Environmental and health implications of Pb-bearing particles in settled urban dust from an arid city affected by Pb-Zn factory emissions.

Metal-rich particles originating from non-ferrous metallurgical activities are the primary source of atmospheric metals in urban environments. These particles vary in size, morphology, and elemental compositions and they undergo weathering processes that alter their composition and affect their toxicity. This study focuses on lead (Pb)-rich particles in settled urban dust within an arid and dusty city, Torreón in North Mexico, affected by Met-Mex Peñoles complex, one of the world's largest Ag-Cd-Pb-Zn smelting and refining facilities in operating since 1901. Torreón is characterized by arid conditions, temperature fluctuations, and low humidity. Dry atmospheric particles were collected in 2015 and 2017 from Torreón's urban area within a 3 km radius of the Met-Mex Peñoles complex. We used various analytical techniques, including scanning electron microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDS), and X-ray powder diffraction (XRD) to determine the size, morphology, elemental composition and mineralogy of Pb-bearing particles. Our analysis revealed a range of Pb-bearing particle sizes and morphologies with varying Pb (0.3 to 51-87.2%) and other element contents, such as As (0.04 to 1-3.4%), Cd (0.4 to 3.3-5.1%), Cu (0.51-14.1%), Hg (ND-0.6%), and Zn (1.7 to 79-90.3%). XRD analysis confirmed the presence of Pb and Zn sulfides, Pb carbonates, Pb sulfate, and Pb oxides in urban dust, both as individual particles and agglomerates. Primary Pb minerals were linked to fugitive feed concentrates and smelter flue gas at Met-Mex Peñoles, while secondary Pb minerals, like Pb carbonates, Pb sulfate, and Pb oxides, resulted from direct emissions and weathering processes. Compared to galena, secondary Pb minerals exhibit higher chemical availability in the environment, posing greater risks to the environment and human health. As the particles analyzed are presumed to be resuspended rather than freshly emitted by Met-Mex, the presence of secondary Pb minerals in settled urban dust is predominantly linked to weathering processes. The physical and chemical transformations in Pb-rich particles contribute to increased Pb bioavailability and toxicity in urban dust, with substantial implications for environmental and human health. These findings highlight the potential consequences of weathered Pb-rich particle in urban areas, particularly in the arid and dusty city of Torreón.

Distribution, bioaccumulation, and trace element transfer among trophic levels in the southeastern Gulf of California.

Our understanding of the trophic transfer of pollutants in marine subtropical ecosystems remains limited due to the complexity of their food webs. Thus, we aimed to evaluate Cd, Cu, Mn, Pb, and Zn sources, incorporation, and trophodynamics throughout the food web of the southeastern Gulf of California by stomach content analysis, stable isotope analysis, isotope mixing models, and trace element analysis in biological and environmental matrices. The food web comprised three main trophic guilds (TG1, TG2, and TG3). The bioaccumulation of Cd and Zn from seawater was efficient (> 1000) in TG2 and TG3. Bioaccumulation factor from sediment (BSAF >1) evidenced of Cd in all trophic guilds. In addition, non-trophic Cd relationships were identified in the food web. Based on the trophic magnification factor (TMF), Mn and Pb showed biodilution (TMFMn = 0.38; TMFPb = 0.16), while Cu and Zn exhibited biomagnification (TMFCu = 2.08; TMFZn = 3.31).

Association of obesity, diabetes, and hypertension with arsenic in drinking water in the Comarca Lagunera province (north-central Mexico).

Chronic endemic regional hydroarsenicism (CERHA) is a global issue that affects over 200 million people exposed to arsenic (As) in drinking water. This includes 1.75 million individuals residing in La Comarca Lagunera, a region in north-central Mexico. Arsenic levels in this region typically exceeds the WHO guideline of 10 µg L-1. Biochemical alterations related to the human As metabolism may increase the risk of overweight and obesity (O&O), type 2 diabetes (T2D), and hypertension (AHT). In our study, we investigated the role of As in drinking water as a risk factor for these metabolic diseases. We focused on populations with historically moderate (San Pedro) and low (Lerdo) drinking water As levels and people with no historical evidence of As water contamination. The exposure assessment to As was based on measurements of the drinking water (medians 67.2, 21.0, 4.3 µg L-1) and urinary As concentrations in women (9.4, 5.3, 0.8 µg L-1) and men (18.1, 4.8, 1.0 µg L-1). A significant correlation between As in drinking water and urine evidenced the As exposure in the population (R2 = 0.72). Adjusted odds ratios with 95% confidence intervals evidenced higher chances of being diagnosed with T2D (1.7, 1.2-2.0) and AHT (1.8, 1.7-1.9) in individuals living in San Pedro than those in Lerdo. Still, there was no significant association with obesity. Individuals living in CERHA towns were found to have a higher risk of obesity (1.3-1.9), T2D (1.5 to 3.3), and AHT (1.4 to 2.4) compared to those residing in non-CERHA towns. Finally, obesity is more probable in women [inverse of OR and 95%CI 0.4 (0.2-0.7)] compared to men, while men is more likely to be diagnosed with T2D [OR = 2.0 (1.4-2.3)] and AHT [OR = 2.0 (1.5-2.3)] than women, independently of the municipality.

