pcb levels at 26 new york city and new jersey wpcps that discharge to the new york/new jersey harbor...

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PCB Levels at 26 New York City andNew Jersey WPCPs That Dischargeto the New York/New Jersey HarborEstuaryG R E G O R Y S . D U R E L L * A N DR O B E R T D . L I Z O T T E , J R .

Battelle Duxbury Operations, 397 Washington Street,Duxbury, Massachusetts 02332

The New York/New Jersey Harbor Estuary containsenvironmentally significant amounts of polychlorinated bi-phenyl (PCB). It is well-known that sources in the upperHudson River have contributed much of this contamination,but little is known about the direct inputs from waterpollution control plant (WPCP) and combined sewer overflow(CSO) discharges to the Estuary. Therefore, a detailedPCB characterization was performed by determining con-centrations of 71 individual PCB congeners in the wastestreams at the 26 New York City and New Jersey WPCPsthat discharge to the Estuary. Individual congenerconcentrations were typically well below 1 ng/L in theeffluent and the total PCB concentration ranged from 10to 55 ng/L, and averaged 25 ng/L, in the effluent at the26 WPCPs. The total PCB concentration in the WPCP influentstream during normal flow conditions ranged from 31 to625 ng/L, with an average of 110 ng/L for the 26 plants; theinfluent PCB levels became slightly elevated at mostplants during storms. The annual PCB contribution fromthe 26 WPCPs to the New York/New Jersey HarborEstuary is estimated to be 88 kg, with only a small portion(3%) of this being diverted and bypassed by the WPCPsand discharged through CSOs due to precipitation events.

IntroductionThe New York/New Jersey Harbor Estuary has among thehighest polychlorinated biphenyl (PCB) concentrations inwater, sediment, and biota along the coastal United States(1-4). Most of the PCB currently in the estuary originatedin PCB discharges into the upper Hudson River during a 25year period from the early 1950s to the mid 1970s (2, 3, 5, 6).The PCB has been, and continues to be, transported downthe Hudson River as dissolved or particulate-bound con-taminants (7-9) ending up in the sediment or water columnof the estuary which acts as a major sink for PCB (3, 6). ThePCB contamination of the upper (10-12) and lower (3, 5, 6)Hudson River has been well documented, but there are lessdata available for the estuary. While it is clear that a largeproportion of the PCB in the estuary has come from theHudson River, some of the PCB in the estuary arrives viaother river systems (e.g., Passaic, Hackensack, Rahway, andRaritan) and other point and nonpoint sources.

Some PCBs are contributed to the estuary through treatedWPCP discharges and CSO discharges. It has been estimatedthat the WPCP discharges contribute approximately one-half of the PCB loading to the estuary, while other investiga-tors put the WPCP contribution to the Harbor at about one-quarter of the total PCB load (3, 13). However, thesecalculations were based on a limited set of historical data,and it is clear that more recent and complete data are neededto better assess the current PCB loadings to the estuary andthe relative contributions of various sources of PCB.

This study provides updated WPCP waste stream PCBdata to gain a better understanding of the loadings to theestuary and also provides detailed PCB composition infor-mation for a set of urban WPCP waste streams. The 14 NewYork City and 12 New Jersey WPCPs that discharge to theestuary were sampled and analyzed. Composite WPCP rawinfluent and treated effluent samples were collected duringnormal flow conditions. Influent was also sampled duringstorm (high flow) events; the WPCP flows were thensignificantly elevated and the composition of the influentwas expected to be similar to what may typically be divertedas plant bypass and potentially be discharged through CSOs.

Analytical Approach. Proper evaluation of the presentday PCB loadings to the estuary requires highly sensitive andspecific analytical methods. Such methods should allow fordetection of PCB at subnanograms per liter (sub-parts-per-trillion) concentrations. The analytical procedures used inthis study were designed for the determination of trace

* To whom correspondence should be addressed. Fax: (781) 934-2124; e-mail: [email protected].

TABLE 1. WPCP Flow Data for the Four Sampling Events andAverage Flow of CSOs in WPCPs Drainage Area

WPCP normal flow WPCP high flowplant

IDevent I(MGD)b

event II(MGD)

event I(MGD)

event II(MGD)

averageCSO flowa

(MGD)

NY-1 28 25 32 22 2.83NY-2 159 162 318 279 0.59NY-3 111 118 151 187 3.45NY-4 264 252 421 483 6.38NY-5 39 43 53 82 1.38NY-6 29 24 44 26 0NY-7 124 124 250 149 9.90NY-8 55 55 97 101 7.59NY-9 147 149 267 130 8.78NY-10 35 34 70 97 8.19NY-11 64 69 153 147 1.45NY-12 92 70 140 122 21.1NY-13 282 290 373 541 8.28NY-14 124 128 276 270 11.2NJ-1 10 12 15 16 NAcNJ-2 24 28 46 45 NANJ-3 5 8 11 10 NANJ-4 53 65 110 117 NANJ-5 2 4 8 9 NANJ-6 12 14 28 34 NANJ-7 258 307 398 407 NANJ-8 3 3 6 5 NANJ-9 10 14 30 33 NANJ-10 68 70 100 101 NANJ-11 3 4 7 5 NANJ-12 111 119 223 207 NA

a NYC WPCP CSO flow data from NYCDEP (18). b MGD: Milliongallons/day. 1 MGD ) 3,785 m3/day. c NA: Not available. Detailed NJWPCP CSO data was not available at the time, but historical data indicatethat the total NJ CSO flow for these WPCP systems is about 1/3 of thetotal CSO flow for the NYC WPCP systems (18).

