Report to the I

Great Lakes Science Advisory Board I

Biological Availability of Phosphorus

Report to the Great Lakes Science Advisory Board

Biological Availability of Phosphorus

by the Expert Committee on Engineering and Technological Aspects of Great LakesWater Quality

This r e p o r t t o t he Science Advisory Board was prepared by t h e Engineer ing

and Technologica l Aspects Exper t Committee. Though t h e Board has reviewed and

approved t h i s r e p o r t f o r p u b l i c a t i o n , some o f t he s p e c i f i c conclus ions and

recommendations may no t be supported by t h e Board.

TABLE OF CONTENTS

P a g e

................................................. L I S T OF TABLES i i

L I S T OF F IGURES ................................................ i i

L I S T OF SYMBOLS ................................................ iii

1: INTRODUCTION ...................................................... 1

..................... 2 . BIOLOGICALLY AVA ILABLE FORMS OF PHOSPHORUS 2

3 . ANALYTICAL PROCEDURES FOR EST IMAT ING B I O L O G I C A L L Y - AVA ILABLE PHOSPHORUS ......................................... 5

................... . . 4 SOURCES OF PHOSPHORUS AND THEIR A V A I L A B I L I T Y 10 ............................................. P o i n t S o u r c e s 11 N o n p o i n t S o u r c e s .......................................... 1 3

........................................ . 5 I N - L A K E TRANSFORMATIONS 1 7

.................................................... . 6 CONCLUSICINS 2 2

REFERENCES ..................................................... 2 4

PART IC IPANTS I N DECEMBER 8; 1 9 7 8 WORKSHCIP ON ........................... "B I O A V A I LAB L E FORMS OF PHOSPHORUS" 2 9

MEMBERSHIP OF THE EXPERT COMMITTEE ON THE ENGINEERING ....... AND TECHNOLOGICAL ASPECTS OF GREAT LAKES WATER Q U A L I T Y 3 0

LIST OF TABLES

NO. - TITLE PAGE

1. I n o r g a n i c and Organic Forms o f Phosphorus and t h e i r R e l a t i v e S o l u b i l i t i e s .................................. 4

2. sumnary o f Studies o f Avai 1 able P a r t i c u l a t e ~ h o s ~ h o r u s f rom Diffuse Sources ..: ..................................... 7

3. Sumary o f Studies on A v a i l ab le Phosphorus .................................... from Atmospheric Sources 8

4. "Best" Est imate o f 1976 Phosphorus Loads t o t he Great Lakes ... 11

5. Annual U n i t Area Loads o f T o t a l Phosphorus b y Land Use .................... .............. and Land Form i n Canada .;. 15

........................... 6. P a r t i c u l a t e Phosphorus D i s t r i b u t i o n 16

LIST OF FIGURES

NO. - TITLE PAGE

1. Poss ib le Components o f P a r t i c u l a t e Phosphorus and T h e i r S u s c e p t i b i l i t y t o Vari,ous Chemical E x t r a c t i o n Methods ....... 9

2. Schematic Representat ion o f t he Phosphate Cycle ............... 19

LIST OF SYMBOLS

A1 P - NAI P - NaOH-IP -

PIP - POP - PTP - SR P - STP - SUP - TP -

A p a t i t e I n o r g a n i c Phosphorus

Non A p a t i t e I n o r g a n i c Phosphorus

Sodium Hydrox ide E x t r a c t a b l e I n o r g a n i c Phosphorus

P a r t i c u l a t e I n o r g a n i c Phosphorus

P a r t i c u l a t e Organ ic Phosphorus

P a r t i c u l a t e T o t a l Phosphorus

S o l u b l e R e a c t i v e Phosphorus

S o l u b l e T o t a l Phosphorus

S o l u b l e U n r e a c t i v e Phosphorus

T o t a l Phosphorus

B IOLOG ICAL AVAILAB IL'ITY OF PHOSPHORUS

1. INTRODUCTION

I n September 1978 t h e Engineer ing and Technolog ica l Aspects (ETA)

Committee expressed i t s concerns t o t h e Great Lakes Science Adv isory Board

t h a t e f f o r t s t o c o n t r o l i n p u t s o f p o l l u t a n t s t o t h e Great Lakes, such as heavy

meta ls and, i n p a r t i c u l a r , phosphorus, were no t d i r e c t e d a t b i o l o g i c a l l y

a v a i l a b l e forms, b u t r a t h e r a t t h e t o t a l i n p u t s o f t h e p o l l u t a n t s . The

Committee requested and rece i ved concurrence o f t h e Board t o i n v e s t i g a t e t h e

concept o f c o n t r o l l i n g b i o l o g i c a l l y a v a i l a b l e forms o f phosphorus. Two major

a c t i v i t i e s took p l ace i n c a r r y i n g ou t t h i s task. ETA Committee members

p a r t i c i p a t e d i n a rev iew o f phosphorus a v a i l a b i l i t y presented a t t h e

IJC/Cornel l U n i v e r s i t y Conference on "Phosphorus Management S t r a t e g i e s f o r t h e

Great Lakes". The major paper on phosphorus a v a i l a b i l i t y presented a t t h e

conference and pub l i shed i n t h e proceedings was prepared by Lee -- e t a l . (1 ) .

Secondly, a s t a t e - o f - t h e - a r t r e p o r t on " B i o l o g i c a l l y Avai l a b l e Phosphorus" ( 2 )

was developed b y a subcommittee o f t h e ETA Committee. Th i s r e p o r t was based

p r i m a r i l y on i n f o r m a t i o n rece i ved a t a meet ing o f expe r t s convened by t h e

Committee on December 8, 1978 i n Chicago. Those who at tended t h i s meet ing a re

1 i s t e d on page 29 o f t h i s r e p o r t .

Based on t h e above r e p o r t s , and o the r r e l e v a n t documents, t h e ETA

Committee has prepared t h i s sumnary r e p o r t t o answer t h e f o l l o w i n g ques t i ons

w i t h r espec t t o phosphorus a v a i l a b i 1 i t y : 1) What forms o f phosphorus a re

b i o l o g i c a l l y a v a i l ab le? 2) What a n a l y t i c a l techniques a re a v a i l a b l e t o measure

d i f f e r e n t forms o f phosphorus and how do t h e y compare w i t h r espec t t o t h e i r

es t ima t i on o f a v a i l a b l e phosphorus? 3 ) What a re t h e d i f f e r e n c e s i n t h e

p r o p o r t i o n o f b i o l o g i c a l l y a v a i l a b l e phosphorus i n t o t a l phosphorus i n p u t s

f rom va r i ous sources? and 4 ) What t r ans fo rma t i ons i n chemical forms o f

phosphorus t ake p l ace i n lakes and what e f f e c t do t h e y have on cons ide ra t i ons

o f phosphorus a v a i l ab i 1 i t y ? The Committee reached severa l conc lus ions

based on i t s rev iew o f t h e ques t ion o f p h o s p h o r u s ' a v a i l a b i l i t y and i n t h i s

sumnary repo r t , d iscusses t h e i m p l i c a t i o n s f o r develop ing f u r t h e r s t r a t e g i e s

t o c o n t r o l phosphorus i n p u t s t o t he Great Lakes.

2. BIOLOGICALLY AVAILABLE FORMS OF PHOSPHORUS

The term " b i o l o g i c a l l y a v a i l a b l e phosphorus" i s n o t w e l l defined, bu t has

an i m p l i c a t i o n t h a t t h e phosphorus can be i nco rpo ra ted i n t o l i v i n g c e l l s w i t h

reasonable speed. Genera l ly , " a v a i l a b i l i t y " m igh t be i n t e r p r e t e d t o mean t h a t

the'phosphorus can become a v a i l a b l e f o r use d u r i n g a s i n g l e growing season.

Phosphorus i s est imated t o be e l even th i n o rder of abundance among

elements i n igneous rocks on t h e e a r t h ' s surface (3 ) . Phosphorus occurs i n

a l l known minera ls as orthophosphate, t h e f u l l y i o n i z e d fo rm o f which i s

represen ted as P O Q - ~ . One minera l fami ly , t h e apa t i t es , r ep resen t by

f a r t h e major amount of phosphorus i n t h e e a r t h ' s c r u s t . Impor tan t members o f

t h e a p a t i t e f a m i l y a re l i s t e d i n Table 1. Al though t h e r e i s an almost

u n l i m i t e d supp ly of a p a t i t e phosphorus a v a i l a b l e i n t h e e a r t h ' s c r u s t , these

minera l forms, p a r t i c u l a r l y t h e h i g h l y c r y s t a l l i n e ones, are ve ry i n s o l u b l e

and become a v a i l a b l e t o organisms o n l y s l o w l y through p h y s i c a l o r b i o l o g i c a l

d i s s o l u t i o n (4 ) ; hence, they a re g e n e r a l l y termed " n o n - b i o l o g i c a l l y

ava i l ab le " . I n a s t r i c t sense t h i s i s n o t t r u e (5, 6, 7), b u t t h e r a t e s of

s o l u t i o n are s u f f i c i e n t l y slow so t h a t t h e presence o f even l a r g e q u a n t i t i e s

o f c r y s t a l l i n e a p a t i t e m inera ls i n l ake sediments i s no t ap t t o c o n t r i b u t e

s i g n i f i c a n t l y t o l a k e eu t roph i ca t i on .

S low ly w i t h t ime, a p a t i t e and o the r i n s o l u b l e phosphorus m ine ra l s can be

brought i n t o s o l u t i o n i n forms which are r e a d i l y a v a i l a b l e f o r t h e growth of

a lgae and o the r aqua t i c 1 i f e . The major i no rgan i c forms o f " b i o l o g i c a l l y

a v a i l a b l e phosphorus" e x i s t i n g n a t u r a l l y i n aquaeous systems are t h e s o l u b l e

orthophosphates. Such orthophosphates a re a l so a component o f f e r t i l i z e r s and

thus a re commonly p resen t i n r u n o f f f rom a g r i c u l t u r a l areas. They are a l s o

p resen t i n d o m e s t i c sewage.

