*3.2.3 Organochlorine pesticides (OC)*

The data for organochlorine pesticides (OC) are presented in sediments of the lagoon systems considered in this study. The TLS has records of these agrotoxics of three practically continuous annual cycles (2009, 2010 and 2012), while the remaining ecosystem data correspond to a particular year; the values are given in ng g<sup>−</sup><sup>1</sup> dry weight. **Figure 5** shows the total data of the OC (ΣOC) reported in sediments of these coastal lagoons. For ALS the sediments evaluated in 2009 occupy the first place with a value of 36.2 ng g<sup>−</sup><sup>1</sup> [3] while in lower concentrations were TLS in the same year with 13.3 ng g<sup>−</sup><sup>1</sup> decreasing to 4 ng g<sup>−</sup><sup>1</sup> in 2012 and the lowest total concentration of organochlorines was for the TELS with 0.18 ng g<sup>−</sup><sup>1</sup> [4]. This marked difference between lagoon systems in the same coastal region of Mexico may be due to the local uses of these agrochemicals, as well as to the particular conditions of temporary runoff and large permanent flows and to the human activities carried out in the nearby of these ecosystems. The area of continental influence of the ALS has a great agricultural activity mainly due to the sugarcane plantations and its main tributaries, the Blanco and Papaloapan rivers, that cross several hundred kilometers of cultivation areas ending in this lagoon. Thus, the suspended material with large amounts of organic matter and a high probability of carrying adsorbed pesticides are finally stored in the lagoon sediments. On the other hand, the hydrodynamics of the TLS is contrasted since human activity in this area is more urban and industrial, and applying pesticides as vector control and to a lesser extent to the agricultural use. The TELS in the south of the GoM, has greater dimensions and a great interaction with the GoM in the replacement of its body of water, as well as a more estuarine environment due to the mixture with tributaries of the flow fluvial Grijalva-Usumacinta


**13**

0.99 ng g<sup>−</sup><sup>1</sup>

a value of 3.8 ng g<sup>−</sup><sup>1</sup>

**Figure 6.**

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

which can contribute with materials and energy to the lagoon system and likewise export to the GoM what can explain the low concentration of reported OC.

*Individual pattern of organochlorine pesticides in coastal lagoon sediments of three Mexican systems,* 

The diversity of OC reported for these three Mexican lagoon systems is presented in **Figure 6**, where 16 representative compounds of the three major chemical families were registered: alicyclic or Lindane group, aromatics or conglomerate of DDT and cyclodienes the most diverse group that includes the "Drines," Heptachlor and Endosulfan. The highest data corresponded to the ALS, the *p,p'*-DDE was

shows until that date of an old use of the insecticide. From the Lindane family, the delta-HCH isomer was found at a higher level in the TLS sediments of 2009 with

that application of this commercial tick due to the persistence of these isomers as a geochemical trace of its use on all livestock. Of the cyclodienes, there were records of a wide variety, in ALS were present Heptachlor and its epoxide and it was wor-

in Mexico since 1991 [45]; this same pesticide although to a lesser degree was also registered in TLS and in TELS, which shows the persistence of this organochlorine and probably recent illegal uses since in the ALS it was higher than that found in Dieldrin and Endrin. Endosulfan and its sulfate form were also recorded in the sediments analyzed in this study, without showing a clear trend; however, an incipient pattern in the degradation of the commercial mixture of Endosulfan can be seen

Because there are no maximum permissible limits for OC in coastal sediments in Mexico, it is important to consider the international sedimentary quality criteria that environmental agencies such as the NOAA of the United States of America have as the reference [46]. In this sense, the concentrations reported for lindane or the gamma-HCH isomer were higher than the threshold concentration or TEL by

for the coastal system TLS of 2009 and ALS of the same year and also in the first case was also greater than the criterion of probable alteration known as PEL of

, so it can be considered a scenario of real anthropogenic environmental

group there was record of *p,p'*-DDT in these sediments of ALS with 3 ng g<sup>−</sup><sup>1</sup>

and beta-HCH in ALS of 2 ng g<sup>−</sup><sup>1</sup>

and from this same

, which highlights the fact

 *dry weight.*

since it is a pesticide banned

to cause adverse effects to estuarine benthos

what

the pesticide with the highest concentration with 11.9 ng g<sup>−</sup><sup>1</sup>

