Sources and Movement of Organic Chemicals in the Delaware River Linda S. Sheldon and Ronald A. Hites’ Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Mass. 02139
50% of its finished drinking water ( 4 ) . All present drinking water standards are being met a t this water treatment plant (6).
The transport of industrial organic chemicals from their source, into the Delaware River, through various treatment facilities, and into Philadelphia’s finished drinking water was studied using water samples collected in August 1977. Solvent extraction, liquid chromatographic cleanup, and gas chromatographic mass spectrometry were used for compound separation and identification. Results confirmed discharge sources for many previously identified compounds. Furthermore, it was shown that many of these compounds circulated into Philadelphia’s drinking water, and that the various water and waste treatment facilities had a minimal effect on the organic levels. For all chemicals, dilution processes were responsible for the largest reduction in organic concentrations. Results were substantiated by a 10-week sampling program designed to monitor seven selected waste chemicals.
Experimental
Nearly 100 organic compounds of biological, municipal, and industrial origin have been identified in the Delaware River ( I ) . Among the industrial contaminants, several compounds seemed to be coming from a specific plant in the Philadelphia area. Furthermore, relatively high levels of anthropogenic chemicals were observed in the river near the Philadelphia area ( I ) , indicating that they may be entering the city’s drinking water. We have, therefore, traced the movement of various industrial chemicals from their origin, through the river, and into Philadelphia’s drinking water. We have also conducted a 10-week, continuous sampling program to monitor seven selected compounds in the aquatic system. This paper is a report on these studies. T h e Sampling Area. Only a small segment of the Delaware River, lying just north of Philadelphia, was studied. A schematic diagram of the complete sampling area is shown in Figure 1. General flow and hydraulic characteristics of the river have been discussed previously (I).The box in the upper left-hand corner of Figure 1 represents a plant in the Philadelphia area which we will refer to as plant A. This plant does not discharge its wastewater directly into the river, but rather into the city sewer along with several other industrial users. These combined industrial wastes are treated a t the City of Philadelphia’s Northeast Sewage Treatment plant using classical secondary treatment methods ( 2 ) .The treated effluent is then discharged into the Delaware River a t river mile 104. Water flow in this segment of the river is dominated by tidal movement rather than by downstream river flow; tidal volumes are an order of magnitude greater than downstream river flows. During periods of normal flow, effluents discharged into the river travel approximately 7 miles upstream during high tide ( 3 ) .Under these conditions, water flow in the upstream direction is sufficient to transport industrial chemicals from the sewer outfall upstream to the intake pipes of Philadelphia’s Torresdale drinking water facility a t river mile 110 ( 4 ) . Intake valves for this plant are open only during high tide, making industrial waste contamination of the city’s drinking water not only possible but probable ( 4 ) .Water entering the drinking water plant is treated using standard techniques ( 4 , 5 ) :prechlorination; settling; coagulation (ferric chloride, alum, and lime); disinfection; flocculation; and filtration (rapid sand filters). After a final chlorination step, drinking water is distributed throughout the city. Water from this treatment facility provides the city of Philadelphia with approximately 574
Environmental Science 8 Technology
