Evidence of oxidative stress responses of green turtles (Chelonia mydas) to differential habitat conditions in the Mexican Caribbean.

Important foraging and nesting habitats for Caribbean green sea turtles (Chelonia mydas) exist within the Mesoamerican Reef System in the Mexican Caribbean. During the last 25 years, urban development and touristic activities have drastically increased in Quintana Roo, Mexico. Moreover, in the last decade, massive pelagic sargasso blooms have also afflicted this region; however, information about the biochemical responses of Caribbean green turtles to these inputs is absent. This study aimed to assess if the oxidative stress indicators in the red blood cells of green turtles are valuable biomarkers of the extent of the anthropic impact in this region. Persistent organic pollutants (POPs) were also measured in the plasma of free-living green turtles during 2015-2018 to characterize these habitats further. As biochemical biomarkers, the production rate of superoxide radical (O2•-), carbonylated protein content, and lipid peroxidation (TBARS) levels, and the activities of superoxide dismutase, glutathione S-transferase (GST), catalase, glutathione peroxidase were measured in erythrocytes. A 15 % occurrence of fibropapillomatosis (FP) was revealed, with tumor size being positively correlated with CAT activity in the affected individuals. A multivariate analysis embracing all oxidative stress markers discriminated green turtles between years of capture (p < 0.001), with those sampled during 2015 presenting the highest production of O2•- (p = 0.001), activities of GST (p < 0.001), levels of TBARS (p < 0.001) and carbonylated proteins (p = 0.02). These local and temporal biochemical responses coincided with the first massive Sargassum spp. bloom reported in the region. The results of this study corroborate the utility of the oxidative stress indicators as biomarkers of environmental conditions (sargasso blooms and POPs) in the green turtle as sentinel species.

Plaguicidas en alimentos: riesgo a la salud y marco regulatorio en Veracruz, México / Pesticide residues in food: health risk and regulation in Veracruz, Mexico

Resumen: Objetivo: Evaluar el cumplimiento de los límites máximos permisibles de residuos de plaguicidas en alimentos del estado de Veracruz, así como evaluar el riesgo para la salud humana debido a su consumo. Material y métodos: Se midieron las concentraciones de residuos de plaguicidas en productos vegetales y se compararon con los valores establecidos como límites de seguridad en el marco regulatorio del uso de plaguicidas. Se calculó el cociente de peligro y sus posibles efectos a la salud. Resultados: El 14.8% de las muestras excedieron la concentración permitida. Se detectaron plaguicidas prohibidos (metamidofos, monocrotofos, triazofos y clorpirifos) que superaron las dosis de referencia establecidas, lo que pone en riesgo de sufrir posibles efectos a la salud del tipo neurológico, hepatotóxico y alteraciones endocrinas a la población. Conclusiones: Se encontraron residuos de plaguicidas altamente peligrosos en los alimentos, los cuales están prohibidos por los convenios internacionales ambientales derivado de su potencial para causar efectos a la salud y al medio ambiente, por lo cual es necesario su eliminación. El marco regulatorio de México debe actualizarse y ser dinámico conforme se avance en el conocimiento de los efectos adversos de los plaguicidas en la salud.

Abstract: Objective: Evaluate compliance with the maximum permissible limits for pesticide residues in food in the state of Veracruz, as well as the risk to human health due to its consumption. Materials and methods: The concentration of pesticide residues in plant products were measured for comparison with the values established as safety limits and the regulatory framework for the use of pesticides. The hazard quotient and its possible effect on health were calculated. Results: 14.8% of the samples exceeded the allowed concentration. We found banned pesticides (methamidophos, monochotophos, triazophos and chlorpyrifos) that exceeded the established references dose, which increase the risk of possible neurological, hepatotoxic and endocrine alterations in health. Conclusions: There is the presence of highly hazardous pesticides, which are prohibited by international environmental conventions due to their impact on health and the environment, which is why their elimination is necessary. The regulatory framework in Mexico must be updated and dynamic as the knowledge of the adverse health effects of pesticides advances.

[Pesticide residues in food: health risk and regulation in Veracruz, Mexico]. / Plaguicidas en alimentos: riesgo a la salud y marco regulatorio en Veracruz, México.

