Halophytes for the treatment of saline aquaculture effluent

Transcription

1 Aquculture Hlophytes for the tretment of sline quculture effluent J. Jed Brown,1, Edwrd P. Glenn,), Kevin M. Fitzsimmons, Steven E. Smith EnÕironmentl Reserch Lortory, UniÕersity of Arizon, 2601 E. Airport DriÕe, Tucson, AZ 85706, USA Deprtment of Plnt Sciences, UniÕersity of Arizon, Tucson, AZ 85721, USA Accepted 15 Ferury 1999 Astrct We determined the fesiility of using slt-tolernt plnts Ž hlophytes. s iofilters to remove nutrients from sline quculture wstewter. Sued estero, Slicorni igeloõii nd Atriplex rclyn Ž Chenopodicee., species with potentil s forge nd oil seed crops, were grown in snd in drining continers Ž lysimeters. in greenhouse experiment. They were irrigted to meet evpotrnspirtion demnd nd to produce 0.3 leching frction, using quculture effluent generted from n intensive tilpi culture system. The effluent slinity ws incresed with NCl to mke slinity tretments of 0.5, 10 nd 35 ppt. The plnt soil system removed 98% nd 94% of the pplied totl nd inorgnic nitrogen, respectively. It removed 99% nd 97% of the pplied totl nd solule rective phosphorus, respectively. High removl rtes occurred despite the high leching frction. Slt inhiited Ž P the growth rte, nutrient removl, nd volume of wter tht ll three plnt species could process. Sued nd Slicorni, which re succulent slt mrsh species, performed etter thn the desert sltush, Atriplex, t the higher slinities. q 1999 Elsevier Science B.V. All rights reserved. Keywords: Hlophytes; Effluent; Sued estero; Slicorni igeloõii; Atriplex rclyn 1. Introduction The lrge volumes of wstewter dischrged from costl quculture projects cn ecome serious source of pollution. Untreted effluent my dmge costl ecosystems ) Corresponding uthor. Tel.: q ; Fx: q Current ddress: Ntionl Ocenic nd Atmospheric Administrtion NOAA Fisheries, FrHC-3, 1315 Est West Highwy, Silver Spring, MD , USA; E-mil: Jed.Brown@no.gov r99r$ - see front mtter q 1999 Elsevier Science B.V. All rights reserved. PII: S

2 256 ( ) J.J. Brown et l.raquculture nd fisheries ŽGowen nd Brdury, 1987; Bell et l., 1989; Iwm, 1991; Hndy nd Poxton, 1993; Hopkins et l., 1995; Wu, 1995; Cost-Pierce, 1996; Diererg nd Kittisimkul, Severl methods of iologicl tretment of effluent hve een tested; however, no single tretment method lwys works. Seweeds cn e effective iofilters in intensive, closed systems Ž Neori et l., 1996; Shpigel nd Neori, However, in open systems where effluent is dischrged into ditches or cnls, seweeds cn ecome light-limited nd fouled with settled solids Ž Phillips, Constructed wetlnds, utilizing higher plnts, hve lso een used to tret quculture effluent Ž Schwrtz nd Boyd, These wetlnds filter solids out of the wstewter strem, ut they re less effective t removing inorgnic N nd P thn they re t removing solids, nd they do not provide n economic return to the grower. Integrting vegetle hydroponics with fish culture is nother effective ut expensive technique to remove nutrients from fish culture system Ž Rkocy nd Hrgreves, Another option tht hs een used successfully for the disposl of freshwter quculture effluent is ppliction to field crops ŽOlsen et l., 1993; D Silv nd Mughn, Crop plnts cn remove significnt frction of the nutrients in the irrigtion strem nd provide n economic return to the grower. Unlike seweed scruing systems, this method ctully reduces effluent wter volume through plnt evpotrnspirtion. It could e extended to sline effluent strems if suitle, slt-tolernt crops were ville. Such crops re eing developed from wild, slt-tolernt plnts Ž hlophytes. with the potentil to produce iomss, forge nd oilseed crops using sltwter irrigtion ŽGlenn et l., 1991, 1994, 1997; Miymoto et l., 1996; Swingle et l., Under high-slinity irrigtion, hlophytes require leching percentge of 30 50% ove consumptive use in order to flush excess slts elow the root zone ŽMiymoto et l., This flushing is necessry ecuse the uild-up of slts in the root zone inhiits plnt growth Ž Miymoto et l., However, this leching frction could result in significnt dischrge of N nd P to the quifer if these nutrients re not efficiently sored y the soil plnt system. We tested the cpcity of three hlophyte species grown t three slinities to remove N nd P from highly concentrted quculture effluent source when irrigted t rte of 30% ove evpotrnspirtion demnd. 2. Methods nd mterils 2.1. Experimentl design nd procedures The study ws conducted in July Octoer 1995 in controlled environment greenhouse in Tucson, AZ. Plnts were strted from seed ŽSlicorni igeloõii nd Sued estero. or cuttings Ž Atriplex rclyn. from wild plnts collected t Estero Moru, ner Puerto Pensco, Sonor, Mexico Ž Glenn nd O Lery, 1985; Glenn et l., Seedlings or rooted cuttings were trnsplnted into 20 l, white plstic pots Ždringe lysimeters., contining 25 kg Ž dry weight. of wshed river snd nd equipped with