There a re a l s o many anthropogenic forms of phosphorus produced

commerc ia l ly from condensat ion of phosphates e x t r a c t e d from a p a t i t e m ine ra l s

f o r use i n detergents , f o r water t reatment , e tc . (3) . These condensed forms

a re a l so g e n e r a l l y s o l u b l e and upon hyd ro l ys i s , which occurs f a i r l y r e a d i l y

through chemical o r enzymatic a c t i v i t y i n n a t u r a l waters (8, 9, l o ) , y i e l d

s o l u b l e orthophosphates. Hence, t h e condensed phosphates (Tab le 1 ) a re a l so

cons idered t o be b i o l o g i c a l l y a v a i l a b l e .

Orthophosphates can a l so combine w i t h d i f f e r e n t meta l ions t o fo rm var ious

i n s o l u b l e m inera ls o t h e r than t he apa t i t es . I n n a t u r a l waters, t h e most

common ca t i ons i nvo l ved a re i r on , aluminum, and ca lc ium (Table 1). So lub le

orthophosphates can a1 so become p a r t of p a r t i c u l a te materia-1s through

adso rp t i on (3, 11). The s o l u b i 1 i t i e s o f these non-d isso lved phosphate

c o n t a i n i n g m a t e r i a l s v a r i e s wide ly , as does t h e b i o l o g i c a l a v a i l a b i l i t y o f t h e

phosphorus which t hey con ta in . Table 1 l i s t s t h e s o l u b i l i t i e s o f some o f t h e

more abundant m a t e r i a l s con ta in i ng phosphorus.

The b i o l o g i c a l a v a i l a b i 1 i t y of i no rgan i c phosphate m ine ra l s depends n o t

o n l y upon t h e minera l i t s e l f bu t a l s o upon i t s c r y s t a l l i n i t y . Most o f t h e

phosphate minera ls o c c u r r i n g i n t h e e a r t h I s s u r f ace a re we1 1 -formed

c r y s t a l l i n e m a t e r i a l s t h a t have r e s u l t e d f r om processes o c c u r r i n g over

geo log i ca l pe r i ods o f t ime. However, many o f t h e minera l p r e c i p i t a t e s t h a t

f o rm d u r i n g wastewater t rea tment o r w i t h i n a season i n a l a k e are p o o r l y

c r y s t a l l i n e . These "amorphous" forms a re more s o l u b l e and more r e a d i l y

a v a i l a b l e t o algae. Thus, i n e v a l u a t i n g t h e ease o r r a p i d i t y w i t h which t h e

phosphorus i n sediments o r p a r t i c u l a t e m a t e r i a l s can become ava i l ab le , one

must cons ider n o t o n l y t h e k i nds o f m ine ra l s i n which i t i s contained, b u t

a l s o t h e i r r espec t i ve degrees o f c r y s t a l l i n i t y .

Other impor tan t forms o f phosphorus are o rgan ic i n na tu re and a r e

genera l ly, b u t n o t always, products o f b i o l o g i c a l processes. Organic

phosphorus may be p a r t o f p a r t i c u l a t e m a t e r i a l s w i t h i n t h e s t r u c t u r e of l i v i n g

o r dead and decaying organisms. Organic phosphorus forms may a l s o be

d i s s o l v e d i n n a t u r a l waters, perhaps r e s u l t i n g f rom e x c r e t i o n by e i t h e r

growing o r decaying organisms. As w i t h t h e i no rgan i c forms, t h e b i o l o g i c a l

TABLE 1. INORGANIC AND ORGANIC FORMS OF PHOSPHORUS AND THEIR RELATIVE SOLUBILITIES

B i o l o g i c a l l y A v a i l a b l e I no rgan i c Forms o f Phosphorus S o l u b i l i t y

So lub le Orthophos hates ~ 2 ~ 0 4 , H P O ~ - ~ , ~ 0 4 - 3 v e r y s o l u b l e Condensed ~ i o s p h a t e s

Pyrophosphate H ~ P ~ o ~ - ~ , H P ~ o ~ - ~ , P ~ o ~ - ~ 6.70 g/100 cc a t 25OC (Na4P207)

T r i po l yphospha te - 3 - 4 H3P2010 , HP3Ol0 , ~ ~ 0 ~ ~ - ~ 20 g/100 cc a t 25OC (Na5P3010)

Tr imetaphosphate - 2 H P ~ O ~ , ~ ~ 0 ~ - ~ v e r y s o l u b l e (NaP03),,

B i o l o g i c a l l y Unava i l ab le M ine ra l Forms of Phosphorus

~ ~ d r o x y a p a t i t e Ca10(OH)2(P04)6 p r a c t i c a l l y i n s o l u b l e

F l u o r a p a t i t e Ca10F2( P04)6 no i n f o r m a t i o n

Carbonate F l u o r a p a t i t e Calo(F,oH)2(Po4.Co3)6 no i n f o r m a t i o n

Phosphate M i n e r a l s w i t h Vary ing A v a i l a b i l i t y

B r u s h i t e CaHP04 2H20

B o b i e r i t e Mg3( P04)2 8H20 i n s o l u b l e

V a r i s c i t e , s t r i n g i t e A1P04 2 . ~ ~ 0 , FeP04 2H20 i nso lub le , very s l i g h t l y s o l u b l e

Wave11 i t e A13(OH)3(P04)2 p r a c t i c a l l y i n s o l u b l e

C l ay-phosphate Si205A12(0H)4 PO4 no i n f o r m a t i o n

Organ ic Phosphates w i t h Vary ing A v a i l a b i l i t y

Phosphates sorbed on amorphous aluminum and i r o n ox ides

B a c t e r i a l c e l l m a t e r i a l I n o s i t o l hexaphosphate P lank ton m a t e r i a l Phospho l ip id D i sso l ved m a t e r i a l Phosphoprotein

Nuc le i c ac ids Po lysacchar ide phosphate Phosphocreat ine Glycerophosphate

poor s o l u b i l i t y ( ca l c i um magnesium s a l t ) no i n f o r m a t i o n no i n f o r m a t i o n no s o l u b i l i t y i n f o r m a t i o n

ve ry s o l u b l e (C4HloN305P) s o l u b l e

a v a i l a b i l i t y o f t he var ious o rgan ic forms o f phosphorus v a r i e s w ide ly . - S tud ies o f phosphorus d i s t r i b u t i o n s i n lakes i n d i c a t e t h a t t h e s o l u b l e o rgan i c

phosphorus may amount t o f rom 30 t o 60 percent o f t h e t o t a l d i s s o l v e d

phosphorus (12, 13, 14). Not much i s known of t h e exac t compos i t ion o f t h e

o rgan ic phosphorus compounds, nor o f t h e i r r e l a t i v e a v a i l a b i l i t y t o growth o f

aqua t i c organisms.

I n sumnary, t h e a c t u a l amount o f phosphorus which i s a v a i l a b l e i n an

aqua t i c system t o a lgae i s a f u n c t i o n o f a complex s e t o f phys ica l , chemical,

and b i o l o g i c a l processes (15) . It i s genera l l y agreed t h a t s o l u b l e i n o r g a n i c

forms of phosphorus i n c l u d i n g b o t h t he orthophosphates and condensed

phosphates a re r e a d i l y ava i 1 ab le b i o l o g i c a l ly. However, severa l s t u d i e s have

shown t h a t i n c e r t a i n s i t u a t i o n s t he a v a i l a b i l i t y o f orthophosphates t o a lgae

may b e reduced by low l e v e l s o f t r a c e meta ls i n t h e water. On t h e o the r hand,

t h e a v a i l a b i l i t y o f d i sso l ved o rgan ic forms i s l e s s c e r t a i n . Some o f t h e

p a r t i c u l a t e i no rgan i c and o rgan i c phosphorus forms a re r e a d i l y a v a i l a b l e and

o the rs are not. It i s g e n e r a l l y agreed t h a t c r y s t a l l i n e a p a t i t e m ine ra l s a re

among those no t r e a d i l y ava'i l a b l e . However, t h e ava'i l a b i 1 i t y o f o ther .

p a r t i c u l a t e forms v a r i e s wide ly . I n genera l n o n - c r y s t a l l i n e forms a re much

more r e a d i l y a v a i l a b l e than c r y s t a l l i n e ones.

3. ANALYTICAL PROCEDURES FOR ESTIMATING BIOLOGICALLY AVAILABLE PHOSPHORUS

Since t h e r e are. many d i f f e r e n t f o r m s of phosphorus and t h e i r genera l

a v a i l a b i l i t y v a r i e s widely, i t i s d i f f i c u l t , i f n o t imposs ib le , t o develop

a n a l y t i c a l procedures t o q u a n t i f y d i r e c t l y each b i o l o g i c a l l y ava i 1 ab le form

which may be present . For t h i s reason c o l l e c t i v e a n a l y t i c a l t e s t s have been

sought t h a t show good c o r r e l a t i o n between ease o f s o l ' u b i l i z a t i o n under

chemical c o n d i t i o n s and r e 1 a t i ve a v a i l a b i 1 i t y t o a1 gae.

Both chemical procedures and bioassay techniques can be used t o es t ima te

t h e b i o l o g i c a l l y a v a i l ab le f r a c t i o n o f phosphorus i n p a r t i c u l a r samples.

Chemical e x t r a c t i o n s a re used t o determine t h e amount o f t o t a l phosphorus

i n a sample which can be conver ted t o s o l u b l e phosphate under p a r t i c u l a r t e s t

cond i t i ons ; Bioassay techniques a re based on a de te rm ina t i on o f t h e amount o f

growth a se lec ted a l g a l species e x h i b i t s on exposure t o a p a r t i c u l a r f o rm

phosphorus o r t he r e d u c t i o n o f t h e n u t r i e n t con ten t observed as a r e s u l t o f

the growth. A sumnary o f t he var ious chemical and b ioassay techniques and

t h e i r l i m i t a t i o n s were presented by Lee -- e t a l . ( 1 ) .

