Organic compounds and trace metals of anthropogenic origin in sediments from Montego Bay,Jamaica: assessment of sources and distribution pathways

Surface sediments throughout Montego Bay, Jamaica were collected in 1995 and analyzed for their trace metal and trace organic contaminant content. A variety of trace metals, petroleum hydrocarbons, polycyclic aromatic hydrocarbons, coprostanol as well as chlorinated hydrocarbons such as pesticides and polychlorinated biphenyls were detected and provide evidence for several anthropogenic inputs to the bay. Two main sources of these chemicals are the Montego River and the North Gully, the latter being more significant. Particle-associated pollutants were found to be distributed along the Montego River plume, as well as being transported by the prevailing water currents to the South-Western sections of the bay, probably through re-suspension of enriched fine sediments from the North Gully outfall area.     

Assessment of management-dependent nutrient losses in tropical industrial tree plantations

Industrial tree plantations in the tropics usually follow short rotations and intensive site management including slash and burn, and the use of heavy machinery. We attempt to quantify the implied nutrient losses (harvest export, erosion, slash and burn, leaching) in order to give plantation managers a chance to understand the significance of their planning and decisions. We used the scarce globally available information and a case study plantation in East Kalimantan, Indonesia (Acacia mangium and Eucalyptus deglupta). Adaptation involves problems and is discussed in some detail. Results are approximate only. Assuming a harvest volume of 200 m3 ha(-1), we assessed a loss of 427-680 kg ha(-1) N, 12-13 kg ha(-1) P, 178-252 kg ha(-1) Ca, 276-370 kg ha(-1) K, and 45-57 kg ha(-1) Mg per rotation. Of this overall loss, stand harvest accounted for 18-29% (N), 21-30% (P), 56-26% (K), 48-64% (Ca) and 22-37% (Mg). This means that the cumulative loss by erosion, slash and burn, and leaching exceeds that of the harvest. These losses can be influenced by management.     

Soil degradation and agricultural sustainability: an overview from Iran

During the past six decades, agriculture as a main sector in Iran’s economy has been affected by economic development, land-use policies, and population growth and its pressures. From the 1940s until 2010, the percentage of the total urban population of Iran increased from about 21?% to around 72?%. Urbanization, industrialization, and intensive cultivation have dramatically affected soil and water resources. The exploitation of groundwater has been increased around fourfold from the 1970s to the mid-2000s. Total water resources per capita reduced around 23?% from 1956 to 2008. The average annual decrease in the groundwater table in Iran during the last two decades is 0.51?m. In 2008, the groundwater table fell around ?1.14?m in average in Iran. The average use of chemical fertilizers increased from around 2.1?million tons in 1990s to about 3.7?million tons in 2009. During that period, fertilizer use efficiency decreased from around 28?% to around 21?%. Approximately 77?% of the agricultural land under irrigation suffers from different levels of salinity. According to the quantification of four indices, such as soil erosion, fall in groundwater levels, salinity, and use of chemical fertilizer, that are directly related to agricultural land use, the results show that agricultural management in Iran needs special attention to reach sustainable conditions. The total cost of soil and water degradation and use of fertilizers in agriculture are estimated around than US $12.8?billion (about 157,000?billion IRRials)—approximately 4?% of the total gross domestic product (GDP) and approximately 35?% of the GDP of the agricultural sector in Iran.     

Fusion of SeaWiFS and TOMS Satellite Data with Surface Observations and Topographic Data during Extreme Aerosol Events

ABSTRACT

Spaceborne sensors allow near-continuous aerosol monitoring throughout the world. This paper illustrates the fusion of Sea-Viewing Wide Field-of-View Sensor (SeaWiFS) and TOMS satellite data with surface observations and topographic data during four extreme aerosol events: (1) the April 1998 Asian dust storm that impacted the west coast of North America, (2) the May 1998 Central American forest fire smoke that impacted eastern North America, (3) the intense fall 1999 northern California fires, and (4) the massive February 2000 Sahara dust storm. During these dust and smoke events, the aerosol was visualized on true color SeaWiFS images as a distinct yellowish dye, the result of the aerosol increasing the reflectance of darker surfaces (ocean and land) and decreasing the reflectance of clouds. TOMS imagery also indicated increased aerosol absorption in the affected areas, while surface monitors measured major reductions in visual range. Fusing these data aids in the determination of the aerosol's spatial, temporal, and optical properties and provides supporting evidence for characterizing what is being visualized as dust or smoke. A 3-dimensional perspective of the events is obtained when incorporating topographic data and provides insight into the vertical properties of the aerosol plumes.