3 ( ) J.J. Brown et l.raquculture ottom tues leding to collection ottles. Wter, slt nd nutrients leching pst the root zone were quntified Ž Miymoto et l., The experiment ws designed s split plot with slinity s the min plot, nd plnt species s the suplot. Three slinity tretments Ž 0.5, 10, 35 ppt. were used with three replictes per species per slinity tretment level. A set of control lysimeters Žsoil without plnts. ws included t ech slinity Ž totl lysimeterss 36.. The lysimeters were plced in six rows Ž two rows per ech of the three locks. ner the middle of the greenhouse in rndomized complete lock design. Wstewter for irrigtion ws generted in two 1 m 3 tnks tht ech held 10 kg hyrid tilpi in freshwter. Fish were fed pelleted food t 2% of ody weight per dy. Ech tnk contined 100 l ed filter with 20 l of eds. Wter ws recycled within the tnks. Once week the filters were ckflushed, nd solids nd wstewter were withdrwn to irrigte the lysimeters. The irrigtion wter ws thoroughly mixed then split into three tches to keep the nutrient content equl mong tretments. NCl ws dded to ech tch to produce the tretment slinities. NCl ws used insted of synthetic se slt in order to void using n undefined mixture of slts, some of which cn precipitte t high slinities. The three slinities, 0.5, 10 nd 35 ppt, simulted the slinity of non-sline irrigtion wter used in the western United Sttes, rckish esturine wter nd sewter, respectively. The lysimeters were weighed weekly on lnce to estimte wter use over the pst week. Lysimeters were irrigted weekly with sline effluent to replce evpotrnspirtion Ž ET. losses nd to provide for leching frction Ž LF. s 0.3, typicl vlue for irrigted crops in rid regions Ž Miymoto et l., The irrigtion volume Ž W. i ws clculted s: W sž ETr1yLF. i. This design simulted est mngement prctices for irrigting with sline wter nd kept the frction of wter dischrged pst the root zone s constnt mong tretments. A smple of weekly irrigtion wter ws retined for wter qulity nlysis. Lysimeters were llowed to drin overnight nd the lechte from ll tretments ws collected on the morning following irrigtion. At the end of the 12-week experiment, ove-ground iomss ws hrvested nd dried t 608C to determine dry mtter yield per lysimeter Wter, plnt nd soil nlyses Electricl conductivity, ph, totl mmoni-nitrogen Ž TAN., nitrte-nitrogen, totl nitrogen, solule rective phosphorus, nd totl phosphorus were mesured in irrigtion nd lechte wter using methods of the Americn Pulic Helth Assocition Ž Nitrite-nitrogen ws mesured initilly, ut ws lter dropped ecuse concentrtions were minor compred to the other nitrogen species. Totl nitrogen ws mesured y first reducing nitrte to mmoni followed y the Kjeldhl nitrogen procedure ŽBremner nd Mulvney, Soil smples were nlyzed for electricl conductivity, ph, TAN, nitrte-nitrogen, totl nitrogen, plnt-ville phosphte Žsodium icronte extrction., nd totl phosphorus following Pge et l. Ž Totl nitrogen in smples of plnt shoot tissue ws mesured with CNS nlyzer nd totl phosphorus ws nlyzed y cid digestion followed y colorimetry Ž Jones et l., Plnt reltive growth rte Ž RGR. ws clculted s RGR sžlnžfinl weight Ž g.. y lnžinitil weight Ž g... r86 dys

