NEWS ALERT

California Develops Analytical Testing Methods for Microplastics in Drinking Water

California’s State Water Board announced last week that it has developed new standard methods for analyzing microplastics in drinking water, the world’s first regulatory standard methods in this medium. The science of measuring microplastics in environmental samples and assessing potential risks to human health and the environment is relatively new. As consumer and regulatory concerns have grown, California has been at the forefront of this issue, having recently developed a regulatory definition of microplastics and guidance for monitoring these materials in drinking water. The new analytical procedures released last week are the first proposed methods to standardize microplastics measurements in environmental samples, and use Raman and infrared spectroscopy to evaluate microplastics in drinking water. These methods will enable the California Water Board to begin collecting consistent, standardized data about the amount and types of microplastics in drinking water sources. Eventually, those data can be used to provide insight regarding exposures and potential risks from microplastics in drinking water.

Gradient is tracking the evolving science and regulatory concerns related to microplastics. Gradient’s expertise related to microplastics and other emerging contaminants includes:

• more than 20 years of experience assessing risks to human health and the environment for a range of chemicals, including emerging contaminants;
• experience developing and assessing standard methods for analyzing existing and emerging contaminants in environmental samples; and
• recognized technical experts in the fields of exposure assessment, human health and marine environmental toxicology, spatial data analysis, and environmental fate and transport.

If you have any questions about Gradient’s capabilities related to microplastics, please visit our website or contact:

Julie Goodman, Ph.D., DABT, FACE, ATS

Principal

Jessie Kneeland, Ph.D.

Principal Scientist

Tom Lewandowski, Ph.D., DABT, ERT, ATS

Principal

Kim Reynolds Reid

Principal Scientist

Matthew Tymchak, M.S.

Senior Hydrologist

Tim Verslycke, Ph.D.

Principal

Andrew Yeh, Ph.D., DABT

Senior Toxicologist

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Science and Strategies for Health and the Environment

 www.gradientcorp.com

NEWS ALERT

MS v. TN Supreme Court Water Rights Case Receives Unanimous Ruling

Gradient contributed scientific analyses in the first interstate water dispute focused solely on groundwater tried before the Supreme Court.

The Supreme Court recently ruled on a decade-plus-long water rights dispute between Mississippi and Tennessee. In a unanimous decision, the Court rejected Mississippi’s claims that it owns groundwater beneath its state borders and that pumping by Tennessee resulted in the wrongful taking of Mississippi’s groundwater. In the first Supreme Court ruling focused solely on groundwater, the Court declared that the doctrine of equitable apportionment applies to groundwater flowing in interstate aquifers. The aquifer at issue was the Middle Claiborne, which is a major source of water for Arkansas, Louisiana, Mississippi, and Tennessee.

To address Mississippi’s claims in the case, Gradient evaluated the vast literature on the Mississippi Embayment aquifer system and characterized regional aquifer behavior using a numerical groundwater model developed by the United States Geological Survey (USGS) that encompassed the 78,000-square-mile aquifer system. We used the model to evaluate pre-development groundwater flow patterns and groundwater-surface water interconnectedness.

Specific Gradient analyses in this matter included:

• Evaluating the aquifer extent, characteristics, and historical definition;
• Modeling pre-development groundwater flow patterns, groundwater-surface water interactions, and sources of recharge;
• Assessing anthropogenic impacts to the aquifer using measured data and mathematical models; and
• Delivering expert testimony in a hearing before the Special Master to the Supreme Court for this case.

Gradient has provided scientific support for two recent original-jurisdiction water rights actions tried before the Supreme Court. These cases have required multidisciplinary hydrologic expertise.

If you have any questions about Gradient’s capabilities, please visit our website or contact:

Andrew Bittner, M.Eng., P.E.
Principal

David Langseth, Sc.D., P.E., D.WRE
Principal

Matt Tymchak, M.S.

Senior Hydrologist

Sam Flewelling, Ph.D.
Principal

John Kondziolka, M.S., E.I.T.

Senior Environmental Engineer

About Gradient | News | Water Resources Services

Science and Strategies for Health and the Environment

 www.gradientcorp.com

NEWS ALERT

Extreme Weather Events Further Complicate Sediment Sites

With less than two weeks remaining in the North Atlantic hurricane season, the National Weather Service (NWS) has exhausted its list of potential storm names for the second year in a row. This feat marks only the third time the NWS has eclipsed the allotted number. Although not all tropical storms make landfall, when they do, damage costs can soar into the billions. Despite widespread media coverage of these damages, hidden environmental costs from extreme weather lie beneath the water’s surface, due to unintended contaminant migration. A newly released study on extreme weather’s potential environmental impacts draws attention to sediment mobilization and the potential redistribution of associated chemicals. This issue could be particularly acute near urban areas where waterways have a rich history of industrial activity, and contaminant remobilization could potentially reopen previously closed sites.

A range of contaminants are typically found at large, complex sediment sites and may include metals, petroleum hydrocarbons, polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), dioxins, pesticides, and solvents, among others. These constituents are often adhered to, or intermixed with, sediments at the seafloor or river bottom and can be remobilized during floods or extreme tides, further complicating an understanding of release timing, source identification, and transport. Figure 1 shows the geographic regions of the country that are most susceptible to tropical storm impacts, as well as the locations of the nation’s Superfund sites. This figure illustrates how broad these effects could be, even for a single storm. For example, although Hurricane Ida made landfall in Louisiana, extensive flooding occurred in northern New Jersey and New York City, a region with many large, complex Superfund sites.

