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Chromated Copper Arsenate
Chromated Copper Arsenate (CCA) is a highly effective chemical wood preservative that prevents wood from rotting or decay as a result of insect activity and fungi. CCA, which consists of copper, chromium and arsenic at differing concentrations is pressure treated into wood a method employed since its invention in India in the mid 1930’s. The manufacture of CCA makes industrial use of copper’s and chromium’s annual production but only minimally. However, it is highly appreciated, as a great consumer of arsenic which if left to accumulate is a hazardous toxic waste and cannot be otherwise utilized.
Copper is the main element amongst the three that protects the wood from fungi and other micro bacterial activity whereas arsenic is the ‘insecticide’ and supplements in the event that there are fungi resistant to copper. The chromium upon reacting with arsenic, copper and the pressure treated wood acts against rusting and the possibilities of leaching (Morrell).
CCA is highly toxic, a factor that makes it such a great wood preservative. Let us examine each of these elements separately. Copper is only toxic when in high concentrations. However, the main concern is the toxicity of copper-based systems in aquatic environments. Arsenic is a by product of major metal refining plants especially those dealing with copper. The use of arsenic as a poison especially in murders has fueled the opinion that amongst the three components it is the worst toxin. Arsenic has also raised great concern in the global arena because it is recognized as a known carcinogen and emphasis has hence been placed on its presence in drinking water. The chromium that is present in this said solution is present in its hexavalent rather than trivalent state. Hexavalent chromium is more toxic than the trivalent chromium found in treated wood and is another known carcinogen. Carcinogens are substances that directly cause cancer, aggravate it or are believed to cause cancer.
TOXICITIES OF COPPER CHROMIUM AND ARSENIC IN THE ECO SYSTEM
Copper, chromium and arsenic occur naturally in the earth's crust and copper and chromium are important micronutrients for many life forms (Hodson). These metals are especially found in higher concentrations in volcanic areas or regions that have a history of volcanic activity. Even in their natural occurrence in the environment they are highly toxic substances.
Chromium and Copper
Chromium is highly toxic to aquatic life however no data are available on the long-term effects of chromium to plants, birds and aquatic animals. On the other hand the fact that copper is used to kill fungi indicates that it is very poisonous to aquatic life. It is a known principle that between aquatic animals and plants, the former is generally more sensitive to the toxic effects of metals. Copper is recorded to be one of the most toxic metals to the aquatic ecosystem as it is semi soluble hence binds easily to organic matter and sediments.
Copper-exposed fish are at risk to death as copper affects their gills and olfactory systems. Fish gills lose their regulatory ability in transporting vital salts such as sodium chloride and potassium chloride that are necessary for the proper functioning of the fish’s nervous and cardiovascular body systems. Death is as a result of the salt imbalance in the body of the fish and the surrounding water that is its habitat.
Copper once in contact with the olfactory tissues competes for binding sites with natural odorants. A fish smells when natural odorants bind with olfactory receptor molecules hence the binding of copper to these sites reduces the fish’s sense of smell. Fish use their sense of smell for various survival purposes. The use it to migrate, get their prey as well as avoid being prey. This means that the copper exposed fish are more vulnerable to disease and predators and it translates into a reduced appetite hence reduction of food intake and subsequent death.
Considering that copper is used to reduce fungi action on wood then it comes as no surprise that once accidentally released into lakes and rivers it causes a decrease in algal growth. A decrease in algae causes a butterfly effect in the affected eco system. The amount of algal biomass present affects the availability of zooplanktons and insects in turn reducing the food available for fish and aquatic mammals. In the same manner that species of insects differ also does their diet and habitat. There are species of insects that survive in polluted waters while others cannot tolerate these waters. Presence of copper in a water body therefore means that there will be alterations in the insect species found in that water body and subsequently a change in the fish species. The presence of copper and also the varying amounts in an aquatic eco system creates ripple effects in the entire eco system.
Arsenic exists as an element and organic and inorganic compounds. In its elemental state it occurs as a metal like substance that is steel grey to the eye. Inorganic arsenic is naturally present in many soils and rocks as a chloride oxide or sulphide whereas organic arsenic is that combined with hydrogen or carbon.
The concentration of arsenic in soil varies widely with the general range at about 1 to 40 parts of arsenic to a million parts of soil (ppm) an average level of 3-4 ppm. It is important to note that soils in areas with arsenic-rich geological deposits, some mining and smelting sites, or agricultural areas where arsenic pesticides had been applied in the past may contain much higher levels of arsenic.
The natural levels of arsenic in water due to dissolving of the earth’s minerals and ores are low ranging from 1 to 2 micrograms per liter of water. Higher levels of arsenic in water can be attributed to industrial activities and the geological nature of a specific region.
Exposure to arsenic through say breathing or the food one eats or even drinking water is quite easy. This is so as it occurs naturally in the environment, does not have any smell or taste hence one may not be able to detect it in food air or water. Of these, exposure is greatest in the food we eat than in the water we drink or the air we breathe.
Moderate levels of arsenic as a result of drinking contaminated water in one’s body have been known to cause abdominal pain, queasiness, skin flush and rashes amongst other symptoms. High levels of arsenic in one’s body may lead to cancers and tumors especially cancer of the skin ass the hair and nails accumulate arsenic over time.
THE WILLAMETTE VALLEY
The Willamette valley is one of the most productive regions in Oregon and it is here that Eugene is located. Due to the high levels and seasonality of rainfall in the valley, the Willamette River is known for flooding.