4 258 ( ) J.J. Brown et l.raquculture Ž length of experiment.. Plnt wter use efficiency Ž WUE. ws clculted s WUEsplnt dry weight ccumulted Ž. g rwter consumed Ž. l. The mount of nutrients removed y the plnt soil system ws clculted y sutrcting the totl mount of nutrients tht exited the lysimeter in the lechte wter from the totl mount dded from the irrigtion wter. The percentge of the totl mount of nutrients pplied tht were removed ws clculted y Ž1 yžtotl outrtotl in.. = Sttisticl nlyses Dt were first tested for homogeneity of vrinces using Brtlett s test. Dt with heterogeneous vrinces were trnsformed using either log, reciprocl or squre root trnsformtions. Percentges were rcsine or logit trnsformed to ensure normlity Ž Sokl nd Rohlf, Dt were nlyzed y prmetric methods using split plot nlysis of vrince with slinity s the min plot ŽF vlue: MS slinityrms replictions = slinity. nd plnt species s the suplot Ž F vlue: MS slinityrms replic- Tle 1 Men vlues Ž "SE, ns3. for plnt shoot finl dry weight Ž DW., plnt reltive growth rte Ž RGR., wter use over the experiment nd plnt wter use efficiency Ž WUE. y three species of hlophytes t three slinities Ž. Ž. Finl DW g RGR per dy Wter use l WUE grl 0.5 ppt Sued Ž Ž Ž Ž Slicorni Ž Ž Ž Ž Atriplex Ž Ž Ž Ž Soil control Ž c Species P-vlue ns ns ns 0.5 ppt men 53.26A 0.046A 26.03A 1.68A 10 ppt Sued Ž Ž Ž Ž Slicorni Ž Ž Ž Ž Atriplex Ž Ž Ž Ž Soil control Ž c Species P-vlue ns ns ns 10 ppt men 43.15A 0.043A 21.17B 1.71A 35 ppt Sued 5.56 Ž Ž Ž Ž Slicorni 2.55 Ž Ž Ž Ž Atriplex 0.81 Ž Ž Ž c 0.19 Ž Soil control Ž c Species P-vlue ppt men 2.97B 0.022B 11.19C 0.74B P-vlues re shown for species Ž or control. tretment within ech slinity tretment. Slinity tretment mens within ech column followed y the sme upper cse letter re not significntly different Ž P G Species Ž or control. mens within ech slinity tretment followed y the sme or no lower cse letter re not significntly different Ž P G Slinity tretment hd significnt effect on this vrile Ž P

5 ( ) J.J. Brown et l.raquculture tions.. The nlyses were crried out using sttisticl softwre pckges ŽJMP IN nd Costt.. Student Neumn Kuels tests were conducted to identify significnt differences mong mens. The significnce criterion ws P Results 3.1. Greenhouse enõironmentl conditions Men weekly mximum nd minimum ir tempertures in the greenhouse over the course of the experiment were Ž men" SEM. 36.4" 1.028C nd 22.6" 0.758C, respectively. Light trnsmission through the greenhouse ws out 59% of mient, nd the Tle 2 Men vlues Ž "SE, ns3. for pplied totl nitrogen, the percent of the pplied totl nitrogen, the pplied inorgnic nitrogen Ž INstotl mmoni-nqnitrte-n., nd the percent of the pplied inorgnic nitrogen removed y the lysimeters with three species of hlophytes t three slinities TN removed mg % TN removed IN removed mg %IN removed 0.5 ppt Sued Ž Ž Ž Ž Slicorni Ž Ž Ž Ž Atriplex Ž Ž Ž Ž Soil control Ž c Ž Ž c 45.4 Ž Species P-vlue ns ppt men A 96.33C 413.3A 79.51B 10 ppt Sued Ž Ž Ž Ž Slicorni Ž Ž Ž Ž Atriplex Ž Ž Ž Ž Soil control Ž c Ž Ž c Ž Species P-vlue ppt men B 97.36B 358.8A 86.78A 35 ppt Sued Ž Ž Ž Ž Slicorni Ž Ž Ž Ž Atriplex Ž c Ž Ž Ž Soil control Ž c Ž Ž c 72.6 Ž Species P-vlue ns ppt men C 98.76A 182.2B 88.34AB P-vlues re shown for species Ž or control. tretment within ech slinity tretment. Slinity tretment mens within ech column followed y the sme upper cse letter re not significntly different Ž P G Species Ž or control. mens within ech slinity tretment followed y the sme or no lower cse letter re not significntly different Ž P G Slinity tretment hd significnt effect on this vrile Ž P

6 260 ( ) J.J. Brown et l.raquculture men dily quntum flux over the course of the experiment in the greenhouse ws Emrdy Ž Brown nd Russell, Reltive humidity rnged from 60 to 80% Žthe greenhouse ws evportively cooled throughout the experiment Plnt growth nd wter use The men experiment-wide leching frction Ž 0.308" ws close to the desired 0.3 trget nd did not differ significntly Ž P) mong species or slinity tretments. Men slinity vlues for the lechte wter for the 0.5, 10 nd 35 ppt tretments were 1.6"0.039, 28.6"0.81 nd 84.7"0.52 ppt, respectively. The rtio of irrigtion slinity to lechte slinity cn e used s check of the volumetric mesurement of LF. LFs clculted from lechte slinity were 0.31, 0.35 nd 0.41, indicting tht some slt storge occurred t the middle nd high slinity tretments. Wter consumption ws gretest in the low slt tretment nd lowest in the high slt tretment Ž P Sued consumed more wter thn the other species Ž Tle 1.. At 35 ppt slinity, Atriplex did not use significntly more wter thn the re-soil, control lysimeters. Plnts produced more dry mtter t the lowest nd middle slinity thn plnts t the highest slinity Ž P s Atriplex plnts were significntly smller thn the other two species t 35 ppt Ž Ps RGR followed the sme trend Tle 3 Men vlues Ž "SE, ns3. for plnt shoot nitrogen, percent of the pplied totl nitrogen sequestered y the plnt shoot of three species of hlophytes t three slinities Plnt N Ž mg. % TN Removed y plnt 0.5 ppt Sued Ž Ž Slicorni Ž Ž Atriplex Ž Ž Species P-vlue ns ns 0.5 ppt men A 22.47A 10 ppt Sued Ž Ž Slicorni Ž Ž Atriplex Ž Ž Species P-vlue ns ns 10 ppt men B 19.60A 35 ppt Sued Ž Ž Slicorni Ž Ž Atriplex Ž Ž Species P-vlue ppt men C 10.64B P-vlues re shown for species tretment within ech slinity tretment. Slinity tretment mens within ech column followed y the sme upper cse letter re not significntly different Ž P G Species mens within ech slinity tretment followed y the sme or no lower cse letter re not significntly different Ž P G Slinity tretment hd significnt effect on this vrile Ž P

