**2.1 Metals**

The technique used for metals was that described [12] consisting of a digestion in a microwave oven (CEM Mars5x) with 3 mL of HF, 10 mL of reagent water and 5 mL

**5**

thickness).

**3. Results**

(DLs) were 0.01 μg g<sup>−</sup><sup>1</sup>

**3.1 Physicochemical composition**

*3.1.1 Tampamachoco lagoon system (TLS)*

*Pollution Issues in Coastal Lagoons in the Gulf of Mexico DOI: http://dx.doi.org/10.5772/intechopen.86537*

**2.2 Petroleum (PAHs)**

under a soft N2 current to dryness.

**2.3 Organochlorine pesticides (OCs)**

of super-pure HNO3. The samples were read in an ICP-MS (ICP 7500c). Analytical quality was controlled using approved standards, reference material certified for marine sediments (IAE-433). The methodologies used for the analysis of metals are based mainly on the use of acid digestion in a microwave, obtaining afterward the

The samples were analyzed for the 16 priority PAHs [13] following the method recommended [14] and used worldwide in marine pollution studies [15–17]. This method involves an organic extraction with n-hexane: methylene chloride 50:50 v/v, concentration of the extract, clean-up using a silica pack, aluminium oxide and anhydrous sodium sulfate, eluted with n-hexane mixtures: methylene chloride 80:20 and 50:50 to obtain the aromatic fraction; the samples were concentrated

The OCs included the HCH (alpha, beta, gamma and delta isomers), DDT and its metabolites (*p,p'*-DDT*, p,p'*-DDD and *p,p'*-DDE) and the cyclodiene group (heptachlor, heptachlor epoxide, aldrin, dieldrin, endrin, endrin aldehyde, endosulfan I, endosulfan II and endosulfan sulfate); the ∑OCPs was calculated from the sum of 16 organochlorine pesticides mentioned. The sediment samples were processed following the technique proposed [18] reported in several studies [19–22]. It consists of extraction with HPLC grade n-hexane, concentration of the organic extract, and cleanup by adsorption chromatography using Florisil and anhydrous sodium sulfate. The cleanup column was eluted with the mixtures n-hexane:ethylic ether 9:1 and 8:2; the final solution was concentrated with N2 to 2–3 mL for GC analysis. All organic pollutants (PAHs and OCs) were quantified using a Hewlett–Packard 5890 series II gas chromatograph (GC) equipped with an HP-5 silica fused capillary column (30 m × 0.25 mm i.d. with 0.25 μm film

A flame ionization detector (FID) and an electron capture detector (ECD) were used for PAHs and the organochlorine compounds, respectively. Quantification was carried out using the internal calibration method based on a five-point calibration curve for individual components. The percentage of recovery of PAHs and OCs ranged from 85 to 105%. For each batch of 10 samples, a procedural blank, a spiked blank and reference standard material were processed (IAEA-417). Detection limits

Tampamachoco lagoon system (TLS) is located in the Coastal Plain of the Gulf

of Mexico, in the state of Veracruz, between the parallels 20°58′ 15″–21°05″ N and the meridians 97°20′ 30″–97 24″ W [23]. It is formed by the Tampamachoco lagoon (1500 ha), occupying a total area of 6870 ha. The climate is of the "Aw type 2" (e) that is to say warm subhumid with rain in the summer [24], with an annual rainfall of 1900 mm, being January the driest month and September the

for OCs.

for PAHs and 0.01 ng g<sup>−</sup><sup>1</sup>

concentrations in an Atomic Absorption Spectrophotometer or in ICP-MS.

of super-pure HNO3. The samples were read in an ICP-MS (ICP 7500c). Analytical quality was controlled using approved standards, reference material certified for marine sediments (IAE-433). The methodologies used for the analysis of metals are based mainly on the use of acid digestion in a microwave, obtaining afterward the concentrations in an Atomic Absorption Spectrophotometer or in ICP-MS.