The major concern w i t h phosphorus i n p u t s i s w i t h respec t t o d i f f e r e n c e s i n

t h e s o l u b l e and p a r t i c u l a t e f r a c t i o n s .

The so lub le t o t a l phosphorus (STP) p o r t i o n i s u s u a l l y f r a c t i o n a t e d as:

7

( i ) SRP - s o l u b l e r e a c t i v e phosphorus as measured by t h e molybdate

method

( i i ) SUP - s o l u b l e un reac t i ve phosphorus

As noted i n Sec t ion 2, i t i s g e n e r a l l y agreed t h a t SRP i s e s s e n t i a l l y a l l

b i oava i 1 ab le and i s r a p i d l y ass im i l a ted by algae as orthophosphorus. However,

t h e r e i s some disagreement on t he a v a i l a b i l i t y o f o the r so lub le phosphorus

f r a c t i o n s . Lee -- e t a l . ( 1 ) ques t ion t h e ex ten t o f h y d r o l y s i s o f s o l u b l e

un reac t i ve (SLIP) and condensed phosphate under a1 gal assay c o n d i t i o n s bu t do

n o t d iscuss d i r e c t i nco rpo ra t i on , enzymatic mod i f i ca t i ons , photodegradat ion,

o r ben th i c decomposit ion.

The a v a i l a b i l i t y o f p a r t i c u l a t e phosphorus i s a much more c o n t r o v e r s i a l

p o i n t . A sumnary o f s t u d i e s which have examined t h e b i o a v a i l a b i l i t y o f

p a r t i c u l a t e t o t a l phosphorus (PTP), us i ng bo th chemical and b i o l o g i c a l

techniques f o r urban r u n o f f , sediments, and t r i b u t a r i e s i s shown i n Table 2,

and f o r atmospheric sources i n Table 3. F i g u r e 1 i n d i c a t e s t h e p o s s i b l e

composit ion o f PTP and at tempts t o show which species are e x t r a c t e d by t h e

va r i ous e x t r a c t i o n methods. For those s o i 1 and sediment p a r t i c u l a t e s t h a t

have been examined (Table 2), t he f r a c t i o n o f phosphorus which i s e x t r a c t a b l e

i n NaOH would appear t o be most h i g h l y c o r r e l a t e d w i t h b i o l o g i c a l growth.

Furthermore, most researchers b e l i e v e t h a t sodium hydrox ide e x t r a c t a b l e

i no rgan i c phosphorus (NaOH-IP) represen ts t h e maximum amount o f PTP t h a t i s

a v a i l able. The minimum amount a v a i l a b l e i s represented by t he i o n

exchangeable p o r t i o n . Th i s means t h a t f o r most p a r t i c u l a t e sources, t h e

TABLE 2: SUMMARY OF STUDIES OF AVAILABLE PARTICULATE PHOSPHORUS FROM DIFFUSE SOURCES (From Lee cfl. ( 1 ) )

P a r t i c u l a t e Chemical F r a c t i o n B ioassy B i o a v a i l a b i l i t y Source Considered A v a i l a b l e Technique C o r r e l a t i o n Reference

Mar ine Sediments NTA Scenedesmus Golterman ( 6 )

Urban Runo f f NaOH o r Anion Selenastrum Exchangeable

S o i l s , S o i l Runoff NaOH

Lake Sediment

S o i l s

Lake Sediment

B l u f f e ros ion, Lake sediments & T r i b u t a r i e s

Lake E r i e T r i b u t a r i e s

Great Lakes T r i b u t a r y Sediments

Great Lakes Shore1 i n e S o i l s

Great Lakes T r i b u t a r y Sediments

NaOH

Aluminum Satura ted- c a t i o n exchange

Exchangeable - I P

NaOH

NaOH + C i t r a t e - D i t h i o n i t e - B icarbonate

NaOH

NAIP

A v a i l a b l e P = SRP Cowen (17 ) + 0.2 PTP Cowen & Lee (18 )

2 and 30-day assays 66-94% o f NaOH-PIP Sagher, fi fl. (19 ) w i t h Selenastrum

28-day assay w i t h 74% o f NaOH-IP Selenastrum

12-wks w i t h macro- 13-17% o f PTP phy te M. sp ica tum

12-18 days w i t h NaOH-IP Scenedesrnus

Up t o 143 days w i t h 40% o f NaOH-IP ind igenous a lgae

14-37% o f PTP

43% o f PTP

20-40% o f PTP

Sagher, fi fl. (19 )

H u e t t l , g fl. (20)

L i , t fl. (21)

W i l l i ams , g fl. (22 )

Logan, fi d. (23 )

Armstrong, g fl. (24 )

Mon te i t h & sonzogni ( 25 )

Thomas (26)

TABLE 3: SUMMARY OF STUDIES ON AVAILABLE PHOSPHORUS FROM ATMOSPHERIC SOURCES (From Lee fl. (1))

Sample Chemical F r a c t i o n Bioassy B i o a v a i l a b i li t y Source Considered Avai 1 a b l e Technique C o r r e l a t i o n Reference

Wisc. Snow

Ra in water

P r e c i p i t a t i o n

R a i n f a l l and D r y F a l l o u t

Exchangeable

18 days w i t h ~ 2 5 % o f PTP Selenastrum + SRP

Cowen (17 ) Cowen & Lee ( 1 8 )

38% o f TP Peters (27 )

' SRP + Ac id Ex t rac tab le

Murphy & Doskey (28)

Delumyea & Pete1 (29, 30)

FIGURE 1: POSSIBLE COMPONENTS OF PARTICULATE PHOSPHORUS AND THEIR SUSCEPTIBILITY TO VARIOUS CHEMICAL EXTRACTION METHODS

PARTICULATE TOTAL PHOSPHORUS

(PTP)

I Organic Phosphorus

POP

I I no rgan i c Phosphorus

PIP

Al(OH>3 Fe( OH3 ) Ca3(P04)2 S t r e n g i t e W a v e l l i t e ~ p a i i t e Occ 1 uded Occ 1 uded FeP04' 2H20 A13 (OH!J ( Po4 Cal ( PO4

P P

NAIP Chemical E x t r a c t i o n Method

( i > NTA Ca3 ( Po4 ) 2 FeP04' 2H20

( i i ) Anion Exchange a l l exchangeable P i n e q u i l i b r i u m w i t h s o l u b l e ortho-PO4

( i i i ) NaOH A1 (OH) 3 Fe(OH)3 o c c l uded occluded

P P

( i v ) C i t r a t e Al(OH>3 Fe(OH)3 occ 1 uded o c c l uded

P P

AIP

ac tua l b i o a v a i l ab le phosphorus 1 i e s somewhere between t he amounts des ignated

as-exchangeabl e-IP and NaOH-IP. These measurements, however, g i v e a s t a t i c

r ep resen ta t i on and f a i l t o recognize t h e exchauge processes among t h e

phosphorus components.

Tab1 e 2 does no t i n c 1 ude p a r t i c u l a t e phosphorus assoc ia ted w i t h wastewater

t reatment p l ant e f f l u e n t s . According t o Lee -- e t a1 . (1) , t h e f r a c t i o n a t i o n

procedures dep i c ted i n F i g u r e 1 may no t be app rop r i a te f o r assessing t h e

b i o a v a i l a b i l i t y o f these ma te r i a l s . A s i g n i f i c a n t p o r t i o n o f t h e PTP a r i s i n g

f rom sewage p l a n t s w i l l be a m i x t u r e o f p a r t i c u l a t e o rgan ic phosphorus (POP).

Two s tud ies o f wastewater sources u t i l i z i n g bo th chemical and b i o l o g i c a l

techniques t o es t imate r e a d i l y b ioava i 1 ab le phosphorus, a re c u r r e n t l y underway

a t t he Wastewater Technology Centre-Great Lakes B io l imno logy Laboratory , a t

CCIW, Bu r l i ng ton , On ta r i o and a t Clarkson Col lege, under t h e d i r e c t i o n o f

Prof . Joe DePinto, under c o n t r a c t w i t h U.S. EPA. The a l g a l growth t e s t i s a

u s e f u l b ioassay method f o r s t ud ies o f t h i s type. I n an a l g a l growth t e s t , t h e

maximum amount o f a lgae produced by growth on a t e s t source o f phos'phorus, i s

r e l a t e d t o t h e amount of a s s i m i l a t e d du r i ng growth. I t i s 'bes t t o

measure phosphorus uptake d i r e c t l y , bu t f o r growth on p a r t i c u l a te sources t h - i s

i s o f t e n d i f f i c u l t . Therefore, i t i s more common t o measure a l g a l growth by

c e l l counts, t u r b i d i t y , acety lene reduc t ion , e tc . and then t o t r ans1 a te these

values t o phosphorus uptake by comparison w i t h s i m i l a r measurements w i t h a

c u l t u r e grown on orthophosphorus a1 one.

F i n a l l y , i t should be s t a t e d t h a t e x p l o r a t o r y s tud ies i n t o t h e ques t i on of

b i o a v a i l a b i l i t y should i n v o l v e a coup l i ng o f chemical f r a c t i o n a t i o n t o

bioassays. As seen f rom Table 2, fbr s o i l s and sediments, t h i s c o r r e l a t i o n

has n o t always been made.

4. SOLIRCES OF PHOSPHORUS INPUTS AND 'THEIR AVAILABILITY

Phosphorus en te r s t h e Great Lakes and t h e i r t r i b u t a r i e s f rom i n d u s t r i a l

and mun ic ipa l p o i n t sources and nonpoint sources. The l a t t e r i n c l u d e d i r e c t

and i n d i r e c t urban and a g r i c u l t u r a l r u n o f f , shore1 i n e e ros ion and atmospheric

depos i t ion . The r e l a t i v e c o n t r i b u t i o n s o f t h e va r i ous sources o f t o t a l

phosphorus va r i es as shown f o r each o f t h e Great Lakes watersheds i n Table 4. Fur ther , each source of phosphorus i n p u t i s unique w i t h respect t o the chemical form of t he phosphorus and thus i t s r e l a t i v e importance i n eu t roph i ca t i on .