7 ( ) J.J. Brown et l.raquculture s plnt dry weight. WUE ws reduced y slinity ecuse soil evportion dominted wter loss t high slinity due to low plnt wter use Irrigtion wter qulity Nitrogen nd phosphorus prmeters in the irrigtion source throughout the experiment were: totl nitrogen 77.22"0.47 mgrl; TAN 9.69"0.91 mgrl; nitrte-n 3.33" 0.28 mgrl; totl phosphorus 25.27" 0.27 mgrl; solule rective phosphorus-p 6.40" 0.94 mgrl. The ph ws 7.31" Nitrogen remoõl Removl of oth totl N nd inorgnic N Ž TAN q nitrte-n. y the plnt soil system ws significntly Ž P , nd P s , respectively. inhiited y incresing Tle 4 Men vlues Ž "SE, ns3. for concentrtions of totl mmoni-nitrogen Ž TAN., nitrte-n, nd inorgnic nitrogen Ž INsTANqnitrte-N., in the lech wter verged over the course of the experiment, nd soil inorgnic nitrogen concentrtion Ž mg nitrte-nqtanrkg of soil. with three species of hlophytes t three slinities TAN mgrl NO -N mgrl IN mgrl Soil IN mgrkg ppt Sued 0.32 Ž Ž c 3.29 Ž c 5.34 Ž Slicorni 0.19 Ž Ž Ž Ž Atriplex 0.26 Ž Ž c 2.20 Ž c 7.50 Ž Soil control 0.19 Ž Ž Ž Ž Species P-vlue ns 0.5 ppt men 0.24B 8.64A 8.88A 7.24A 10 ppt Sued 0.21 Ž Ž Ž Ž Slicorni 0.22 Ž Ž Ž Ž Atriplex 0.20 Ž Ž Ž Ž Soil control 0.21 Ž Ž Ž Ž Species P-vlue ns ppt men 0.21B 5.19B 5.41B 2.14B 35 ppt Sued 0.32 Ž Ž c 2.63 Ž Ž c Slicorni 0.48 Ž Ž c 2.14 Ž Ž c Atriplex 0.31 Ž Ž Ž Ž Soil control 0.47 Ž Ž Ž Ž Species P-vlue ns ppt men 0.39A 4.73AB 5.12AB 2.23B P-vlues re shown for species Ž or control. tretment within ech slinity tretment. Slinity tretment mens within ech column followed y the sme upper cse letter re not significntly different Ž P G Species Ž or control. mens within ech slinity tretment followed y the sme or no lower cse letter re not significntly different Ž P G Slinity tretment hd significnt effect on this vrile Ž P

8 262 ( ) J.J. Brown et l.raquculture slinity Ž Tle 2.. The lysimeters t the lowest slinity tretment processed the most wter nd therefore removed the most totl nitrogen. Sued removed more totl nd inorgnic nitrogen thn Atriplex or Slicorni t the lowest slinity. Atriplex did not remove significntly more totl nitrogen thn the soil control t the highest slinity. All plnted lysimeters removed 96% or more of the pplied totl nitrogen. Removl efficiency declined slightly t the lower slinities Ži.e., lthough lysimeters in the lower slinity tretments received nd removed greter mount of nitrogen, the percentge of nitrogen removed reltive to the mount pplied declined.. Lysimeters with plnts removed significntly greter percentge of inorgnic nitrogen thn the control lysimeters; the overll men percent inorgnic nitrogen removed y lysimeters with plnts ws 94%, compred to 58% for soil control lysimeters. Slinity hd significnt inhiitory effect on totl nitrogen content in the plnt shoot Ž P At the highest slinity, Atriplex contined significntly less nitrogen thn the other two species Ž Tle 3.. The percentge of the pplied totl nitrogen incorpo- Tle 5 Men vlues Ž "SE, ns3. for pplied totl phosphorus Ž TP., the percent of the pplied totl phosphorus, the pplied solule rective phosphorus-p Ž SRP., nd the percent of the pplied SRP removed y the lysimeters with three species of hlophytes t three slinities TP removed mg % TP removed SRP removed mg % SRP removed 0.5 ppt Sued Ž Ž c Ž Ž Slicorni Ž Ž Ž Ž Atriplex Ž Ž c Ž Ž Soil control Ž c Ž Ž c Ž Species P-vlue ppt men 983.6A A 96.61B 10 ppt Sued Ž Ž Ž Ž Slicorni Ž Ž Ž Ž Atriplex Ž Ž Ž Ž Soil control Ž c Ž Ž c Ž Species P-vlue ppt men 782.9B B 97.69B 35 ppt Sued Ž Ž Ž Ž Slicorni Ž Ž Ž Ž Atriplex Ž c Ž Ž c Ž Soil control Ž c Ž Ž c Ž Species P-vlue ns ns 35 ppt men 390.5C C 98.87A P-vlues re shown for species Ž or control. tretment within ech slinity tretment. Slinity tretment mens within ech column followed y the sme or no upper cse letter re not significntly different Ž P G Species Ž or control. mens within ech slinity tretment followed y the sme or no lower cse letter re not significntly different Ž P G Slinity tretment hd significnt effect on this vrile Ž P Slinity tretment did not hve significnt effect on this vrile Ž P G0.05..