Lanthanoid analysis in seawater by seaFAST-SP3™ system in off-line mode and magnetic sector high-resolution inductively coupled plasma source mass spectrometer.

Analysis of lanthanoids in seawater is challenging due to the complex matrix (∼35 g L-1 TDS) and low dissolved concentrations (in ng L-1). A 4-step strict analytical protocol and state-of-the-art technology were implemented and validated in this study. The 4-steps method involves the 1) sample filtration and acidification (pH<2); 2) pre-concentration by the matrix separation system, 3) off-line injection of the eluted sample; and 4) determination of lanthanoids by high-resolution inductively coupled plasma mass spectrometer (HR-ICP-MS). Since there are no certified values for lanthanoids in seawater are available, the method validation was done by analyzing SLEW-3 (estuarine water reference samples) and comparing with other reports and artificial seawater (100 ng L-1 lanthanoid multi-element standard solutions). SLEW-3 recovery varied from 78.6% to 106% and in artificial samples it ranged from 87 to 110%. Low recovery can be explained by complex organic in seawater, because the UV oxidation was not performed in the acidified samples. The variation was ≤10%, except for Gd, Tb, and Yb (11-13.75%). Blanks varied between 0.01 and 0.07 ng L-1, except for La and Ce (0.13-0.21 ng L-1). Blanks represent <5% SLEW-3 values and <1% synthetic seawater. The procedural detection limit varied from 0.01 to 0.03 ng L-1.•Lanthanoids as geochemical tracers in seawaters•A 4-step strict analytical protocol and state-of-the-art technology for lanthanoids analyses in seawaters•Sample pre-concentration system for matrix separation for the detection of ultra-low lanthanoids levels.

Detailed Morphological Analysis of Cryoinjury in Human Ovarian Tissue Following Vitrification or Slow Freezing.

Cryopreservation of human ovarian tissue represents a key procedure for fertility preservation. The two most widely used cryopreservation methods for human ovarian cortex samples are slow freezing\thawing (SF\T) and vitrification\warming (V\W). The aim of the present study was to analyze the effects of SF\T and V\W using a metal chamber, on specific follicle and oocyte structures and on the stromal organization post-cryopreservation. We did histology analysis of SF\T and V\W ovarian fragments from nine healthy subjects. Overall results showed that cryopreserved tissues presented significant rates of damage in primordial and primary follicles. Altered nuclear structure of primordial follicles and cell detachment from primordial and primary follicles were the main injuries observed after V/W and SF/T. The stromal components were similarly well preserved after cryopreservation. We conclude that both cryopreservation methods may be used for fertility preservation purposes with similar outcomes in terms of follicular and stromal integrity. Detachment of follicle cells from basal membrane represents an important cryoinjury that deserves further investigation.

Geogenic lanthanoid signature in coastal and marine waters from the southern Gulf of California.

Lanthanoids in the southern Gulf of California (GC) seawater are reported for the first time. Lanthanoids showed differences between peninsular and continental coastline, coastal or marine ecosystems, and dry or rainy season. The chondrite-normalized values showed high variability but followed a same pattern. Light lanthanoids were more enriched than heavy ones. Values of ∑Ln and La/Lu were higher in continental than peninsular coastlines, coastal than adjacent marine ecosystems, and rainy than dry season. Differences were related to the lithology and perturbation degree of the ecosystem watersheds. The chondrite-normalized patterns are typical of geological origin. Slightly negative Ce anomaly was related to the low levels of oxygen in water for the oxidation of Ce (III) to Ce (IV) and its posterior scavenging. Negative δEu anomaly is explained by an influx of fluvial and eolian materials from the upper continental, while a positive Eu anomaly related to hydrothermal vent inputs was non-evidenced.

