Maryland has for several decades monitored for certain chemical contaminant levels (e.g., PCBs and mercury) in Maryland’s recreationally caught fish. When routine monitoring indicates potential hazards to the public and the environment, additional monitoring of the affected area may be conducted to verify the initial findings and identify the appropriate species and size classes associated with harmful contaminant levels. Findings from such studies are the basis for MDE’s fish consumption guidelines. In fall 2020, MDE began sampling of fish tissue for PFAS on the Eastern Shore, which includes stations in the Chester, Choptank, Corsica, Elk and Wicomico rivers and Isle of Wight and Chesapeake bays. The results from that sampling showed no levels of concern.
MDE also added two fish tissue sample locations in Piscataway Creek in Prince George’s County because Joint Base Andrews, which is located adjacent to the upper reaches of the creek, is a known source of PFAS, and an area near the mouth of the Piscataway is popular for recreational fishing. The results from the fall fish tissue collection in Piscataway Creek showed highly elevated levels of PFOS in sunfish collected west of Route 210 in the non-tidal portion of the creek. Yellow bullhead catfish were also collected at the same location and the results were mostly non-detect and similar to all other fish tissue results from the fall collection.
Because this warranted further investigation, fish tissue and water samples were collected from the area in 2021 to, among other things, validate the 2020 measurements in sunfish. MDE found elevated concentrations of PFOS in redbreast sunfish, yellow bullhead catfish and largemouth bass, leading to Maryland’s first fish consumption advisory based on levels of a PFAS
compound. MDE is also expanding sample collection in the larger Potomac area downstream of Piscataway Creek between fall 2021 and fall 2022.
Since then, MDE has initiated a statewide monitoring strategy, including targeted monitoring for PFAS in specific water bodies that have been identified as having nearby potential sources of PFAS, to determine the concentrations of PFAS contaminants in fish tissue that may require FCA’s. Areas frequented by subsistence anglers and fishers were also monitored. The targeted fish samples for PFAS remain the same as those from previous collections: game/predator, panfish, and bottom feeders as well as species known to be consumed by recreational anglers were sampled including rockfish, crabs and oysters.
Samples were analyzed for many of the various PFAS compounds including 5 of the 6 PFAS, PFOA, PFOS, PFHxS, PFBS and PFNA, proposed by EPA for National Primary Drinking Water regulation. The sixth proposed PFAS Drinking Water compound, GenX, was not included, as the laboratories used did not analyze for that contaminant, however, it will be included moving forward. One compound, PFOS, was identified at greater concentrations and a higher frequency than other PFAS and has been the focus pollutant for FCAs. Using the CDC reference doses, a comparison was done for fish tissue data with the upper advisory threshold limit (8 meals/month) for PFBS, PFHxS, PFNA, and PFOA in addition to PFOS, there are no advisories for any of these analytes.
FCAs (meal recommendations) are calculated for several of the PFAS compounds, and only PFOS levels in certain fish from specific waterbodies result in fish consumption advisories where MDE would recommend limiting consumption for certain population groups: general population, women, and children. There are no advisory recommendations for other PFAS at this time. Overall, PCBs and mercury continue to be the fish consumption risk driver (the contaminant that results in the fewest recommended meals consumed per month) for most species and waterbodies. Proposed PFOS fish consumption advisories would be 16% of the total advisories in Maryland. There are currently 457 total consumption advisories, of which there are 73 recommended advisories for PFOS (16%).
|"Avoid"(>1 Meal every other Month)
|"No limit" (>8 Meals/Month)
|Range (1 - 8 Meals per Month)
From the fall of 2020 to the fall of 2022, there were a total of 150 PFAS fish composites collected in Maryland, resulting in 106 separate consumption advisories specifically for PFAS. Of those, 73 of the collection locations resulted in Fish Consumption Advisories with PFOS as the driver, and 33 remained unchanged based on the existing contaminant drivers. It is also important to note that of the 73 PFOS advisories, 40 of those are newly sampled areas (22 new areas) or newly caught fish species in existing areas (18 new fish species) with no data available for other potential chemical contaminants.
Crabs and oysters sample concentrations of PFAS were below consumption screening criteria, therefore, no advisories are warranted. However, surveillance will continue as needed.
Striped Bass (Rockfish) were specifically targeted for collection and analysis for PFAS. Of the eight separate locations where PFAS were collected, seven sites had a resulting consumption advisory based on PFAS. Of those seven sites, two of the sites have multiple PFOS advisories based on different sizes of Striped Bass. It should be noted that all seven of these sites with the resulting PFAS advisories had no previous advisories for other contaminants, thus per procedure, the PFAS advisory is the driving advisory. In all locations where Striped Bass had previously been collected and analyzed for PCBs and Hg, these advisories remained the same, with the same drivers.
The goal of MDE’s PFAS strategic sampling plan is to better understand the occurrence of PFAS in surface waters and fish tissue to reduce human health risks. MDE will assess fish tissue sampling results for PFOA and PFOS in specific waters and develop advisories when necessary to reduce human health risk. MDE will also utilize the results of the sampling to determine the need to designate waters as impaired for PFAS and to determine the need for limits on any point source discharges.
The data used to calculate the PFAS Fish Consumption Advisories is available in a .pdf file
. A interactive webmap application layer for this data is forthcoming. In some cases, other data (such as surface water) can also be found in the .pdf.