9 ( ) J.J. Brown et l.raquculture rted into the plnt shoot ws significntly greter t the 0.5 nd 10 ppt slinity tretments thn t the 35 ppt slinity tretment. Higher concentrtions of mmoni were found in lechtes from the 35 ppt lysimeters thn the other slinities Ž Tle 4.. However, 96% of lechte inorgnic nitrogen ws in the form of nitrte. The men concentrtions of oth the inorgnic nitrogen nd the nitrte in the lech wter were significntly greter Ž six-fold higher. in the control lysimeters without plnts, thn in the lysimeters with plnts. Soil inorgnic nitrogen content ws significntly greter Ž P s in the 0.5 ppt tretment thn in 10 nd 35 ppt tretments. In the 10 nd 35 ppt tretments, soil inorgnic nitrogen content ws significntly higher in the control lysimeters contining no plnts thn in plnted lysimeters Ž P s 0.008, P s , respectively. Ž Tle Phosphorus remoõl The lysimeters in the lowest slinity tretment removed significntly more totl nd solule rective phosphorus thn the lysimeters in the 10 ppt tretment, which in turn removed significntly more phosphorus thn the lysimeters in the 35 ppt tretment Ž P Ž Tle 5.. Sued removed significntly greter mount of totl nd solule rective phosphorus t the lowest slinity tretment ŽP s , P s , Tle 6 Men vlues Ž "SE, ns3. for plnt shoot phosphorus, nd the percent of the pplied totl phosphorus sequestered y the plnt shoot of three species of hlophytes t three slinities Plnt P Ž mg. % TP removed y plnt 0.5 ppt Sued Ž Ž Slicorni Ž Ž Atriplex Ž Ž Species P-vlue ns ns 0.5 ppt men A 15.39A 10 ppt Sued Ž Ž Slicorni Ž Ž Atriplex Ž Ž Species P-vlue ppt men B 14.51A 35 ppt Sued Ž Ž Slicorni Ž Ž Atriplex 3.49 Ž Ž Species P-vlue ppt men 15.96C 3.86B P-vlues re shown for species tretment within ech slinity tretment. Slinity tretment mens within ech column followed y the sme upper cse letter re not significntly different Ž P G Species mens within ech slinity tretment followed y the sme or no lower cse letter re not significntly different Ž P G Slinity tretment hd significnt effect on this vrile Ž P

10 264 ( ) J.J. Brown et l.raquculture respectively.. Atriplex did not remove significntly more totl nd solule rective phosphorus thn the soil control t 35 ppt. Overll, the lysimeters removed 99.4% nd 97.4% Ž men of ll non-control lysimeters over ll tretments. of the pplied totl nd solule rective phosphorus, respectively. Unlike nitrogen removl, the control lysimeters without plnts hd similr removl efficiency s lysimeters with plnts. Men removl efficiency for solule rective phosphorus ws significntly greter t the 35 ppt tretment compred to the two lower slinity tretments Ž P s Slinity hd significnt inhiitory effect on totl phosphorus in the plnt shoot Ž P At the highest slinity Atriplex hd significntly less shoot phosphorus thn the other two species Ž Ps Ž Tle 6.. The percentge of the pplied totl phosphorus removed y the plnt shoot ws significntly greter Ž P t the lowest nd the middle slinity thn t the highest slinity tretment. Men concentrtion of solule rective phosphorus in the lech wter ws significntly lower Ž P s in the highest slinity tretment thn the concentrtion in the Tle 7 Men vlues Ž "SE, ns3. for concentrtions of solule rective phosphorus-p Ž SRP. nd totl phosphorus Ž TP. in the lech wter verged over the course of the experiment, nd soil plnt-ville phosphorus-prkg soil with three species of hlophytes t three slinities SRP mgr1 TP mgr1 Soil phosphte mgrkg 0.5 ppt Sued 1.46 Ž Ž Ž Slicorni 0.48 Ž Ž Ž Atriplex 0.93 Ž Ž Ž Soil control 0.29 Ž Ž c 3.52 Ž Species P-vlue ns 0.5 ppt men 0.79A ppt Sued 0.95 Ž Ž Ž Slicorni 0.44 Ž Ž Ž Atriplex 0.39 Ž Ž Ž Soil control 0.26 Ž Ž Ž Species P-vlue ns 10 ppt men 0.51A ppt Sued 0.19 Ž Ž Ž Slicorni 0.31 Ž Ž Ž Atriplex 0.16 Ž Ž Ž Soil control 0.19 Ž Ž Ž Species P-vlue ns ns ns 35 ppt men 0.21B P-vlues re shown for species Ž or control. tretment within ech slinity tretment. Slinity tretment mens within ech column followed y the sme or no upper cse letter re not significntly different Ž P G Species Ž or control. mens within ech slinity tretment followed y the sme or no lower cse letter re not significntly different Ž P G Slinity tretment hd significnt effect on this vrile Ž P Slinity tretment did not hve significnt effect on this vrile Ž P G0.05..

