The fluvial–lagoon–deltaic system of the Palizada River in Campeche is an ecosystem of socioeconomic and ecological importance. It is justifiable to carry out studies in this system due to its connection with another larger ecosystem called the Términos Lagoon. The objective of this investigation was to analyze the concentration of Pb and Cd in sediments of the fluvial–lagoon–deltaic system of the Palizada River and to determine, with this, the contamination index of these metals. Cd showed the highest concentration in sampling sites and climatic seasons with respect to Pb, with a maximum value of 53.9 ± 5.0, while the Pb concentration was 10.4 ± 0.2 μg∙g⁻¹. The same tendency was present with pollution and geoaccumulation indexes; here, the Cd index stands out. The enrichment of heavy metals was identified through the accumulation of Cd and Pb; such a process was evaluated through the geoacumulation index (Igeo). The results of this indicated that the contamination of these elements is mainly of anthropogenic origin. This element represents an ecological toxic risk due to the chronic presence of heavy metals in a priority area for the conservation of aquatic and terrestrial biota such as the Palizada system, owing to its high toxicity even at low concentrations. Thus, it is important to evaluate its sublethal effects in the organisms that inhabit this system, which requires the implementation of integral monitoring.

Organochlorine pesticides are used in agricultural areas and health campaigns, which reach the coastal environment through rivers, drains, runoffs, and atmospheric transport. In aquatic environments, they are adsorbed by particles of organic matter, depositing themselves in sediments in the bottom of these bodies, in which benthic organisms of commercial interest for human consumption inhabit. The objective of this research was to evaluate the concentration of organochlorine pesticides in sediment from the Alvarado lagoon system in Veracruz, Mexico. In 20 out of 41 sampling sites analyzed, 11 banned organochlorine pesticides were identified, such as hexachlorocyclohexane (HCH), lindane, aldrin, dieldrin, and endrin. The highest concentrations were as follows: aldrin: 46.05 ng g⁻¹; β-HCH: 42.11 ng g⁻¹; α-HCH: 38.44 ng g⁻¹; gamma γ-HCH (lindane): 34.20 ng g⁻¹; δ-HCH: 31.61 ng g⁻¹; methoxychlor: 29.40 ng g⁻¹; heptachlor epoxide: 25.70 ng g⁻¹; heptachlor: 24.11 ng g⁻¹; dieldrin: 22.13 ng g⁻¹; endrin: 21.23 ng g⁻¹; endrin aldehyde: 12.40 ng g⁻¹. Concentrations reported are prohibited in international standards. There is a strong need to further evaluate, with scientific studies, the level of concentration reported by impact of compounds widely used in agricultural livestock activities.

Cd, Cu, Hg and Pb, and Organochlorines Pesticides in Commercially Important Benthic Organisms Coastal Lagoons SW Gulf of Mexico

The presence of macroplastics in the marine ecosystem is one of the most serious types of pollution today. On the seabed of reef ecosystems, macroplastics are an indicator of contamination because they are easily observable due to their size greater than 2.5 cm. When these wastes sink, they cause serious damage, such as physical changes to the seabed, entanglement, ingestion and transport of invasive species, and can serve as vectors for other pollutants. The main types of macroplastics found in this research work correspond to 57% fishing gear, 14% plastic fragments and 9% textiles. Most of the macroplastics were located in the Veracruz reef subsystem, in the Gallega, Anegada de adentro, Ingenieros, Pájaros and Hornos reefs; In the Antón Li-zardo reef subsystem, macroplastics were found in the Anegadilla reef and in the middle. In reference to the concentration of macroplastics at the bottom of the PNSAV, it is possible to point out that the higher the density of the material with respect to seawater, the economic activities carried out near the reefs have a greater influence, both in the distribution and in the classification of macroplastics, compared to the hydrodynamics. Finally, with all these elements, a theoretical model of distribution and concentration of macroplastics in reef bottoms is proposed.

The present work analyzes the current situation of scientific research on heavy metals and current regulations in macroinvertebrates (Penaeus) from the coastal region of the Gulf of Mexico. Its association with public health was identified based on national and international permissible limits for this fishery resource. The research analysis identified a high percentage of studies that report concentrations within the permissible limits established by the Mexican Official Standards and European regulations, reflecting a high percentage of consumption of this fishery resource that does not represent a risk to public health. However, specific cases exceeded national and international concentration limits, which justifies the importance of monitoring this fishery resource with emphasis on compliance with current regulations, supporting the need to redefine regulatory policies to address the current situation. Likewise, it is important to quantify these metals in a homogeneous, systematic, and continuous way to contrast the different studies on macroinvertebrates as environmental health bioindicator organisms and to know the distribution of these pollutants in the ecosystems inhabited by this important fishery resource.