Spatial and Temporal Variability of Trace and Macro Elements in the Red Crab Pleuroncodes planipes in the Pacific Coast of the Baja California Peninsula, Mexico.

The red crab, Pleuroncodes planipes, is a decapod crustacean abundant off the Pacific coast of the Baja California Peninsula. This species is caught and used in preparing animal feed, such as flour, particularly for aquaculture. Levels of calcium (Ca), cadmium (Cd), copper (Cu), iron (Fe), lead (Pb), magnesium (Mg), manganese (Mn), nickel (Ni), phosphorus (P), and zinc (Zn) were measured in red crabs collected from three geographic zones during three cruises in different seasons. Significant differences were found in the levels of Ca, Cd, Cu, Fe, Mg, Ni, P, and Zn between the two El Niño years (cruises C1 and C3, based on a threshold of ±0.5 °C for the Oceanic Niño Index). The highest concentrations of most elements were observed in the south of the Baja California Peninsula, a highly productive area influenced by upwelling events. Our findings suggest that while environmental temperature plays a central role in the benthic or pelagic distribution of red crabs, their content and variability of trace and macro elements appear to be associated with the presence of oceanic conditions, such as upwelling and potential changes in the composition of their diet associated with the depth in which these crustaceans are collected.

Oxidative damage to proteins related to metals and antioxidant defenses in breastmilk.

INTRODUCTION: Breast milk contains molecules needed for the development of children; the integrity and function of these molecules is affected by the presence of pro-oxidants. Protein carbonyls are mainly produced as a result of the interaction of metals with reactive oxygen species (ROS), which may initiate a chain reaction that promotes molecular oxidation. OBJECTIVE: This study aimed to determine the association between the concentration of protein carbonyls with the concentration of trace elements (lead [Pb], cadmium [Cd] and selenium [Se]), superoxide radical (O2•-) production, and glutathione (GSH) content, as well with the activity of the main antioxidant enzymes (superoxide dismutase [SOD], catalase [CAT], glutathione peroxidase [GPx], glutathione reductase [GR] and glutathione S-transferase [GST]) in breast milk. METHODS: In this study 108 transitional milk samples (7-10 days) were analyzed. Antioxidant enzyme activities, O2•-production, protein carbonyl and GSH concentrations were analyzed by spectrophotometry. Trace element concentration was quantified by atomic absorption spectrophotometry. Generalized linear modelling was used to assess the relationship between protein carbonyls concentration with oxidative stress indicators and trace elements concentration. RESULTS: Cd and Pb were detected in 21.3 and 55.6% of breast milk samples, respectively. The median concentration of Cd was 0.01 µg L-1 (0.01-3.52 µg L-1) and Pb concentration was 2.61 µg L-1 (0.08-195.20 µg L-1). According to the best-fit model, the main factors contributing to protein carbonyl concentrations were the activity of GPx, GR, and concentration of GSH, Se, Pb and Cd. CONCLUSIONS: According to the generalized linear model, the activity of GPx and GR, could help explain protein oxidation induced by Pb and Cd in breast milk.

Oxidative damage to proteins related to metals and antioxidant defenses in breastmilk / Daño oxidativo a las proteínas relacionado con metales y defensas antioxidantes en la leche materna