11 ( ) J.J. Brown et l.raquculture two lower slinity tretments Ž Tle 7.. Concentrtions of oth solule rective nd totl phosphorus in the lechtes from the control lysimeters were s low or lower thn the concentrtions in the lechtes from plnted lysimeters. The mjority of the phosphorus leching from the lysimeters ws in the dissolved form, nd the mesured solule rective phosphorus ws greter thn the men concentrtion of totl phosphorus in six of the 12 tretments. This unexpected result ws ttriuted to the different nlyticl techniques tht were used to mesure wht ws essentilly the sme quntity. Slinity did not ffect the mount of plnt-ville phosphte in the soil, nd there were no significnt differences mong the species within ech slinity tretment with respect to plnt-ville phosphte in the soil Ž Tle Discussion Overll, the plnt soil system ws effective in sequestering nitrogen nd phosphorus from the pplied effluent cross tretments nd species. The lysimeters with plnts removed over 98% nd 94% of the pplied totl nd inorgnic nitrogen, respectively; nd 99% nd 97% of the pplied totl nd solule rective phosphorus, respectively. The high removl occurred in spite of the fct tht 31% of the pplied wter leched from the lysimeters. In ddition, the quculture effluent used for irrigtion in this experiment ws sustntilly higher in nitrogen nd phosphorus concentrtion thn typicl mriculture effluent. In fct, the nutrient concentrtion of the irrigtion wter in this experiment ws close to n order of mgnitude greter thn the nutrient concentrtions found in typicl shrimp pond effluent Ž Phillips, Removl efficiencies tended to increse with the higher slinity tretments proly ecuse t lower slinities much greter volume of wter ws processed thn t higher slinities. Removl efficiencies exceeded those reported y Schwrtz nd Boyd Ž for constructed wetlnd tht received ctfish pond-effluent. In ddition to greter removl efficiency, the hlophytes grown here might provide n economic return for the grower if they re utilized in niml feeds. Biomss of the three species used in our study hs een used to replce grss hy in sheep fttening rtions Ž Swingle et l., In the 0.5 nd 10 ppt tretments, the plnt shoot sequestered pproximtely 21% nd 15% of the pplied totl nitrogen nd phosphorus, respectively. Three percent of the pplied totl nitrogen nd 1% of pplied totl phosphorus ws lost from the system vi leching in these two tretments. The reminder of the nitrogen Ž 76%. in the 0.5 nd 10 ppt tretments ws either incorported into plnt root tissues, retined in the soil s orgnic mtter or inorgnic nutrients, or lost to the system vi mmoni voltiliztion or denitrifiction. Similrly, the reminder of the phosphorus nd phosphorus Ž 84%. ws either in the plnt root, or in the soil s orgnic mtter or s inorgnic phosphte. Thus, most of the totl nutrient removl ws not due to uptke into hrvestle plnt tissues, s might e expected, ecuse plnts cn only tke up inorgnic nutrients. However, the ultimte fte of the nitrogen nd phosphorus remining in the soil, whether in orgnic forms such s uneten feed, lge nd fish feces, plnt root tissue or in plnt-ville inorgnic forms, cn only e determined through multi-yer experiments.