[Description of the use of inhaled rescue medication in an asthmatic population treated in the Primary Care clinics. UMI-ASMA Study]. / Descripción del uso de medicación inhalada de rescate en una población asmática atendida en el ámbito de Atención Primaria. Estudio UMI-ASMA.

OBJECTIVE: To describe the quantitative use of inhaled rescue medication in an asthmatic population treated in the Primary Care clinics, and secondly to determine its possible relationship as regards other variables associated with control. MATERIAL AND METHODS: An observational, descriptive study was conducted on a randomised sample of all the asthmatic patients with more than one year of onset, and coming from 17 Primary Care catchment areas. 1 year observation period. The data collected included sociodemographic variables and characteristics of the asthma, such as the use of short-acting beta-agonists (SABA) and level of control as regards its frequency of use, the use of inhaled control medication (ICM), number of hospital exacerbations, smoking habits, and availability of an action plan. The data were obtained from the clinical history and the computerised prescription modules. RESULTS: A total of 442 asthmatic patients were included (59.5% female), with a mean age of 45.4 years. The total number of SABA containers prescribed in one year per patient was between 0 and 25 containers, with a mean of 4.26 (SD=4.1). Only 46.6% showed a regular use of an ICM. The number of SABA containers prescribed to patients with an intermittent use of an ICM was significantly higher than those patients that used it regularly (P=.001). There was an association between the number of exacerbations and the number of SABA containers prescribed (Spearman correlation coefficient=0.474, P<.001), as such that the higher the number of containers prescribed there was also a higher number of hospitalised asthmatic exacerbations. CONCLUSIONS: A considerable number of asthmatics in the sample had elevated prescriptions for SABA inhalers and within the defined quantitative ranges of at least a partially or poor-controlled asthma. There is a positive relationship between the overuse of SABA and the intermittent use of the ICM, the same as with hospital exacerbations, smoking, and the lack of a written action plan..

Immunological response of white shrimp (Litopenaeus vannamei) to sublethal concentrations of malathion and endosulfan, and their mixture.

Cellular and humoral responses were evaluated in Litopenaeus vannamei juveniles when exposed to malathion, endosulfan, and their mixture. Each experiment was performed in the hemolymph collected at each exposure time (5 and 96 h) in duplicate; total hemocyte count, coagulation time, hemocyanin concentration, phenoloxidase (PO) and superoxide dismutase (SOD) activities were quantified. Survival was not affected by pesticides applied individually and mixed. Clotting time did not show significant differences concerning increase of concentration percentage of the pesticides tested. In organisms exposed to the pesticide mixture, hemocyanin decreased at 5 h of exposure as the concentration increased. Only in the malathion experiment did exposed shrimp to 10 and 50% of the LC50-96 h show significantly (p < 0.05) higher hemocyte contents. For malathion, significantly (p < 0.05) lower PO values in shrimp exposed to higher concentrations (10 and 50% of the LC50-96 h) were determined. While for the mixture treatment, high SOD value was determined at high exposure time and concentration. Malathion was the pesticide that showed an effect on some variables even at sublethal concentrations. The Continuous Concentration Criteria of the United States Environmental Protection Agency did not represent effects on the variables when they were compared with the averages of the control group.

Trace Elements in Tissues of Whale Sharks (Rhincodon typus) Stranded in the Gulf of California, Mexico.

Concentration of essential (Se, Zn and Cu) and non-essential (As, Cd, Hg and Pb) trace elements were measured in selected tissues of two dead whale sharks (Rhincodon typus) stranded in the Gulf of California (GC) in 2017 and 2018. Concentrations of Cd and Pb in the skeletal muscle of the whale shark from La Paz Bay, GC were higher compared to a previous study on whale shark from China. The shark from La Paz Bay also presented higher concentration of Pb in the epidermis, compared to the same tissue of the other whale shark stranded in Punta Bufeo, GC. The Hg in all analysed tissues was lower than those documented in carnivorous sharks. Molar ratio Se:Hg shows an excess of Se over Hg in all the tissues sampled in both sharks.

Assessing Human Health Risks Associated with Consumption of Metal Content in Shrimp from NW Mexico.

