Experience

Publications

• The Geochemistry of Heavy Metals in Mudflat of Salinas de San Pedro Lagoon, California.

  Journal of Environmental Protection

  Sediment core samples were collected from the Salinas de San Pedro to assess the pollutant deposition processes in re-sponse to extensive human activities. Analysis of the sediment samples for heavy metals and some trace elements was conducted with ICP-OES for 20 sites showing enrichment for some of trace and heavy metals. The results demonstrated that heavy metal concentrations in mud varied greatly for each metal, with concentration values (mg/g) ranging from 1.05 - 4.8 (Al); 0.003 - 0.011(As); 0.001 - 0.005 (Cd); 0.02 to 0.82 (Cr); 0.085 - 0.47 (Cu); 5.98 - 14.22 (Fe); 0.06 - 0.19 (Mn); 0.03 - 0.67 (Ni); 0.05 - 0.38 (Pb); <0.008 - 0.069 (Se); 0.18 - 0.63 (Ti); 0.040 - 0.091 (V) and 0.149 - 0.336 (Zn). The Index of Geo-accumulation factor showed highest values for Pb, Mn, As, and Cu. Enrichment factors >1for these elements suggest anthropogenic inputs for most metals. The bioavailability of metals in lagoon sediments has the poten-tial to be highly dynamic with local waste and natural H2S discharge from existing fault line.

• The Geochemistry of Heavy Metals in Mudflat of Salinas de San Pedro Lagoon, California.

  Journal of Environmental Protection

  Sediment core samples were collected from the Salinas de San Pedro to assess the pollutant deposition processes in re-sponse to extensive human activities. Analysis of the sediment samples for heavy metals and some trace elements was conducted with ICP-OES for 20 sites showing enrichment for some of trace and heavy metals. The results demonstrated that heavy metal concentrations in mud varied greatly for each metal, with concentration values (mg/g) ranging from 1.05 - 4.8 (Al); 0.003 - 0.011(As); 0.001 - 0.005 (Cd); 0.02 to 0.82 (Cr); 0.085 - 0.47 (Cu); 5.98 - 14.22 (Fe); 0.06 - 0.19 (Mn); 0.03 - 0.67 (Ni); 0.05 - 0.38 (Pb); <0.008 - 0.069 (Se); 0.18 - 0.63 (Ti); 0.040 - 0.091 (V) and 0.149 - 0.336 (Zn). The Index of Geo-accumulation factor showed highest values for Pb, Mn, As, and Cu. Enrichment factors >1for these elements suggest anthropogenic inputs for most metals. The bioavailability of metals in lagoon sediments has the poten-tial to be highly dynamic with local waste and natural H2S discharge from existing fault line.

• The Geochemical Characterization of Mine Effluents from the Phosphorite Processing Plant of Kpémé (Southern Togo).

  Mine Water and the Environment Journal; Vol 28, No 1, 65-73; Berlin, Germany.

• The Geochemistry of Heavy Metals in Mudflat of Salinas de San Pedro Lagoon, California.

  Journal of Environmental Protection

  Sediment core samples were collected from the Salinas de San Pedro to assess the pollutant deposition processes in re-sponse to extensive human activities. Analysis of the sediment samples for heavy metals and some trace elements was conducted with ICP-OES for 20 sites showing enrichment for some of trace and heavy metals. The results demonstrated that heavy metal concentrations in mud varied greatly for each metal, with concentration values (mg/g) ranging from 1.05 - 4.8 (Al); 0.003 - 0.011(As); 0.001 - 0.005 (Cd); 0.02 to 0.82 (Cr); 0.085 - 0.47 (Cu); 5.98 - 14.22 (Fe); 0.06 - 0.19 (Mn); 0.03 - 0.67 (Ni); 0.05 - 0.38 (Pb); <0.008 - 0.069 (Se); 0.18 - 0.63 (Ti); 0.040 - 0.091 (V) and 0.149 - 0.336 (Zn). The Index of Geo-accumulation factor showed highest values for Pb, Mn, As, and Cu. Enrichment factors >1for these elements suggest anthropogenic inputs for most metals. The bioavailability of metals in lagoon sediments has the poten-tial to be highly dynamic with local waste and natural H2S discharge from existing fault line.

