Dissolved/dispersed polycyclic aromatic hydrocarbon spatial and temporal changes in the Western Gulf of Mexico

Oil extraction and transport activities in the Gulf of Mexico (GoM), along with major marine oil spills and riverine inputs, are exerting environmental pressure on this system by increasing the concentration of oil-related pollutants such as polycyclic aromatic hydrocarbons (PAHs). To fully identify these changes related to oil activities, current PAH levels should be established. Here, we present the PAH concentration and the low molecular weight/high molecular weight (LMW/HMW) ratios obtained in the Perdido Fold Belt area in surface and bottom water at four cruises from May 2016 to September 2017. The Perdido 1 (P1) cruise was conducted in May 2016, the Perdido 2 (P2) cruise in September–October 2016, the Perdido 3 (P3) cruise in June 2017, and the Perdido 4 (P4) cruise in September 2017. Samples were taken during each cruise at up to 3,500-m depth, the deepest ever recorded for the GoM. Results show that the highest concentrations of PAH, LMW PAHs, and HMW PAHs were found in the P4 cruise (1.15, 1.05, and 0.10 µg/L, respectively), well below the 300 µg/L guideline for acute exposure. LMW/HMW ratios show that only the P1 cruise indicates pyrogenic hydrocarbons, while P2, P3, and P4 were petrogenic. The spatial distribution of total PAH, LMW, and HMW showed higher values in the southern and northeastern areas, except for P4, which showed high values related to riverine inputs. The complex hydrodynamic in the region was found to have a significant effect on PAH seasonal changes, river contributions, eddy circulation, and fronts to promote their dispersion

PLASMA AND ERYTHROCYTE CHOLINESTERASE ACTIVITIES IN CHILDREN FROM YUCATAN, MEXICO: RELATIONSHIP WITH ANTHROPOMETRY AND OBESITY

Objective: To examine cholinesterase activities in children from three towns in Yucatan, Mexico and their relationship with anthropometry.Methods: Plasma and erythrocyte cholinesterase a ctivities were measured in 104 children from Ticul, Merida and Progreso. Differences between gender, sampling sites and body mass index (BMI ) group  were evaluated. Weight, height, BMI, hip and waist circumferences were correlated with cholinesterase activities.Results: Significant differences in the waist circumference and BChE activity were found among sites. Children from Ticul presented higher BChE activity compared to children from the other towns. Children from Progreso had a smaller hip circumference compared to children from the other two locations. There was a high prevalence of overweight and obese children (40.3%). The results indicated that obese children had higher BChE activity respect to healthy weight children. As expected, there were also significant waist and hip circumference differences for BMI groups. The results demonstrated a positive significant correlation between BChE activity and weight, waist and hip circumference.Conclusions: These results support the hypothesized role of BChE in lipid metabolism. Because of the high prevalence of obese children in Mexico, BChE activity may be used as a biomarker in combination with anthropometry to monitor obesity.Keywords: Cholinesterase, Children, Anthropometry, Obesity

Wet deposition and atmospheric mercury monitoring in Celestún, Yucatán, México, as part of the Global Mercury Observation System - Mercury concentration in ambient air - Results 2012

This report describes work conducted by the European Commission’s Joint Research Centre in the contest of GMOS (Global Mercury Observation System). GMOS is an FP VII funded large-scale collaborative project aiming at the establishment of a Global Mercury Observation System including ocean-based, ground-based and atmospheric measurement activities under the umbrella of the GEO/GEOSS and the UNEP’s Mercury program. Within this 5 year project that started in 19 Nov 2010, JRC got the task to set-up a ground based station for measuring total atmospheric Mercury in Yucatán, Mexico. The system is fully automatic and transmits the acquired raw data via internet to the JRC for data analysis and evaluation prior to further reporting to the GMOS coordinator. Moreover, the time series obtained for Hg will be reported in the framework of Task Force on Hemispheric Transport of Air Pollution (LRTAP-Convention) co-chaired by the JRC (Climate change Unit). In order to assist the JRC in the set up and routine maintenance of the Hg monitoring station, cooperation was initiated with the National Institute of Ecology and Climate Change - Secretariat of Environment and Natural Resources (INECC-SEMARNAT) in Mexico City and DUMAC foundation in Yucatán. INECC agreed to assist the JRC in selecting an appropriate site partner, support maintaining the instrumentation, taking care of the wet deposition sampling/dispatch logistics, and supply meteorological data from the selected site. Data regarding the total gaseous mercury concentration in air measured during the year 2012 at Celestún, Yucatán, México are here reported. The annual TGM average obtained from 44537 data was 1.047 ± 0.271 ng/m3. The minimum value (0.50 ng/m3) was registered from February to May; the lowest monthly average (0.752 ng/m3) was recorded in April. The maximum value (2.822 ng/m3) was observed in March, while the highest monthly average TGM value was obtained in June (1.388 ng/m3).JRC.H.1-Water Resource

Fecal sterols, seasonal variability, and probable sources along the ring of cenotes, Yucatan, Mexico

Abstract not availableF. Arcega-Cabrera, N. Velázquez-Tavera, L. Fargher, M. Derrien, E. Noreña-Barros