuca sativa). Metal Irrigation with Treated Wa-Irrigation with Untreated Significance * (mMge/tkagl )(m g/kg) ter I(rBriAgaFt)i on with IrrigWataitoenr w(BitAhFU)n treated Significance * Cu 0.06T2re4a3t e(d0.W00a0t)e r (BAF) 0.055W53at5e r(0(.B0A56F)) ns Cr Cu 0.092104.0 (602.40304(0) .000) 0.005.058545 (305.0(0.30)5 6) nsn s Ni Cr 2.46260. 0(09.251341()0 .004) 2.403.20580 (804.5(02.80)0 3) nsn s Pb Ni 0.3580925.4 (602.600(02.)5 31) 0.32625.45352 8 (0.528) nsPb 0.358095 (0.002) 0.32655(50.(000.020)2 ) nsn s Zn Zn 0.039507.053 (905.70500(0). 000) 0.0306.00376 0(70.(000.000)0 ) nsn s Noottee: :* *n notosti sginginficifaincta.nt. 3..4.. Coliforms in Radishes Figure 8 shows a dot pllott chart wiitth tthe rressulltts off ccolliifform CFU per gram off pllant tiissue iin radiish cropss.. In the comparison,, no signifificantt diiffffeerreenncceess( (pp= = 0..07) in the number off Escheriichiia collii iin radiishes ((4 samplles per experiimenttall pllott,, 16 ttottall samplles));; however,, iin a llarrgerr samplle ssiize,, a ssiigniifificcaantt diiffffeerreennccee sshhoouullddb beed deetteecctteedd.. Fiigurree 88.. CCFFUU ofo fEsEcshcehreicrhiciha iacoclio lpiepr egrragmra mof poflapnlta tniststuiess, udeo,tpdlottp wloitthw mitehanmse aands 9a5n%d c9o5n%fidcoencfie- dinetnecrevailnst.e Ervaachls .poEiancth repporiensternetps rtehsee natvsetrhaegea voef rfaoguer osfamfopulress apmerp lpelsopt egrropuloptedg raosu pa esdinagslea esxipnegrlie- emxepnetraiml uennitta. l unit. 44.. DDiissccuussssiioonn FFeerrrraattee((VVII)) iiss uusseedd aass aann aaddvvaanncceedd ooxxiiddaattiioonn aaggeenntt ffoorr tthhee rreemoovvaall ooff muullttiippllee ppooll-- lluuttaannttss ffrroom waatteerr,, ssuucchh aass meettaallss,, miiccrroooorrggaanniissmss,, aanndd oorrggaanniicc ccoonnttaamiinnaannttss,, aanndd hhaass pprreevviioouussllyy bbeeeenn uusseedd ffoorr waatteerr ttrreeaattmeenntt [[5533]].. FFeerrrraattee((VII)) ssoolluuttiioonnss hhaavvee bbeeeenn pprroovveenn ttoo bbee eeffffeeccttiivee iin rreemooviingg aallggaaee aand tturrbbiidiittyy ffrroom waatteerr [[5544,,5555]].. IIn tthiiss ssttudyy,, ffeerrrraattee((VII)) ssolluttiionss weerree abllee tto ssucccceessssffulllly rreemoovvee bbootthh ttuurrbbiiddiittyy aanndd BBOD55.. As expectted,, tthe ellecttriicall conducttiiviitty iincreased ffrom 730 ± 5577 toto 880011 ±± 333 3mmS/Sc/mc m(p (