- - - - - - --

TABLE 4

"BEST" ESTIMATE** OF 1976 PHOSPHORUS LOADS TO THE GREAT LAKES (me t r i c tons)

D i r e c t D i r e c t . T r i bu ta ry * Urban Upstream Lake Munic ipal I n d u s t r i a l To ta l Atmosphere D i r e c t Load . To ta l

SUPERIOR 72 103 2,455 1,566 16 - 4,212

MICHIGAN 1,041 38 3,596 1,682 - - - 6,357

HURON 126 38 2,901 1,129 16 657 4,867

ERIE 6,292 27 5 9,960 774 4 4 1,080 18,425

ONTAR I 0 2,093 82 4,047 488 324 4,769 11,803

*cons is ts of i n d i r e c t p o i n t sources and nonpoint sources i n t r i b u t a r y basin.

**Source: F i n a l Report o f Phosphorus Management S t ra teg ies Task Force (31)

November

P o i n t Sources

I n t h e past, t h e major anthropogenic sources of phosphorus t o the .Great

Lakes were munic ipal and i n d u s t r i a l wastewaters. Under t he terms o f t h e 1972

Great Lakes Water Q u a l i t y Agreement, Canada and t h e Un i ted States agreed t o

reduce these i npu ts by l i m i t i n g the t o t a l phosphorus concent ra t ion i n

mun ic ipa l wastewater e f f l u e n t s t o l . 0 mg/L and p r o v i d i n g t reatment f o r

i n d u s t r i a l wastewaters con ta in ing s i g n i f i c a n t amounts of phosphorus.

These programs o f p o l l u t i o n abatement have l e d t o a s u b s t a n t i a l drop i n

phosphorus l oad ing t o t h e lower Great Lakes. According t o t h e Water Qua1 i t y

Board (32), aggregate concentrat ions o f phosphorus i n mun ic ipa l wastewaters

discharged i n t h e Great Lakes bas in have been reduced f rom 2.6 mg/L i n 1975 t o

1.8 mg/L i n 1978.

Phosphorus i n wastewater i s no rma l l y p resen t as o rgan ic phosphorus,

i no rgan i c condensed phosphates, and orthophosphates (33). Most o f t h e o rgan ic

phosphorus i s p a r t i c u l a t e i n na tu re and inc ludes b a c t e r i a l c e l l s . I no rgan i c

condensed phosphates f rom s y n t h e t i c detergents , t oge the r w i t h orthophosphate

f rom ur ine, m i c r o b i a l degradat ion o f o rgan ic phosphates o r h y d r o l y s i s o f

condensed phosphates compri se t h e major d i sso l ved f r a c t i o n .

The inc rease i n t h e i no rgan i c condensed phosphorus f r a c t i o n i n mun i c i pa l

wastewaters which accompanied t h e i n t r o d u c t i o n o f s y n t h e t i c de te rgen ts has

s i nce been reduced by 1 eg is1 a t i ve 1 i m i t a t i o n s imposed on phosphorus con ten t o f

de te rgen t fo rmu la t ions . Subsequent t o t h e adopt ion o f l e g i s l a t i v e

1 i m i t a t i o n s , decreases i n t he phosphorus con ten t of domestic wastewaters were

repo r ted t o be as h i g h as 50 t o 60% where t h e i n d u s t r i a l c o n t r i b u t i o n i s low;

Lee -- e t a l . (1 ) . Other observa t ions f o l l o w i n g l e g i s l a t i v e l i m i t a t i o n s have

shown reduc t ions i n e f f l u e n t phosphorus con ten t as h i gh as 67% (34) . I n areas

o f t he U.S. w i t hou t l e g i s l a t i v e con t ro l s , t h e r e have been v o l u n t a r y decreases

i n t h e phosphorus con ten t o f de te rgen t formulat ions; and i t i s es t imated t h a t

a complete phosphorus ban would now produce o n l y a 30 t o 35% r e d u c t i o n i n t h e

phosphorus con ten t o f mun ic ipa l wastewaters i n these areas (35) . However,

s ince de te rgen t phosphorus i s b o t h h i g h l y so lub le and b i o a v a i l able, r educ t i ons

i n t h e phosphorus con ten t o f de te rgen ts t o 2.2 t o 0.5% by weight may slow

e u t r o p h i c a t i o n more than mere ly 1 ower i ng t h e t o t a l phosphorus i n mun i c i pa l

wastewater by a t h i r d . Th is r e d u c t i o n p robab ly has most s i g n i f i c a n c e i n

reduc ing phosphorus i n p u t s from i n d i v i d u a l t rea tment systems o r where

phosphorus removal i s no t r e q u i r e d under t h e Great Lakes Water Q u a l i t y

Agreement.

I t i s g e n e r a l l y b e l i e v e d t h a t t h e major f r a c t i o n o f wastewater phosphorus

i s ava i l ab le . Lee -- e t a l . (1) have quest ioned whether upon h y d r o l y s i s of t h e

condensed phosphate i n wastewater, a l l t h e phosphate becomes a v a i l a b l e as

orthophosphate and hypothes ize t h a t up t o 50% may be conver ted t o

non-ava i lab le forms. A t p r ima ry and secondary wastewater t rea tment p l a n t s

p r a c t i c i n g chemical p r e c i p i t a t i o n t o meet t h e 1 mg/L t o t a l phosphorus

requirement, most o f t h e r e s i d u a l phosphorus i s p resen t as m ix tu res of o rgan i c

and p a r t i c u l a t e i r on , aluminum, o r ca lc ium hydroxides. The meta l hydrox ides

cou ld be unava i l ab le f o r d i r e c t a l g a l growth. Residual so lub le phosphorus

g e n e r a l l y i s l e s s than 0.3 mg/L. Lee -- e t a l . ( 1 ) i n d i c a t e d t h a t phosphorus

assoc ia ted w i t h i r o n and aluminum w i l l be i nc l uded i n non a p a t i t e i n o r g a n i c

p h o s p h o r ~ ~ s (NAIP) determined by hydrox ide e x t r a c t i o n . I n a p rev ious s tudy by

Lee (35), i t was concluded t h a t phosphorus i nco rpo ra ted i n t o hydrous ox ide

f l o c s i s n o t r e a d i l y r e t u r n e d t o t h e water column over extended per iods o f

t ime and i s thus cons idered unava i lab le . On t he o the r hand, Dor ich and Nelson

(34) found, i n t h e i r i n v e s t i g a t i o n o f t h e p o r t i o n s o f s o l u b l e and sediment

bound phospho r~~s i n dra inage f r om a g r i c u l t u r a l watersheds i n t h e Maumee R i v e r

basin, t h a t phosphates l o o s e l y sorbed on amorphous aluminum and i r o n ox ide

complexes supp l i ed t he h i g h e s t p r o p o r t i o n o f phosphorus a s s i m i l a ted by algae.

For systems us ing i r o n f o r phosphorus removal, r e l ease o f orthophosphate may

occur under reduc ing c o n d i t i o n s i n anoxic hypol imnia. Fu r the r l ong and s h o r t

term a v a i l ab i 1 i t y s tud ies a re r e q u i r e d t o determine t h e b i o l o g i c a l

a v a i l ab i 1 i t y o f t he r e s i d u a l phosphorus i n mun i c i pa l wastewaters f o l l owing

t rea tment by t h e t h r e e w i d e l y p r a c t i c e d chemical p r e c i p i t a t i o n processes.

Nonpoint sources

Wi th t h e -implementation o f p o i n t source phosphorus c o n t r o l programs

a t t e n t i o n has focused on t he c o n t r i b u t i o n o f nonpoint sources. The ma jo r

nonpo in t sources f o r phosphorus i n t h e Great Lakes Basin have been i d e n t i f i e d

by the I JC ' s I n t e r n a t i o n a l Reference Group on Great Lakes P o l l u t i o n f r om Land

Use A c t i v i t i e s (PLUARG) (37); as:

1. urban r u n o f f ;

2. a g r i c u l t u r a l r u n o f f ;

3. s h o r e l i n e eros ion; .and

4. .atmospheric depos i t i on .

Urban r u n o f f samples c o l l e c t e d du r i ng 12 events a t Madison, Wisconsin f rom

r e s i d e n t i a1 , comnercial and urban c o n s t r u c t i o n 1 and areas were examined f o r

phosphorus con ten t and b i o a v a i l a b i l i t y by Cowen and Lee (38). A f u r t h e r s tudy

by t he same authors was r e p o r t e d f o r two u rban - res iden t i a l areas i n t h e

Genesee R i v e r bas in . From a l g a l assays o f t h e samples t hey concluded t h a t

NaOH and anion exchange r e s i n e x t r a c t i o n techniques gave t h e bes t es t imates o f

a v a i l a b l e p a r t i c u l a t e phosphorus . At Madison, mean values o f t h e e x t r a c t a b l e

phosphorus were between 22 and 27% of p a r t i c u l a t e t o t a l phosphorus (PTP) w h i l e

f o r t h e Genesee s tudy base ex t rac tab les averaged between.18 and 30%. Cowen

and Lee (38) concluded t h a t an upper bound f o r a v a i l a b l e phosphorus i n urban

r u n o f f cou ld be ob ta ined f rom

A v a i l a b l e P = SRP + 0.3 PTP

Subsequently, Lee -- e t a l . ( 1 ) modi f ied t h e es t ima te t o account f o r f a c t o r s

a f f e c t i n g a v a i l ab i 1 i t y i n r e c e i v i n g waters. They suggested t h a t t h e u l t i m a t e

ava i l a b i 1 i t y can be est imated, based on s o l u b l e r e a c t i v e phosphorus (SRP) and

PTP, as fo l lows :

A v a i l a b l e P = SRP + 0.2 PTP

The general a p p l i c a b i l i t y o f t h i s r e l a t i o n s h i p needs f u r t h e r i n v e s t i g a t i o n and

v e r i f i c a t i o n .