Shrimp of Farfantepenaeus californiensis (78 groups) and Litopenaeus stylirostris (14 groups) were caught in the northwestern fishing zones in Mexico during the 2014-2015 fishing season (September-February); both shrimp species have high commercial value. Muscle, hepatopancreas and exoskeleton were analyzed to determine their metal contents. For F. californiensis, the highest Cd, Pb and Zn contents were determined in specimens caught off the State of Baja California Sur (BCS) with 22.4 ± 8.9 (hepatopancreas), 2.83 ± 4.63 (muscle), and 748.5 ± 1567 (muscle) µg/g, in the regions off Mulegé, Los Cabos and Los Cabos, respectively. For L. stylirostris, the fishing zone of Comundú (BCS) showed higher Cd (12.3 ± 11.5 µg/g), Cu (569.1 ± 646.5 µg/g) and Zn (549.7 ± 400.7 µg/g) contents; all values were determined in the hepatopancreas. Regarding the hazard quotient and total hazard quotient calculated in this study, the consumption of marine shrimp caught off NW Mexico does not represent a risk to human health (both < 1).

Geochemical Fractionation and Potential Ecological Risk of Cadmium and Lead in Soils Impacted by Secondary Lead Refinery.

Total and geochemical associations of Cd and Pb were studied on 75 topsoil samples around a small secondary metal recovery factory, which stopped operations in April 2006 due to metal environmental problems in surrounding communities. After a decade, we evaluated the potential ecological risk of Cd and Pb in impacted soils calculating the risk assessment code (RAC) and the risk index (RI) based on the Hakanson method. High concentrations of metals were found in soils around the factory, with dispersion pattern towards the north-west and south-east quadrants. Cadmium was predominant in exchangeable and carbonate fractions, while Pb was more associated to oxides, sulfides and in lesser extent to carbonates. The values of RAC and RI revealed a serious-considerable ecological risk in the surroundings of the land occupied by the factory and toward W-NW and SE. Statistical analyses showed that smelting activities had a great influence on the metals spatial distribution and their geochemical fractions in polluted soils.

Mercury and selenium concentrations in marine shrimps of NW Mexico: health risk assessment.

We determined total Hg and Se contents of hepatopancreas, exoskeleton, and muscle, and the Se:Hg molar ratios in the muscle of shrimps Farfantepenaeus californiensis and Litopenaeus stylirostris caught in NE Pacific Mexican waters. Total Hg mean values in muscle, hepatopancreas, and exoskeleton were 0.31 ± 0.26, 0.28 ± 0.29, and 0.24 ± 0.06 µg g-1, and 0.46 ± 0.46, 0.41 ± .034, and 0.24 ± 0.06 µg g-1 for F. californiensis and L. stylirostris, respectively. In all tissues, the mean concentrations of Se tended to be close to one order of magnitude higher than the respective Hg values. In F. californiensis, the hepatopancreas of the larger commercial size had significantly (p < 0.05) higher Hg content than smaller sizes, but correlations size-Hg concentration calculated for each tissue of either species were not significant. The Hg content of the muscle of all commercial sizes of both species was lower than the permissible limit and their Se:Hg ratios in all sizes were higher than 1, indicating low risk for human consumption.

²¹°Po, Cd and Pb distribution and biomagnification in the yellowfin tuna Thunnus albacares and skipjack tuna Katsuwonus pelamis from the Eastern Pacific.

We measured Cd and Pb in the muscle and stomach contents of Thunnus albacares and Katsuwonus pelamis to define the distribution of the elements in the tissues and their degrees of biomagnification. (210)Po was measured in the livers of both species and compared to the results of similar studies. The trophic position of the tuna species was determined by N isotope measurements. The average activity of (210)Po in the liver ranged from 119 to 157 (Bq kg(-1) wet weight) in K. pelamis and T. albacares. The trophic position of T. albacares (4.60) was higher than that of K. pelamis (3.94). The Cd content of the muscle increased significantly with the trophic position of the tuna. δ(13)C in T. albacares and K. pelamis varied, with values of 3.13 and 1.88‰, respectively. The δ(15)N values in yellowfin tuna were higher than in skipjack tuna. The trophic position of T. albacares (4.60 ± 0.67) was therefore more elevated than that of K. pelamis (3.94 ± 1.06). Pb was biomagnified in T. albacares (transfer factor=1.46).

Biogeochemical responses to nutrient inputs in a Cuban coastal lagoon: runoff, anthropogenic, and groundwater sources.

