water pollutants and water pollution

Question 1

what are markers of water pollution?

Answer 1

are observable manifestations of pollution sources
-these include herbicide indicative of agricultural runoff, fecal coliform bacteria that are characteristic of pollution from sewage, and pharmaceuticals, pharmaceutical metabolites and even caffeine that show contamination by domestic wastewater

Question 2

what are biomarkers of water pollution?

Answer 2

are organisms that live in or closely associated with bodies of water and that provide evidence of pollution either from accumulation of water pollutants or their metabolites or from effects on the organism because of pollutant exposure

Question 3

what are the general types of water pollutants?

Answer 3

-trace elements
-heavy metals
-metalloids
-inorganic chemicals

Question 4

what are the heavy metals found in water?

Answer 4

-cadmium
-lead
-mercury

Question 5

what is cadmium in water?

Answer 5

cadmium pollution arises from mining wastes and industrial discharges, like metal plating
-is very similar to zinc, so these two metals frequently undergo geochemical processes together. Both metals are found in water in the +2 oxidation state
-typically, during summer when the water stagnates, the anaerobic bottom layer of harbor water has a low soluble Cd concentration because microbial reduction of sulfate by organic matter, (CH2O), produces sulfide, which precipitates cadmium as insoluble cadmium sulfide
-this dissolved cadmium is carried out into the bay where it is absorbed by suspended solid materials, which become incorporated with the bay sediments

Question 6

what is lead in water?

Answer 6

inorganic lead arises from a number of industrial and mining sources

Question 7

what is mercury in water?

Answer 7

because of its toxicity, mobilization as methylated forms by anaerobic bacteria, mercury generates a great deal of concern
-most inorganic forms of mercury are relatively insoluble
-formation of soluble monomethylmercury ion (CH3Hg+) and volatile dimethylmercury (CH3)2HG by anaerobic bacteria in sediments
-mercury from these compounds becomes concentrated in fish fat
-it is believed that the bacteria that synthesizes methane produce methylcobalamine as an intermediate in the synthesis. Thus, waters and sediments in which anaerobic decay is occurring provide the conditions under which methylmercury production occurs. In neutral or alkaline water, volatile dimethylmercury may be formed

Question 8

what is the most concerning metalloid in water pollution?

Answer 8

arsenic
-like mercury, arsenic may be converted to more mobile and toxic methyl derivatives by bacteria, first by reduction of H3AsO4 to H3AsO3 and then by methylation to produce CH3AsO(OH2)

Question 9

what are the inorganic species in water pollution?

Answer 9

-cyanide
-ammonia and other inorganic pollutants

Question 10

what is ammonia and other inorganic pollutants?

Answer 10

-hydrogen sulfide
-free carbon dioxide
-nitrite ion
-sulfite ion
-perchlorate ion