*Tampamachoco, Alvarado and Terminos in the Gulf of Mexico. Values in ng g<sup>−</sup><sup>1</sup>*

rying the concentration found of Aldrin with 5 ng g<sup>−</sup><sup>1</sup>

due to a higher level of sulfate in the three lagoon ecosystems.

its acronym in English, of 0.32 ng g<sup>−</sup><sup>1</sup>

#### **Figure 5.**

*Total concentration of organochlorine pesticides (ΣOC) in coastal lagoon sediments of three Mexican systems, Tampamachoco, Alvarado and Terminos in the Gulf of Mexico. Values in ng g<sup>−</sup><sup>1</sup> dry weight.*

#### **Figure 6.**

*Lagoon Environments around the World - A Scientific Perspective*

basal values of Cd (0.22 μg g<sup>−</sup><sup>1</sup>

*3.2.3 Organochlorine pesticides (OC)*

with a value of 36.2 ng g<sup>−</sup><sup>1</sup>

year with 13.3 ng g<sup>−</sup><sup>1</sup>

stratum (1908) with surface maximums, the values of Ni and Pb are below the concentrations reported in Literature for other coastal and lacustrine systems. The

were also determined. From previous reports, becomes clear that the atmospheric transport is one of the main sources of Pb towards the lagoons, rivers, and oceans; and this is reflected in its levels in the sediments of the lagoons studied. For which it is recommended to analyze sedimentary nuclei and determine the origin of it. Also, the Ni detected in the studied lagoons, has a mixed origin: one part is of lithological origin and another part from the urban discharges through the particulate solids, as well as through the use of fertilizers and the mining industry and steel, and whose concentration surpasses the ELR and ERM values proposed by Long et al. [43] to the up to 100%, causing enrichment of the sedimentary substrate analyzed.

The data for organochlorine pesticides (OC) are presented in sediments of the lagoon systems considered in this study. The TLS has records of these agrotoxics of three practically continuous annual cycles (2009, 2010 and 2012), while the remaining ecosystem data correspond to a particular year; the values are given in ng g<sup>−</sup><sup>1</sup> dry weight. **Figure 5** shows the total data of the OC (ΣOC) reported in sediments of these coastal lagoons. For ALS the sediments evaluated in 2009 occupy the first place

ence between lagoon systems in the same coastal region of Mexico may be due to the local uses of these agrochemicals, as well as to the particular conditions of temporary runoff and large permanent flows and to the human activities carried out in the nearby of these ecosystems. The area of continental influence of the ALS has a great agricultural activity mainly due to the sugarcane plantations and its main tributaries, the Blanco and Papaloapan rivers, that cross several hundred kilometers of cultivation areas ending in this lagoon. Thus, the suspended material with large amounts of organic matter and a high probability of carrying adsorbed pesticides are finally stored in the lagoon sediments. On the other hand, the hydrodynamics of the TLS is contrasted since human activity in this area is more urban and industrial, and applying pesticides as vector control and to a lesser extent to the agricultural use. The TELS in the south of the GoM, has greater dimensions and a great interaction with the GoM in the replacement of its body of water, as well as a more estuarine environment due to the mixture with tributaries of the flow fluvial Grijalva-Usumacinta

*Total concentration of organochlorine pesticides (ΣOC) in coastal lagoon sediments of three Mexican systems,* 

*Tampamachoco, Alvarado and Terminos in the Gulf of Mexico. Values in ng g<sup>−</sup><sup>1</sup>*

decreasing to 4 ng g<sup>−</sup><sup>1</sup>

tion of organochlorines was for the TELS with 0.18 ng g<sup>−</sup><sup>1</sup>

), Ni (26 μg g<sup>−</sup><sup>1</sup>

[3] while in lower concentrations were TLS in the same

in 2012 and the lowest total concentra-

 *dry weight.*

[4]. This marked differ-

) and Pb (12 μg g<sup>−</sup><sup>1</sup>

)

), Cr (31 μg g<sup>−</sup><sup>1</sup>

**12**

**Figure 5.**

*Individual pattern of organochlorine pesticides in coastal lagoon sediments of three Mexican systems, Tampamachoco, Alvarado and Terminos in the Gulf of Mexico. Values in ng g<sup>−</sup><sup>1</sup> dry weight.*

which can contribute with materials and energy to the lagoon system and likewise export to the GoM what can explain the low concentration of reported OC.