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TABLE 2. Individual PCB Congener Concentrations in Normal Flow Influent and Effluent at Selected WPCPs

individual PCB congener concentrations (ng/L)

PCBcongenera

NJ-11effluent-I

NJ-11influent-I

NY-5effluent-II

NY-5influent-II

NJ-6effluent-II

NJ-6influent-II

Cl1(01) 0.41 2.95 0.95 1.33 ND NDCl1(03) ND ND ND ND 23.40 28.77Cl2(04) 0.58 ND 0.91 2.49 ND 2.57Cl2(07)Cl2(09) ND ND ND ND ND NDCl2(06) 0.14 0.17 ND ND 0.68 1.36Cl2(08) 0.16 0.68 0.16 2.47 0.17 5.20Cl3(19) 0.37 0.53 0.31 1.38 0.39 0.57Cl3(18) 0.61 1.49 0.43 2.45 3.10 2.08Cl3(17)/Cl2(15) 0.47 1.24 0.21 1.77 0.55 1.99Cl3(16)/Cl3(32) 0.78 1.74 0.83 3.84 0.59 2.50Cl3(26) 0.10 0.26 ND 0.57 0.56 0.19Cl3(25) ND ND ND ND ND NDCl3(31) 0.26 0.56 0.39 2.79 0.57 1.80Cl3(28) 0.27 0.41 0.15 2.08 0.19 1.66Cl3(33) 0.17 0.63 0.13 1.34 0.14 1.77Cl3(22) 0.08 0.33 ND 0.75 ND 1.05Cl4(45) 0.29 0.99 ND 1.02 1.55 1.14Cl4(52) 0.30 1.24 0.23 4.31 2.10 19.14Cl4(49) 0.18 0.53 0.38 2.97 1.65 11.05Cl4(47) 0.08 0.17 0.48 6.61 0.05 1.36Cl4(48) 0.04 0.14 0.15 0.78 0.07 2.67Cl4(44) 0.12 0.49 0.16 2.71 0.21 2.29Cl4(41)/Cl4(64) 0.09 0.42 0.17 0.30 ND NDCl4(40) 0.06 0.66 ND 0.93 ND 0.14Cl4(74) 0.06 0.27 0.13 1.51 0.25 2.21Cl4(70) 0.13 0.55 0.20 3.72 2.93 21.25Cl4(66) 0.08 0.30 0.16 2.54 0.37 3.53Cl5(95) 0.18 0.97 0.29 3.27 1.26 9.98Cl4(56)/Cl4(60) 0.07 0.29 0.15 1.78 0.35 2.19Cl5(92) 0.06 0.25 0.05 0.74 0.31 2.93Cl5(84) 0.01 0.61 0.16 1.49 0.62 4.20Cl5(101) 0.28 1.07 0.31 4.73 1.95 17.30Cl5(99) 0.16 0.49 0.15 2.79 0.46 7.26Cl5(97) 0.08 0.45 0.06 1.01 0.48 4.78Cl5(87) 0.29 0.81 0.29 1.78 0.78 8.28Cl5(85) 0.51 1.83 0.40 0.81 0.47 1.43Cl6(136) 0.07 0.21 0.14 0.91 0.37 1.26Cl5(110) 0.24 1.40 0.32 4.80 2.12 22.76Cl5(82) ND 0.19 0.04 0.58 0.17 1.92Cl6(151) 0.06 0.16 0.07 1.72 0.25 1.81Cl6(135) 0.04 0.13 0.08 1.08 0.24 1.82Cl6(149) 0.16 0.81 0.29 4.49 1.04 8.52Cl5(118) 0.30 1.45 0.34 4.39 1.64 19.95Cl6(146) 0.03 0.13 0.05 0.95 0.25 1.77Cl6(153) 0.23 0.85 0.33 6.18 1.46 11.48Cl6(132) 0.10 0.53 0.09 1.51 0.66 5.15Cl5(105) 0.08 0.43 0.11 1.89 0.77 8.71Cl6(141)/Cl7(179) 0.04 0.15 0.05 1.40 0.32 2.38Cl7(176) ND ND ND ND ND 0.08Cl6(138) 0.24 0.96 0.39 6.06 1.84 19.46Cl6(158) 0.11 0.23 0.22 0.79 0.40 1.95Cl6(129) ND 0.05 ND ND 0.10 1.19Cl7(178) 0.12 0.05 ND ND ND 0.42Cl7(187) 0.04 0.12 0.13 2.61 0.12 0.97Cl7(183) 0.02 0.08 0.07 1.30 0.10 0.72Cl6(128) 0.02 0.18 0.05 0.78 0.50 3.70Cl7(185) 0.01 ND 0.01 0.25 ND 0.11Cl7(174) 0.04 0.11 0.10 2.03 0.12 1.21Cl7(177) 0.02 0.05 0.04 1.17 0.12 0.64Cl7(171) 0.11 0.80 0.08 1.75 0.19 1.73Cl6(156) 0.03 0.10 0.03 0.60 0.27 2.35Cl8(201) ND ND ND 0.19 ND 0.07Cl8(200) ND ND ND 0.17 0.18 0.12Cl7(170)/Cl7(190) 0.04 0.13 0.11 2.54 0.26 1.90Cl8(199) 0.03 0.10 0.08 1.35 0.07 0.52Cl8(203)/Cl8(196) 0.03 0.05 0.07 1.45 0.03 0.39Cl8(195)/Cl9(208) 0.02 0.05 0.03 0.61 0.03 0.35Cl8(194) 0.02 0.15 0.11 2.51 0.03 0.37Cl9(206) 0.02 0.45 0.83 0.57 0.06 0.12Cl10(209) 0.04 0.17 0.08 0.17 0.20 0.03

