Organic pollutants and heavy metal concentrations in tidal creek sediments after Hurricane Sandy: A Baseline for susceptible low lying areas in the Hackensack River estuary Francisco Artigas, Ji Meng Loh, Jin Young Shin, Joe Grzyb and Ying Yao Abstract The relatively low cost of lands along with a privileged location near an urban center attracted industry to the Meadowlands estuary and the absence of regulations resulted in vast amounts of industrial waste emitted into the air and dumped to nearby estuaries and marshlands. Hurricane Sandy created an unprecedented sea surge that overtopped berms and tide gates and extensively flooded approximately 2, 280 Ha of a low lying basin that includes Berry’s Creek, a tributary to the Hackensack River and well known for its legacy of contamination The sea surge connected Berry’s with eastern creek that flow into the Hackensack River for several tidal cycles. The objectives were to establish a baseline for organic pollutants and heavy metals post Super Storm Sandy and determine if contaminants from highly contaminated areas moved to the eastern creeks during the surge and finally, measure contaminant gradients around tide gates, Results show that most enriched sediments contained cadmium, mercury and chromium. Concentrations of PCB’s were higher in the western creeks and overall no differences were observed from either side of tide gates. Massive export of contaminants from western to eastern creeks from the sea surge was not apparent. Heavy metal concentrations were greater close to tide gates and may play a role in their distribution across the estuary. Keywords: Metals, Polychlorinated biphenyls (PCBs), Organochlorine pesticides (OCPs), Tidal creek sediments, Hurricane Sandy Introduction Coastal marsh environments provide a unique physical chemical environment with the capacity to immobilize and retain contaminants. Historically, low lying coastal wetlands were viewed as unproductive areas that needed to be transformed into “productive areas” by ditching and filling. The relatively low cost of the land along with a privileged location near urban centers attracted industry which in the absence of regulations resulted in vast amounts of industrial waste emitted into the air and dumped to nearby estuaries and marshlands. The combination of a tidal system with high sulfur and organic matter content along with low redox potentials (Eh) and moderate pH’s provides the conditions for organic pollutants to degrade and metals to be adsorbed to clay surfaces and to precipitate as metal sulfides (e.g. Galena PbS; Cinnabar HgS and Pyrite FeS). Coastal wetlands are among the few ecosystems that support such a unique physical chemical 1 environment that effectively provides the conditions for heavy metals to drop out of solution. The principal form of transport of the existing pollutants is as suspended solids and overland flow as persistent organic pollutants (PCBs and OCPs) and metals associated to the solid phase by adsorption to sediments and organic matter (Adriano 1986; Bohn et al. 1985). Heavy metals are indestructible and will remain as precipitates or adsorbed to organic matter as long as the conditions allow. Persistent organic pollutants on the other hand are man made and are a source of carbon to microorganisms and degrade by undergoing biotic and abotic transformations. The amount of organic pollutants adsorbed to the clay fraction and/or organic matter depends on the compounds distribution coefficient (octanol/water) Kow. Compounds with high Kow will mostly be retained by the sediments and be less available to biological processes1. A normally functioning marsh sustains conditions that limits the mobility of contaminants and with time they are buried under new silt deposits. Hurricane Sandy created an unprecedented sea surge that overtopped berms and tide gates and extensively flooded approximately 2, 280 Ha of a low lying basin that includes Berry’s Creek, a tributary to the Hackensack River and well known for its legacy of contamination (Citations). A continuous monitoring sensor network recorded water quality and water elevation in the western and eastern creeks before, during and after the hurricane. Water elevation around midnight on October 29th reached 2.8 m which translated into about 1 m of water above street level for most of the study area. Water turbidity almost doubled with the surge and increased almost threefold during the next two tide cycles after the initial surge (Figure 2). Similarly, salinity increased from 9 ppm to 13 ppm during the surge (Chun and Artigas, 2013). The flooded connected the highly contaminated Berrys creek system wuth historically less impacted eastern creeks along residential areas that flow directly into the Hackensack river. The most contaminated sites occur along occur along the western creeks and belong to EPA’s National Priorities List. (Figure 1. A, C, D and B and E, respectively). Western creeks are known to be contaminated with heavy metals, especially with mercury (Galluzzi and Sabounjian, 1980; Dames and Moor, 1990; Weis et al, 2005). Limited remediation has taken place since contamination was discovered in Berrys creeks complex in the early 1970’s (citation). For decades facilities in this area operated as recovery and recycling centers for off-spec fungicides, pesticides and solvent refining and recovery facilities that left soils and nearby creeks and ditches contaminated with heavy metals, volatile organic compounds (VOCs), polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) (USEPA. 