Introduction: Breast milk contains molecules needed for the development of children; the integrity and function of these molecules is affected by the presence of pro-oxidants. Protein carbonyls are mainly produced as a result of the interaction of metals with reactive oxygen species (ROS), which may initiate a chain reaction that promotes molecular oxidation. Objective: This study aimed to determine the association between the concentration of protein carbonyls with the concentration of trace elements (lead [Pb], cadmium [Cd] and selenium [Se]), superoxide radical (O2 •-) production, and glutathione (GSH) content, as well with the activity of the main antioxidant enzymes (superoxide dismutase [SOD], catalase [CAT], glutathione peroxidase [GPx], glutathione reductase [GR] and glutathione S-transferase [GST]) in breast milk. Methods: In this study 108 transitional milk samples (7-10 days) were analyzed. Antioxidant enzyme activities, O2 •- production, protein carbonyl and GSH concentrations were analyzed by spectrophotometry. Trace element concentration was quantified by atomic absorption spectrophotometry. Generalized linear modelling was used to assess the relationship between protein carbonyls concentration with oxidative stress indicators and trace elements concentration. Results: Cd and Pb were detected in 21.3 and 55.6% of breast milk samples, respectively. The median concentration of Cd was 0.01 μg L-1 (0.01-3.52 μg L-1) and Pb concentration was 2.61 μg L-1 (0.08-195.20 μg L-1). According to the best-fi t model, the main factors contributing to protein carbonyl concentrations were the activity of GPx, GR, and concentration of GSH, Se, Pb and Cd. Conclusions: According to the generalized linear model, the activity of GPx and GR, could help explain protein oxidation induced by Pb and Cd in breast milk (AU)

Introducción: la leche materna contiene las moléculas necesarias para el desarrollo de los niños; la integridad y función de estas moléculas se afecta por la presencia de prooxidantes. Los carbonilos proteicos se producen principalmente como resultado de la interacción de metales con especies reactivas de oxígeno (ERO), los cuales pueden iniciar una reacción en cadena que promueve la oxidación molecular. Objetivo: este estudio tiene como objetivo determinar la asociación entre la concentración de carbonilos proteicos con la concentración de elementos traza (plomo [Pb], cadmio [Cd] y selenio [Se]), producción de radical superóxido (O2 •-), y contenido de glutatión (GSH), así como con la actividad de las principales enzimas (superóxido dismutasa [SOD], catalasa [CAT], glutatión peroxidasa [GPx], glutatión reductasa [GR] y glutatión S-transferasa [GST]) en leche materna. Métodos: en este estudio se analizaron 108 muestras de leche de transición (7-10 días). La actividad de las enzimas antioxidantes, producción de O2 •-, concentración de carbonilos proteicos y GSH se analizaron por espectrofotometría. La concentración de elementos traza se cuantificó por espectrometría de absorción atómica. Se utilizó un modelo lineal generalizado para evaluar la relación entre la concentración de carbonilos proteicos con los indicadores de estrés oxidativo y las concentraciones de elementos traza. Resultados: Cd y Pb fueron detectados en 21,3 y 55,6% de las muestras de leche materna, respectivamente. La mediana de la concentración de Cd fue 0,01 μg l-1 (0,01-3,52 μg l-1) y para la concentración de Pb fue 2,61 μg l-1 (0,08-195,20 μg l-1). De acuerdo con el modelo de mejor ajuste, los principales factores de afectan la concentración de carbonilos proteicos, son la actividad de GPx y GR, y las concentraciones de GSH, Se, Pb y Cd. Conclusiones: de acuerdo con el modelo lineal generalizado, la actividad de GPx y GR podría ayudar a explicar la oxidación proteica, inducida por Pb y Cd en leche materna (AU)

Interaction between mercury (Hg), arsenic (As) and selenium (Se) affects the activity of glutathione S-transferase in breast milk; possible relationship with fish and sellfish intake.

Breast milk is regarded as an ideal source of nutrients for the growth and development of neonates, but it can also be a potential source of pollutants. Mothers can be exposed to different contaminants as a result of their lifestyle and environmental pollution. Mercury (Hg) and arsenic (As) could adversely affect the development of fetal and neonatal nervous system. Some fish and shellfish are rich in selenium (Se), an essential trace element that forms part of several enzymes related to the detoxification process, including glutathione S-transferase (GST). The goal of this study was to determine the interaction between Hg, As and Se and analyze its effect on the activity of GST in breast milk. Milk samples were collected from women between day 7 and 10 postpartum. The GST activity was determined spectrophotometrically; total Hg, As and Se concentrations were measured by atomic absorption spectrometry. To explain the possible association of Hg, As and Se concentrations with GST activity in breast milk, generalized linear models were constructed. The model explained 44% of the GST activity measured in breast milk. The GLM suggests that GST activity was positively correlated with Hg, As and Se concentrations. The activity of the enzyme was also explained by the frequency of consumption of marine fish and shellfish in the diet of the breastfeeding women.