• The Geochemical Characterization of Mine Effluents from the Phosphorite Processing Plant of Kpémé (Southern Togo).

  Mine Water and the Environment Journal; Vol 28, No 1, 65-73; Berlin, Germany.

• Presence and Distribution of Toxic Trace Elements in Water and Sediments of the Southern Togo Rivers Watershed, West Africa,

  PSP Environmental Bulitin

• The Geochemistry of Heavy Metals in Mudflat of Salinas de San Pedro Lagoon, California.

  Journal of Environmental Protection

  Sediment core samples were collected from the Salinas de San Pedro to assess the pollutant deposition processes in re-sponse to extensive human activities. Analysis of the sediment samples for heavy metals and some trace elements was conducted with ICP-OES for 20 sites showing enrichment for some of trace and heavy metals. The results demonstrated that heavy metal concentrations in mud varied greatly for each metal, with concentration values (mg/g) ranging from 1.05 - 4.8 (Al); 0.003 - 0.011(As); 0.001 - 0.005 (Cd); 0.02 to 0.82 (Cr); 0.085 - 0.47 (Cu); 5.98 - 14.22 (Fe); 0.06 - 0.19 (Mn); 0.03 - 0.67 (Ni); 0.05 - 0.38 (Pb); <0.008 - 0.069 (Se); 0.18 - 0.63 (Ti); 0.040 - 0.091 (V) and 0.149 - 0.336 (Zn). The Index of Geo-accumulation factor showed highest values for Pb, Mn, As, and Cu. Enrichment factors >1for these elements suggest anthropogenic inputs for most metals. The bioavailability of metals in lagoon sediments has the poten-tial to be highly dynamic with local waste and natural H2S discharge from existing fault line.

• The Geochemical Characterization of Mine Effluents from the Phosphorite Processing Plant of Kpémé (Southern Togo).

  Mine Water and the Environment Journal; Vol 28, No 1, 65-73; Berlin, Germany.

• Presence and Distribution of Toxic Trace Elements in Water and Sediments of the Southern Togo Rivers Watershed, West Africa,

  PSP Environmental Bulitin

• Distribution, Speciation and Extractability of Cadmium in the Sedimentary Phosphorite of Hahotoé-Kpogamé (Southern Togo),

  Journal of the 3rd International Conference on Environmental science and Technology

• The Geochemistry of Heavy Metals in Mudflat of Salinas de San Pedro Lagoon, California.

  Journal of Environmental Protection

  Sediment core samples were collected from the Salinas de San Pedro to assess the pollutant deposition processes in re-sponse to extensive human activities. Analysis of the sediment samples for heavy metals and some trace elements was conducted with ICP-OES for 20 sites showing enrichment for some of trace and heavy metals. The results demonstrated that heavy metal concentrations in mud varied greatly for each metal, with concentration values (mg/g) ranging from 1.05 - 4.8 (Al); 0.003 - 0.011(As); 0.001 - 0.005 (Cd); 0.02 to 0.82 (Cr); 0.085 - 0.47 (Cu); 5.98 - 14.22 (Fe); 0.06 - 0.19 (Mn); 0.03 - 0.67 (Ni); 0.05 - 0.38 (Pb); <0.008 - 0.069 (Se); 0.18 - 0.63 (Ti); 0.040 - 0.091 (V) and 0.149 - 0.336 (Zn). The Index of Geo-accumulation factor showed highest values for Pb, Mn, As, and Cu. Enrichment factors >1for these elements suggest anthropogenic inputs for most metals. The bioavailability of metals in lagoon sediments has the poten-tial to be highly dynamic with local waste and natural H2S discharge from existing fault line.

• The Geochemical Characterization of Mine Effluents from the Phosphorite Processing Plant of Kpémé (Southern Togo).

