*3.2.1 Petroleum (PAHs)*

Oil pollution and its derivatives are considered to be one of the biggest environmental problems in the Gulf of Mexico [40] and in its waters have been occurred the two largest oil spills at the sea, such as: the Ixtoc-1 well in the Campeche Sound and that of the Deepwater Horizon, off the coast of Louisiana, USA. Both affected significantly the diverse ecosystems of the coastal areas. Thus and in spite of the fact that the Mexican coastal lagoons settled on the margins of Veracruz, Tabasco, and Campeche, are highly productive and of high economic value. Analysis of petroleum hydrocarbons conducted in these lagoons showed important concentrations of aromatic hydrocarbons originating from the intense oil activities that develop along their coasts. In the present contribution, the updated available information on the levels of concentration of PAHs in sediments of the lagoons of Tampamachoco, Mandinga, Alvarado in the state of Veracruz and one of Terminos in Campeche is gathered. In the cases of the lagoons of Tampamachoco and Alvarado also sedimentary nuclei analysis were carried out, which give us a historical view of these pollutants for approximately 80 years old and in the same way the tendency in time that have these compounds.

### *3.2.1.1 TLS*

The sediments of the TLS and the Tuxpan River, Veracruz, were evaluated during the end of July 2012. From the results of the 16 priority PAHs determined, the greater (1.30 μg g<sup>−</sup><sup>1</sup> ΣHAPs) was registered in the station located in front of the Thermoelectric Power Plant (CTPALM) and the minimum (0.02 μg g<sup>−</sup><sup>1</sup> ) in site located in the north of the lagoon body. The analysis of a sedimentary core [7] in the TLS showed an average concentration of PAHs of the nucleus of 0.98 ± 0.38 μg g<sup>−</sup><sup>1</sup> . When analyzing the vertical distribution of the PAHs content, it was found that the historical pattern showed an increase from the basal level of the ΣPAHs of 0.29 μg g<sup>−</sup><sup>1</sup> at the beginning of the last century (1908), until reaching the maximum of 1.79 μg g<sup>−</sup><sup>1</sup> in 1999, and decrease towards the beginning of the twenty-first century in 0.58 μg g<sup>−</sup><sup>1</sup> (2003) to show a new increase in 2010 with 0.84 μg g<sup>−</sup><sup>1</sup> . The compounds with the highest concentrations were, dibenzo[ah]anthracene (0.28 μg g<sup>−</sup><sup>1</sup> ), in order of decreasing followed fluorene (0.13 μg g<sup>−</sup><sup>1</sup> ) and benzo[a]anthracene (0.12 μg g<sup>−</sup><sup>1</sup> ). The molecular profile in the eight analyzed strata, changed, of petrogenic origin in 1908, to be dominated by pyrolytic compounds and to a lesser extent by petrogenic from 1999 to the present time. It should be noted that the individual concentrations of PAHs in sediments were lower than the international sedimentary quality criterion (**Figure 3**), with less probability of causing adverse effects to the benthic community. Thus, it can be said that there is no risk derived from the intrinsic toxicity of the coastal sediments analyzed from this group of hydrocarbons.

**9**

**Figure 2.**

*ALS core concentrations of PAHs (μg g<sup>−</sup><sup>1</sup>*

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

bons from human activities around the lagoon.

*3.2.1.2 MLS*

*3.2.1.3 ALS*

to 1.3 μg g<sup>−</sup><sup>1</sup>

4.02 μg g<sup>−</sup><sup>1</sup>

0.591 μg g<sup>−</sup><sup>1</sup>

to the year 1998 (about 2.0 μg g<sup>−</sup><sup>1</sup>

the latter showed a concentration of 0.0427 μg g<sup>−</sup><sup>1</sup>

range of 2.2–18.2 μg g<sup>−</sup><sup>1</sup>

From the analysis of individual PAHs, it can be seen that the predominance of compounds with 3–4 rings indicates inputs of pyrolytic and petrogenic hydrocar-

In **MLS** was in which the highest values of PAHs were determined with a

chrysene, benzo[b]fluoranthene, benzo[a]pyrene, indeno[1,2,3-cd]pyrene and benzo[a]anthracene, all of them considered of environmental concern. This lagoon receive directly the urban discharges of settlements south of the Port of Veracruz

The analysis conducted in a sediment core into ALS did not show a tendency to increase over time, possibly due to the source types of those compounds. The average sum of the 16 PAHs analyzed in the four strata was 1.84 ± 0.54 μg g<sup>−</sup><sup>1</sup>

except for the stratum from 26 to 36 cm, where it was below the detection limit; the highest concentration in this stratum corresponded to benzo[α]anthracene with

not detected by the analytical method employed for their determination [41]; only

sponding to the year 1929. This study showed that compounds with four aromatic rings were predominant in all core strata (**Figure 2**), which suggests that they were byproducts of pyrolytic processes near the study zone, such as high-temperature combustion of organic matter and fossil fuels. The sum of the four-ring PAHs presented practically the same collective tendency as the sum of the 16 quantified PAHs. This indicates that the contribution to the entire historical profile of both

*) based on number of aromatic rings.*

), and a slight increase near the superficial stratum corresponding

. The compound with the highest value in all core strata was chrysene,

, benzo[κ]fluoranthene and indeno[1,2,3,c,d]pyrene compounds were

). These values are far below the ERL index of

in the deepest stratum corre-

which indicates a downtrend from the year 1929 to 1971 (with values from 1.5

). The compounds that stood out were

,

(average 5.68 μg g<sup>−</sup><sup>1</sup>

and refuses from steel and iron plant placed in its nearby.

From the analysis of individual PAHs, it can be seen that the predominance of compounds with 3–4 rings indicates inputs of pyrolytic and petrogenic hydrocarbons from human activities around the lagoon.
