C. González-Macías

Pollution in estuarine and bay sediments at a refinery complex located on the Mexican Pacific Ocean

The study was designed to determine potential environmental impacts to aquatic biota that may be linked to heavy metals and polycyclic aromatic hydrocarbons (PAHs) resulting from effluents of the oil refinery and industrial activities in the estuarine system, inner port and Bay of Salina Cruz, Mexico. The data indicate that the studied area is chronically polluted.

Ecological and human risk assessment of long-term produced water discharge to the ocean at the Sonda de Campeche, Gulf of México

Management of produced water (PW) is a challenge for mature fields like those of Sonda de Campeche in the southern Gulf of Mexico and for the future development of deep water fields. Past studies suggest that PW effects are local; however, the risk of widespread, long-term impact on the population and ecosystem is considered low, but not verified from the published literature. The study describes monitoring events done in years 2003 and 2013, considering physicochemical characteristics, organic and inorganic environmental measurements as well as comparing the prognostic results of an environmental and health risk assessment. The study examined ambient water samples and sediments for Al, Ba, Ni, Cd, Pb, Zn, V, Cr, Cu, Fe, and As, and also polycyclic aromatics compounds included in tissues of collected fish near the discharge area and a reference coastal site assumed to be unaffected. From a regional perspective, the ecological and human risk data suggest that the effects of the present discharge are not confined locally, but increased with time and space.

Sediment Quality Index: An Effective Tool for Environmental Evaluation

Myriam A. Amezcua-Allieri—School of Geography and Environmental Science, The University of Birmingham, Edgbaston Birmingham B15 2TT United Kingdom, myriamamezcua@hotmail.com, Telephone: (0121) 4145543, Fax: (0121) 4145682; Carmen González-Macías—Subdirección de Protección Ambiental, Instituto Mexicano del Petróleo. Eje Central Lázaro Cárdenas No. 152, Col. San Bartolo Atepehuacan, C.P. 07730, México, D.F. México, magonzal@imp.mx, Telephone: (015) 3336000, Fax: (015) 3338067

The effects of addition of co-solvents on the physicochemical properties of gasoline–methanol blended fuels

The scope of the work carried out is aimed to evaluate the effects of blending methanol in the gasoline pool, particularly octane number and Reid vapor pressure increase when methanol is substituting methyl-tertiary-butyl ether in the formulation of Regular and Premium base gasolines. Isopropyl alcohol and ethanol have been investigated and found to be a promising co-blending alcohol to be mixed in gasoline methanol blends. Isopropyl alcohol is most effective below 3 vol%. Ethanol has been found to be the most promising co-blending alcohol able to reduce the Reid vapor pressure increase by 1.4 psi even with concentrations in the range of 2 vol%. The addition of isopropyl alcohol to the methanol–gasoline blends has shown the ability of a ternary mixture to further reduce the Reid vapor pressure of the finished gasoline and, subject to availability and price of isopropyl alcohol, could be of interest in further formulation studies focused on maximizing the saving on finished gasoline cost by reducing the Reid vapor pressure of base gasoline and/or increasing the methanol content.

Fluorescence characteristics in the deep waters of South Gulf of México

Vertical profiles of deep-water fluorescence determined by the chlorophyll sensor, polycyclic aromatic hydrocarbons, biomarkers, and other miscellaneous parameters measured in the southern Gulf of Mexico are reported. In the course of the survey, unexpected deep fluorescences were recorded (>1100m depth) in half of the 40 stations studied, a novel finding in this area of the Gulf. Currently, the deep-water fluorescence phenomenon is not completely understood, however we observe linear correlation between the fluorescence intensity and chlorophyll-α concentrations and coincidence of higher number of hydrocarbonoclastic bacteria in samples collected precisely in the deep-water fluorescence. This information is particularly interesting in relation to the Deepwater Horizon oil spill in 2010, in view that the aftermaths of the spill can be observed till today as oil plumes trapped in deep water layers that may disturb the natural water ecosystem.

Performance and emissions of gasoline–dual alcohol blends in spark-ignited single cylinder engine:

Three alcohols (ethanol, methanol and isobutanol), two ethers (ethyl tert-butyl ether and methyl tert-butyl ether) and dimethyl carbonate were blended in a base fuel at 3.5 wt % oxygen. Two of the fuels were dual alcohol–gasoline blends with methanol/ethanol and methanol/isobutanol having the same added volume of each alcohol. The performance was analyzed on a single spark-ignited engine. Emissions of nitrogen oxides, carbon monoxide, unburned hydrocarbons and carbon dioxide were monitored online. The dual-alcohol blends present higher cooling effect, power and thermal efficiency as well as low combustion cyclic dispersion and fast combustion. Combustion effects due to the addition of oxygenates can be attributed to base gasoline dilution, for a given oxygen content. Also, dilution increases the hydrogen proportion, and this seems to have a strong relationship with the observed increases in combustion duration.