  Mine Water and the Environment Journal; Vol 28, No 1, 65-73; Berlin, Germany.

• Presence and Distribution of Toxic Trace Elements in Water and Sediments of the Southern Togo Rivers Watershed, West Africa,

  PSP Environmental Bulitin

• Distribution, Speciation and Extractability of Cadmium in the Sedimentary Phosphorite of Hahotoé-Kpogamé (Southern Togo),

  Journal of the 3rd International Conference on Environmental science and Technology

• Increased Bioavailability of Mercury in the Lagoons of Lome´, Togo: The Possible Role of Dredging

  AMBIO

  Surface sediments of the lagoons of Lome´, Togo, were analyzed for mercury, methylmercury, and trace elements. Concentrations were greater than typical for natural lagoon sediments, and with greater variability within the Eastern lagoon compared to the Western one. The Eastern lagoon is larger and has been dredged in the past, while the Western lagoon, which also receives major waste inputs, has not been dredged and shows less tidal flushing. Accordingly, one naturally believes that the Eastern lagoon is cleaner and probably safe to use due to its natural resources, including fishes to eat. Unexpectedly, we describe here that mercury methylation was greater in the Eastern lagoon, indicating increased bioavailability of mercury, as probably facilitated by past dredging that decreased solid phaseretention of inorganic mercury. Urbanization has historically been more developed in the southern part of the lagoons, which is still reflected in contamination levels of sediment despite dredging, probably because sources of contamination are still more important there today. Such urban contamination emphasizes the need to regulate waste discharges and possible airborne contamination in growing cities of developing countries, and implements environmental and public health monitoring, especially in relation to misbelieves systematically associated with the cleansing effect of dredging activity.

• The Geochemistry of Heavy Metals in Mudflat of Salinas de San Pedro Lagoon, California.

  Journal of Environmental Protection

  Sediment core samples were collected from the Salinas de San Pedro to assess the pollutant deposition processes in re-sponse to extensive human activities. Analysis of the sediment samples for heavy metals and some trace elements was conducted with ICP-OES for 20 sites showing enrichment for some of trace and heavy metals. The results demonstrated that heavy metal concentrations in mud varied greatly for each metal, with concentration values (mg/g) ranging from 1.05 - 4.8 (Al); 0.003 - 0.011(As); 0.001 - 0.005 (Cd); 0.02 to 0.82 (Cr); 0.085 - 0.47 (Cu); 5.98 - 14.22 (Fe); 0.06 - 0.19 (Mn); 0.03 - 0.67 (Ni); 0.05 - 0.38 (Pb); <0.008 - 0.069 (Se); 0.18 - 0.63 (Ti); 0.040 - 0.091 (V) and 0.149 - 0.336 (Zn). The Index of Geo-accumulation factor showed highest values for Pb, Mn, As, and Cu. Enrichment factors >1for these elements suggest anthropogenic inputs for most metals. The bioavailability of metals in lagoon sediments has the poten-tial to be highly dynamic with local waste and natural H2S discharge from existing fault line.

• The Geochemical Characterization of Mine Effluents from the Phosphorite Processing Plant of Kpémé (Southern Togo).

  Mine Water and the Environment Journal; Vol 28, No 1, 65-73; Berlin, Germany.

• Presence and Distribution of Toxic Trace Elements in Water and Sediments of the Southern Togo Rivers Watershed, West Africa,

  PSP Environmental Bulitin

• Distribution, Speciation and Extractability of Cadmium in the Sedimentary Phosphorite of Hahotoé-Kpogamé (Southern Togo),

  Journal of the 3rd International Conference on Environmental science and Technology

• Increased Bioavailability of Mercury in the Lagoons of Lome´, Togo: The Possible Role of Dredging