The Willamette valley is very fertile and owes its high levels of agricultural productivity to flooding that occurred at the end of the last ice age and deposited silt rich in volcanic and glacial soils in the region till the south of Eugene. The area is well known for its production of some of the most expensive wines such as the pinot minor and has been recognized as a great wine producer. This are has also gained prominence for its production of agricultural produce in green houses and nurseries. The agricultural productivity of this region is not limited to only these, the region is a great producer of berries vegetables and other natural produce.
The great agricultural productivity in this region also means that it greatly consumes pesticides in treating the plants. Before the last decade, most pesticides especially those used in orchards used arsenic in their manufacture. This means that the area most likely has higher levels of arsenic in its environment than most due to emission from use of these pesticides
Composition of soils
Generally the soils found in Willamette valley where the city of Eugene is located are volcanic owing to the fact that the river basin was as a result of volcanic activity and tectonic plates.
Oregon is characterized by volcanic soils owing to the presence of Cascade mountain ranges in the region. Also soils of volcanic origin such as the weathered soils of Oregon have a great affinity for arsenic due to the presence of amorphous metal oxides.
The particular soil that is found in Oregon particularly in the Willamette valley is has high proportions of clay with balanced pH levels and adequate phosphorus, potassium, calcium and magnesium. These metals are highly reactive and would most probably react forming complex compounds that are insoluble in water and unavailable to plants.
Possibility of digging a well
An aquifier is a porous or permeable rock that holds water and allows for movement of water between non porous rocks that is found beneath the water table. Water seeps through to the ground till it gets to the saturation level. This saturation level is due to the region of non porous rocks that rests below the aquifier that no longer allow movement of water further inward. The water table is the highest level of the water and is found much higher in areas that experience high rainfall as compared to those with low levels of rain. Even in regions with high rainfall, it is much higher in the rainy season. Wells are usually dug into aquifier and the water extracted is what referred to as ground water that can be pumped out.
The aquifier present in this region is made of sand that is made up of altered volcanic material with many grains coated with iron. Sand has large air spaces between its particles making it very porous and since the region experiences high levels of rainfall it holds large amounts of water.
The inhabitants desire to obtain drinking water by the means of digging wells is therefore not unfounded. The aquifier below the water table in this region is viable for this purpose.
However considering the manner in which water gets to the aquifier through cracks and pores, there is a possibility that the water from the aquifier if a well were to be dug would be acidic. The seeping water would carry along with it traces of copper arsenic and chromium from the volcanic soils resulting from the existing and added amounts.
A figure showing how ground water is stored in rocks- an aquifier ( Source: USGS Water science for schools)
POSSIBILITIES THE COMPANIES ACTIVITIES MAY HAVE CONTAMINATED THE WATERS OF WILLAMETTE RIVER
The settling pond has a capacity of 10,000m3 translating to 106 liters of the used solution. Out of this only 10, 000 liters of the used solution spilled over and mixed with 90,000 liters of water. Considering that the location of the settling pond is an approximate 1km from the river and that the solution has a flow of 200m per day it translates that it would take an approximate of 4 days for the solution to get to the Willamette River.
Considering that the soils found in this region contain amorphous oxides in their make up which have a great affinity for arsenic, the percentage of arsenic that would get to the Willamette River from the original used solution would be very minimal. Furthermore these little amounts of arsenic that would eventually get to the river would not have a significant effect on the ecosystem. This is so as once arsenic from reaches water sources it is absorbed by sediments in the water making it not available to aquatic plants and animals.
Similarly the copper present in the chromated copper arsenate would also get absorbed into the soil and react with the metals present in this case the oxides in the weathered volcanic soils of the region considering the acidity of the used solution.
This area also like most in the Willamette valley has higher concentrations on arsenate than most which accrues from the agricultural activity especially that of the green houses and the nurseries. Secondly the soils of this area as mentioned earlier contain higher amounts of arsenate copper, potassium and other reactive metals as they are volcanic.
Despite this encouraging information, the increased levels of copper, chromium and arsenate in this region due to the company’s activities are not negligible. The company’s activities have served to increase the levels of these toxins to the pre existing levels due to the extended period of exposure (30-35 years) meaning that the little has accumulated over the years.
With the recent global trends that place emphasis on environmental sustainability and ecological responsibility, society is orienting its thinking towards an all encompassing notion of environmental responsibility. Hence despite the minimal effects that the company’s activities had on the eco system of Eugene, Oregon it is advisable for the company to hire a PR firm not only to enlighten the inhabitants on its activities in the region but also to direct on appropriate corporate social responsibility activities.
Hope is not lost for the possibility of obtaining safe clean water from wells as the water can be pumped and treated as a remediation method. This means extracting the water from the aquifier then treating it once it reaches to the surface not otherwise. Once the water has been effectively neutralized of all risks it can be returned to the aquifier or it can be discharged to be used. Using P&T as a remediation method means reducing the contaminants to levels acceptable in drinking water as it is not possible to completely eradicate. Contaminants in this situation as mentioned earlier occur naturally hence it would be unviable to try to completely do away with them.
In order to increase the efficiency of the pump and treat method, further contamination of the water can be minimized through measures of eliminating or isolating the source causing the contamination reducing any further introduction of contaminants as the method takes a number of years ranging from 40 to 60 to gain the required results.
It is untrue to remark that the fish floating up belly past the downtown bridge are solely due the activities of the All American Playground in Eugene Oregon. However to claim that the company did not have a hand in the death of this fish would be a fallacy. It is more futuristic to focus on how the already contaminated water can be remedied and how further contamination can be reduced rather than apportioning blame to the relevant parties.
Noting the high impact the contaminants have on the eco system both plants and animals and the normal functioning of the human body, remedial and preventive measures should be undertaken with speed and reasonable efficiency.
As remediation to the region of Eugene Oregon is possible, the inhabitants will be able to draw safe and clean water for drinking albeit after a considerable waiting period of water treatment.