An excellent compilation of standard and reference materials for marine science was made by Cantillo (1993) which included the addresses of the sources of these materials. Among the more important sources of CRMS is the National Research Council (NRC) of Canada that has produced reference materials over many years. These materials include seawater, sediments and biological samples for which the concentrations of inorganic or organic parameters have been accurately determined. The International Atomic Energy Administration (IAEA) is also an important source of CRMS for marine laboratories.
However, I am uncertain if the information is widely known to laboratories in the region and more importantly, whether laboratories routinely use CRMS as part of their quality control (QC) protocols. In the 1997/1998 ASEAN-Canada inter-laboratory exercise, for example, only 5 of the 21 participating laboratories indicated that they analyzed one or more CRMS alongside the samples. Many laboratories experience persistent problems with the lack of available quality control (QC) resources (i.e., CRMs, calibration standards, analyte spike solutions).
A related issue is that CRMS are expensive and may be difficult to acquire for laboratories in the region. A 500-ml CASS-1 sample (a CRM for trace elements in seawater), for instance, costs Can$ 145 today. If you add in the mailing charges and taxes (in some countries), the price for this CRM could easily be twice the original off-the-shelf cost.
5. Monitoring of contaminants are often confined to nearshore areas and the number of samples acquired as well as the data generated are limited. Principally because the acquisition of marine pollution data is laborious and does not have the luxury of automated systems available to physical oceanographers, contaminant levels tend to be assessed only in nearshore areas. More often, the determinations are made at or near point sources of contaminants.
The high analysis costs as well as the relatively long turn-around time for samples also becomes a major consideration in the acquisition of more marine pollution data.
6. Unlike physical parameters, contaminants generally exhibit non-conservative behavior so that their concentrations can be greatly affected by temporal and spatial factors. For example, the vertical distribution of oxygen in the photic zone can be affected by diurnal migration of phytoplankton so that oxygen concentrations at one site obtained during the day can change markedly in magnitude and with depth from oxygen concentrations determined at night at the same site.
In coastal areas, where many of the contaminants are measured, sampling done during flooding or ebbing periods can markedly affect the measured concentrations of contaminants especially in estuaries.
These factors, among others, can make difficult any attempt to compare and assess contaminant data obtained at varying temporal and spatial scales.
7. Data sharing/access is limited. This problem is difficult enough with physical oceanographic data but the issue is even more pronounced with marine pollution data. Among the contributory factors to this problem is that many of the reliable marine pollution data may be obtained by academic or research institutions.