Samples were collected in late August 1977 from sites a to h, as shown in Figure 1. Our purpose was to follow a 24-h slug of industrial wastes through the cycle from plant A to the finished drinking water. The sampling scheme was designed to account for retention times between the various sampling locations, as well as for tidal movement in the river (3, 4 ) . Details of this sampling regime are outlined in Table I. The composite sample from plant A was taken from a 5-gal continuous sampler after the 24-h sampling period. All other samples were composites of individual grab samples collected a t a particular location. River water samples were collected approximately 100 yards from the western shore a t the designated river mile and a t a depth of about 0.5 m. Another set of samples was collected weekly over the 10week period extending from January 15 to March 28, 1978, from points c, g, and h (see Figure 1) and from the center channel of the Delaware a t river mile 98. Samples from sites c, g, and h were composites of 200-mL grab samples collected every 8 h beginning Tuesday 8 a.m., Tuesday 8 p.m., and Wednesday 8 a.m., respectively. River samples were 1-galgrab samples taken every Wednesday morning. All samples were collected in glass bottles fitted with Teflon-lined screw caps. Methylene chloride and hydrochloric acid were added to the water samples a t the collection site in order to minimize biological degradation and to start the extraction process. Since waste effluents from plant A do not support microbial activity ( 6 ) ,sample preservation in the 24-h continuous sampler was not needed. All samples were stored in the dark. Small samples were kept on ice during transport to the laboratory. Larger samples were refrigerated as soon as possible after collection. Analytical techniques and instrumentation for the concentration, separation, and identification of sample components have been discussed in detail elsewhere (I). In general, analytical techniques used in this study included solvent extraction, liquid chromatographic fractionation, high-resolution gas chromatography, computerized gas chromatographic mass spectrometry (GC-MS) in both the electron impact (EI) and chemical ionization (CI) modes, mass spectrometric selected ion monitoring (SIM), and high-resolution mass spectrometry (HRMS). For the initial phase of this study (August, 1977), concentration values were semiquantitative and were based on standard curves for selected compounds. Estimated errors in quantitation are approximately f 2 0 % in plant A’s waste effluent, f50% in the Northeast influent and effluent and the river water, and an order of magnitude in the finished drinking water. During the second phase of this study (January-March, 1978), experimental procedures were developed to more precisely quantitate seven previously identified compounds. Concentration values were measured using selected ion monitoring (SIM) performed on the unfractionated, combined neutral and acidic extracts for each sample. Sample concentrations were calculated by comparing the computer-integrated peak areas of selected masses with those obtained from standard solutions containing the seven compounds.
0013-936X/79/0913-0574$01.00/0 @ 1979 American
Chemical Society
Table 1. Sampling Scheme Giving Details of Timing, Volumes, Types, and Locations (See Figure 1) locatlon
(a) plant A effluent (b) Northeast influent (c) Northeast effluent (d) river mile 106 (e) river mile 108 ( f ) river mile 118 (9) Torresdale influent (h) Torresdale effluent a
8/23 8/24 8/24 8/25 8/25 8/25 8/25 8/25
sampling interval, h
total VOI, L
collectlon perlod a
12 p.m. to 8/24 12 p m 2 a.m. to 8/25 2 a.m. 8 a.m. to 8/25 8 a.m. 10 a.m. 10:30 a.m. 11 a.m. 8 a.m. to 8/26 8 a.m. 8 p.m. to 8/26 8 p.m.
0.5 0.5 1 23 23 23 4 4
no. of samples
4 4
4 4
type
continuous
1 7 7 1 1 1 7 7
grhI,
grab grab grab grab grab grab
All samples taken in August, 1977.
Chemical Plant A Philadelphia Drlnking Water
,
Industrial Effluents Torresdale Water Treat m e n t Plant
Sewage Treatment Plant
riwer mile
110
I04
c2 FLOW
R=OH, n=I R =OH, n = 2 R = O H , n.3
IO
12
R = OH, n = 4 R=OH, n=5 R = C I , n.2
13
R=CI,
II
river mile
-NET
7 8 9
@
DELAWARE RIVER
0 -NET
n=3
FLOW
Figure 1. The sampling area, showing collection sites. River mileages
are measured upstream from the mouth; net flow proceeds from right to left
18.
I 0
CI
CH3
Solvent extraction efficiencies were measured for these seven compounds. Preextracted water samples were spiked with a known aliquot of a standard solution. Spiked samples were extracted and quantitated using the above procedures. Tests were run in triplicate using water samples from all four sampling locations. Recoveries were better than 75% in all cases. Reported concentration values were corrected for solvent extraction efficiencies and have errors of less than f20%. excluding sampling errors.
