Heavy metal concentrations were monitored in edible soft tissues of shellfish from Trinidad and Venezuela. Oysters (Crassostrea sp.) and the green mussel (Perna viridis), which is a recently transplanted species to the Caribbean from the Far East, were collected at six locations in Venezuela and five in Trinidad, the latter along the coast line of the Gulf of Paria. Simple and low-cost methods of analysis were optimized and validated using standard reference materials. Cadmium, copper, lead, nickel, and zinc were analyzed by flame atomic absorption spectrometry. Mercury was determined by cold-vapor atomic absorption spectrometry. The present study has confirmed that oysters have a much greater capacity for accumulation of copper and zinc than does green mussel. In addition, concentrations of copper and zinc in oysters (Crassostrea sp.) at many of the sites in the Gulf of Paria exceeded local and international standards, whereas green mussel P. viridis contained generally acceptable levels for human consumption.

An interlaboratory study was conducted for the determination of paralytic shellfish poisoning (PSP) toxins in shellfish. The method used liquid chromatography with fluorescence detection after prechromatographic oxidation of the toxins with hydrogen peroxide and periodate. The PSP toxins studied were saxitoxin (STX), neosaxitoxin (NEO), gonyautoxins 2 and 3 (GTX2,3 together), gonyautoxins 1 and 4 (GTX1,4 together), decarbamoyl saxitoxin (dcSTX), B-1 (GTX5), C-1 and C-2 (C1,2 together), and C-3 and C-4 (C3,4 together). B-2 (GTX6) toxin was also included, but for qualitative identification only. Samples of mussels, both blank and naturally contaminated, were mixed and homogenized to provide a variety of PSP toxin mixtures and concentration levels. The same procedure was followed with samples of clams, oysters, and scallops. Twenty-one samples in total were sent to 21 collaborators who agreed to participate in the study. Results were obtained from 18 laboratories representing 14 different countries.

The primary source of cadmium in cocoa beans has been linked to its direct uptake by the cacao plant from cadmium contaminated soils. This research was conducted to evaluate and interpret significant relationships between cadmium levels in tissues of the cacao plant and soils from cocoa-growing areas in Trinidad and Tobago. Total (HNO3-extractable) concentrations of cadmium in both tissues and soils were determined. The levels of cadmium measured varied in the order: leaves > pods > shells > nibs > soil. Cadmium levels in all the cacao tissues analyzed were significantly (p < 0.05), positively and strongly correlated with each other. Additionally, significant (p < 0.05) positive relationships were also identified between Cd in cacao tissues and corresponding total HNO3-extractable Cd levels in soils. These findings suggest that they can possibly be used as predictive tools for assessing Cd levels in cacao.

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