La leche materna es considerada como una fuente ideal de nutrientes para el crecimiento y el desarrollo de los recién nacidos, pero también puede ser una fuente potencial de contaminantes. Las madres pueden estar expuestas a diversos contaminantes como resultado de su estilo de vida y de la contaminación ambiental. Mercurio (Hg) y arsénico (As) pueden afectar negativamente el desarrollo del sistema nervioso fetal y neonatal. Algunos peces y mariscos son ricos en selenio (Se), un oligoelemento esencial que forma parte de diversas enzimas relacionadas con el proceso de desintoxicación, incluyendo glutatión S-transferasa (GST). El objetivo de este estudio fue determinar la interacción entre Hg, As y Se, así como analizar su efecto sobre la actividad de GST en la leche materna. Muestras de leche materna fueron obtenidas entre los días 7 y 10 después del parto. La actividad de la GST fue determinada espectrofotométricamente. Las concentraciones totales de Hg, As y Se fueron medidas por espectrometría de absorción atómica. Para explicar la posible asociación de las concentraciones de Hg, As y Se con la actividad de la GST en la leche materna, se construyeron modelos lineales generalizados. El modelo explicó el 44% de la actividad de GST medida en leche materna. El MLG sugiere que la actividad de GST se correlacionó positivamente con las concentraciones de Hg, As y Se. La actividad de la enzima se explica también por la frecuencia de consumo de peces marinos y mariscos en la dieta de las mujeres que se encuentran en periodo de lactancia.

Interaction between mercury (Hg), arsenic (As) and selenium (Se) affects the activity of glutathione S-transferase in breast milk; possible relationship with fish and shellfish intake / Efecto de la interacción entre mercurio (hg), arsénico (as) y selenio (se) en la actividad de glutatión s-transferasa en leche materna; potencial relación con el consumo de pescados y mariscos

Breast milk is regarded as an ideal source of nutrients for the growth and development of neonates, but it can also be a potential source of pollutants. Mothers can be exposed to different contaminants as a result of their lifestyle and environmental pollution. Mercury (Hg) and arsenic (As) could adversely affect the development of fetal and neonatal nervous system. Some fish and shellfish are rich in selenium (Se), an essential trace element that forms part of several enzymes related to the detoxification process, including glutathione S-transferase (GST). The goal of this study was to determine the interaction between Hg, As and Se and analyze its effect on the activity of GST in breast milk. Milk samples were collected from women between day 7 and 10 postpartum. The GST activity was determined spectrophotometrically; total Hg, As and Se concentrations were measured by atomic absorption spectrometry. To explain the possible association of Hg, As and Se concentrations with GST activity in breast milk, generalized linear models were constructed. The model explained 44% of the GST activity measured in breast milk. The GLM suggests that GST activity was positively correlated with Hg, As and Se concentrations. The activity of the enzyme was also explained by the frequency of consumption of marine fish and shellfish in the diet of the breastfeeding women (AU)

La leche materna es considerada como una fuente ideal de nutrientes para el crecimiento y el desarrollo de los recién nacidos, pero también puede ser una fuente potencial de contaminantes. Las madres pueden estar expuestas a diversos contaminantes como resultado de su estilo de vida y de la contaminación ambiental. Mercurio (Hg) y arsénico (As) pueden afectar negativamente el desarrollo del sistema nervioso fetal y neonatal. Algunos peces y mariscos son ricos en selenio (Se), un oligoelemento esencial que forma parte de diversas enzimas relacionadas con el proceso de desintoxicación, incluyendo glutatión S-transferasa (GST). El objetivo de este estudio fue determinar la interacción entre Hg, As y Se, así como analizar su efecto sobre la actividad de GST en la leche materna. Muestras de leche materna fueron obtenidas entre los días 7 y 10 después del parto. La actividad de la GST fue determinada espectrofotométricamente. Las concentraciones totales de Hg, As y Se fueron medidas por espectrometría de absorción atómica. Para explicar la posible asociación de las concentraciones de Hg, As y Se con la actividad de la GST en la leche materna, se construyeron modelos lineales generalizados. El modelo explicó el 44% de la actividad de GST medida en leche materna. El MLG sugiere que la actividad de GST se correlacionó positivamente con las concentraciones de Hg, As y Se. La actividad de la enzima se explica también por la frecuencia de consumo de peces marinos y mariscos en la dieta de las mujeres que se encuentran en periodo de lactancia (AU)