Results and Discussion All of the compounds identified in the industrial wastewater, the municipal sewage effluent, the river water, and Philadelphia’s finished drinking water are listed in Table 11. Some structures are given in Figure 2. Estimated concentrations have been included for most of the abundant compounds. The compounds in Table I1 are listed according to location of first appearance. Within each of these groups, chemicals have been subdivided by compound type. This arrangement allows for both a quick identification of specific pollution sources and for a facile appraisal of the movement of these chemicals in the aquatic system. For an overview of the occurrence and environmental significance of many of the compounds listed in Table 11, the reader is referred to our previous paper on the Delaware River ( I ). During the following discussion, only those compounds which were not previously identified in the Delaware River or which gave some insight into the movement of chemicals through the various treatment processes and in the Delaware River will be considered. Identification of Contamination Sources. The first objective of this study was to verify that plant A was the specific source for a set of previously identified compounds. These compounds included 1,2-bis(chloroethoxy)ethane (6), the phenyl glycols (7-1 l ) ,the chlorinated phenyl glycols (12 and 13), DDE (171, dichlorobenzophenone (16), and the binaph-
0
0
II
CH2= C
64 65. 66
-C
( O C H 2 CH2),
II
0 C -C=
I
I
CH3
CH3
CH2
n = 2 n = 3
n = 4
Figure 2. Structures of selected organic compounds found in the Delaware River (see Table 11)
thy1 sulfones (37). Our data (see Table 11) verify that these chemicals are, id fact, being discharged from plant A along with various othet phenolic compounds (1-5), chlorinated compounds (16-20), and esterified species (25 and 26). All of the above compounds are either commercial products manufactured a t plant A or are process byproducts. The commercial herbicide ( 7 ) 2,5-dichloro-N-(l,l-dimethyl-2-propyny1)benzamide(18) was discharged in plant A’s waste effluent in relatively high concentration (500 ppb). We should point out that this compound was not detected during our earlier work ( I ) , but plant A operates in a batch mode (6) and does not consistently discharge the same mix Volume 13, Number 5, May 1979 575
Table II. Compounds and Their Concentrations (ppb) Observed at the Various Sampling Sites (See Figure 1)
I. plant A A. phenols 1. phenol 2. cresol 3. octylphenolsd 4. nonylphenolse 5 . 4-octyI-2,6-di-tert-butylphenoI B. ethylene glycol derivatives 6. 1,2-bis(2-chloroethoxy)ethane 7. 2-(p-1',1',3',3'-tetramethylbutylphenoxy)ethanolm 8. 2-[2-(p1',1',3',3'-tetramethylbutylphenoxy)ethoxy]ethanolm 9. 242- [ 2 - ( p 1',1',3',3'-tetrarr~thylbutylphenoxy)ethoxy]ethoxy)ethanol 10. 2- [ 242- [ 2 - ( p l', 1',3',3'-tetramethylbutylphenoxy)ethoxy] ethoxy)ethoxy] ethanol 11. 2-(2-[2-(2-[2-(p-l',1',3',3'-tetramethylbutylphenoxy)ethoxy]ethoxy)ethoxy]ethoxy)ethanol 12. 1-chloro-2- [ 2 - ( p 1', 1',3',3'-tetramethylbutylphenoxy)ethoxy]ethanem 13. l-chloro-2-(2- [ 2 - ( p 1', 1',3',3'-tetramethylbutylphenoxy)ethoxy]ethoxy)ethanem C. chlorinated compounds 14. tetrachlorostyrenese 15. hexachloroethylbenzeneg 16. dichlorobenzophenonesg 17. 1,l-bis(chlorophenyl)-2,2-dichloroethylene (DDE) 18. 2,5-dichloro-K( 1, 1-dimethyl-2-propynyI)benzamidem 19. chloro-K( 1, l-diisopropyl)benzamideg*m 20. dichloro-K( 1, l-diisopropyl)benzamidegsm 21. dichlorobenzenese 22. chlorotolueneg 23. trichlorobenzenese 24. tetrachlorobenzenese D. plasticizers 25. bis(2-ethylhexyl) adipate 26. dioctyl sebacate 27. tris( tert-butyl) phosphate E. hydrocarbons 28. C2 benzenese 29. C3 benzenese 30. naphthalene 31. methylnaphthalenes 32. C p naphthalenese 33. C3 naphthalenese 34. C4 benzenese 35. Cj4H2ai 36. CjtjH32' F. others 37. binaphthyl sulfonese 38. isophorone 11. Northeast influent A. phenols 39. phenylphe 01 40. cumylphenol 41. tert-butylmethoxyphenol C. chlorinated compounds 42. dichlorophenolse 43. trichlorophenolse 44. bis(chlorophenyl)methanolg D. plasticizers 45. triphenyl phosphate 46. dibutyl phthalate 47. butylbenzyl phthalate 48. bis(2-ethylhexyl) phthalate