Laguna Larga, a coastal lagoon in central Cuba, has been heavily altered by tourism infrastructure construction and sewage disposal. We hypothesize that this has decreased the circulation and caused eutrophication of the lagoon. To assess this, 12 bimonthly samplings were carried out in 2007-2008. Temperature, salinity, oxygen, nutrients and nitrogen, and phosphorous fractions (inorganic, organic, and total) were determined. Water and salt budgets, as well as biogeochemical fluxes of nitrogen and phosphorus were calculated using the LOICZ budget model for the three sections of the lagoon identified by morphological constrains and salinity patterns. Laguna Larga is a choked lagoon with restricted water circulation, low exchange, and high residence times that vary significantly along its sections. Residence time was estimated to be 0.1-0.7 years for the inner section and 1-9 days for the outer one. High levels of total nitrogen (annual means 126-137 µM, peaks up to 475 µM) and phosphorus (2.5-4.4 µM, peaks up to 14.5 µM) are evidence of eutrophication of Laguna Larga. During 2007, an average precipitation year, Laguna Larga exported water (703 m(3) d(-1)) and was a source of nitrogen (9.026 mmol m(-2) d(-1)) and phosphorus (0.112 mmol m(-2) d(-1)) to the adjacent sea. δ(15)N determinations in the seagrass Thalassia testudinum (-1.83 to +3.02 ‰) differed significantly between sites in the lagoon and offshore reference sites located W of the inlet, but were similar to those located E of the inlet. δ(15)N determinations in the seaweed Penicillus dumetosus (+1.02 to +4.2) did not show significant differences.

Cadmium and lead concentrations in the fish tissues of a coastal lagoon system of the SE Gulf of California.

Mean Cd trend in the muscle of omnivorous (O), planktivorous (P), benthopelagic-carnivorous (BPC), and benthic carnivorous (BC) fish of one lagoon of NW Mexico was BPC > BC > P > O (0.89, 0.59, 0.55 and 0.24 µg g(-1)). That of Pb was P > BC > O > BPC (1.07, 0.48, 0.17 and 0.04 µg g(-1)). In the liver Cd was P > BPC > O > BC (5.09, 2.40, 2.07 and 1.95 µg g(-1)). Pb was P > O > BPC > BC (0.63, 0.40, 0.13 and 0.07 µg g(-1)). There were no differences in Cd and Pb contents due to feeding habits, and the correlations between metals and troph level were not significant (p > 0.05 in all cases).

Radiotherapy issues in non-small cell lung cancer: radiotherapy versus surgery in the treatment of early stage.

We discussed in this article about the role of surgery, in a broad sense, and radiotherapy for the treatment of early stage of non-small cell lung cancer (NSCLC), and we also examined if patients' outcomes after radiation therapy are comparable to the ones after surgery. Radiotherapy is at present a less attractive alternative to surgery in operable patients with early stage of NSCLC. Indeed, radiotherapy is frequently reserved for patients who are deemed unfit for surgery due to poor pulmonary function or other comorbidities. This introduces a large patient selection bias compared to surgery, rendering overall survival less suitable for comparison. When we compare patients who are deemed operable but refuse surgery, the 5-year overall survival rate observed, after a high effective dose, is equivalent to the outcome after surgery. On the other hand, it is difficult to enroll patients in randomized clinical trials for this purpose, propensity matched analysis allows to compares the effectiveness of radiotherapy and surgery using comparable series of patients, using this methodology two studies obtained similar results. This data support the need of continuous investigation for non-surgical alternatives in this disease, radiotherapy can be a good option. Until then, surgery remains the treatment of choice for early stage of NSCLC.

Mercury in blood and eggs of the sea turtle Lepidochelys olivacea from a nesting colony in Oaxaca, Mexico.

Mercury concentrations were assessed in the sea turtle Lepidochelys olivacea from a nesting colony of Oaxaca, Mexico; 25 female turtles were sampled, a total of 250 eggs were collected during the season 2005-2006. Higher concentrations were found in yolk fraction, while in blood and albumen mean levels were below of 0.0010µg g(-1) dry wt. On the basis of one nesting season, the maternal transfer of Hg via eggs-laying was estimated in 2.0±1.1%. According to international norms, the health of this population and its habitats is acceptable for Hg and corresponds to baseline levels of a nearly pristine environment.