Objective. Evaluate compliance with the maximum permissible limits for pesticide residues in food in the state of Veracruz, as well as the risk to human health due to its consumption. Materials and methods. The concentration of pesticide residues in plant products were measured for comparison with the values established as safety limits and the regulatory framework for the use of pesticides. The hazard quotient and its possible effect on health were calculated. Results. 14.8% of the samples exceeded the allowed concentration. We found banned pesticides (methamidophos, monochotophos, triazophos and chlorpyrifos) that exceeded the established references dose, which increase the risk of possible neurological, hepatotoxic and endocrine alterations in health. Conclusions. There is the presence of highly hazardous pesticides, which are prohibited by international environmental conventions due to their impact on health and the environment, which is why their elimination is necessary. The regulatory framework in Mexico must be updated and dynamic as the knowledge of the adverse health effects of pesticides advances.

Para-occupational exposure to pesticides, PON1 polymorphisms and hypothyroxinemia during the first half of pregnancy in women living in a Mexican floricultural area.

BACKGROUND: Adequate maternal thyroxine (T4) concentrations during the first half of pregnancy are fundamental to the embryo's or fetus' neural development. Organophosphate pesticides (OP) can act as thyroid disruptors and genetic polymorphisms for paraoxonase 1 (PON1), an enzyme that detoxifies OP, could be involved in individual's susceptibility to them. We assessed the association between para-occupational exposure to pesticides, including OP, during pregnancy and maternal hypothyroxinemia, as well as the potential genetic susceptibility conferred by PON1 polymorphisms. METHODS: We analyzed information from 381 healthy pregnant women (< 17 gestational weeks), who lived in a floricultural region of Mexico where pesticides, including OP, are routinely used. Women who were para-occupationally exposed to pesticides were those whose partner had an occupation involving contact with these products. Thyroid-Stimulating Hormone (TSH) and free T4 concentrations were determined using ELISA, and hypothyroxinemia was defined as free T4 concentrations <0.76 ng/dL. PON1192QR, PON155LM and PON1-108CT polymorphisms were determined through Polymerase Chain Reaction (PCR). The association between para-occupational exposure and genetic polymorphisms and hypothyroxinemia was estimated using logistic regression models. RESULTS: One hundred and sixty two women (42.52%) were classified as para-occupationally exposed to pesticides. Hypothyroxinemia prevalence was 54%, and it was not significantly associated with pesticide para-occupational exposure (OR: 1.21 95% CI 0.75-1.94). Independently of para-occupational exposure, the likelihood of hypothyroxinemia was higher among women who were carriers of PON155MM than in those with PON155LL genotype (OR MM vs LL: 3.03; 95%CI 1.62, 5.70). PON1192 RR (OR RR vs QQ: 1.72; 95%CI 0.93, 3.17) and PON1-108TT (OR TT vs CC: 1.60; 95%CI 0.90, 2.70) genotypes were marginally associated with hypothyroxinemia. No significant interaction was observed between pesticides para-occupational exposure and PON1 polymorphisms. CONCLUSIONS: These results suggest that PON1 polymorphisms could affect thyroid function during pregnancy in women living in areas where pesticides, including OP, are routinely used. Low exposure variability in this population, could be a possible explanation for the lack of association between para-occupational exposure and thyroid function.

Relationship Between Paraoxonase-1 and Butyrylcholinesterase Activities and Nutritional Status in Mexican Children.

BACKGROUND: The enzymes butyrylcholinesterase (BuChE) and paraoxonase-1 (PON1) are the primary bioscavenging enzymes in serum and exhibit antioxidant and anti-inflammatory activities. PON1 has been associated with diseases caused by high oxidative stress, whereas BuChE appears to be involved in the pathophysiology of the metabolic syndrome and related disorders. It has been suggested that children from rural communities in Mexico may have a predisposition to develop obesity or type 2 diabetes during adolescence or adulthood. The objective of this study was to determine whether associations exist between the paraoxonase (PONase)/arylesterase (AREase) activity of PON1, its PON1-Q192R and PON1-L55M polymorphisms, and BuChE activity with the nutritional status and lipid profiles in a group of children from rural communities in Mexico. METHODS: A group of 97 boys and girls from a rural community in Mexico were assessed for body mass index, the enzymatic activities of BuChE, PONase, and AREase were measured in serum, and their lipid profiles were determined. Genetic polymorphisms of PON1-L55M and PON1-Q192R were determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). RESULTS: The children were classified into four groups: thinness, normal weight, overweight, and obese. Of the children studied, 34.4% were overweight and obese. The mean age of the participants was 9.5 years (standard deviation = 1.8). The L allele of the PON1-L55M genotype was the most frequent (83.3%), and the R allele of the PON1-Q192R genotype was the most frequent (61.8%). Overweight and obese children had higher values of BuChE, total cholesterol, triglycerides (TG), and lower high-density lipoprotein (HDL-C) values than children with thinness or normal weight (P = 0.028, P = 0.019, P = 0.004, P = 0.069 and P = 0.021, respectively). The levels of AREase and PONase and the prevalence of PON1-L55M and PON1-Q192R genotypes were similar between groups (P = 0.484 and P = 0.380, respectively). CONCLUSIONS: This study establishes a positive association of BuChE activity with nutritional status and serum TG.