a The PCB congeners are named by listing the level of chlorination followed by the IUPAC congener number [e.g., Cl6(138) is IUPAC congener#138, which has six chlorine atoms on the biphenyl molecule].

VOL. 32, NO. 8, 1998 / ENVIRONMENTAL SCIENCE & TECHNOLOGY 9 1023

amounts of individual PCB congeners in complex WPCPwaste stream samples. The actual detection limits variedfor the different congener and sample matrices, but werees-timated to be about 0.02-0.1 ng/L and 0.1-0.3 ng/L foreffluent and influent, respectively.

Because of the complex nature of most environmentalPCB contamination, it can seldom be adequately character-ized using methods that describe the contamination on thebasis of Aroclors alone; detailed PCB congener informationis usually needed (11, 14-16), and a target analyte listconsisting of 71 PCB congeners was chosen. This includesall congeners that are present at greater than 1% of the totalPCB in any Aroclor formulation and most that are presentat greater than 0.5%. The sum of the 71 congeners constitutesbetween 90 and 95% of the total PCB in all Aroclorformulations and most environmental samples (17, andinternal determinations). The absence or insignificance ofspecific congeners in Aroclor formulations does, however,not necessarily mean that this is the case with environmentalsamples; other congeners may be important from anenvironmental or health perspective. Additionally, therelative PCB congener composition changes in the environ-ment due to degradation, selective solubility and adsorption,and metabolism. Nonetheless, it was evident that the chosencongeners indeed represented the vast majority (>90%) ofthe PCB in these samples and were suitable for a broadcharacterization study such as this.

Materials and MethodsSample Collection and Handling. Samples were collectedbetween October 1994 and May 1995. The influent samplewas unprocessed wastewater flowing into the plant, and theeffluent sample represented the treated plant discharge.

There were two sampling events, performed several weeksapart, for each flow condition. The normal flow compositesamples were obtained by collecting 300 mL every 3 h overa 24 h period, and the high flow sample composites werecollected over a 2 h period (shorter if the elevated flow beganto decline rapidly). Samples were chilled, transported to thelaboratory, and extracted within 7 days of collection. Arigorous field and laboratory quality control program wasadhered to (e.g., analysis of field and laboratory blanks,replicates, and spiked samples).

Sample Preparation. Approximately 2.4 L of unfilteredsample was fortified with surrogate internal standard (SIS)PCB congeners 34, 103, and 112 (IUPAC congener numbers)and serially extracted three times with hexane. The extractwas concentrated by Kuderna-Danish technique and nitrogenevaporation, purified using a high performance liquidchromatographic (HPLC) silica gel clean-up procedure, andtreated with activated copper for removal of residual sulfur.The HPLC procedure employed a 100 mm 25 mm Porasil(125 pore size, 10 m particle size) HPLC silica column(Waters Corp.), with a 10 mm 25 mm Porasil precolumn.The HPLC system was calibrated with PCB congeners 1 and209 to cover the PCB molecular weight and silica retentivityrange. The sample was loaded onto the column, eluted with100% hexane at a flow rate of 10 mL/min, the eluantmonitored with a UV detector (at 254 nm), and the targetanalytes collected using a fraction collector. The columnwas backflushed with dichloromethane and methanol andregenerated with hexane. This HPLC procedure is auto-mated, and the accuracy and reproducibility exceeds whatis obtained with traditional, gravity-fed chromatographycolumns. The final sample was adjusted to 150-200 L usinga gentle stream of nitrogen and spiked with the recovery

FIGURE 1. PCB congener distribution in normal flow influent at NJ-4 and NJ-6.

