Lab Matters Fall 2017 | Page 7

environmental health

FDA to improve testing methods, and sometimes collaborates with private institutions to develop and apply biotoxin testing assays. Recent events include a Karenia brevis bloom that started in fall 2016, continued through spring 2017 and resulted in commercial bivalve harvest closures by FDACS in Southwest Florida that extended through the summer. In mid-July, concentrations of ASP toxins in shellfish meat samples warranted a closure in a different area.

Washington

Washington has over 800 miles of saltwater coast capable of growing shellfish. Shellfish toxicity levels are regulated by the Washington State Department of Health Office of Environmental Health and Safety( OEHS) and PSP, ASP and DSP testing is conducted by the Shellfish Biotoxins Laboratory at the Washington State Public Health Laboratories. The laboratory has a $ 1.25 million / year budget, six full-time employees and analyzes 8,000 – 10,000 live shellfish samples per year. Shellfish are shucked, and toxins are extracted from appropriate tissues and tested. The mouse bioassay is used for PSP since it has a complicated set of toxins, and high performance liquid chromatography is used for ASP and DSP toxins since they have only one and three congeners respectively.

Analytical turnaround times of 24 hours or less not only allows the shipment of fresh Washington shellfish all over the world, but also for quick identification of unsafe harvest areas. In 2015, the biggest Pseudo-nitzschia bloom in history occurred along the US and Canadian Pacific coastlines, affecting untold sea mammals and birds. But because of the efforts of coastal shellfish programs and laboratories, no humans were sickened. ■

DIGITAL EXTRA: Read how Rhode Island State Health Laboratories combatted large numbers of Pseudo-nitzschia algae in the Narragansett Bay.

by John Schneider, toxicologist, BiomonitoringNH, New Hampshire Public Health Laboratories

Results for a group of samples show highly elevated levels of inorganic arsenic(+ 3) and arsenic(+ 5). The lab identification numbers are consecutive, indicating that the samples are likely from the same household and that the household probably accesses a well with arsenic concentrations above the recommended safe limit for drinking water. Immediately I notify our program epidemiologists who contact the household to explain the health effects of arsenic exposure and discuss well remediation options.

Though this is not a common occurrence at the New Hampshire Public Health Laboratories, we see it occasionally since certain areas of New Hampshire have a high probability for arsenic concentrations that exceed the US Environmental Protection Agency’ s maximum contaminant level for well water. Residents of these areas are sometimes unaware that their well may be a source of exposure to arsenic and other contaminants.

Measuring Chemicals of Concern

Our biomonitoring laboratory group team, BiomonitoringNH, is working on two studies to assess exposure of New Hampshire residents to specific chemicals of concern. One is a targeted biomonitoring study measuring urinary concentrations of arsenic and uranium. The other is a randomized, statewide surveillance study to measure background levels in the population of various toxic metals, pesticides and emerging contaminants such as perfluoroalkyl substances( PFAS). For the past 18 months, BiomonitoringNH has worked to develop the laboratory testing capability necessary for these studies.

BiomonitoringNH selected high-performance liquid chromatographyinductively coupled plasma-mass spectrometry( HPLC-ICP-MS) to measure six arsenic species in urine. This method can indicate whether arsenic exposure is coming from dietary sources such as seafood, or from the more toxic inorganic species found in drinking water. Many steps were involved in the set-up of this method, including making quality control materials in-house because none were available commercially. Preparation of quality controls for arsenic speciation was carried out in an oxygen-free environment for better preservation. However, the lab initially did not have a procedure to follow. All preparation and aliquoting was conducted inside the glove box once the oxygen had been removed. We did not know how well this process would work; it was a case of“ let’ s try it and see what happens.” Fortunately, the materials have already lasted much longer than if prepared in the presence of oxygen.

A Solid Foundation for Future Testing

BiomonitoringNH has ramped up testing for its targeted study and is quickly approaching its goal of analyzing 500 participants. The laboratory group also is working to validate additional methods to be used in an upcoming statewide surveillance study. These new methods all utilize liquid chromatography-tandem mass spectrometry( LC-MS / MS). Method validation for the analysis of twelve perfluoroalkyl substances in serum is currently wrapping up. BiomonitoringNH will then focus on validating two additional methods: one for serum cotinine, a marker for environmental tobacco smoke exposure, and another for a panel of ten metabolites of commonly used pesticides and herbicides.

BiomonitoringNH looks forward to applying these new methods to help state residents minimize their exposure to potentially harmful chemicals present in the environment. The initiative reaffirms the value of biomonitoring laboratories in protecting the health and safety of their communities. ■