2006). 1 G. Petruzzelli, F. Gorini, B. Pezzarossa, F. Pedron CNR, Institute of the Ecosystem Studies (ISE), Pisa (Italy) [email protected] 2 A sea surge that lasts over several tidal cycles has the potential to redistribute contaminants by resuspending sediments and moving them around in the flood waters. Sea water also brings metal alkali which have the effect of moving pollutants into solution. This area depends heavily on miles of dikes and numerous tide gates to protect industrial and residential areas from high water. Dikes in this case are elevated earthen embankments 5 feet above sea level designed to keep low lying lands from being flooded during high tides. The presence of tide gates influences oxidation potential (Eh) and pH of surface sediments and affects their mobility l(Portnoy, 1999, Ansfield and Benoit, 1997). Tide gates also change water velocity and affect water turbidity and turbulence from fluctuations between stagnation and flushing flows (Giannico and Souder, 2004). This study has three objectives; 1.- To base line post Super Storm Sandy pollutant levels for a system of tidal creeks, 2.- find evidence that contaminants associated with Berry’s Creek were exported to eastern creeks and 3.- Measure if tide gates play a role in modulating the distribution of contaminants. Study area This study includes seven well known creeks and ditches that drain the target area (Figure 1): Eastern creeks that branch off the Hackensack River include: Depyster, Losen Slote and Moonachie. Creeks that are part of the Berrys creek complex include: West Riser, East Riser, Peach Island North and Peach Island East. Also included in the study is a segment of the Hackensack River. These creeks are part of the towns of Carlstadt, Little Ferry, Moonachie, as well as South Hackensack Township in Bergen County, New Jersey (Figure 1). An outcrop along Washington Ave. in Carlstadt provides the highest elevation of the area at 3 to 5 m and divides the western and eastern creek systems. The average street elevation is 1.5 m and the average elevation of tidal creek banks is also 1.5 m. During Sandy, flood water entering from the western and eastern creeks met at the intersection of the towns of Carlstadt, Moonachie and South Hackensack. Residential areas are close to the eastern creeks while mainly industrial areas exist along the western creeks. Aside from the three super fund sites along Berry’s creek, the entire 2,280 Ha study area also includes more than 20 known contaminated sites (NJDEP 2008). 3 Figure 1 Map of creeks and sediment sampling locations (black dots) along the creeks and in the Hackensack River. Sites A, B, C, D and E are highly contaminated sites. Figure 2 Barge Marina depth and turbidity measurements during Hurricane Sandy from 10/26/2012 to 11/1/2012. 4 Materials and Methods Field Sampling A 12-foot Nasco swing sampler was used to take surface sediment samples from the designated creeks. At each creek, a total of six to nine locations were sampled on the land side of the tide gate. In addition, at each creek, 4 samples were taken from the river side of the tide gate and 5 samples were taken directly from the main stem of the Hackensack River (Figure 1). Three sediment samples at each sampling locations were combined into one composite sample and transferred to a labeled plastic bag. Samples were brought back to the lab and stored in a refrigerator at 4 oC. GPS locations with decimeter horizontal accuracy were recorded at each sampling point using a Trimble GeoXH 6000 Series handheld GPS. Laboratory Analysis PCB congeners and OCPs: An accelerated solvent extractor (ASE 100, Dionex, USA) was used to extract PCBs and OCPs from the sediment samples by using a mixture of hexane and acetone in a 1:1 ratio. After extraction, gel permeation chromatography (GPC, Autoprep 2000, O I Analytical, USA) was used to clean the samples before GC-ECD. The extracts were concentrated to 1mL by rotary evaporation at a temperature 30°C. The extracted samples were fractioned by florisil column (10mm i.d. x 300 mm length) filled with 10 g of florisil (60-100 mesh; J.T Baker, NJ, activated at 550 °C for 4 hours), and then partially deactivated by the addition of deionized H2O (2.5% by wt.). The sample was loaded into the head of the florisil column and covered with a layer of sodium sulfate to a depth of 10mm.