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 . ■