Impact of Humans

Microbial cells with high urease activity Enzymes Fungal cellulose Living cells 

Microbial single cell protein production Immobilization enzymes Ionic control of immobilized acid phosphatase 

Feed-grade protein from carbohydrate cabohydrate 145 

Kinetics of enzyme bound to cell walls of sycamore 113 

While the contribution of extracellular nitrogenous compounds is uncertain, preparations of poplar (Populus) sp. leaves have been used as a high-energy feed supplement for livestock (e.g., 36). Some preparations may contain toxic extracellular compounds. Lectins from Robinia pseudoacacia are toxic to mammalian cells, and have been explored as therapeutic agents in cancer patients (cf., 81, 88). 

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Over the course of human history rivers have reflected the impact of human activity. Since the beginnings of the great civilizations 5000 years ago, humankind, in its pursuit of agriculture, exploration and conquest, has exploited and mistreated the environment on a broad scale. Major changes on the face of the earth occurred. Forests were cut, pastures grazed, fields cleared and plowed "... as the landscape was carved to fit the new economic demands of humankind." (7). Such changes have been well documented (2-5). 

A Semi-quantitative Approach Erosion and Deposition. Over the centuries the primary impact of human activity has been to deforest the surrounding countryside and increase the rate of erosion and deposition into rivers. This results primarily from the destruction of vegetation cover which stabilizes soil systems on gradient. The ecological impact of erosion has at present reached catastrophic proportions. The magnitude of continental erosion into rivers is illustrated in Figure 3. 

Figure 3. Process for assessing impact of human land use activity on river quality.

The results of map generation cannot be expressed effectively with the format available here. However, the State of Oregon utilized the map and matrix techniques in their nonpoint source evaluation and as a basis for designing more intensive survey approaches to assessing the impact of human activity on river quality. In addition to reflecting deposition of sediments, the methods can be applied to transport of pesticides, nutrients and trace elements since many of these substances tend to adsorb to the organic and inorganic fractions of soil. 

Mercury provides an excellent example of the importance of metal speciation in understanding biogeochemical cycling and the impact of human activities on these cycles. Mercury exists in solid, aqueous, and gaseous phases, and is transported among reservoirs in all these forms. It undergoes precipitation-dissolution, volatilization, complexation, sorption, and biological reactions, all of which alter its mobility and its effect on exposed populations. The effect of all... 

Mink M, Mosier SM, Janumpalli S, Davison D, Jin L, Melby T, Sista P, Erickson J, Lambert D, Stanfleld-Oakley SA, Salgo M, Cammack N, Matthews T, Greenberg ML (2005) Impact of human immunodeficiency virus type 1 gp41 amino acid substitutions selected during enfuvirtide treatment on gp41 binding and antiviral potency of enfuvirtide in vitro. J Virol 79 12447-12454... 

The synthesis of toxic organic compounds by humans, and their release into the natural environment began to assume significant proportions during the 20th century, especially after the Second World War. Prior to 1900, the chemical industry was relatively small, and the largest chemical impact of humans on the environment was probably dne to the release of hydrocarbons, especially polycyclic aromatic hydrocarbons (PAHs), with the combnstion of coal and other fuels. 

In this introductory chapter, a broad overview is given of the history of chemical warfare on earth, and the compounds, species, and mechanisms involved. The impact of human-made compounds on the environment, which is the subject of this book, is an extremely recent event in evolutionary terms. It is important to take a holistic view, and to see the effects of human-made pollutants on the environment against the background of chemical warfare in nature. 

Epps, P.G., White Pill, Yellow Pill, Red Pill, Brown Pill Pharmacoeconomics and the Changing Face of Medicine The Challenges and the Impact of Humane Genome Research in Minority Communities. Zeta Phi Beta Society, Inc., National Educational Foundation, July 7-8, 2000, Philadelphia PA (2000). 

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