Concentraciones de mercurio en leche de mujeres del noroeste de México; posible asociación a la dieta, tabaco y otros factores maternos / Mercury concentration in breast milk of women from Northwest Mexico; possible association with diet, tabaco and other maternal factors

Objetivo: Determinar los niveles de mercurio total (THg) en leche de mujeres del Noroeste de México y su posible asociación con factores maternos, la dieta y el tabaco. Método: El estudio se realizó en leches donadas por 108 mujeres de Baja California Sur. Se estratificaron en tres grupos de 36 donantes según el número de gesta. Se exploraron datos generales, hábito tabáquico, exposición al humo de tabaco ambiental, ingesta de mariscos y pescados. Los niveles de THg fueron cuantificados utilizando espectrofotometría de absorción atómica. La diferencia entres grupos se evaluó con estadística no paramétrica. Para explicar la posible asociación de las diferentes variables estudiadas y las concentraciones de THg en la leche, se realizaron modelos lineales generalizados. Resultados: Los niveles de THg fueron desde 1.23 ?g/L en las primigestas (GI) a 2,96 ?g/L para las mujeres con 3 o más gestas (GIII) (p = 0,07). En el grupo de GI encontramos una concentración del THg 175% mayor (p = 0,02) entre las mujeres que no comen pescado, en comparación con las que si comen pescado. En el modelo lineal generalizado ajustado por las concentraciones de THg, las variables fueron: edad, número de embarazos, duración de la lactancia y exposición al tabaco (p =?0,05). Conclusiones: El consumo de pescado fue el factor que mejor ajustó los modelos en relación a los niveles de THg. El aporte de Hg por la dieta que se pudo asociar fue bajo, por lo que el consumo de pescado de las costas de Baja California Sur es seguro. El tabaco, incrementa las concentraciones de Hg en la leche materna, por lo que debe de limitarse su hábito durante el embarazo y la lactancia (AU)

OBJECTIVE: To determine THg levels in milk of women from Northwest Mexico and its potential association with maternal factors such as diet and tobacco smoke. METHOD: The study was performed in 108 milk samples donated by women in Baja California Sur. Data were stratified into three groups of 36 donors by number of pregnancies. General data, smoking, exposure to environmental tobacco smoke and seafood intake were explored. THg levels were measured using atomic absorption spectrophotometry. The difference between groups was evaluated with non-parametric statistics. To explain the possible association of the different variables with THg concentrations in milk, generalized linear models were performed. RESULTS: THg levels ranged from 1.23 μg/L in single-pregnancy women (GI) to 2.96 μg/L for women with 3 or more pregnancies (GIII) (p = 0.07). In the GI group THg concentration was 175% higher (p = 0.02) in women who do not eat fish, compared to those who eat fish. In the generalized linear model to adjust THg concentrations, the variables were: age, number of pregnancies, breastfeeding duration and exposure to tobacco smoke (p ≤ 0.05).CONCLUSIONS: Fish consumption was the factor that better adjusted models, relative to THg levels. The contribution associated to this factor was low; therefore, consumption of fish from the coast of Baja California Sur is safe. Tobacco increased Hg concentrations in breast milk; it is necessary to avoid the smoking habit during pregnancy and breast-feeding (AU)

Assessment of metallothioneins in tissues of the clam Megapitaria squalida as biomarkers for environmental cadmium pollution from areas enriched in phosphorite.