  AMBIO

  Surface sediments of the lagoons of Lome´, Togo, were analyzed for mercury, methylmercury, and trace elements. Concentrations were greater than typical for natural lagoon sediments, and with greater variability within the Eastern lagoon compared to the Western one. The Eastern lagoon is larger and has been dredged in the past, while the Western lagoon, which also receives major waste inputs, has not been dredged and shows less tidal flushing. Accordingly, one naturally believes that the Eastern lagoon is cleaner and probably safe to use due to its natural resources, including fishes to eat. Unexpectedly, we describe here that mercury methylation was greater in the Eastern lagoon, indicating increased bioavailability of mercury, as probably facilitated by past dredging that decreased solid phaseretention of inorganic mercury. Urbanization has historically been more developed in the southern part of the lagoons, which is still reflected in contamination levels of sediment despite dredging, probably because sources of contamination are still more important there today. Such urban contamination emphasizes the need to regulate waste discharges and possible airborne contamination in growing cities of developing countries, and implements environmental and public health monitoring, especially in relation to misbelieves systematically associated with the cleansing effect of dredging activity.

• Linking Groundwater Quality and Quantity: An Assessment of Satellite-Based Groundwater Storage Anomalies from GRACE Against Ground Measurements of Contaminants in California.

  Journal of Environmental. Science and Engineering B 1 (2012) 1271-1284.

  Abstract: Groundwater comprises a large portion of irrigation for California’s agriculture, and sustains a wide diversity of ecosystems as well as consumptive use, but pumping is occurring faster than replenishment. At the same time, contaminants from fertilizers and pesticides are infiltrating into the groundwater, becoming increasingly concentrated as water is extracted. It compared space-based observations of groundwater anomalies from California’s San Joaquin Valley using the GRACE (gravity recovery and climate experiment) against measurements of 42 organic and inorganic chemicals from 41,667 wells in the valley from 2003 to 2010. It compared Arsenic, Boron, Cadmium, Chloride, Selenium, Trichloroethylene, and TDS (total dissolved solid) concentrations with the groundwater storage anomaly from 2003 to 2010. The results show strong correlations for groundwater depletion against increasing chloride (r2 = 0.78, p < 0.05) and boron (r2 = 0.88, p < 0.05). This indicates increasing contaminant concentrations while groundwater was depleting over the last eight years. Solubilization by complexation with Cl, CO3 and/or organic chelates may account for the increasing concentration of some heavy metals when groundwater depletion occurs. These results are the first to link space-based groundwater mass change with groundwater contaminant concentration change.

• The Geochemistry of Heavy Metals in Mudflat of Salinas de San Pedro Lagoon, California.

  Journal of Environmental Protection

  Sediment core samples were collected from the Salinas de San Pedro to assess the pollutant deposition processes in re-sponse to extensive human activities. Analysis of the sediment samples for heavy metals and some trace elements was conducted with ICP-OES for 20 sites showing enrichment for some of trace and heavy metals. The results demonstrated that heavy metal concentrations in mud varied greatly for each metal, with concentration values (mg/g) ranging from 1.05 - 4.8 (Al); 0.003 - 0.011(As); 0.001 - 0.005 (Cd); 0.02 to 0.82 (Cr); 0.085 - 0.47 (Cu); 5.98 - 14.22 (Fe); 0.06 - 0.19 (Mn); 0.03 - 0.67 (Ni); 0.05 - 0.38 (Pb); <0.008 - 0.069 (Se); 0.18 - 0.63 (Ti); 0.040 - 0.091 (V) and 0.149 - 0.336 (Zn). The Index of Geo-accumulation factor showed highest values for Pb, Mn, As, and Cu. Enrichment factors >1for these elements suggest anthropogenic inputs for most metals. The bioavailability of metals in lagoon sediments has the poten-tial to be highly dynamic with local waste and natural H2S discharge from existing fault line.

• The Geochemical Characterization of Mine Effluents from the Phosphorite Processing Plant of Kpémé (Southern Togo).

  Mine Water and the Environment Journal; Vol 28, No 1, 65-73; Berlin, Germany.