1024 9 ENVIRONMENTAL SCIENCE & TECHNOLOGY / VOL. 32, NO. 8, 1998

internal standard (RIS) PCB congeners 29 and 166, andsubmitted for instrumental analysis.

Instrumental Analysis. Analysis was performed on aHewlett-Packard 5890-II gas chromatograph equipped witha 63Ni electron capture detector (GC/ECD). The GC separa-tion was carried out on a 60 m, 0.25 mm i.d., fused silicacapillary column with 0.25 m film thickness of DB-5 (5%phenyl-methylsiloxane; J&W Scientific, Inc.). A 1 L portionof the extract was injected onto the instrument. Hydrogencarrier gas, an electronic pressure controlled inlet set at aconstant flow (after a high pressure pulse), and a three-stepPCB congener-specific temperature program ensured op-timum resolution and a high level of accuracy and precision.A 5 point quadratic equation calibration was performed witheach congener ranging in concentration from approximately0.005 to 0.12 ng/L, and a calibration check standard wasanalyzed every 10 samples. Congener concentrations weredetermined by the method of internal standards using theSISs as quantification internal standards. The RISs were usedto monitor recoveries.

Results and DiscussionThe average plant flows during sample collection aresummarized in Table 1. The flow rates were quite similar forboth normal flow sampling events, and the two elevatedstorm event flows were generally also comparable. TheWPCP flow was, on average, approximately 80% higher duringhigh flow than during normal flow conditions. Table 1 alsoincludes recent total CSO flow data (general rain runoff,unauthorized connection discharges etc., in addition to WPCPbypass) for the New York City WPCPs (18).

PCB Congener Data. Table 2 lists the target analytes andpresents typical normal flow data for selected influent and

effluent samples. The individual congener concentrationsin the normal flow influent samples from the 26 WPCPsranged from not detected to approximately 100 ng/L, butwere mostly less than 5 ng/L. The concentrations weretypically below 1 ng/L in the effluent samples, with the highestindividual congener concentrations being approximately 10ng/L in a few samples.

Most of the 71 congeners were detected in most samplesand PCB patterns were consistently evident. Congeners withIUPAC numbers 52 (chlorines in the 2,2,5,5 positions), 70(2,3,4,5), 95 (2,2,3,5,6), 101 (2,2,4,5,5), 105 (2,3,3,4,4), 110(2,3,3,4,6), 118 (2,3,4,4,5), 138 (2,2,3,4,4,5), 149 (2,2,3,4,5,6),and 153 (2,2,4, 4,5,5) were typically the ones detected at thehighest concentrations; these are elevated in most mid-molecular weight (Aroclor 1248/1254-type) PCB contami-nation. Many samples also contained elevated amounts ofcongeners 16/32 (2,23/2,46), 28 (2,4,4), and 31 (2,45);congeners frequently found to be elevated in lower molecularweight (e.g., Aroclor 1242-type) PCB contamination.

The determined concentrations of a few congeners,particularly 180, were occasionally uncharacteristically highcompared to the rest of the PCB congener concentrations,commercial Aroclor formulations, or common environmentalsamples, and were likely contributed by interfering, non-PCB, matrix components (the contaminant bis(2-ethylhexyl)-phthalate, for instance, is ubiquitous in samples such as theseand coelutes with 180 in the chromatographic scheme used).There also appeared to be an over-estimation of congeners3 and 8 in some influent samples. Blank samples wereconsistently clean, so these elevated datapoints were likelydue to coeluting sample matrix components: the relativeconcentrations of these di- and trichlorobiphenyls werehigher than what might be expected from elevations due to

FIGURE 2. PCB congener distribution in normal flow influent at NJ-4: event I vs event II.


selective solubility/partitioning or degradation/dechlorina-tion of higher molecular weight congeners.

The congener distribution varied somewhat betweenplants (Figure 1), indicating that each plant had a uniquecombination of PCB sources. No samples had PCB patternsthat closely matched any commercial Aroclor formulation,although many resembled Aroclors 1242 and/or 1254 morethan other formulations. The lack of good Aroclor fit isexpected, considering the complex nature of these sampleswith thousands of potential sources of PCB. Additionally, asignificant amount of degradation, transformation, andselective solubility and adsorption has undoubtedly occurredsince the contaminants were released.

The PCB congener distribution was generally similar forthe two events sampled during normal flow conditions atany given plant, even when the concentrations varied greatly(Figure 2). This event-to-event consistency in compositionindicates that the major sources of the PCB remains the same,and the sometimes large concentration difference suggeststhat, for these plants, PCB input rates vary even during normalflow.

The high flow (storm) event influent samples had slightlydifferent PCB composition than the normal flow influent atsome plants, suggesting that additional sources (e.g., stormrunoff) were contributing during storms and/or that therelative contribution of the regular sources had changed.However, this change in the influent PCB makeup wassurprisingly small, and not noticeable at most plants, and acomplex PCB composition was clearly maintained during allflow conditions.