The diversity of OC reported for these three Mexican lagoon systems is presented in **Figure 6**, where 16 representative compounds of the three major chemical families were registered: alicyclic or Lindane group, aromatics or conglomerate of DDT and cyclodienes the most diverse group that includes the "Drines," Heptachlor and Endosulfan. The highest data corresponded to the ALS, the *p,p'*-DDE was the pesticide with the highest concentration with 11.9 ng g<sup>−</sup><sup>1</sup> and from this same group there was record of *p,p'*-DDT in these sediments of ALS with 3 ng g<sup>−</sup><sup>1</sup> what shows until that date of an old use of the insecticide. From the Lindane family, the delta-HCH isomer was found at a higher level in the TLS sediments of 2009 with a value of 3.8 ng g<sup>−</sup><sup>1</sup> and beta-HCH in ALS of 2 ng g<sup>−</sup><sup>1</sup> , which highlights the fact that application of this commercial tick due to the persistence of these isomers as a geochemical trace of its use on all livestock. Of the cyclodienes, there were records of a wide variety, in ALS were present Heptachlor and its epoxide and it was worrying the concentration found of Aldrin with 5 ng g<sup>−</sup><sup>1</sup> since it is a pesticide banned in Mexico since 1991 [45]; this same pesticide although to a lesser degree was also registered in TLS and in TELS, which shows the persistence of this organochlorine and probably recent illegal uses since in the ALS it was higher than that found in Dieldrin and Endrin. Endosulfan and its sulfate form were also recorded in the sediments analyzed in this study, without showing a clear trend; however, an incipient pattern in the degradation of the commercial mixture of Endosulfan can be seen due to a higher level of sulfate in the three lagoon ecosystems.

Because there are no maximum permissible limits for OC in coastal sediments in Mexico, it is important to consider the international sedimentary quality criteria that environmental agencies such as the NOAA of the United States of America have as the reference [46]. In this sense, the concentrations reported for lindane or the gamma-HCH isomer were higher than the threshold concentration or TEL by its acronym in English, of 0.32 ng g<sup>−</sup><sup>1</sup> to cause adverse effects to estuarine benthos for the coastal system TLS of 2009 and ALS of the same year and also in the first case was also greater than the criterion of probable alteration known as PEL of 0.99 ng g<sup>−</sup><sup>1</sup> , so it can be considered a scenario of real anthropogenic environmental alteration and of potential risk to human health since various benthic organisms of these coastal sites are for food consumption [47]. Another similar case is that which occurs for *p,p'*-DDT since in the sediments of the ALS, it exceeded the biological damage threshold established in 1.19 ng/gas well as a second ecotoxicological criterion, the ERL was known as the level of effect low by its acronym in English that has a value of 1 ng g<sup>−</sup><sup>1</sup> ; of this aromatic family, the *p,p'*-DDE reported in this analysis was much higher than the environmental references TEL and ERL, that is, 2.07 and 2.2 ng g<sup>−</sup><sup>1</sup> respectively for what was reported in ALS, as has already been described, means that, in spite of the biogeochemical transformation of *p,p'*-DDT in *p,p'*-DDE, the benthic toxicity continues for this ecosystem that harbors several species of edible mollusks such as oysters and clams. It is worth mentioning the case of Dieldrin in the context of biotic damage since, despite not having presented large concentrations in the analyzed systems, its environmental reference concentrations are very low, evidencing the danger it has for organisms since from 0.02 ng g<sup>−</sup><sup>1</sup> can cause harmful effects (ERL) so, this risk already exists initially in the TLS since 2009.