DNA damage in Mexican children living in high-risk contaminated scenarios.

The aim of this study was to evaluate the deoxyribonucleic acid (DNA) damage (as a biomarker of biological effects) in children living in areas at high risk of contamination in Mexico using the comet assay. The alkaline comet assay was performed in order to assess DNA damage levels in blood cells of 276 children living in eleven communities in four states of Mexico. Moreover, levels of arsenic and 1-hydroxypyrene (1-OHP) in urine and lead and total DDT [sum of 1,1-dichloro-2,2-bis(p-chlorophenyl) ethylene (DDE) and 1,1-bis(p-chlorophenyl)-2,2,2-trichloroethane (DDT)] in blood were quantified. We found urinary 1-OHP levels between

Assessment of exposure to organochlorine pesticides and levels of DNA damage in mother-infant pairs of an agrarian community.

Exposure to organochlorine pesticides was studied in a group of mother-infant pairs living in a rural area where agriculture is the main economic activity. Fumigation in this zone is performed with airplanes, thus affecting the inhabited areas around them, including schools. Heparinized venous blood of mothers and umbilical cords was used to evaluate the olive tail moment in the comet assay, and micronuclei, chromatin buds, and nucleoplasmic bridges in peripheral blood lymphocytes. Cord blood samples were taken at the moment of birth only from natural and normal parturitions. Determinations of hexachlorobenzene, aldrin, heptachlor epoxide, oxichlordane, t and c-chlordane, cis-nonachlor, mirex, alpha and beta-endosulfan, alpha, beta and gamma hexachlorocyclohexane, and p'p'-DDT, p'p'-DDE were conducted to establish the differential distribution of the toxicants between compartments, i.e., mother and umbilical cord. Significantly higher pesticide levels were found in umbilical cord plasma than in mothers' plasma for almost all compounds tested, except DDE and oxychlordane. Significantly higher olive tail moments were found in umbilical cords than in mothers, whereas micronuclei frequencies were higher in mothers than in umbilical cords. However, neither the levels of micronuclei nor the olive tail moment were correlated with pesticide levels. Given that no other exposure to toxic compounds has been identified in this region, the lack of correlation between genotoxicity biomarkers and pesticide levels may be due to the variability of the exposure and to endogenous processes related to lipid mobility during pregnancy, the metabolism of the compounds, and individual susceptibilities.

Exposure assessment of organochlorine pesticides, arsenic, and lead in children from the major agricultural areas in Sonora, Mexico.

There is a lack of information of exposure to organochlorine pesticides (OCP) and some metals, such as lead (Pb) and arsenic (As), both of which were used as arsenicals pesticides, in children living in the major agricultural areas of Mexico. The objective of this study was to assess the exposure of children to different OCP, As, and Pb in the Yaqui and Mayo valleys of Sonora to generate population baseline levels of these toxins. A cross-sectional study was undertaken in 165 children (age 6-12 years old) from 10 communities from both valleys during 2009. Blood samples were analyzed for OCP and Pb and first morning void urine for inorganic As (InAs). All of the blood samples had detectable levels of dichlorodiphenyltrichloroethylene (p,p'-DDE) ranging from 0.25 to 10.3 µg/L. However lindane, dichlorodiphenyltrichloroethane (p,p'-DDT), aldrin, and endosulfan were detected in far less of the population (36.4, 23.6, 9.1, and 3 %, respectively). Methoxychlor and endrin were not found in any sample. The average value of Pb in this population was 3.2 µg Pb/dL (range 0.17-9.0) with 8.5 % of the samples having levels <5.0 µg Pb/dL. Urinary As levels ranged from 5.4 to 199 µg As/L with an average value of 31.0 µg As/L. Levels > 50 µg/L were observed in 12.7 % of the samples. Our results show that is important to start a risk-reduction program to decrease exposure to these toxins in Mexican communities. In addition, the results can be used to establish the baseline levels of exposure to these toxins in this agricultural region and may be used as a reference point for regulatory agencies.