576
Environmental Science & Technology
plant A
NE In
NE out
7000 50 5000 600 200
60 unc 400 un un
20 20
100 200 100 400
200 40
RM 106
0.3
3 1
RM 108
0.3
Tor In
Tor out
RM 118
ta
-
-
2 0.02
0.4 0.02
-
un
-
un 50 un un
un 10 un un
1 un 0.6 0.4
1 un 0.3 0.2
t un un un
t 0.02 0.02 0.002
5 5 t
200
un
un
un
NA'
NA
NA
-
un
un
NA
NA
NA
NA
NA
NA
2000
200
80
0.6
0.4
0.3
0.2
-
1500
120
50
0.6
0.5
0.3
0.2
-
400 un 1000 1800
60 un 110 200 40 t un 100 t 20 t
0.06
-
-
-
-
0.2 0.3 0.2 t 0.06
0.1 un 0.02
Vh
V
V
V
V
v t t
V
V
V
V
500 50
un 100 un 200 200
20
0.5
-
-
60 30 20 t un t t 10 t
1 0.4 0.4 t 0.2
0.02
-
t t
-
2000 200 50
90
1000 un
un 500 t un un 200 2000
100 40 20 un t t 200 10 30
0.4 t t 40 un 10
-
-
0.6 un
un 100
un 10
un 3
-
-
0.6
t
un t t
un t t
un 0.3 t
un 0.01 t
0.01 t
0.4 0.1 0.7
t t 0.2
t t 0.1
un un 0.002
-
0.3 0.6 0.6 1
0.2 0.4 0.3 1
0.2 0.1 0.3 0.5
0.03 0.1 0.1 0.6
t 0.3 0.4 0.5
un
un t 3 16 50 40 200
10
0.04
0.1 un 0.01
un v 10
4
0.4 0.1 5
2 25 100 100
0.2
0.5 V
2 t 0.2 t t 2
0.04
0.02
-
-
-
0.4
0.3
0.4
V
V
V
V
-
-
-
t -
t t
-
-
t
t
0.6 t 0.02 t t t
0.002
0.8
t
-
t
-
-
Table II. Continued plant A
E. hydrocarbons 49. pyrene 50. fluoranthene 51. anthracene 52. phenanthrene 53. methylphenanthrene 54. chrysene F. others 55. cholesterol 56. cholestanol 57. a-terpineol 58. 2-phenyl-2-propanol 59. stearic acid 60. palmitic acid 61. benzil 62. bornyl acetate 63. N-(n-tiutyl)benzenesulfonamide Ill. Northeast etfluent B. ethylene glycol derivatives 64. diethyleneglycol dimethacrylate'" 65. triethyleneglycol dimethacrylate'" 66. tetraethyleneglycol dimethacrylatem 67. chlorophenylphenylmethanolg F. others 68. menthol IV. river B. ethylene glycol derivatives 69. bis(2-/[2-(n-butoxy)ethoxy]ethoxy)methane 70. triethyleneglycol bis(2-ethylhexanoate) 71. tetraethyleneglycol bis(2-ethylhexanoate) C. chlorinated compounds 72. dimethyl 2,3,5,6-tetrachloroterphthalate D. plasticizers 73. 2,2,4-trimethylpentane-l,3-diol-l-isobutyrate 74. 2,2,4-trimethylpentane- 1,3-diol-3-isobutyrate 75. 2,2,4-trimethylpentane-1,3-dioldiisobutyrate F. others 76. chlorophyll' 77. fluorenone 78. ethylthiopyridineg 79. l,l-bi~;(chlorophenyl)-2,2,2-trichloroethane (DDT) V. drinking water C. halogenated compounds 80. dichloroisopropenyltolueneg 81. bromochlorophenolg 82. dibromophenolg 83. dichlorobromophenolg 84. dibroniochlorophenolQ
-
-
-
NE In
t t t t t t
400 600 80 70 hi h t 100 un
NE out
RM 108
t t
t t t t t t
Tor In
t t t t
RM 118
-
t t t t t t
0.9 0.9
t
t
2 3
1 2
0.6 1
-
-
-
-
h h
-
t
t
-
-
2 h h 0.4 1 0.6
0.5 h h 0.2 1 0.3
0.2 0.5 10 0.1
t 0.1 3 0.1
5 0.5 0.1
-
-
1 0.1 3
un
un
0.2 0.3 0.3
t t t
t t t
4
un
-
-
-
-
10 35 700 t
-
-
8
-
-
-
-
-
-
-
un 0.2 2
-
-
-
un
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
2 7 0.04 0.02 t t t t
-
-
-
-
-
Tor out
t t t t t t
t t
200 300 80 70 h h un 50 un
RM 108
Un
0.2 0.2
0.5
-
Un
0.1
-
mk m 0.02 0.002 -
t
t
-
t
-
-
0.02
un
-
-
-
2
t
-
-
t
-
3 0.1 2
0.03
t -
-
-
t
t
9 t t
t
un
-
-
un
-
un