12 266 ( ) J.J. Brown et l.raquculture In the snd soil in this experiment, nitrte ws the predominnt form of inorgnic nitrogen. Nitrte is typiclly very moile in the soil wter, nd therefore very high proportion of soil nitrte is ville to the plnt Ž Tisdle nd Nelson, Therefore, the lysimeters with plnts removed much greter percentge of the pplied inorgnic nitrogen thn did the control lysimeters without plnts. By contrst, the soil itself ws responsile for the mjority of phosphorus removl from the wstewter. Phosphte is redily sored to soil prticles nd, therefore, typiclly only very smll percentge of soil phosphorus is ville to the plnt Ž Tisdle nd Nelson, The control lysimeters Ž without plnts. removed s much or more of the pplied phosphorus on percentge sis s the lysimeters with plnts. However, the lysimeters with plnts removed greter mount of oth nitrogen nd phosphorus ecuse they received more wter to meet the evpotrnspirtion demnds of the plnt. One of the min drwcks of lnd disposl systems is the potentil for nutrients to lech pst the plnt root zone nd contminte the quifer. However, despite the unchrcteristiclly concentrted irrigtion wter used, the men concentrtions of mmoni nd nitrte in the lech wter were lwys lower thn the men concentrtion limits recommended y the U.S. Environmentl Protection Agency for effluents Ž Schwrtz nd Boyd, The men Environmentl Protection Agency stndrds re 1.77 mgrl for TAN nd 16.9 mgrl for nitrte-n. The men lech wter concentrtion for ll plnt-contining lysimeters ws 0.28 mgrl for TAN nd 2.6 mgrl for nitrte-n. On the other hnd, the men EPA stndrd for totl phosphorus is 0.17 mgrl, level tht ws exceeded in ll the tretments Žmen for plnt-contining lysimeterss 0.53 mgrl.. However, this concentrtion would hve certinly een lower if the lysimeters hd een irrigted with more typicl effluent or if the soil hd een other thn snd. A deeper soil profile or higher cly content would provide more inding sites for phosphorus thn were present in the snd lysimeters. Sued nd Atriplex generlly performed etter thn Slicorni t low slinity, wheres Atriplex performed very poorly reltive to the other two species on high slinity wter. Atriplex clerly is not s slt tolernt s the other two species. Plnt dry mtter production, RGR, ET nd the mount of nitrogen nd phosphorus removed decresed with incresing slinity. At sewter slinity, the plnt soil system ws not cple of treting lrge volume of wter ecuse the plnts grew very little nd therefore hd low evpotrnspirtion rtes. Slow growth occurred ecuse root zone slinity reched levels high enough to cuse serious inhiition. Hd we designed the experiment to provide the sme volume of wstewter to ll tretments, the plnts receiving 35 ppt wter would hve received more wter nd nutrients. These plnts would hve proly grown etter ecuse root zone slinity would decrese s the dditionl volume of wter would flush slts from the soil. However, the volume of wter leched from the high slinity tretments would hve certinly een much greter thn the volume leched from the low slinity tretments, nd therefore would not represent est mngement irrigtion prctice. The weekly irrigtion schedule ws proly insufficient to keep soil slinity t levels tht would support dequte plnt growth. Irrigtion strtegies employing greter irrigtion frequency will e necessry to chieve efficient iofiltrtion of nutrients if hlophytes re to e used to tret quculture effluent pproching sewter slinity. The

13 ( ) J.J. Brown et l.raquculture findings from the present experiment were used to conduct further experiments utilizing lrger soil volumes nd more frequent irrigtions. At sewter slinity, much greter yields were produced thn in this study ŽBrown nd Glenn, Aquculturl Engineering, in press.. Extensive field testing nd site considertions would e needed efore sline quculture effluent could e used to grow crops t given loction, due to the potentil hzrds presented y the slt s well s the nutrient lod. However, where costl soils overly sline quifers with hydrulic connection to the se, this strtegy offers potentil low-cost nd effective method of removing nutrients y using soil plnt wter system for iotretment of effluent. Acknowledgements We would like to cknowledge the ssistnce of John Junius for filter construction, Gry Dickenson for fish rering, nd Anthony Glvn for lortory nlyses. Prtil funding ws provided y the Western Regionl Aquculture Center of the CSREES, US Deprtment of Agriculture, under greement No , nd STAR US Environmentl Protection Agency Grdute Fellowship to J. Brown. References Americn Pulic Helth Assocition, Americn Wter Works Assocition, Wter Environment Federtion, Stndrd Methods for the Exmintion of Wter nd Wstewter. Americn Pulic Helth Assocition, Wshington, DC. Bell, P.R.F., Greenfield, P.F., Hwker, D., Connell, D., The impct of wste dischrges on corl reef regions. Wter Sci. Tech. 21, Bremner, J.M., Mulvney, C.S., Nitrogen-totl. In: Pge, A.L., Miller, R.H., Keeney, D.R. Ž Eds.., Methods of Soil Anlysis: Prt 2. Chemicl nd Microiologicl Properties. Americn Society of Agronomy, Soil Science Society of Americ, Mdison, WI, pp Brown, J.J., Glenn, E.P., in press. Reuse of highly sline quculture effluent to irrigte potentil forge hlophyte, Sued estero. Aqucult. Eng. Brown, P.W., Russell, B., AZMET, The Arizon Meteorologicl Network. Arizon Coopertive Extension, Tucson, AZ, Cost-Pierce, B.A., Environmentl impcts of nutrients from quculture: towrds the evolution of sustinle quculture systems. In: Bird, D.J., Beveridge, M.C.M. Kelly, L.A., Muir, J.F. Ž Eds.., Aquculture nd Wter Resource Mngement. Blckwell Science, Oxford, pp Diererg, F.E., Kittisimkul, W., Issues, impcts nd implictions of shrimp quculture in Thilnd. Environ. Mnge. 20, D Silv, A.M., Mughn, O.E., Optimum density of red tilpi Oreochromis mossmicus=o. hornorum in pulsed-flow culture system. J. World Aqucult. Soc. 27, Glenn, E.P., O Lery, J.W., Productivity nd irrigtion requirements of hlophytes grown with sewter in the Sonorn Desert. J. Arid Environ. 9, Glenn, E.P., O Lery, J.W., Wtson, M.C., Thoms, T.L., Kuehl, R.O., Slicorni igeloõii Torr.: n oilseed hlophyte for sewter irrigtion. Science 251, Glenn, E.P., Swingle, R.S., Riley, J.J., Squires, V.R., North Americn hlophytes: potentil use in niml husndry. In: Squires, V.R., Ayou, A.T. Ž Eds.., Hlophytes s Resource for Livestock nd for Rehilittion of Degrded Lnds. Kluwer Acd. Pulishers, Netherlnds, pp

