نتایج جستجو برای: anthropogenic factor

تعداد نتایج: 867506  

Journal: :journal of research in health sciences 0

background : airborne particulate matter is one of the most important atmospheric pollutants. tile sources of particulate matter in the atmosphere are divided into two groups; 1) natural sources and 2) anthropogenic sources. the important components of airborne particulate matter and invarying concentrations are the ubiquitous components of the lower atmosphere. heavy metals are mainly emitted ...

2013
Helen M. Amos Daniel J. Jacob David G. Streets Elsie M. Sunderland

[1] Elevated mercury (Hg) in marine and terrestrial ecosystems is a global health concern because of the formation of toxic methylmercury. Humans have emitted Hg to the atmosphere for millennia, and this Hg has deposited and accumulated into ecosystems globally. Here we present a global biogeochemical model with fully coupled atmospheric, terrestrial, and oceanic Hg reservoirs to better underst...

Journal: :international journal of environmental research 2010
c.s. ratheesh kumar m.m. joseph t.r. gireesh kumar k.r. renjith m.n. manju

heavy metals in the surface sediments of the two coastal ecosystems of cochin, southwest india were assessed. the study intends to evaluate the degree of anthropogenic influence on heavy metal concentration in the sediments of the mangrove and adjacent estuarine stations using enrichment factor and geoaccumulation index. the inverse relationship of cd and zn with texture in the mangrove sedimen...

2007
Sarah A. Strode Lyatt Jaeglé Daniel A. Jaffe Philip C. Swartzendruber Noelle E. Selin Christopher Holmes Robert M. Yantosca

We examine the trans-Pacific transport of mercury using a global chemical transport model. Using existing anthropogenic inventories, the model reproduces the observed Hg/CO ratio in Asian long-range transport events observed at a surface site in Okinawa, Japan and Mount Bachelor, Oregon, with an underestimate of 18-26% in the ratio. This is in contrast with previous studies that inferred a fact...

2015
John P. Y. Arnould Jacquomo Monk Daniel Ierodiaconou Mark A. Hindell Jayson Semmens Andrew J. Hoskins Daniel P. Costa Kyler Abernathy Greg J. Marshall Daniel E Crocker

Human-induced changes to habitats can have deleterious effects on many species that occupy them. However, some species can adapt and even benefit from such modifications. Artificial reefs have long been used to provide habitat for invertebrate communities and promote local fish populations. With the increasing demand for energy resources within ocean systems, there has been an expansion of infr...

2009
Abbas F.M. Alkarkhi

Multivariate statistical techniques such as factor analysis (FA) and Discriminant analysis (DA), were applied for the evaluation of spatial variations and the interpretation of a large complex water quality data set of two rivers (Juru and Jejawi) in Malaysia, monitoring 10 parameters at 10 different sites each. Factor analysis resulted in two factors explaining more than 82% of the total varia...

2014
D. Polson M. Bollasina G. C. Hegerl L. J. Wilcox

The Northern Hemisphere monsoons are an integral component of Earth’s hydrological cycle and affect the lives of billions of people. Observed precipitation in the monsoon regions underwent substantial changes during the second half of the twentieth century, with drying from the 1950s to mid-1980s and increasing precipitation in recent decades. Modeling studies suggest that anthropogenic aerosol...

A. Parizanganeh A. Zamani M.R. Yaftian

Heavy metal contamination around the National Iranian Lead and Zinc Company (NILZ) in Zanjan province was evaluated in this paper. Collected data were used to appraise the degree of soil contamination and also the source of pollution in the study area based on geoaccumulation index (Igeo), and enrichment factor (EF). The levels of Fe, Zn, Cd and Pb in the samples exceed those reported in litera...

Background and Purpose: The contamination by potentially toxic element (PTE) is a common environmental issue in worldwide rivers. The present study examined PTEs concentration in sediments of Talar River which is one of the main rivers in the Sothern Caspian Basin. Materials and Methods: The sediment samples (n= 44) were collected from top 0–5 cm of surface sediment in the main channel and flo...

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