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June 2004

TDI-Brooks collects SRM for NIST

At the conclusion of the 2004 collection for NOAA's National Status and Trends Mussel Watch project, TDI-Brooks International was contracted by the National Institute of Standards & Technology (http://www.nist.gov) to collect mussels for their Standard Reference Materials (SRMs) program. SRM is made available from the NIST to organic and inorganic analysts (environmental labs) who routinely analyze fresh tissue samples for the most part as part of marine pollution monitoring and damage assessment programs.

Beginning in 1988 NIST has developed mussel tissue SRMs for the determination of the concentration of organic contaminants. Initially, and with subsequent additions as demand quickly exceeded supply, blue mussels (Mytilus edulis) from Boston Harbor have been used to prepare the fresh frozen tissue homogenate. Other SRMs have been added to the inventory from Guanabara Brazil and Raritan Bay New Jersey. The present mussel tissue SRM has certified concentration values for 22 polycyclic aromatic hydrocarbons, 31 polychlorinate biphenyl congeners (PCBs) and 7 chlorinated pesticides. In addition the SRM provides reference values for 16 PAHs, 8 PCBs and total PCBs, 6 pesticides, total extractable organics, methylmercury, and 11 trace elements.

The original supply of SRM, made from 2400 individual mussels yeilding 28kg biomass, was depleted in 5 years because of its widespread use in marine monitoring and related quality assurance programs. The renewal SRM was expanded to include extended availability and a larger number of certified values. The "evenly contaminated" mussels of Boston Harbor addressed the second objective, and 6000 mussels (almost three times the number, yielding 81 kg biomass) intended to increase the availability. Attesting to the significance and importance in SRMs to marine monitoring, this replacement supply (almost 4 times the amount) was exhausted in 5 years also. A third replacement of 6000 was collected in 1999, and consistent with the previous history as 2004 came around the supply is almost exhausted.

Thus in March 2004 TDI-Brooks was contacted about re-supply of mussels for the SRM. Scientists at TDI-Brooks, have been involved in key roles (both analytically and in field collection) in the Status and Trends Mussel Watch project since it's inception in 1985. Since 1999 TDI-Brooks has held the contract for collection and analytical of the Mussel Watch project for the entire country (all three coasts, Alaska, Hawaii, and Puerto Rico). With the final northeast coast collections scheduled to begin at the end of March and early April,TDI-Brooks was uniquely qualified and postioned to provide the quality collection for NIST on a timely basis.

Coordination with the tides, daylight, and sufficient manpower were key to the successful collection of 10,000 specimens by hand. The collection site specified was in the southern end of Boston Harbor in an area known as Dorchester Bay. There is a Mussel Watch site located there, which was last sampled in 2003, thus the area and mussel distribution and abundance was well known. Tidal access (both amplitude and chronology) required either a daybreak or sunset collection window of only 2 hours each (collectors following the tide out and back in). The samples were required to be cleaned of mud, frozen while still alive, and maintained frozen thru delivery for transfer to liquid nitrogen at the NIST laboratory in Charleston, SC.

The collection site is located south of the JFK Presidental Library and adjacent to a marina/condominium development known as Marina Bay. Mussels are densely distributed in vast beds covering hundreds of yards, but only exposed with tides approaching Mean Low Water. The collection was accomplished in 2 sampling periods employing locally based fish processors as collectors from Norpel in New Bedford. Mussels were washed on site, bagged (approximately 120 per gallon zip-lock freezer bag), and placed in ice chests for immediate transport to the Bridge Terminal blast freezing and cold storage facility in New Bedford, where they remained frozen for a minimum of 4 days before being loading and expresse trucked to Charleston, 30 hours in transit. Approximately 11,200 individual mussels were delivered to NIST, where they will be processed into the frozen tissue homogenate. Sample processing is expected to take up to a year.

For additonal information about the mussel collection or the Status and Trends Mussel Watch program contact Dr. Roger Fay (rogerfay@tdi-bi.com). For information about the SRMs or the NIST, link to their web site (http://ts.nist.gov/ts/htdocs/230/232/232.htm), or contact Dr. Steve Wise (stephen.wise@nist.gov)