The aim of this study was to evaluate the use of metallothionein (MT) concentrations in tissues of the clam Megapitaria squalida as biomarkers of environmental cadmium (Cd) pollution from phosphorite enrichments in the marine environment, which resulted from mining activities in La Paz Bay, Baja California Sur, Mexico. Cd and MT were quantified in gills, digestive gland, and kidney of clams exposed to 0.2 or 0.5 mg Cd l(-1) for 10, 20, or 30 days. In addition, clams from four strategically selected natural sites of La Paz Bay were collected for analysis. In tissues of bioassayed and untreated clams, the gradient of Cd concentrations was digestive gland>>gills>kidney, whereas that of MT was digestive gland>gills>kidney. Digestive gland of the clams exposed to 0.5 mg Cd l(-1) for 30 days showed the highest concentrations of Cd (16.3+/-3.9 microg Cd g(-1)). The highest statistically significant MT concentrations were found in digestive gland at 10 days of exposure to Cd. In the untreated clams, one of the highest Cd concentrations, but not MT levels, was found in digestive glands of the organisms collected from the area close to phosphorite mining activities. For environmental monitoring, MT levels in digestive gland can be used as a first approximation of the presence of high levels of divalent metals in the environment. However, in this study, MT levels did not correlate with high Cd levels in clams that had been collected from areas associated with phosphorite enrichment.

Heavy metal levels in marine mollusks from areas with, or without, mining activities along the Gulf of California, Mexico.

To assess the safety for human consumption of commercially important bivalves harvested from areas with or without mining activities, we compared the levels of heavy metals in mollusks collected from different coastal environments along the Gulf of California. We sampled the mussel Mytilus edulis and the clams Laevicardium elatum and Megapitaria squalida (June 2004) and the clam Chione californiensis (November 2006). Concentrations of cadmium, lead, nickel, zinc, iron, copper, and manganese in the soft tissue of the mollusks were measured by atomic absorption spectrophotometry. Based on dry weight, the highest average concentrations of iron, copper, and cadmium were found in clams from Loreto (572, 181, and 4.66 mg/kg, respectively); that of nickel, in mussels from San Luquitas (12.2 mg/kg); that of zinc, both in mussels from San Luquitas and in clams from Golfo de Santa Clara (94.3 and 91.8 mg/kg, respectively); and those of lead and manganese in clams from the Golfo de Santa Clara (9.2 and 3.68 mg/kg, respectively). Although mollusks were taken from coastal areas of the Gulf of California, which are considered to be contaminated by mining activities, the heavy metals in the sediments apparently were in a chemical form that had low bioavailability for the bivalves feeding in those areas. The interplay of oceanographic conditions and the chemical composition of anthropogenic inputs into the environment is not well understood. Thus, these factors or their interaction could potentially result in increased concentration and bioavailability of such metals in areas without effluent generated by mining activities.

Metal profiles used as environmental markers of green turtle (Chelonia mydas) foraging resources.

The Baja California Peninsula, Mexico serves an important role for feeding and developing sea turtles. High concentrations of metals detected in green turtles (Chelonia mydas) from Magdalena Bay prompted an investigation into the sources of metals in the region. We compared metal concentrations in sea turtle tissues with plant species found in their stomach contents, and with the same species of plants collected inside a sea turtle refuge area known as Estero Banderitas. Differences in the metal concentrations between marine plant species were minimal. Principal components analysis of the percent contribution of individual metals to the overall metal signature of each plant or tissue sample generated three principal components that explained 80.7% of the total variance in the data. The plant samples collected within Estero Banderitas formed a separate grouping from the green turtle tissue samples and the plants from the stomach contents. The plants in the stomach contents contained greater percent contributions of Cd and Zn than the plants collected inside the bay, while Pb and Mn contributed more to the metal profiles in the bay samples. The metal profiles in the sea turtle tissues more closely resembled the stomach contents than the same species of plants collected within Estero Banderitas, and suggest that sea turtles collected inside Magdalena Bay use foraging resources outside of the Estero Banderitas region. This work supports the suggestion that metal profiles can be used as "environmentally acquired markers" to improve our understanding of the extent of sea turtle foraging areas.