I n i t s F i n a l Report (37) t o t h e IJC, PLUARG i d e n t i f i e d i n t e n s i v e

a g r i c u l t u r a l ope ra t i ons as a major nonpoint source o f phosphorus. The most

impor tan t land r e l a t e d f a c t o r s a re s o i l type, l and use, and m a t e r i a l s usage.

As can be seen f rom Table 5, u n i t area loads vary f rom l e s s than 0.1

k i lograms/hectare/year f o r land w i t h mos t l y f o r e s t t o over 1.5

k i lograms/hectare-year from l and w i t h ex tens i ve row crops on f i n e t e x t u r e d

s o i l s .

Resu l ts of s tudy ing t h e r e l a t i v e b i o a v a i l a b i l i t y o f phosphorus i n

ex tens i ve samples of Great Lakes waters and t r i b u t a r i e s have been r e p o r t e d by

Armstrong -- e t a l . (39) and PLUARG (37). Both used t h e NaOH-extractable

phosphorus t o es t imate t he non-apa t i te i no rgan i c phosphorus (NAIP). Mean

d i s t r i b u t i o n o f phosphorus species f rom t h e PLUARG study conducted i n t h e Lake

Ontar io , E r i e and Huron bas ins a re g i ven i n Table 6. A cons is tency o f

percentage composi t ion p a r t i c u l a r l y f o r t h e NAIP f r a c t i o n was noted between

moni tored streams and 1 akes. For t he streams t h e c o e f f i c i e n t of v a r i a t i o n

( s / x ) o f t h e a p a t i t e (18%) was s i g n i f i c a n t l y lower than e i t h e r t h e NAIP (50%)

TABLE 5: ANNUAL UNIT AREA LOADS OF TOTAL PHOSPHORUS BY LAND USE AND LAND FORM I N CANADA

Greater than 50% rowcrops; (sand on c lay ) low animal dens i ty* 1.5 - 0.7 ' - 0.2- - 0.9

Greater than 50% rowcrops; medium animal dens i ty* - - - - 0.2 - -

25-50% rowcrops; med i um animal d e n s i t y 0.6 4.7 0.2 0.3 0.1 0.2 -

25-50% rowcrops; (sand on c l a y ) h igh animal density*** 0.7 0.8 0.3 0.4 0.2 0.2 0.7

Less than 25% rowcrops; (sand on c lay ) A med i um animal d e n s i t y 0.3 0.4 0.1 0.1 0.1 0.1 cn

0.4

Less than 25% rowcrops; h igh animal d e n s i t y 0.4 0.5 0.1 0.2 - 0.1 0.1 -

Greater than 60% f o r e s t 0.2 0.2 0.1 0.1 0.1 0.1 ( s h i e l d ) 0.1

* Less than 0.1 animals/km2 ** Greater than 0.1 and l ess than o r equal t o 0.3 animals/km2 *** Greater than 0.3 animals/km2

kg/ha-yr - k i lograms per hectare per year M u l t i p l y kg/ha-yr by the f a c t o r 1.12 t o conver t t o pounds per acre per year ( I b /ac /y r )

Source: Ref. (40) , .

o r t he organic phosphorus (59%). I t was concluded t h a t t h i s represen ted a

r e f l e c t i o n o f t h e t e x t u r e and s o i l s o f t h e i n d i v i d u a l watersheds. Both t h e

NAIP and Organophosphorus showed more v a r i a t i o n r e f l e c t i n g bo th stream

p r o d u c t i v i t y and a d j o i n i n g 1 and usage. These values a re i n genera l agreement

w i t h those r e p o r t e d by Armstrong -- e t a l . (24), bu t h i ghe r i n NAIP o r base

e x t r a c t e d p a r t i c u l a t e phosphorus when compared w i t h t h e range o f 13 t o 18%

repo r ted by Cowen and Lee (18) f o r non-urban Genesee R i v e r watersheds.

Analyses o f 36 t r i b u t a r i e s i n t h e U.S. Lake E r i e Basin by Logan (39) and Logan

e t a l . (23) i n d i c a t e d t he NaOH e x t r a c t a b l e was 30 t o 40% o f t h e t o t a l -- inorgan i c phosphorus o r 6 t o 15% o f t h e p a r t i c u l a t e f r a c t i o n .

Pub1 ished da ta i n d i c a t e r e 1 a t i v e l y low percentages o f p a r t i c u l a t e

phosphorus i n sedimentary m a t e r i a l e i t h e r f rom e ros ion o f shore l i n e b l u f f o r

l ake bot tom sediments are a v a i l a b l e f o r a l g a l growth. I n samples f r o m 22

l oca t i ons , W i l l i a m s -- e t a l . (22) showed t h a t w i t h two except ions, a p a t i t e

phosphorus averaged 51% o f t o t a l p a r t i c u l a t e w h i l e NAIP averaged 31%. The two

t y p i c a l except ions had h i g h p a r t i c u l a t e t o t a l phosphorus. They concluded t h a t

t h e percentage o f a v a i l a b l e phosphorus i n geo log ic m a t e r i a l s i s h i g h l y

va r i ab le . I n unweathered samples o r samples o f low t o t a l p a r t i c u l a t e

phosphorus, t h e a v a i l a b l e phosphorus i n NAIP tended t o be low.

TABLE 6:

PARTICULATE PHOSPHORUS DISTRIBUTION

Apa t i t e ' NAIP Organic % % %

Streams 28.1 33.4 38.5

Lake O n t a r i o 24.5 31.6 43.9

Lake E r i e 29.8 37.4 32.8

Lake Huron 43.4 23.1 33.5

Source: Ref. No. (37)

Thomas and Haras (41) es t imated t h a t , ,on t he bas i s o f Canadian data, t h e

c o n t r i b u t i o n s o f t o t a l phosphorus f rom s h o r e l i n e e ros ion t o Lakes Huron and

On ta r i o a re low w i t h maximum values o f 9.3 and 6 .2% r e s p e c t i v e l y . Conversely,

t h e l oad ing t o Lake E r i e i s est imated ' a t 35.2%. The a v a i l a b l e o r NAIP

load ings were es t imated t o be 4.0, 1.1 and 5.0% f o r Lakes Huron, Onta r io , and

.Er ie, r e s p e c t i v e l y . Th i s i n d i c a t e s t h a t phosphorus eroded b l u f f m a t e r i a l i s

g e n e r a l l y no t a v a i l a b l e f o r . a l g a 1 growth as concluded by PLUARG (37) . The

corresponding U.S. s tudy b y ~ o n t e i t h and Sonzogni , (25) i n d i c a t e d t h a t 25% ' of

t he t o t a l phosphorus l oad ing cou ld r e s u l t f rom s h o r e l i n e e ros ion .

A number o f i n v e s t i g a t o r s have at tempted t o assess t h e atmospheric

c o n t r i b u t i o n s o f phosphorus t o water bodies. As i n d i c a t e d i n Table 4, t h i s

i n p u t i s a s u b s t a n t i a l p o r t i o n o f t o t a l phosphorus loads e s p e c i a l l y f o r Lakes

Super ior , Michigan and Huron. A f u r t h e r q u a n t i t y o f phosphorus i s depos i ted

on l and and c o u l d m ig ra te i n t o t h e Lakes.

Delumyea and Pete1 (29, 30) found h i g h l y v a r i a b l e so lub le phosphorus

concent ra t ions rang ing f rom 1 t o 36 pg/L d u r i n g 21 event samples on t h e Lake

Huron shore l ine . Analyses o f i n t e g r a t e d wet samples, leached a t pH 2 i n

H2S04, were a l so h i g h l y v a r i a b l e rang ing f rom a 10 pg/L up t o 700 pg/L. Th is

p robab ly exceeds t h e a v a i l a b l e f r a c t i o n . Murphy (42) r e p o r t e d 34 pg/L o f -

t o t a l phosphorus i n r a i n f a l l i n urban Chicago. So lub le orthophosphate

corr~pr ised approx imate ly 35%. A f u r t h e r survey around Lake Mich igan by Murphy

and Doskey (28), i n d i c a t e d a weighted average i n 188 samples from s i x

l o c a t i o n s v a r i e d f rom 16 t o 36 pg/L t o t a l phosphorus. So lub le orthophosphate

ranged from 30 t o 50%. Snow samples had t o t a l phosphorus con ten t of .7 t o

58 pg/L. They es t imated p o s s i b l y 50% o f t h e t o t a l phosphorus may u l t i m a t e l y

be ava i l ab le .

A survey o f t h e p r i n c i p a l sources o f emissions i n t h e U.S. bo rde r i ng t h e

Great Lakes would i n d i c a t e t h a t orthophosphate ( o r P205) would

predominate i n p r e c i p i t a t i o n (43). Major orthophosphate emissions r e p o r t e d

were 4600 m e t r i c tons f rom hand1 i n g and spreading o f f e r t i 1 i z e r , .2800 m e t r i c

tons f rom t h e i r o n and s t e e l i n d u s t r y and 3900 m e t r i c tons f rom combustion o f

coal . ~.

5. IN-LAKE TRANSFORMATIONS

As descr ibed i n Sect ions 2 and 4, phosphates become a v a i l a b l e t o t h e

aquat ic b i o l o g i c a l comnunity i n the Great Lakes through erosion, a i r

t ranspor t , and t h e a c t i v i t i e s o f man.

B i o l o g i c a l systems r e q u i r e severa l elements a t a r a t e t o s a t i s f y t h e i r

n u t r i t i o n a l demands, which f o r algae has been expressed by Go1 terman (44) as:

106 CO2.+ 90 H20 + 16 NOs + POI++ L i g h t + C106H1800~5N16P + 154402

I n a d d i t i o n t o phosphorus o ther n u t r i e n t s such as carbon and n i t r o g e n are

' r e q u i r e d f o r growth. The maximum biomass which can r e s u l t i s a f u n c t i o n o f , : among o ther th ings , t h e essen t i a l n u t r i e n t which i s a v a i l a b l e i n t h e l e a s t

amount r e l a t i v e t o t h e need. Assuming phosphorus i s t h e l i m i t i n g n ~ ~ t r i e n t f o r

aquat ic organisms i n a lake, then one has t o consider no t o n l y t he

a v a i l a b i l i t y o f t he var ious forms o f phosphorus bu t a l s o the se lec t i on ,

c y c l i n g and u t i l i z a t i o n o f these var ious forms by t h e b i o l o g i c a l community.