a t indicates that onljy trace levels were detected. - indicates not detected. un indicates that compound was not resolved gas chromatographicallyand, therefore, was not quantitated. The predominant species was pl ,1,3,3-tetramethylbutylphenol, although other isomers were present. e Several isomers present. NA indicates that analysis for these compounds was not carried out (not analyzed). Isomer unknown. v indicates volatile compound: these compounds would not be retained in the water column during the summer months. ' Structure unknown, mol wt from CI, present in hexane fraction. h indicates very high concentrations: these compounds give broad unresolvedpeaks which could not be quantitated. m indicates moderate concentration. 'Chlorophyll was observed as a series of phytadienes (see ref ;I). See Figure 2 for the structure of this compound.
'
of waste chemicals. Concentrations of compound 18 around 0.003 ppb were found in drinking water samples during our 10-week quantitation study (see below). An interesting case is presented by several of the multichlorinated aromatic compounds (14-17): tetrachlorostyrene, hexachloroethylbenzene, DDE, and dichlorobenzophenone. None of these compounds are produced commercially; however, plant A did manufacture the pesticide 1,lbis(p-chlorophenyl)-2,2,2-trichloroethanol. This pesticide was
produced commercially using the reaction scheme outlined in Figure 3 (8). DDE is the unreacted starting material; tetrachlorostyrene and hexachloroethylbenzene are probably cleavage byproducts formed during the initial chlorination step or from the reaction intermediate 1,l-bis(p-chloropheny1)tetrachloroethane. Dichlorobenzophenone could form during alkaline hydrolysis of either the tosylate ester intermediate or the pesticide itself. Two other structurally related compounds, bis(chloropheny1)methanol (44) and chloroVolume 13, Number 5, May 1979
577
l0.000
-
1000- 5oo
1
CUI
ArS03 H H2S04
,P
NE
rm
rm
out
I06
I08
Torr n
Torr out
Figure 4. Concentration levels of 2,5-dichloro-K( lI1-dimethyl-2-propyny1)benzamide(18) throughout the sampling system
H20 lO,000
1 60
I
C'
(TJ-[-c' CCI3 NE
Figure 3. Reaction pathway for the commercial production of 1 , l bis(pchlorophenyl)-2,2,2-trichloroethanoI(see ref 8)
phenylphenylmethanol (67), first appear in the Northeast influent and effluent water, respectively. We think that these are probably degradation products of one of the above chlorinated species. We should point out that the pesticide itself was not detected in any of the wastewater or river water samples. Although some of the methyl substituted compounds (28-34) and chlorinated aromatics (21-24) and the solvent isophorone (38) first appear in plant A's waste effluent, they are common industrial chemicals which could also be entering the water system at various other points. This was confirmed by comparing concentration data for these compounds with the same data for the compounds specific t o plant A. The former compounds show much smaller changes in concentration between sampling locations, suggesting multiple discharge sources. Most of the compounds which appear for the first time in the Northeast treatment plant's influent (39-63) are common industrial or municipal contaminants. They are not unusual and have been discussed in detail elsewhere (1, 9-11) N (n-Buty1)benzenesulfonamide (63) is interesting because it has never been identified in environmental samples. Its major commercial use is as a plasticizer for polyamide materials (12-14). It has also been patented as a starting material in the production of sulfonyl carbamate herbicides ( 2 5 ) .The exact source of this contaminate is not yet known. Those compounds originally appearing in the treatment plant's effluent water (64-68) were, of course, not present in the influent water; this suggests that they were formed during the treatment process. The