• Presence and Distribution of Toxic Trace Elements in Water and Sediments of the Southern Togo Rivers Watershed, West Africa,

  PSP Environmental Bulitin

• Distribution, Speciation and Extractability of Cadmium in the Sedimentary Phosphorite of Hahotoé-Kpogamé (Southern Togo),

  Journal of the 3rd International Conference on Environmental science and Technology

• Increased Bioavailability of Mercury in the Lagoons of Lome´, Togo: The Possible Role of Dredging

  AMBIO

  Surface sediments of the lagoons of Lome´, Togo, were analyzed for mercury, methylmercury, and trace elements. Concentrations were greater than typical for natural lagoon sediments, and with greater variability within the Eastern lagoon compared to the Western one. The Eastern lagoon is larger and has been dredged in the past, while the Western lagoon, which also receives major waste inputs, has not been dredged and shows less tidal flushing. Accordingly, one naturally believes that the Eastern lagoon is cleaner and probably safe to use due to its natural resources, including fishes to eat. Unexpectedly, we describe here that mercury methylation was greater in the Eastern lagoon, indicating increased bioavailability of mercury, as probably facilitated by past dredging that decreased solid phaseretention of inorganic mercury. Urbanization has historically been more developed in the southern part of the lagoons, which is still reflected in contamination levels of sediment despite dredging, probably because sources of contamination are still more important there today. Such urban contamination emphasizes the need to regulate waste discharges and possible airborne contamination in growing cities of developing countries, and implements environmental and public health monitoring, especially in relation to misbelieves systematically associated with the cleansing effect of dredging activity.

• Linking Groundwater Quality and Quantity: An Assessment of Satellite-Based Groundwater Storage Anomalies from GRACE Against Ground Measurements of Contaminants in California.

  Journal of Environmental. Science and Engineering B 1 (2012) 1271-1284.

  Abstract: Groundwater comprises a large portion of irrigation for California’s agriculture, and sustains a wide diversity of ecosystems as well as consumptive use, but pumping is occurring faster than replenishment. At the same time, contaminants from fertilizers and pesticides are infiltrating into the groundwater, becoming increasingly concentrated as water is extracted. It compared space-based observations of groundwater anomalies from California’s San Joaquin Valley using the GRACE (gravity recovery and climate experiment) against measurements of 42 organic and inorganic chemicals from 41,667 wells in the valley from 2003 to 2010. It compared Arsenic, Boron, Cadmium, Chloride, Selenium, Trichloroethylene, and TDS (total dissolved solid) concentrations with the groundwater storage anomaly from 2003 to 2010. The results show strong correlations for groundwater depletion against increasing chloride (r2 = 0.78, p < 0.05) and boron (r2 = 0.88, p < 0.05). This indicates increasing contaminant concentrations while groundwater was depleting over the last eight years. Solubilization by complexation with Cl, CO3 and/or organic chelates may account for the increasing concentration of some heavy metals when groundwater depletion occurs. These results are the first to link space-based groundwater mass change with groundwater contaminant concentration change.

• Distribution, Speciation and Bioavailability of Trace Metals in the Sedimentary Phosphorite of Hahotoé-Kpogamé Southern Togo.

  Aquatic Geochemistry Journal, Vol 15.

• The Geochemistry of Heavy Metals in Mudflat of Salinas de San Pedro Lagoon, California.

  Journal of Environmental Protection

  Sediment core samples were collected from the Salinas de San Pedro to assess the pollutant deposition processes in re-sponse to extensive human activities. Analysis of the sediment samples for heavy metals and some trace elements was conducted with ICP-OES for 20 sites showing enrichment for some of trace and heavy metals. The results demonstrated that heavy metal concentrations in mud varied greatly for each metal, with concentration values (mg/g) ranging from 1.05 - 4.8 (Al); 0.003 - 0.011(As); 0.001 - 0.005 (Cd); 0.02 to 0.82 (Cr); 0.085 - 0.47 (Cu); 5.98 - 14.22 (Fe); 0.06 - 0.19 (Mn); 0.03 - 0.67 (Ni); 0.05 - 0.38 (Pb); <0.008 - 0.069 (Se); 0.18 - 0.63 (Ti); 0.040 - 0.091 (V) and 0.149 - 0.336 (Zn). The Index of Geo-accumulation factor showed highest values for Pb, Mn, As, and Cu. Enrichment factors >1for these elements suggest anthropogenic inputs for most metals. The bioavailability of metals in lagoon sediments has the poten-tial to be highly dynamic with local waste and natural H2S discharge from existing fault line.