As the d i f f e r e n t b i o l o g i c a l species f r e q u e n t l y have d i f f e r e n t s t r a t e g i e s t o

meet t h e i r n u t r i t i o n a l demands, t h e s i t u a t i o n becomes q u i t e complex. These

complex i t ies have r e s u l t e d i n experimental "evidence" which c o n f l i c t and

numerous debates about which forms o f phosphorus are a v a i l a b l e and which are

not.

The d i f f e r e n t phosphate components o f t h e phosphorus c y c l e are recognized

by a n a l y t i c a l procedures and can be grouped as fo l l ows :

I - Inorgan ic orthophosphate: PO4 - P (=H2POI, HPO; + PO:)

I 1 - Hydro lysable phosphate: Dissolved polyphosphate +

Dissolved organic phosphate

I 1 1 - Tota l d i sso l ved phosphate: I + I 1

I V - P a r t i c u l a t e phosphate: Pa r t P

V - Sum o f 111 + I V = To ta l P = (Pa r t phosphate +

To ta l d i sso l ved phosphate)

It i s essent ia l t o note t h a t the above chemical components are as

perceived by t h e i r chemistry, and does not represent the i n t e r p r e t a t i o n o f t he

chemical environment by the algae. With t h i s caveat i n mind, the phosphate

c y c l e i n lakes can be presented as i n F igure 2.

ALGAL Po4 D

Flgure 2: Schematic representation of the phosphate cycle. The indicated turnover of 20 times per year may vary between 10 and 40. (Source: reference

(44

Wi th in t h i s cycle, two i n t e r a c t i v e processes can be i d e n t i f i e d . The f i r s t

i s a metabol ic process, represented by - two phases:

(1) PO4-P water Primary Product ion M i n e r a l i z a t i o n water Org - C e l l P O 4

Heterotrophy P 0 4 (2) Org P ___3

The second cyc le i s an "ex te rna l " phosphate cyc le represented by:

(3 ) POs - P 'wa.ter - sediment - PO4 - P water & Org P

Clays are c a t i o n exchangers capable o f adsorbing 1 arge amounts o f

phosphates. Go1 terman ( 6 ) reviewed t h e mechanisms o f phosphate adsorpt ion,

and Olsen (45, 46) i l l u s t r a t e d t h a t t h e exchange o f phosphate i s a r a p i d

process t h a t d i r e c t l y r e f l e c t s uptake r a t e s b y algae. his i n f o r m a t i o n

combined w i t h o t h e r observ-at ions such as t h e use o f a p a t i t e (47), and t h e 'use

o f FeP04 (48, 7 ) by algae, i n d i c a t e s t h a t t h e r e are p robab ly few forms of

phosphorus which a re n o t u l t i m a t e l y b i o l o g i c a l l y a v a i l a b l e . It i s t h e r a t e

process, combined w i t h t he b i o l o g i c a l s t r a t e g y o f u t i l i z a t i o n invo lved, which

determines ava i 1ab i1 i t y . The e x c r e t i o n o f e x t r a c e l l u l a r enzymes ( a l k a l i n e

phosphatase) a1 so represen ts a b iochemica l " c o n d i t i o n i n g " o f t h e aqua t i c

chemical environment which w i 11 r e s u i t i n a d d i t i o n a l phosphorus components

becoming b i o a v a i 1 able.

Another f a c t o r o f importance i s t h e r a t e o f processes. Lean and Nalewajko

(49) descr ibed uptake r a t e s o f p3' w i t h t h e conc lus ion t h a t uptake r a t e s i n

l a r g e lakes were lower than those measured i n smal l lakes. Phosphorus demand

cannot be d i r e c t l y assessed by a n a l y t i c a l measurements o f s o l u b l e r e a c t i v e ,

s o l u b l e unreac t i ve , and p a r t i c u l a t e phosphorus which p r o v i d e a s t a t i c

r ep resen ta t i on o f t h e phosphorus pools . Lean's observa t ions w i t h n a t u r a l

communit ies suggest t h a t a n a l y t i c a l measurements cannot be used t o d i s t i n g u i s h

areas o f h i g h o r low phosphorus demands. Attempts t o d e f i n e b i o l o g i c a l l y

a v a i l a b l e phosphorus by growth c u l t u r e s (22, 23) may a l so be o f l i m i t e d va lue

because r a t e processes w i l l be a l t e r e d by t h e c u l t u r e cond i t i ons .

I n t h i s sense, b ioassay work 111ust be viewed w i t h g rea t t r e p i d a t i o n . A t

t he December 8 meeting, H a r r i s ( 2 ) cau t ioned about e x t r a p o l a t i o n o f b ioassay

r e s u l t s t o " i n l ake " phosphorus a v a i l a b i l i t y . Even -- i n s i t u work, however, has

i t s problems. F i t z g e r a l d (2) noted t h a t a1 k a l i n e phosphatase a c t i v i t y

measured -- i n s i t u c o u l d d e p i c t t h e n u t r i t i o n a l s t a t u s o f t h e b i o l o g i c a l

comnunity. H igh a l k a l i n e phosphatase l e v e l s were i n d i c a t i v e o f a lgae w i t h

h i g h phosphorus demands. Only a p o r t i o n of t h e a l g a l community, however, w i l l

use t h i s e x t r a c e l l u l ar enzyme s t ra tegy . Muc i 1 agenous a1 gae c rea te t h e i r own

su r face t o t r a p p a r t i c u l a t e s , o the rs extend f i b r i l s , and s t i l l o t he rs are

capable o f i n g e s t i o n o f p a r t i c u l a te o r h e t e r o t r o p h i c uptake o f o rgan i c

phosphorus, and t he re fo re , do n o t depend on e x t r a c e l l u l a r phosphatase. Th i s

d i v e r s i t y i n s t r a t e g i e s o f o b t a i n i q g phosphorus means t h e ques t i on o f

a v a i l a b l e phosphorus i s complex and n o t w e l l r eso l ved by s imple chemical

measurements o r bioassays.

Phosphorus a v a i l ab i 1 i t y and u t i 1 i z a t i o n do f o l low t h e c e n t r a l tendency

theorem. Models such as those developed by Vol lenweider (50) and D i l l o n (51)

a re g e n e r a l l y a p p l i e d w i t h some success. Sch ind le r (52) notes t h a t t h e Great

Lakes and n a t u r a l l y 1 oaded smal l 1 akes responded 1 ess t o phosphorus l o a d i n g

than sma l l e r exper imenta l lakes where t h e phosphorus l oad was almost e n t i r e l y

PO4-P. Th is i s what i s p r e d i c t e d from Lean & Na l iwa j ko (49); o the r

f a c t o r s , p a r t i c u l a r l y r a t e processes, 1 i m i t phosphorus u t i 1 i z a t i o n i n t h e

Great Lakes. S i m i l a r arguments have been developed by H a r r i s -- e t a l . (53) and

Ha f f ne r -- e t a l . (54), where even though t h e same chemical compartments e x i s t i n

t h e Great Lakes as i n o t h e r lakes, t h e r e i s evidence t o suggest t h a t

u t i l i z a t i o n o f these phosphorus forms d i f f e r s cons iderab ly .

T h i s l a t t e r p o i n t , t h e d i f f e r e n t u t i l i z a t i o n o f phosphorus under d i f f e r e n t

cond i t i ons , can be emphasized by rev iew ing s i t u a t i o n s which e x i s t i n two o the r

1 akes.

Lake' K- inneret i n I s r a e l , r ece i ves about grams o f phosphate pe r square

meter per year 1.0 g P04-P m-2yr-1 compared w i t h a l oad ing o f 0.98 g

PO4-P m-2yr-1 t o Lake E r i e , and y e t i s c l a s s i f i e d as 01 i g o t r o p h i c . (55,56)

It i s p o s t u l a t e d t h a t excess ive e u t r o p h i c a t i o n does n o t occur because t h e major

phosphorus i n p ~ ~ t s a re t r a n s p o r t e d d i r e c t l y t o t h e hypol imnion, and t h e phosphorus ' .

i s s t r o n g l y bound w i t h i n t h e c l a y s t r u c t u r e .

Great Slave Lake i n t h e Northwest T e r r i t o r i e s , r ece i ves about 3 g POI,-P m-2yr- '

i s a l s o o l i g o t r o p h i c p r i m a r i l y because t h e phosphorus t r anspo r ted by c l a y i s

unavai 1 ab le (57).

These r e p r e s e n t two examples where n a t u r a l i n p u t s o f phosphorus a re such

t h a t t he b i o l o g i c a l comnunity cannot respond t o them. It can. g e n e r a l l y be

concluded t h a t phosphorus f rom n a t u r a l sources i s l e s s a v a i l a b l e than t h a t

i n t r oduced by man's a c t i v i t i e s .

The a v a i l a b i l i t y o f phosphorus assoc ia ted w i t h c l a y p a r t i c l e s i s n o t

simple. Braidech -- e t a l . (58) observed t h a t algae i n Lake E r i e ob ta i ned

n u t r i e n t s d i r e c t l y from t h e sediment. L i n and Blum (59) noted t h a t nearshore

algae i n Lake Mich igan d i d no t u t i l i z e i n s o l u b l e polyphosphate o r o rgan ic

phosphates, bu t t he of fshore algae were capable of hyd ro l yz i ng

polyphosphates. Also, b i o - r e c y c l i n g o f phosphorus by f i s h , zooplankton, and

zoo benthos may a f f e c t b i o a v a i l a b i l i t y and very l i t t l e i s known o f t h e i r r o l e

i n t h i s complex problem.