most striking example is the poly(ethy1ene glycol) derivative, tetraethyleneglycol dimethacrylate (66). This particular chemical is commonly used as a copolymer in many synthetic materials (16-18). It seems possible that a polymer entering the Northeast treatment plant is being degraded to monomer units during treatment, or that residual monomer is being washed off polymers during treatment. This compound was the most abundant chemical discharged in the Northeast treatment plant effluent; this leads to correspondingly high river water values. The di- and triethyleneglycol homologues (64 and 65) were also identi578
Environmental Science & Technology
Oiit
out
rm IO6
rm
I08
Torr in
Torr out
Figure 5. Concentration levels of dichlorobenzophenone (16) throughout the sampling system
fied. Compounds first appearing in the river water (69-79) may be categorized into three groups according to source: first, those entering the river system from other industrial discharges such as various ethylene glycol derivatives (69-71) and various plasticizers; second, those compounds formed by the natural biological activity in the river, for example, chlorophyll (76); lastly, compounds which enter the river via rainwater runoff, most notably the herbicide dimethyl 2,3,5,6-tetrachloroterphthalate (72) (19). In the finished drinking water a series of halogenated compounds appears which were previously undetected. I t seems logical that these compounds, especially the halogenated phenols (81-.84), are formed during the chlorination process (20). Movement of Compounds through the System. It is easiest to assess concentration changes as various compounds travel from industrial wastewater to finished drinking water if the data are presented graphically. Figures 4 to 7 are a series of bar graphs showing concentration data for several compounds a t each of the seven sampling locations. These particular compounds were chosen because: (a) they are unique chemicals entering from a single, well-defined source, and (b) they complete the sample loop and were found a t all sample locations. This second characteristic makes it possible to assess the effects of all treatment processes and of dilution during upstream river movement. Figures 4 to 7 indicate several trends. Large changes in concentration (approximatelyfour orders of magnitude) were observed between plant A's effluent and the finished drinking water. Obviously, this large decrease in organic concentration is important when considering allowable discharge levels and treatment processes. For all four compounds, a definite concentration pattern developed over the sample system. The greatest concentration decreases occurred between plant A's effluent and the Northeast Treatment plant's influent (sites a to b) and between the Northeast Treatment plant's effluent and the first upstream river sampling location (sites c to d). It is interesting that these large decreases in concentration are
Table 111. Median Concentrations a and Relative Concentrations for the 10-Week Study (January to March, 1978) and Grab Sample Concentrations (August 1977) IO-week concn, ppb Torr
NE compdb
elf
river
3 7 8 12 13 17 18
200 8 10 20 20 20 4
8
inf
0.3 0.5 0.3 0.5 0.3 0.2
Torr
NE
eft
eff
0.4 0.03 0.05 0.02 0.07 0.04
0.2 0.03 0.06 0.04 0.04 0.02
0.003
0.003
100 100 100 100 100 100 100
relative concn Torr river
inf
4 4 5 2
0.2 0.4 0.5 0.1
3
0.3
2 5
0.2 0.08
Torr
NE
grab concn, ppb Torr
eff
eff
river d
0.1 0.4 0.6 0.2 0.2 0.1 0.08
a The range of the individual measurements is usually a factor of 3 above and below the median; for example, for See Table Ii. River mile 98. River mile 106.
10,000
4 CI l C H 2 CH2 0 l 2