The PCB concentrations were higher in influent thaneffluent (Figure 3), and at some plants, these waste streamshad slightly different congener composition. However, thePCB composition of the effluent and influent were surpris-ingly similar at most plants during normal flow conditions.Minor differences could be seen for selected congeners, but

the lack of consistency made it impossible to attribute specificcongener removal to the treatment process. One might have,for example, expected proportionately more of the highermolecular weight, less polar, congeners to be removed duringthe various filtration, flocculation, and settling processes atthe WPCPs than the low molecular weight congeners, butthis was generally not observed.

Total PCB Data. The individual PCB congener data yieldsmuch detailed interpretive information, while total PCB dataare useful to generally assess the WPCPs contribution to thecontamination of the NY/NJ Harbor Estuary. The total PCB,as used in this document, is defined as the sum of theindividual PCB congener concentrations. A careful sample-by-sample data review was performed, and congener 180was excluded from the summation, as were congeners 3 and8 for a few influent samples when it was determined thatthese data were clearly mostly attributable to non-PCB matrixcomponents, as discussed earlier.

Table 3 summarizes the total PCB concentrations mea-sured at all 26 WPCPs. The total PCB concentrations in theindividual samples ranged from 9 to 63 ng/L in the effluent,26 to 1096 ng/L in the normal-flow influent, and 44 to 773ng/L in the high-flow influent samples. The concentrationsfor the two normal-flow event replicates were, for the mostpart, relatively consistent, considering the complexity of thesesamples; the relative percent difference in the total PCBconcentrations for the two normal-flow influent and effluentsamples averaged 50 and 34%, respectively. However, higherevent-to-event variability in PCB levels (100% difference,or more) was observed for some normal-flow effluent (NJ-4)and influent (NY-2, NY-7, NY-8, NJ-4, NJ-5, and NJ-6) wastestreams. The PCB levels in the high-flow influent were, ascould be expected, more changeable between events, due tothe varying length of time since the previous storm eventresulting in varying amounts of accumulations for runoff,differences in the magnitude of the rainfall, and slightdifferences in the timing of sample collection vis-a-vis thestorm.

Normal Flow Influent vs Effluent Concentrations. Figure4 presents the average normal-flow influent and effluent totalPCB concentrations for all plants. The average concentra-tions ranged from 31 to 655 ng/L and 10 to 55 ng/L for influentand effluent, respectively. Overall, the average PCB con-centrations at all plants was about 4 times higher for thenormal-flow influent than for the effluent (110 vs 25 ng/L).

An approximate PCB removal efficiency under normal-flow conditions (Table 3) can be calculated for each plant bycomparing the effluent and influent PCB concentrations asfollows:

This assumes that the simultaneously collected influent andeffluent are representative of each other; it does not takeinto account the greater fluctuations in influent than ineffluent concentrations, in-plant mixing, and plant residencetimes. However, this analysis provides a rough assessmentof PCB removal at the plants. The average PCB removal was64%, even though removal of trace organic contaminants,such as PCBs, are not what the plants have been optimizedfor. The removal efficiencies at most of the WPCPs whichhandle the highest flows (e.g., NY-4, NY-9, NJ-7, and NJ-12)were higher than the average. One plant with a large flow(NY-13) appears to have a low removal efficiency, butsignificant plant improvements have since been made atthis WPCP and it was not operating at full efficiency whenthis study was conducted. NY-13 was also the WPCP withthe highest effluent PCB concentration (averaged 55 ng/L).

FIGURE 3. GC/ECD chromatograms of NY-5 normal flow samples:influent vs effluent.

Removal efficiency ) (([influent] - [effluent])/[influent]) 100%


The other 25 plants had average PCB concentrations between10 and 48 ng/L of PCB in their discharge.

The PCB levels in the WPCP discharges (10-55 ng/L) canbe compared with concentrations of 40-80 ng/L in the Deer

TABLE 3. Total PCB Concentration in all Influent and Effluent Samples

[total PCB] - normal flow [total PCB - high flowplant

IDevent I

effluent (ng/L)event II

effluent (ng/L)event I

influent (ng/L)event II

influent (ng/L)event I

influent (ng/L)event II

influent (ng/L)

% of PCBremoved from

influenta

NY-1 31 18 36 26 127 44 22NY-2 25 35 103 35 385 195 38NY-3 22 21 92 42 77 228 63NY-4 13 18 99 43 201 227 73NY-5 19 13 132 126 74 163 88NY-6 12 10 78 72 160 83 85NY-7 32 47 98 34 245 64 67NY-8 14 32 169 54 100 129 66NY-9 15 21 63 67 109 86 72NY-10 35 23 66 76 192 140 58NY-11 9 10 64 45 332 116 82NY-12 21 20 68 66 225 142 69NY-13 56 53 70 45 85 235 20NY-14 16 13 76 55 103 180 78NJ-1 14 22 33 32 58 63 44NJ-2 29 26 73 81 110 100 64NJ-3 57 26 50 64 773 42 59NJ-4 19 63 153 1096 217 173 91NJ-5 25 33 27 58 57 48 25NJ-6 58 37 917 272 244 146 90NJ-7 36 34 94 127 246 354 67NJ-8 17 18 36 60 56 62 61NJ-9 20 20 32 87 247 293 58NJ-10 21 16 118 83 132 74 81NJ-11 10 22 35 61 65 44 68NJ-12 20 29 67 74 158 101 65

a Average percent of total PCB removed from influent prior to effluent discharge during normal flow conditions.