• The Geochemical Characterization of Mine Effluents from the Phosphorite Processing Plant of Kpémé (Southern Togo).

  Mine Water and the Environment Journal; Vol 28, No 1, 65-73; Berlin, Germany.

• Presence and Distribution of Toxic Trace Elements in Water and Sediments of the Southern Togo Rivers Watershed, West Africa,

  PSP Environmental Bulitin

• Distribution, Speciation and Extractability of Cadmium in the Sedimentary Phosphorite of Hahotoé-Kpogamé (Southern Togo),

  Journal of the 3rd International Conference on Environmental science and Technology

• Increased Bioavailability of Mercury in the Lagoons of Lome´, Togo: The Possible Role of Dredging

  AMBIO

  Surface sediments of the lagoons of Lome´, Togo, were analyzed for mercury, methylmercury, and trace elements. Concentrations were greater than typical for natural lagoon sediments, and with greater variability within the Eastern lagoon compared to the Western one. The Eastern lagoon is larger and has been dredged in the past, while the Western lagoon, which also receives major waste inputs, has not been dredged and shows less tidal flushing. Accordingly, one naturally believes that the Eastern lagoon is cleaner and probably safe to use due to its natural resources, including fishes to eat. Unexpectedly, we describe here that mercury methylation was greater in the Eastern lagoon, indicating increased bioavailability of mercury, as probably facilitated by past dredging that decreased solid phaseretention of inorganic mercury. Urbanization has historically been more developed in the southern part of the lagoons, which is still reflected in contamination levels of sediment despite dredging, probably because sources of contamination are still more important there today. Such urban contamination emphasizes the need to regulate waste discharges and possible airborne contamination in growing cities of developing countries, and implements environmental and public health monitoring, especially in relation to misbelieves systematically associated with the cleansing effect of dredging activity.

• Linking Groundwater Quality and Quantity: An Assessment of Satellite-Based Groundwater Storage Anomalies from GRACE Against Ground Measurements of Contaminants in California.

  Journal of Environmental. Science and Engineering B 1 (2012) 1271-1284.

  Abstract: Groundwater comprises a large portion of irrigation for California’s agriculture, and sustains a wide diversity of ecosystems as well as consumptive use, but pumping is occurring faster than replenishment. At the same time, contaminants from fertilizers and pesticides are infiltrating into the groundwater, becoming increasingly concentrated as water is extracted. It compared space-based observations of groundwater anomalies from California’s San Joaquin Valley using the GRACE (gravity recovery and climate experiment) against measurements of 42 organic and inorganic chemicals from 41,667 wells in the valley from 2003 to 2010. It compared Arsenic, Boron, Cadmium, Chloride, Selenium, Trichloroethylene, and TDS (total dissolved solid) concentrations with the groundwater storage anomaly from 2003 to 2010. The results show strong correlations for groundwater depletion against increasing chloride (r2 = 0.78, p < 0.05) and boron (r2 = 0.88, p < 0.05). This indicates increasing contaminant concentrations while groundwater was depleting over the last eight years. Solubilization by complexation with Cl, CO3 and/or organic chelates may account for the increasing concentration of some heavy metals when groundwater depletion occurs. These results are the first to link space-based groundwater mass change with groundwater contaminant concentration change.

• Distribution, Speciation and Bioavailability of Trace Metals in the Sedimentary Phosphorite of Hahotoé-Kpogamé Southern Togo.

  Aquatic Geochemistry Journal, Vol 15.