Thus, t h e r e l a t i o n s h i p s among phosphorus loading, phosphorus forms, and

b i o l o g i c a l p r o d u c t i v i t y are complex. Some r e a d i l y a v a i l a b l e forms may become

complexed o r adsorbed on to p a r t i c u l a t e ma t te r w i t h i n t he lake, s e t t l e t o t h e

bottom, and through these phys i ca l and chemical processes become l e s s

ava i l ab le . Other l e s s r e a d i l y a v a i l a b l e forms may be t r anspo r ted t o a

b i o l o g i c a l l y a c t i v e zone and chem ica l l y o r b i o l o g i c a l l y be conver ted s l o w l y t o

useable forms. Once taken up by algae, t h e phosphorus may be used over and

over many t imes, be fo re e i t h e r l e a v i n g t h e l ake o r s e t t l i n g t o t he bot tom as

r e f r a c t o r y o rgan ic o r p o o r l y a v a i l a b l e i no rgan i c p a r t i c u l a t e s . Nevertheless,

g i ven equal i n p u t s o f r e a d i l y a v a i l a b l e and p o o r l y a v a i l a b l e forms o f

phosphorus, t h e r e a d i l y a v a i l a b l e forms have g r e a t e r p o t e n t i a l f o r s t i m u l a t i o n

o f a l g a l growth and p roduc t i on o f h i g h concent ra t ions o f a l g a l mass. For t h i s

reason, i t would be u s e f u l i n a phosphorus management s t r a t e g y t o d i s t i n g u i s h

between forms o f phosphorus e n t e r i n g a l ake which are r e a d i l y a v a i l a b l e and

those which a re not.

6. CONCLUSIONS

1. Phosphorus e x i s t s i n many o the r forms i n an aqua t i c environment, some

o f which may, under c e r t a i n cond i t i ons , become a v a i l a b l e t o t h e

b i o l o g i c a l community. So lub le i no rgan i c forms o f phosphorus are

r e a d i l y a v a i l ab le f o r b i o l o g i c a l growth. The r a t e and o p p o r t u n i t y

f o r va r i ous forms, espec ia l l y p a r t i c u l a t e phosphorus, t o become

b i o l o g i c a l l y a v a i l ab le v a r i e s wide ly . For a1 1 p r a c t i c a l purposes

a p a t i t e phosphorus can be cons idered t o be unava i lab le .

2. Chemical and b ioassay techniques are a v a i l a b l e t o es t ima te t h e

b i o l o g i c a l l y a v a i l a b l e f r a c t i o n o f t o t a l phosphorus con ta ined i n a

sample. A l though t h e r e i s o n l y a l i m i t e d amount o f data a v a i l a b l e on

d i r e c t comparisons between est imates p rov ided by t h e d i f f e r e n t

techniques, t hey do n o t appear t o d i f f e r s i g n i f i c a n t l y .

3. None o f t h e e x i s t i n g chemical o r b ioassay techniques can p rov ide a

meaningful assess~nent o f what f r a c t i o n o f phosphorus i s ava i l ab le , on

a whole lake, long- term scale. A cons ide rab l y h i ghe r l e v e l o f

research a c t i v i t y i s r e q u i r e d i n t h i s area i f accurate methods are t o

be deve 1 oped.

4. The r e l a t i v e b i o a v a i l a b - i l i t y o f phosphorus assoc ia ted w i t h t h e

p a r t i c u l a t e ma t te r i n e f f l u e n t s f rom wastewater t rea tment p l a n t s

us ing t h e a d d i t i o n of aluminum o r i r o n s a l t s t o achieve 1.0 mg/L P i s

c u r r e n t l y under i n v e s t i g a t i o n . The. r e s u l t s o f these i n v e s t i g a t i o s n s

cou ld have a bear ing on t h e cho ice o f chemical t o be used, t o achieve

t h e 1.0 mg/L t o t a l phosphorus o b j e c t i v e i f t h e l o n g te rm

b i o a v a i l a b i l i t y o f t h e r e s i d u a l phosphorus i n t h e e f f l u e n t i s

s i g n i f i c a n t l y d i f f e r e n t depending upon t h e chemical used.

5. Continued research i s r e q u i r e d t o p rov ide a b e t t e r understanding o f

t h e r e 1 a t i o n s h i p s between a1 ga l p r o d u c t i o n - n u t r i e n t 1 i m i t a t i o n i n t h e

Great Lakes. These programs should be designed t o determine t h e

impact o f f u r t h e r r educ t i ons i n e x t e r n a l c o n t r o l 1 ab le phosphorus

load ings on t h e Great Lakes eu t roph i ca t i on . I n t h e meantime,

however, assessments o f t h e r e l a t i v e b i o a v a i l a b i l i t y o f phosphorus as

es t imated by c u r r e n t l y a v a i l a b l e techniques should be used t o ass ign

p r i o r i t i e s f o r t h e c o n t r o l o f va r ious p o i n t and nonpoint sources o f

phosphorus i n p u t s where u n i t cos t s f o r c o n t r o l a re comparable.

6. I n v iew o f t h e s i g n i f i c a n t cos t s assoc ia ted w i t h t h e implementat ion

o f more r e s t r i c t i v e phosphorus c o n t r o l measures f o r p o i n t sources,

i.e., r e q u i r i n g 0.5 mg/L t o t a l phosphorus o r l e s s i n t h e e f f l u e n t s

f rom mun ic ipa l wastewater t rea tment p l ants, and t h e u n c e r t a i n t y

assoc ia ted w i t h commensurate s o c i a l b e n e f i t s , f u r t h e r r e s t r i c t i o n s

should awa i t r e s o l u t i o n o f t h e b i o a v a i l a b i l i t y quest ion.

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28. Murphy, T.J. and P.V. Doskey, " Inputs o f Phosphorus f rom P r e c i p i t a t i o n t o Lake Michigan", Duluth, Environmental P ro tec t i on Agency, (EPA 600/3-75-005), 1975.

29. Delumyea, R.G.. and R.L. Petel , Atmospheric I npu ts o f Phosphorus t o Southern Lake Huron, A r i l -Oc tobe r 1975. Duluth, Environmental P ro tec t i on Agency, (EPA 600/3-77-038 ? 1977.

30. Delumyea, R.G. and R.L. Petel , "Wet and Dry Deposi t ion o f Phosphorus i n t o Lake Huron," Water, A i r & S o i l P o l l . Vol. 10, 1978, pp. 187-198.

31. Phosphorus Management S t ra teg ies Task Force, "Phosphorus Management f o r the Great Lakes", F i n a l Report t o the I n t e r n a t i o n a l J o i n t Commission's Great Lakes Water Q u a l i t y Board and Great Lakes Science Advisory Board, Windsor, Ontar io, J u l y 1980.

32. I n t e r n a t i o n a l J o i n t Commission. Great Lakes Water Q u a l i t y Board Seventh Annual Report. Windsor, Ontario, 1979.

33. Cohen, J.M., "Nu t r i en t Removal from Wastewater by Physical-Chemical Processes," Nu t r i en ts i n Natura l Waters. New York, J. Wiley & Sons, Inc., 1972, pp. 353-390.

34. ~ue- in^, C. and D.T. Lord i , "Report on C i t y o f Chicago's Phosphorus Ban and I t s E f f e c t - Upon E f f l u e n t Q u a l i t y " . Report o f the Department o f Research and Development o f t he Met ropo l i tan San i ta ry D i s t r i c t o f Greater Chicago, February 1973.

35. Lee, G.F., "Review o f t he Po ten t i a l Water Q u a l i t y Bene f i t s from a Phosphate-Bui l t Detergent Ban i n the Sta te o f Michigan", Michigan Hearings on Proposed Phosphate Detergeht Ban, S ta te o f Michigan, 1976.

36. Dorich, R.A. and D.W. Nelson, "A lga l A v a i l a b i l i t y o f Soluble and Sediment Phosphorus i n Drainage Water of t he Black Creek Watershed", Proceedings o f a Conference on Vol untary and Regul a to ry Approaches f o r Nonpoi n t Source P o l l u t i o n Control , May 22-23, 1978, Chicago, I 1 1 i n o i s . U.S. €PA Report EPA 905/9-78-001, J u l y 1978.

37. Environmental Management S t ra tegy f o r the Great Lakes System, F i n a l Report t o the I n t e r n a t i o n a l J o i n t C ~ m ~ i s s i o n f rom the I n t e r n a t i o n a l Reference Group on Great -Lakes P o l l u t i o n from Land Use A c t i v i t i e s (PLUARG). Windsor, Ontar io, 1978.

38. Cowen, W.F. and G.F. Lee. "Phosphorus A v a i l a b i l i t y i n P a r t i c u l a t e Ma te r i a l s Transported by Urban Runoff," J. Water P o l l . Contr. Fed., Vol. - -- - - 48, 1976, pp. 580-591 .

39. Logan, T.J., "Chemical Ex t rac t i on as an Index of B i o a v a i l a b i l i t y o f Phosphate i n Lake E r i e Basin Suspended Sediments", F i n a l P ro jec t Report Lake E r i e Wastewater Management Study. Buf fa lo , U.S. Army Corps o f Engineers, 1978.

40. Johnson, M.G. and N.A. Berg. "A Framework f o r Nonpoint P o l l u t i o n Contro l i n the Great Lakes Basin", J. S o i l and Water Conser. March-Apr i l 1979 pp.

41. Thomas, R.L., and W.S. Haras, "Contributions o f Sediment and Assoc ia ted Elements t o t h e Great Lakes from Eros ion o f t h e Canadian Shorel ine," I n t e r n a t i o n a l Reference Group on Great Lakes P o l l u t i o n f rom Land Use A c t i v i t i e s (PLUARG), Task D - Technica l Report, IJC Windsor, Ontar io , 1978.

42. Murphy, T.J., "Sources o f Phosphorus I npu t s f rom t h e Atmosphere and .The i r S i g n i f i c a n c e t o O l i g o t r o p h i c Lakes", WRC Research Repor t No. 92. Urbana, I 1 l i n o i s , U n i v e r s i t y o f I 1 1 i n o i s Water Resources Center, 1974.

43. U.S. Environmental P r o t e c t i o n Agency. Na t i ona l Emissions I n v e n t o r y - of Sources and Emissions o f Phosphorus. Research T r i a n g l e Park, N.C1, Environmental P r o t e c t i o n Agency, 1973.