As a result of sediment mobilization and mixing caused by hurricanes and other extreme weather, understanding chemical movement through urban waterways and coastal environments often requires a multidisciplinary technical approach. For more than two decades, Gradient has addressed a wide range of contaminated sediment issues at some of the nation’s most complicated sites. Specific areas of Gradient’s expertise relevant to these matters include:

• Quantifying sediment transport in urban waterways that have been disrupted by flooding, storm surges, currents, and bioturbation, in addition to human influences such as dredging or barge traffic;
• Experience with state-of-the-art chemical testing and oversight of data collection efforts to support liability claims, cost allocation, and remedy selection;
• Evaluating forensic patterns with multiple fingerprinting techniques to determine release timing, source(s), and the age of numerous chemical contaminants;
• Identifying potentially responsible parties (PRPs) that may have contributed contaminants identified during post-storm sampling events; and
• Understanding how extreme weather events may affect remedy selection and implementation, in addition to potential effects on liability and cost allocation matters.

Gradient has deep expertise in several technical areas associated with sediment transport and environmental forensics, and is well positioned to help parties evaluate these issues at complex sediment sites.

Figure 1. Paths of Storms in the North Atlantic Tracked by the National Weather Service from 1970 – 2020 and the Locations of Superfund Sites in the Eastern US. The storms include tropical depressions, tropical storms, and hurricanes (categories 1-5), and the Superfund sites include deleted, proposed, and active sites.

If you have any questions about Gradient’s capabilities, please visit our website or contact:

Eric L. Butler, Ph.D.
Principal
 

Jessie M. Kneeland, Ph.D.

Principal Scientist

Jeffrey T. Rominger, Ph.D.

Senior Environmental Engineer

Tim Verslycke, Ph.D.

Principal

Kurt Herman, M.Eng., P.G.
Principal

James W. Rice, Ph.D.

Senior Environmental Scientist

Caroline B. Tuit, Ph.D.

Senior Environmental Chemist

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Science and Strategies for Health and the Environment

 www.gradientcorp.com

NEWS ALERT

Children’s Products Facing Deadline for Compliance with Key Part of Oregon’s Toxic-Free Kids Act

By December 31, 2021, manufacturers of three categories of children’s products containing any of 64 high priority chemicals or classes of chemicals of concern for children’s health (HPCCCH) will either have to replace those chemicals with less hazardous alternatives or petition the state to be allowed to continue selling the products in Oregon. The requirement will apply to manufacturers who have reported the presence of the chemical(s) in their product(s) during last 3 biennial reporting cycles. This is a unique requirement beyond the reporting function the Oregon Law shares with similar programs in the states of Washington, Vermont and New York.

The three product categories subject to this part of the regulation are:

• Mouthable children’s products
• Children’s cosmetics
• Products made or marketed to children under three years of age

Petitions to continue sale of the product with the HPCCCH can take the form of a request for regulatory exemption (e.g., the product is already covered by certain ASTM standards or CPSC regulations) or a waiver (see figure below). A waiver requires that the company conduct a quantitative exposure assessment (QEA) demonstrating exposure below specified detection limits or an alternatives assessment demonstrating that chemical substitutes are not feasible from a hazard, technical, or cost standpoint. Companies which are unable to seek an exemption for their products should first try for a waiver via the QEA. Given lab turn around times and the likely need to test multiple units, testing should begin within the next few weeks in order to meet the deadline of December 31, 2021 to submit the required documentation.

Gradient has been helping companies design product testing programs and having conversations with the Oregon Health Authority to receive informal feedback regarding the acceptability of particular testing approaches.

Click Image to Enlarge

Contact:

Tom Lewandowski, Ph.D., DABT, ERT, ATS
Principal 

Kim Reynolds Reid

Principal Scientist

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Science and Strategies for Health and the Environment

 www.gradientcorp.com

NEWS ALERT

US CDC Adopts Lower Blood Lead Reference Value

On October 29, 2021, the US CDC adopted an updated blood lead reference value (BLRV) of 3.5 μg/dL—a reduction from the previous BLRV of 5 μg/dL established in 2012.

The BLRV is a population-based measurement and has decreased to reflect continued decreases in blood lead concentrations in US children across time.

The updated BLRV is based on the 97.5^th percentile of the blood lead level distribution in US children aged 1-5 years as measured in the 2015-2016 and 2017-2018 cycles of the National Health and Nutrition Examination Survey (NHANES). The BLRV is not a health-based value or toxicity threshold; rather, it is a measure of a specific distribution of BLLs in a specific population at a specific time (CDC, 2021).

The updated BLRV could have significant implications for projects involving human health exposure, site remediation, or human health risk assessment. For example, because CDC calls for the BLRV to be updated every 4 years based on the most recent two NHANES cycles, this could mean that cleanup levels for lead-contaminated sites undergoing remediation could potentially have to be developed every four years. It would also be challenging to use the updated BLRV for most site remediation situations because cleanup levels may be less than urban background.

If you have any questions about the updated BLRV or its implications, please visit our website or contact:

Barbara D. Beck, Ph.D., DABT, ATS, AAAS Fellow
Principal 

 
Steven Boomhower, Ph.D.

Senior Toxicologist

Julie Lemay, M.P.H.
Senior Environmental Health Scientist

Rosemary Mattuck, M.S.

Senior Environmental Engineer

About Gradient | News | Toxicology and Risk Services

Science and Strategies for Health and the Environment

 www.gradientcorp.com