**3. Organisms**

**Table 1** shows the mercury content measured in the two species of fish, the mullet and the silver mojarra (*Mugil incilis* and *Euguerres plumieri*), during the sampling period.

The contents in the two species of fish showed large fluctuations, which is to be expected, since they are two resident species in the bay, but they move throughout the study area and are, therefore, subjected to different concentrations for short periods of time. The highest concentrations for the two species occurred during the March sampling followed by November. During the four samplings, the contents were higher in the mojarra. According to the authors, significant differences were determined in the contents (p < 0.001), and the differences were 7.3 times greater in *E. plumieri* than


*The mean value and standard error are given. LOD Limit of detection (7.4 μg Hg g−1 < d.w.).*

#### **Table 1.**

*Total mercury content (μg Hg g−1 d.w.) in two species of fish from the Bay of Cartagena, collected between March and November 1996.*

#### **Figure 4.**

*Total mercury concentrations in muscle of two species of crab of the genus Callinectes in two areas of the Colombian Caribbean, Gulf of Morrosquillo and Bahía Cartagena. COV: Coveñas, BOC: Bocachica; CHA: Puerto Charcoal; ALC: Planta de cloro-alkalis; MAN: Manga; CGR: Castillo Grande; LOM: Lomarena in the Departamento del Atlántico. From Oliveros et al. [9].*

in *M. incilis*. These results are understandable, taking into account that the mojarra is a secondary consumer, while the mullet is a detritivore. The contents in the fish from the bay were 7.3 times higher than those from the swamp.

The content of HgT has also been measured in species of crab for human consumption, crabs or swimming crabs (*Callinectes sapidus* and *C. bocourti*) from different collection points (Cartagena and Coveñas), along the Caribbean coast in Colombia [9]. Unfortunately, these authors did not include the HgT content in the crab samples, they only give the values of the percentage of crabs in which Hg was determined.

**Figure 4** shows the HgT contents in crab muscle. The highest contents were measured in the specimens collected in the area of influence of the old chlor-alkali plant, followed by those collected in the Charcoal port, on the western side of the mouth of the Clarín Channel. The contents of the crabs collected in the other stations were lower. These results show that despite the chlor-alkali plant having been closed for so long, the presence of Hg in the environment is still notorious.