14 268 ( ) J.J. Brown et l.raquculture Glenn, E.P., Miymoto, S., Moore, D., Brown, J.J., Thompson, T.L., Brown, P., Wter requirements for cultivting Slicorni igeloõii Torr. with sewter on snd in costl desert environment. J. Arid Environ. 36, Gowen, R.J., Brdury, N.B., The ecologicl impct of slmonid frming in the costl wters: review. In: Brnes, M. Ž Ed.., Ocenogr. Mr. Biol. Ann. Rev. Aerdeen Univ. Press, Aerdeen, pp Hndy, R.D., Poxton, M.G., Nitrogen pollution in mriculture: toxicity nd excretion of nitrogenous compounds y mrine fish. Rev. Fish Biol. Fish. 3, Hopkins, J.S., Sndifer, P.A., Devoe, M.R., Hollnd, A.F., Browdy, C.L., Stokes, A.D., Environmentl impct of shrimp frming with specil reference to the sitution in the Continentl United Sttes. Esturies 18 Ž 1A., Iwm, G.K., Interctions etween quculture nd the environment. Crit. Rev. Environ. Control 21, Jones, J.B., Wolf, B., Mills, H.A., Plnt Anlysis Hndook: A Prcticl Smpling, Preprtion, Anlysis nd Interprettion Guide. Micro Mcro Pulishing, Athens, GA. Miymoto, S., Glenn, E.P., Olsen, M.W., Growth, wter use nd slt uptke of four hlophytes irrigted with highly sline wter. J. Arid Environ. 32, Neori, A., Krom, M.D., Ellner, S.P., Boyd, C.E., Popper, D., Rinovitch, R., Dvidson, P.J., Divr, O., Zuer, D., Ucko, M., Angel, D., Gordin, H., Seweed iofilters s regultors of wter qulity in integrted fish seweed culture units. Aquculture 141, Olsen, M.W., Fitzsimmons, K.M., Moore, D.W., Surfce irrigtion of cotton using quculture effluent. In: Wng, J.K. Ž Ed.., Techniques for Modern Aquculture. ASAE, St. Joseph, MI, pp Pge, A.L., Miller, R.H., Keeney, D.R. Ž Eds.., Methods of Soil Anlysis: Prt 2. Chemicl nd Microiologicl Properties. Americn Society of Agronomy, Soil Science Society of Americ, Mdison, WI, 1159 pp. Phillips, M., Aquculture nd the environment striking lnce. In: Nmir, K.P.P., Singh, T. Ž Eds.., Interntionl Conference on Aquculture: Aquculture Towrds the 21st Century. Infofish, Kul Lumpur, pp Rkocy, J.E., Hrgreves, J.A., Integrtion of vegetle hydroponics with fish culture: review. In: Wng, J.K. Ž Ed.., Techniques for Modern Aquculture. ASAE, St. Joseph, MI, pp Schwrtz, M.F., Boyd, C.E., Chnnel ctfish pond effluents. Prog. Fish-Cult. 56, Schwrtz, M.F., Boyd, C.E., Constructed wetlnds for tretment of chnnel ctfish pond effluents. Prog. Fish-Cult. 57, Shpigel, M., Neori, A., The integrted culture of seweed, lone, fish nd clms in modulr intensive lnd-sed systems: I. Proportions of size nd projected revenues. Aqucult. Eng. 15, Sokl, R.R., Rohlf, F.J., Biometry: The Principles nd Prctice of Sttistics in Biologicl Reserch, 2nd edn. Freemn, New York. Swingle, R.S., Glenn, E.P., Squires, V.R., Growth performnce of lms fed mixed diets contining hlophyte ingredients. Anim. Feed Sci. Tech. 63, Tisdle, S.L., Nelson, W.L., Soil Fertility nd Fertilizers. Mcmilln, New York. Wu, R.S.S., The environmentl impct of mrine fish culture: towrds sustinle future. Mr. Pollut. Bull. 31,