There's poison in the drinking water!!!

Last week I mentioned a handful of the chemicals that I keep stumbling across in my research on cigarette butts; Cadmium, arsenic, and lead. I was asked the question: “What levels are acceptable in the environment, based on EPA standards, and what levels actually produce the impacts that you mentioned in your post?” 

while looking at the EPA website I could only find the “acceptable” levels for drinking water and they are as follows:

Cadmium- 0.005 mg/L

Arsenic- 0.010 mg/L

Lead- 0.015 mg/L

However I have been trying to research the different chemicals that are associated with cigarette butts and the tobacco within them and I was running into very vague explanations. After extensive research over the past weeks finally (Eureka!) I have found information on the chemical’s effects on the marine environment! I found a UK website that researched the effects of the chemicals on marine environments and the toxic levels.

Cadmium is naturally found in the earth’s crust at an average concentration of 0.1 mg/kg and is in higher concentration in sedimentary rocks. Cadmium also occurs naturally in the atmosphere because of volcanic activity; this atmospheric cadmium is absorbed by phytoplankton in the ocean’s surface waters and then transported to the depths. Due to upwelling the cadmium will be brought back to the surface and added to the concentrations from human activity. Cadmium is toxic to a range of micro organisms and effects the growth and replication. What I found interesting is that apparently the toxicity is reduced by the presence of sediments and high concentrations of dissolved salts and organic matter. I am expecting the presence of sand and aquatic plants will have a positive result on the levels of cadmium when I run my experiments. Certain factors like increased temperature, lowered salinity, and the combination with zinc will increase the toxicity on marine invertebrates effecting not only the growth and reproduction but also cause structural abnormalities in gill structures. The effects of cadmium toxicity on fish include malformation of the spine and is most susceptible to the embryo and larvae, surprisingly the egg is least susceptible to the effects of toxicity. To answer the question about the “acceptable” levels in the environment are any concentrations above 2.5 µg/l in the water column and 0.7 mg/kg in sediments (Canadian interim marine sediment quality guidelines) pose a risk to marine organisms and sediment dwelling organisms

Lead is poorly soluble in water so its main entry into the water is through releases. Due to its low solubility in water lead deposits into sediments and suspended particles. The organic compounds are found to be more toxic than the inorganic lead salts to fish and is more susceptible to younger fish than adults and eggs; the symptoms of lead toxicity include spinal deformity and blackening of the caudal region. The toxic range for fish has been documented as a range from 0.04 mg/L to 0.198 mg/L. Since lead deposits into the sediment it can possibly be toxic to sediment-dwelling organisms at concentrations above 30.2 mg/kg. Lead will bioaccumulate in the environment and it is unsure whether organisms absorb the lead or consume it. In fish lead is accumulated mostly in gill, liver, kidney, and bone. The eggs show increasing lead levels with increased exposure concentration, but there are indications that lead is present on the egg surface and not accumulated in the embryo. In shell fish the lead accumulates in the shell rather than the flesh, and dolphins will pass it to young through fetal development and lactation. The acceptable levels in the environment are as follows: acute toxicity to algae, invertebrates and fish at concentrations of dissolved lead above 10 µg/L annual average in the water column and concentrations above 30.2 mg/kg in sediment will effect sediment dwelling organisms. 

Arsenic is naturally found in the environment as a result of biological activity, the acceptable range of arsenic in the marine environment is 25 mg/L annual concentrations. Concentrations in sediments above concentrations above 7.24 mg/kg have been found to pose a risk for sediment dwelling organisms. Bioaccumulation can occur due to the sediments and the water column; however it is not biomagnified in food chains. This means that arsenic will accumulate in the environment through sediments and suspended particles, and will be absorbed by organisms, but will not be increased from fish feeding on each other like the accumulation of mercury.