Assessment of DDT levels in selected environmental media and biological samples from Mexico and Central America.

Taking into account the environmental persistence and the toxicity of DDT, the Pan American Health Organization (PAHO) organized a surveillance program in Mesoamerica which included the detection of residual DDT in environmental (soil) and biological samples (fish tissue and children's blood). This program was carried out in communities from Mexico, Guatemala, El Salvador, Honduras, Nicaragua, Costa Rica and Panama. This paper presents the first report of that program. As expected, the results show that the levels for [summation operator] DDT in soil (outdoor or indoor) and fish samples in the majority of the locations studied are below guidelines. However, in some locations, we found children with high concentrations of DDT as in Mexico (mean level 50.2 ng/mL). Furthermore, in some communities and for some matrices, the DDT/DDE quotient is higher than one and this may reflect a recent DDT exposure. Therefore, more efforts are needed to avoid exposure and to prevent the reintroduction of DDT into the region. In this regard it is important to know that under the surveillance of PAHO and with the support of UNEP, a regional program in Mesoamerica for the collection and disposal of DDT and other POPs stockpiles is in progress.

Determinación de los niveles de DDT, DDE y DDE-MESO2 en leche materna y sangre de poblaciones contaminadas por DDT en México / DDT, DDE and DDE-MeSO2 levels in maternal milk and blood serum from DDT exposed populations in Mexico

Se determinaron los niveles de DDE-MeSO2, DDT y DDE en 51 muestras de leche materna y en 40 muestras de sangre venosa de mujeres que viven en zonas donde el DDT se aplicó para el control de la malaria. Las concentraciones de los tres compuestos en leche materna en las diferentes comunidades fueron: El Ramonal 2.8 ng/glípido, 911 ng/glípido, 3100 ng/glípido; La Cigüeña 1.2 ng/glípido,134 ng/glípido, 764 ng/glípido; Tapachula 0.5 ng/glípido, 17 ng/glípido, 683 ng/glípido; la Huasteca 1.4 ng/glípido, 46 ng/glípido,490 ng/glípido; y Faja de Oro 0.4 ng/glípido, 18 ng/glípido, 268 ng/glípido. Las concentraciones encontradas de DDE-MeSO2 enEl Ramonal son siete veces mayores a las reportadas en Suecia en 1992 (0.4 ng/glípido). Los niveles de exposición a los 3 compuestos en sangre venosa fueron: Lacanjá 64 ng/glípido, 1323 ng/glípido, 3738 ng/glípido; El Ramonal 20 ng/glípido, 748 ng/glípido, 1271 ng/glípido; La Cigüeña 66 ng/glípido, 424 ng/glípido, 1059 ng/glípido; y Ventanilla 43 ng/glípido, 335 ng/glípido,1362 ng/glípido; de DDE-MeSO2, DDT y DDE respectivamente. Las comunidades de Lacanjá y La Cigüeña presentaron los mayores niveles de exposición al DDE-MeSO2, que comparados con los reportes de Eslovaquia son nueve veces mayor (7.3 ng/glípido).

The levels of the DDE-MeSO2, DDT andDDE were determined in 51 breast milk samples and in 40 blood samples from women living in endemic areas of malaria. The concentrations of the three compounds in maternal milk were: El Ramonal 2.8 ng/glipid, 911 ng/glipid, 3100 ng/glipid; La Cigueña 1.2 ng/glipid, 134 ng/glipid, 764 ng/glipid; Tapachula 0.5 ng/glipid, 17 ng/glipid, 683 ng/glipid; Huasteca 1.4 ng/glipid,46 ng/glipid, 490 ng/glipid; and Faja de Oro 0.4 ng/glipid, 18 ng/glipid, 268 ng/glipid. The concentrations of DDE-MeSO2 found in El Ramonal were seven times higher than those reported in Sweden in 1992 (0.4 ng/glipid). In blood the levels of the threecompounds were: Lacanjá 64 ng/glipid, 1323 ng/glipid, 3738 ng/glipid; El Ramonal 20 ng/glipid, 748 ng/glipid, 1271 ng/glipid; La Cigueña 66 ng/glipid, 424 ng/glipid, 1059 ng/glipid; and Ventanilla 43 ng/glipid, 335 ng/glipid, 1362 ng/glipid. The concentrations of DDE-MeSO2 in Lacanjá and La Cigueña were nine times than those reported in Slovakia (7.3 ng/glipid).