FIGURE 4. Normal flow influent and effluent total PCB concentration (ng/L) at all WPCPs.


Island (Boston, MA) effluent for the winter/spring monthsin 1994 (19). PCB concentrations in the Hudson River, withan annual flow into the estuary greater than all 26 WPCPscombined, were reported in the 100-200 ng/L range in thelower tidal portion of the river in the late 1970s and haddeclined to the 50-100 ng/L range by the mid-1980s (2).Other investigators measured PCB concentrations of 180 ng/Lin the lower Hudson River in 1978 and 70 ng/L in 1981 (9),and concentrations of 20-50 ng/L were measured for theHudson, Hackensack, Raritan, and Passaic Rivers in 1992near the mouth of these rivers, with the Hudson River havingthe highest concentration (20). PCB concentrations in themid-1980s were approximately 20 ng/L in surface watercollected in the New York Bight 15 km from the estuary (21),and off-shore North Atlantic PCB levels were determined tobe 35 ng/L in the early 1970s, and at a depth of 200 m, theconcentrations were 10 ng/L (22).

PCB levels in the water, surface sediment, fish and otherbiota in the Hudson River and estuary declined rapidly fromthe mid-1970s, when the seriousness of the PCB problembecame evident and regulatory action was taken to the early1980s (1-3, 7, 9, 23). This decline in PCB levels has beenobserved worldwide in a variety of environmental systems(24-26). The decline clearly continues; blue mussels col-lected over several years in the early 1990s at six Hudson-Raritan Estuary and New York Bight sites consistently showeda decrease in tissue PCB concentrations (1, 23). However,the rate of decline has slowed in the last 15 years (2, 7, 11,24, 25), and PCB levels in the waters of the Harbor are probablynot much lower today than they were 10 years ago.Unfortunately, there are little data on actual in-harbor watercolumn PCB concentrations. Nonetheless, the data gener-ated in this study, in combination with historical data,indicate that WPCP discharge PCB levels are comparable tothose of the local rivers and suggest that PCB levels in mostWPCP discharges are comparable to, or less than, the levelsin the receiving waters.

High Flow Influent Concentrations (Potential WPCP BypassConcentrations). The average high-flow influent total PCBconcentration ranged from 53 to 408 ng/L for the 26 plants(Table 4), and the average of all plants was 160 ng/L;approximately 50% higher than during normal flow (Table3 and Figure 5). The influent PCB concentration was higherduring high (storm)- than during normal flow at most of the26 plants, but at eight WPCPs, the PCB levels were essentiallyunchanged. The data suggest that for these plants (a) thenatural variability in the influent concentration is so largethat the increase in flow during storms does not significantlyaffect the average PCB levels and/or (b) the increase in flowdoes not significantly add PCB from new sources. At mostplants, however, the increase in flow during storms appearsto initially flush additional PCB, from the same or newsources, into the waste stream and increase the PCBconcentrations slightly; the magnitude of the elevation isvariable and probably reflects differences in the industrial/urban characteristics of the drainage areas for the differentWPCPs and differences in accumulations in the sewers. Theimpact of the timing of sample collection in relation to thefirst flush was not determined, although attempts were madeto use the same sampling strategy at all plants to maximizedata comparability.

Mass Loadings to the Estuary. To perform annual massloadings estimations with these data, one must assume thatthe samples are representative of the whole year, even thoughsome uncaptured seasonal variability is likely. An estimationof the annual PCB mass released from the 26 WPCPs througheffluent discharges, and that bypassed to CSOs and dis-charged, is summarized in Table 4. The high-flow influentconcentrations are used to simulate potential bypass con-centrations. These mass loading estimations for each plantare based on the following calculations:

TABLE 4. Estimated PCB Mass Discharge from All 24 WPCPs

plantID

normal flow(MGD)a

high flow(MGD)

normal floweffluent

[total PCB](ng/L)

high flowinfluent

[total PCB](ng/L)

effluentPCB massdischarge

(kg/yr)

bypass PCBmass discharge

(kg/yr)

total PCBmass discharge

(kg/yr)

