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SECTION TWO Question1. Is this an Acute or Chronic Environmental Threat? The presence of heavy metals in our environment causes chronic hazards to aquatic life and environment. This is because the metals are accumulative poisons that affect their health adversely when they expose or consume them frequently for a longer period of time. Similarly, it has a long-term effect on the environment through constant emissions or discharge to soil, water and surface depending on the source of the contaminants, level and duration of exposure (Palmer 121) Question 2 Is this a systemic (ecosystem) or Targeted Species Threat?
Heavy metals are majorly released into the environment largely by manmade activities such as industrial processing and discharge from sewage plants and agricultural activities. This makes it to be more hazardous to both environment and aquatic life, hence, attracting deep concern globally on its mitigation options and control. Question 3 How likely is it that the chemical will be discharged in sufficient amount to do serious harm? The rate at which wastes from the industries and agricultural or sewage plants are releasing their contaminated discharges having lethal heavy metals into aquatic environment is astonishingly high.
Given that these activities are manmade and owing to steady increase of global population, the rate at which these activities takes place also increases, generating sufficient amount of deadly heavy metals into marine ecosystem that can result into negative impact on the lives of aquatic population. Question 4 How severe are the consequences of the potential exposure? Potential exposure to heavy metals has adverse effects to aquatic life. For example, presence of cadmium in the ecosystem and in aquatic environment poses adverse effect to both the environment and the aquatic life.
According to UNEP (2002), it is recognized as one of the most lethal hazardous water contaminants and could be harmful at every level in ranging from organism to cell elements. The harmful value for fish falls within the acceptable limit range of 0.5 ?g/dm3 to 21.1 mg/dm3. Given that this heavy metal has a chronic effect, its accumulative contamination effects can cause detrimental disturbance to aquatic life and the ecosystem. For example, in the case of fish, its effects range from abnormal behavior in fish metabolism, movement behavior to anorexia.
Safety and Health Agency (OSHA) clarifies that it is a prospective aquatic carcinogen and is highly linked with anomalous functioning of the aquatic blood cell system. Based on its effects, both the species of chromium are connected to DNA malfunctions of the aquatic animal upon exposure. Similarly, long term accumulation of chromium in the marine environment has adversely affected the aquatic life in this ecosystem. Chromium majorly exist in both Cr (III) and Cr (VI) oxidation states. Chromium (VI) is considered to be more disastrous to aquatic life compared to the former ion Cr 3+.
This is because it is readily soluble and mobile in aquatic environment. Question 5 How wide spread is the ecological threat - How many ecosystems and/or species are threatened by the expected exposure? According to Environmental Protection Agency (EPA) report released in 2004, this group of
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