Trophic transfer of lead through a model marine four-level food chain: Tetraselmis suecica, Artemia franciscana, Litopenaeus vannamei, and Haemulon scudderi.

The objective of this investigation was to assess the transfer of lead (Pb) along an experimental, four-level food chain: Tetraselmis suecica (phytoplankton) â†’ Artemia franciscana (crustacean, brine shrimp) â†’ Litopenaeus vannamei (crustacean, white shrimp) â†’ Haemulon scudderi (fish, grunt). T. suecica was exposed to a sublethal dose of Pb in solution and then used as the base of a marine food chain. Significant differences in Pb concentrations were found between exposed organisms of the different trophic levels and the control. Particularly, Pb concentrations in fish of the simulated trophic chain were two-to three times higher in the exposed specimens than in the control. Levels of Pb in phytoplankton showed a substantial increase with respect to the solution (level I), with bioconcentration factors averaging from 930 to 3630. In contrast, a strong decrease in Pb concentration from phytoplankton to zooplankton (level II) and from zooplankton to shrimp tissues (level III) was evidenced by bioaccumulation factors <1. Despite the decrease in the assimilation efficiency of metal transfer observed in these two predators, Pb concentration in the grunt fish (level IV) was higher than in the shrimp (level III) (bioaccumulation factor >1.0). Some of the added Pb is transferred from the phytoplankton along the food chain, thus producing a net accumulation of Pb mainly in fish and, to a lesser extent, in shrimp tissues. Because Pb is one of the most pervasive contaminants in coastal ecosystems, its transference by way of diet and potential net accumulation in higher predators is of ecologic importance for marine life. In addition, because shrimp and adult Haemulon scudderi are commercially important resources, this issue is of particular relevance to the safety of marine products.

Nonessential metals in striped marlin and Indo-Pacific sailfish in the southeast Gulf of California, Mexico: concentration and assessment of human health risk.

Seventeen sailfish (Istiophorus platypterus; 166-246 cm long) and 13 striped marlin (Tetrapturus audax; 159-254 cm long) specimens from the southern Gulf of California were analyzed for As, Cd, Hg, and Pb concentrations. More than 20% of the As and Cd levels exceeded the guideline levels of the World Health Organization (WHO), the U.S. Food and Drug Administration, and the European Union. About 65-90% of the specimens exceeded the limit value for Hg. Pb levels in billfish were significantly lower than guideline values. The intakes of As and Cd through billfish consumption by the population represented 20-40% of the provisional tolerable weekly intake (PTWI) values as recommended by the WHO. Levels of Hg exceeded the PTWI value. Pb intake represented <5% of the PTWI through these species in all age and gender groups. The target hazard quotients (THQs) for Cd and Pb were <1 in each group of interest. In contrast, THQ values based on As and Hg showed large variations, with the highest values for children, then pregnant women, and, finally, adults. Values of THQ >1 indicate risk for As and Hg; the risk from As was estimated assuming that 20% of the total As was inorganic. These metals can affect the nervous system and intellectual and physical development of unborn children and infants. A national moratorium on billfish consumption in México is recommended for children (0-6 years old), pregnant women, and women planning pregnancy.

Lead in blood and eggs of the sea turtle, Lepidochelys olivacea, from the Eastern Pacific: concentration, isotopic composition and maternal transfer.

Concentrations of lead were assessed in the sea turtle, Lepidochelys olivacea, from a nesting colony of the Eastern Pacific. Twenty-five female turtles were sampled and a total of 250 eggs were collected during the "arribada" event of the 2005-2006 season. Considering the nesting season, the maternal transfer of lead (Pb) via egg-laying, in terms of metal burden in whole body, was 0.5%. Pb concentrations (in dry weight) in blood (0.95+/-0.18microgg(-1)) and egg samples (yolk, 0.80+/-0.10microg g(-1); albumen, 1.08+/-0.20microg g(-1); eggshell, 1.05+/-0.20microg g(-1)) were comparable or even lower than those found in other sea turtles. The isotope ratios ((206)Pb/(207)Pb and (206)Pb/(208)Pb) in blood (1.183+/-0.0006 and 2.452+/-0.0006, respectively) were comparable to that of natural Pb-bearing bedrock in Mexico (1.188+/-0.005 and 2.455+/-0.008, respectively). According to international norms of Pb, the health of this population and its habitats is acceptable for Pb and corresponds to basic levels of a nearly pristine environment.