NY-1 27 27 25 86 0.93 0.01 0.94NY-2 161 299 30 290 6.67 0.33 7.00NY-3 115 169 22 153 3.50 0.10 3.59NY-4 258 452 16 214 5.70 0.37 6.07NY-5 41 68 16 119 0.91 0.03 0.94NY-6 27 35 11 122 0.41 0.02 0.43NY-7 124 200 40 155 6.85 0.12 6.97NY-8 55 99 23 115 1.75 0.04 1.79NY-9 148 199 18 98 3.68 0.07 3.75NY-10 35 84 29 166 1.40 0.05 1.46NY-11 67 150 10 224 0.93 0.13 1.05NY-12 81 131 21 184 2.35 0.09 2.44NY-13 286 457 55 160 21.73 0.28 22.01NY-14 126 273 15 142 2.61 0.15 2.76NJ-1 11 16 18 61 0.27 0.00 0.28NJ-2 26 46 28 105 1.01 0.02 1.02NJ-3 7 11 42 408 0.41 0.02 0.42NJ-4 59 114 41 195 3.34 0.08 3.43NJ-5 3 9 29 53 0.12 0.00 0.12NJ-6 13 31 48 195 0.86 0.02 0.89NJ-7 283 403 35 300 13.69 0.46 14.14NJ-8 3 6 18 59 0.07 0.00 0.08NJ-9 12 32 20 270 0.33 0.03 0.36NJ-10 69 101 19 103 1.81 0.04 1.85NJ-11 4 6 16 55 0.09 0.00 0.09NJ-12 115 215 25 130 3.97 0.11 4.08Total 85.4 2.56 88.0a MGD: Million gallons/day. 1 MGD ) 3785 m3/day.


where A ) average normal flow effluent concentration (ng/L) and B ) flow rate (MGD; million gallons per day): averagenormal flow.

where C ) average high flow influent concentration (ng/L),D ) number of days in bypass per year (2 days; based on 2bypass conditions/month of 2 h each), and E ) flow rate:bypass/overflow flow (assumed to be half the high eventinfluent flow).

Accurate bypass flow and duration data are not availablefor the bypass mass loading calculations. However, basedon discussions with the WPCP operators, the assumptionslisted above may actually overestimate the amount bypassedby the WPCPs. For example, several of the WPCPs rarely ornever bypass at all, and most of the plants that bypass do soless frequently than the assumption (24 times a year), andthe duration of the bypass is generally less than the assumed2 h/event. Additionally, when bypass does occur, the volumediverted is typically much less than the half of the influentflow used in the above estimation.

The treated effluent streams contain most of the PCB theWPCPs release to the estuary with, at most plants, only minorproportions being diverted as plant bypass during stormevents for discharge through CSOs. Using the abovecalculations, an estimated total of 88 kg of PCB is currentlydischarged annually into the New York/New Jersey HarborEstuary from the 26 WPCPs; 85 kg through effluent dischargesand 3 kg from plant bypass diverted through CSOs. Two of

the 26 WPCPs (NY-13 and NJ-7) account for 41% of the totalPCB discharges (22.0 and 14.1 kg/yr, respectively).However, these higher discharge amounts are mostly areflection of the high volumes of wastewater being treatedat these two plants and not of high PCB concentrations inthe discharge. When considering the overall impact ofindividual WPCPs and the PCB mass loadings contributedby the plants, both the flow rates and actual effluent PCBconcentrations must clearly be considered. The annualreleases from the other 24 WPCPs range from0.08 kg/yearto 7.0 kg/year.

Approximately 2.9% of the 88 kg total annual PCB inputto the estuary by the WPCPs is from plant bypass. The plantbypass volume is the proportion of the CSO discharge thatcan potentially be controlled at the WPCPs; the othercomponents of the CSO discharges (e.g., miscellaneousstormwater runoff, illegal hookups, and dumping) aretypically out of the control of the individual plants. Thisestimated bypass amount is much smaller than what haspreviously been used in mass balance models for the harbor;as much as about 33% of the WPCP total PCB discharge tothe estuary has earlier been attributed to discharges throughCSOs (13). The total CSO discharge volumes are certainlyhigher than the plant bypass volumes, but the plant bypassvolume has been used in this analysis because of the potentialdirect control the WPCPs have over this waste stream (andthe treated effluent). However, a separate estimate can beobtained using recent total CSO flow information for theNYC WPCPs (Table 1). Assuming the PCB concentration inthe final CSO discharge is half the high-flow influentconcentration (a likely overestimation of the actual PCB levelsconsidering the stormwater dilutions), a total PCB dischargeamount of 9.8 kg/year can be calculated for the NYC CSOs.The NJ WPCPs, with a CSO drainage area and flow that is

FIGURE 5. Influent total PCB concentration (ng/L) at all WPCPs: normal vs high flow.

Effluent PCB Discharge (kg/yr) ) (A 365 days/year B 3.7854 106 L/MG 10-12 kg/ng)

Bypass PCB Discharge (kg/year) ) (CDE 3.7854 106 L/MG 10-12 kg/ng)


about 1/3 that of the NYC WPCPs, would then have a CSOPCB discharge of about 3 kg/year. These estimates yield atotal PCB from WPCP and CSO discharge of 98 kg/year forthe 26 WPCP regions (as opposed to the previously discussed88 kg/year), with 87% coming from WPCP effluent and 13%coming from CSO discharges. About 20% of the CSOdischarges would be from WPCP bypass and 80% otherunidentified, and less controllable, CSO waste streams.