44. Golterman, H. L., P h y s i o l o g i c a l Limnology: An Approach t o t h e Phys io logy o f Lake Ecosystems. New York, American E l s e v i e r Pub. Co., Inc., 1975.

45. Olsen, S., " Phosphate Adsorp t ion and I s o t o p i c Exchange i n Lake Muds. Experiment w i t h P-32, -- M i t t . Verh. I n t e r n a t . Vere in Theor. Limnol., Vol. 13, 1958, pp. 915-922.

46. Olsen, S., " Phosphate E q u i l i b r i u m Between Reduced Sediments and Water Labora to ry ~ x p e r i m e n t s w i t h R e t r o a c t i v e Phosphorus, -- M i t t . Verh. I n t e r n a t . Verein. Theor. Limnol, Vol. 15, 1964, pp. 333-341.

47. Smith, E.A., C . I . M a y f i e l d and D.T.S. Wong. "E f f ec t s o f Phosphorus from ~ p a t i t e on ~eve lopmen t o f Freshwater ~ommuni t ies " , J. -- F i s h Res. -- Board o f Canada, Vol. 34, 1977. pp 2405-2409.

48. Armstrong, F.A.J. and H.M. Harvey. "The Cyc le o f Phosphorus i n t h e Waters o f t he Eng l i sh Channel," J. Mar. B i o l . Assn. o f Nova Sco t ia , Vol. 29, 1951, pp. 145-162.

49. Lean, D.R.S. and C. Nalewajko, "Phosphorus Turnover Time and Phosphorus Demand i n Large and Small Lakes", Uppsala Univ. 500 Years, J u b i l e e Symposium on Lake Metabol ism and Lake Management, 1979.

50. Vol lenweider, R.A., "Advances i n D e f i n i n g C r i t i c a l Loading Leve ls f o r Phosphorus i n Lake Eut roph ica t ion , " Memoirs, Vol . 33, 1976, pp. 53-83.

51. D i l l o n , P. J. The A p p l i c a t i o n o f t h e Phosphorus-Loading Concept t o Eu t roph i ca t i on Research. Environment Canada, I n l a n d Waters D i r e c t o r a t e S c i e n t i f i c Se r i es No. 46. Ottawa, I n l a n d Waters D i rec to ra te , 1975.

52. Sch ind le r , D.W. "Factors Regu la t ing Phytop lankton Produc t ion and Standing Crop i n t he Wor ld 's Freshwater", Limn01 ogy - and Oceanography, Vol . 23, 1977, pp 478-486.

53. Ha r r i s , G. P., G. D. Ha f f ne r and P i c c i n i n . '' Phys ica l V a r i a b i l i t y and Phytop lankton Comnunit ies: I 1 Pr imary P r o d u c t i v i t y i n V e r t i c a l l y Uns tab le Water Columns," Arch. Hydrob io l . ( i n press) .

54. Haf fner , G. D., G. P. H a r r i s and M. K. J a r a i . "Phys ica l V a r i a b i l i t y and Phytop lankton Communities: I 1 1 V e r t i c a l S t r u c t u r e i n Phytop lankton Comnunit ies. Arch. Hydrobio l . ( i n p ress) .

55. Serruya, C. and U. Po l l i nghe r . "An Attempt a t Fo recas t i ng t h e Pe r i d i n i um Bloom on Lake K inne re t (Lake T i b e r i a s ) , " M i t t . - Ver. I n t e r n a t Vere in Theor. Limnol., Vol. 19, 1971, pp. 2 7 7 - 2 9 1 7

56. Berman, T., " A l k a l i n e Phosphatases and Phosphorus A v a i l a b i l i t y i n Lake K innere t " , Nature, Vol. 224, 1970, pp. 1231-1232.

57. Lark in , P.A. "Canadian Lakes", Verh. ' I n t . Ver. Theor. Angew. Limnol. Vol . 15, 1964, p. 76-90 ( C i t e d i n G o l t e r m a n 4 x 17).

58. Braidech, T., P. deh r i ng and C . Kleveno. " B i o l o g i c a l S tud ies . Re1 a ted t o Oxygen Dep le t i on and N u t r i e n t Regenerat ion Processes i n t h e Lake E r i e Cen t ra l Basin," P r o j e c t Hypo, ed. N..Burns and C. Ross, Bu r l i ng ton , Ontar io , Canada Centre f o r I n l a n d Waters, 1972, pp. 51-70.

59. L in , K. C. and J. L. Blum. Adaptat ion t o Eu t roph ic Cond i t i ons by Lake Mich igan Algae. Madison, Wisconsin, U n i v e r s i t y o f Wisconsin Water Resources Center, 1973.

LIST OF ATTENDEES.AT DECEMBER 8, 1978 WORKSHOP ON "BIOAVAILABLE FORMS OF PHOSPHORUS"

D r . George F i t z g e r a l d 3644 R i v e r c r e s t Road McFarl and, Wisconsin 53558

Dr. David Lean Na t i ona l Water Research I n s t i t u t e Canada Centre f o r I n 1 and Waters P.O. Box 5050 Bu r l i ng ton , O n t a r i o L7R 4A6

Dr. R ichard Thomas Great Lakes B io l imno logy Lab. Canada Centre f o r I n 1 and Waters P.O. Box 5050 B u r l i ngton, On ta r i o L7R 4A6

Dr. Stephan T. Tarapchuk Great Lakes Env. Research Lab. NOAA 2300 Was htenaw Road Ann Arbor, Mich igan 48104

D r . David Armstrong Water Chemistry Program U n i v e r s i t y of Wisconsin-Madison Madison, Wisconsin 53706

Dr. Harvey Shear Great Lakes B io l imno logy Lab. Canada Centre f o r I n l a n d Waters 867 Lakeshore- Road R1lr1 ing ton , O n t a r i o L7R 4A6

Dr. Graham F. H a r r i s Department o f B i o l o g y McMaster U n i v e r s i t y Hamil ton, O n t a r i o L8S 4K1

M r . J.D. W i l l i ams Na t i ona l Water Research I n s t i t u t e Canada Centre f o r I n l a n d Waters P.O. Box 5050 Bu r l i ng ton , O n t a r i o L7R 4A6

D r . P.A. Krenke l U n i v e r s i t y o f Nevada System P.O. Box 60220 Reno, Nevada 89506

M r . D. Gregor Dept. o f F i s h e r i e s & Env. Canada Centre f o r I n l a n d Waters P.O. Box 5050 Bu r l i ng ton , O n t a r i o L7R 4A6

D r . G.F. Lee Colorado S t a t e U n i v e r s i t y F o r t C o l l i n s , Colorado 80523

Ms. . Jones Colorado S t a t e U n i v e r s i t y F o r t Col 1 i n s , Colorado 80523

Dr. C. Lue-Hing Met. S a n i t a r y D i s t . -

Grea te r Chicago 100 E. E r i e S t r e e t Chicago, I l l i n o i s 60611

Dr. D. Konasewich Great Lakes Regional O f f i c e I n t e r n a t i o n a l J o i n t Commission 100 O u e l l e t t e Avenue Windsor, O n t a r i o N9A 6T3

Dr. G.D. Ha f f ne r Great Lakes Regional O f f i c e I n t e r n a t i o n a l J o i n t Commission 100 Oue 11 e t t e Avenue Windsor, O n t a r i o N9A 6T3

GREAT LAKES SCIENCE ADVISORY BOARn EXPERT COMMITTEE ON

ENGINEERING AND TECHNOLOGICAL ASPECTS OF GREAT LAKES WATER QUALITY

D r . Cec i l Lue-Hing (Chairman) D i rec tor , Research and Development Met ropo l i tan San i ta ry D i s t r i c t -

Greater Chicago 100 E. E r i e S t ree t Chicago, I l l i n o i s 60611

Prof. Wes W. Eckenfelder D is t ingu ished Prof . o f Environmental

and Water Resources Engineering Vanderbil t U n i v e r s i t y P.O. Box 6222, S t a t i o n B Nashvi l le , Tennessee 37203

D r . Peter A. Krenkel Execut ive D i r e c t o r Water Resources Center Desert Research I n s t i t u t e U n i v e r s i t y of Nevada System P.O. Box 60220 Reno, Nevada 83506

D r . Perry L. McCarty ' I ' Professor

Environmental Engineering C i v i l Engineering Department Stanford U n i v e r s i t y Stanford, C a l i f o r n i a 94305

D r . Norman W. Schmidtke Ac t ing DPrector Wastewater Technology Centre Department o f F isher ies and Environment Canada Centre f o r I n land Waters P.O. Box 5050 Bur l ington, Ontar io L7R 4A6

M r . Car l J. Schafer D i r e c t o r I n d u s t r i a1 and. E x t r a t i v e Processes Div. O f f i ce o f Research and Development U.S. Environmental P ro tec t i on Agency 401 M S t ree t S.W., Waterside Ma l l Washington, D . C . 20460

M r . Donald E. Schwinn Stearns and Wheler 10 Albany S t ree t Cazenovia, New York 13035

SAB L ia i son Member M r . Paul D. Foley - Coordinator Development & Research Group P o l l u t i o n Cont ro l Branch Ontar io M i n i s t r y o f Environment 135 S t . C l a i r Avenue West Toronto, Ontar io M4V 1P5

D r . K e i t h L. Murphy Sec re ta r i a t R e s p o n s i b i l i t i e s I n t e r n a t i o n a l Environmental Consultants D r . W.R. Drvnan 5233 Dundas S t ree t West, Su i te 410 Sen i o r ~n~ ineer I s l i n g t o n , Toronto, Ontar io M9B 1A6 Great Lakes Regional O f f i c e

I n t e r n a t i o n a l J o i n t Commission 100 O u e l l e t t e Avenue, 8 t h F loo r Windsor, On ta r i o N9A 6T3

A International Joint Commission Great Lakes Regional Office

100 Ouellette Avenue Eighth Floor

N9A 6T3