The PCB discharged by WPCPs as treated effluent is rapidlymixed with the receiving water becomes associated withparticulate matter (unless it already was at the time ofdischarge) and is transported to the surface sediment. Thesettling out process occurs fairly rapidly in most bay andestuary environments (15, 16, 21, 27). It has been estimatedthat a total of approximately 250 000 kg of PCB was dischargedinto the upper Hudson River from the early 1950s to the mid1970s and that much of this has been transported to theHudson River estuary where the majority of it has becomeassociated with the sediment (4, 8, 13). Investigators haveconcluded that contaminated water and suspended matterfrom the upper Hudson River have been the single dominantsource of PCBs entering the tidal Hudson River Estuary sincethe late 1940s (3) and act as the major source of PCB todownstream environments (4). Most of the Hudson RiverPCB settles into the sediment in high depositional areas,such as New York Harbor, even though these areas only makeup about 10% of the area of the downstream estuary (3). Inthe early 1970s, the PCB loadings to the harbor from theHudson River were as high as 25 000 kg/year (13). Inves-tigators have in recent years estimated that approximately1000 kg (11), 500 kg (13), and 365 kg (12) of additional PCBare annually being transported to the estuary from theHudson River. Combined, the 26 New York/New JerseyWPCP are currently adding approximately 88 kg of PCB peryear to the New York/New Jersey Harbor Estuary, an estuarywhich already contains several tens of thousand, and possiblyhundreds of thousand, kilograms of PCB in the sediment (3,4, 8, 13), and receives several hundred kilograms of PCB fromriver sources annually (11-13), and unknown amounts fromother sources.

ConclusionThe New York/New Jersey Harbor Estuary clearly has highPCB levels compared to most U.S. coastal environments,and potentially has a significant PCB environmental problem.The estimated 88 kg of PCB discharged from the NY/NJWPCPs annually may or may not have a detrimental impacton the estuary. The data generated in this study, incombination with currently available historical data on therest of the estuary, suggest that the discharges from the WPCPdo not notably alter the water column or sediment PCBconcentrations of the harbor, which have been declining forthe past 20 years and appear to still be declining slowly.Because most of the PCB discharged from WPCP end up inthe sediment of the estuary shortly after discharge, thesediment PCB mass and flux (sedimentation and resuspen-sion) associated with the harbor also needs to be incorporatedinto any analysis attempting to determine if WPCP dischargeshave an environmentally significant impact on the estuary.

Important questions that need to be addressed at thispoint are how much are current inputs to the estuarycontributing to the larger PCB problem and what are therelative contributions of the current sources, such as WPCPs,various rivers, other point- and nonpoint sources, sedimentrelease, and atmospheric deposition. Are current inputscontributing significantly to maintaining the current PCBlevels in the sediment, water, and biota of the estuary, andwhat would the long-term effect be from reducing the PCBfrom individual sources? Are a few isolated hot spots inthe upper Hudson River still the major sources of new PCB

to the Estuary? Once the answers to these questions areavailable, decisions can be made on how to proceed withaddressing the issues. If current freshwater inputs (riverineor WPCP) are found to minimally contribute to the PCBproblem, and old PCB residing in the sediment is foundto be the primary problem, concrete and useful discussionscan be held on whether the sediment contamination shouldbe remediated or if it is best left alone to be capped by theprogressively cleaner sediments being deposited in theestuary.

Supporting Information AvailableTen figures an six tables (17 pages) will appear followingthese pages in the microfilm edition of this volume of thejournal. Photocopies of the Supporting Information fromthis paper or microfiche (105 148 mm, 24 reduction,negatives) may be obtained from Microforms Office, Ameri-can Chemical Society, 1155 16th St. NW, Washington, DC20036. Full bibliographic citation (journal, title of article,names of authors, inclusive pagination, volume number, andissue number) and prepayment, check or money order for$33.00 for photocopy ($35.00 foreign) or $12.00 for microfiche($13.00 foreign), are required. Canadian residents shouldadd 7% GST. Supporting Information is also available viathe World Wide Web at URL http://www.chemcenter.org.Users should select Electronic Publications and then Envi-ronmental Science and Technology under Electronic Editions.Detailed instructions for using this service, along with adescription of the file formats, are available at this site. Todownload the Supporting Information, enter the journalsubscription number from your mailing label. For additionalinformation on electronic access, send electronic mail [email protected] or phone (202)872-6333.

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Received for review January 2, 1997. Revised manuscriptreceived January 26, 1998. Accepted January 30, 1998.

ES970002S


pcb levels at 26 new york city and new jersey wpcps that discharge to the new york/new jersey harbor...

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