Influence of pollutants on environmental and human health

¶ … globalization on the environment are both empowering and detrimental. Improvements in technology and the resulting increase in lifespan and access to medical care in the developing world place pressure on the environment via pollution, overpopulation, and possible global warming. Drastic mistakes made by First World countries during their period of modernization began a long cycle of environmental problems. As the underdeveloped world searches for its place in global culture, pressures on the environment will, if not mitigated, increase and ultimately may damage the earth to the point of mankind's inability to rectify the situation (Speth, ed, 2003).

Nowhere is this more endemic than the preponderance of chemicals that leech through the environment and collect within plants or species. Shellfish and crustaceans, for instance, are particularly susceptible to this, and zinc ion concentrations are particularly problematical as they interfere with hematological activity. Heavy metal toxicity is nothing new, and has been investigated since the 1970s, however, we now have certain populations that have been exposed to these toxins for over four decades, perhaps more, and considering the life-cycle, this means multiple generations.

One particular study looked specifically at the manner in which zinc levels influenced the immune response of the rather prolific species of Holothuria polii, an ocean invertebrate often inhabiting heavily polluted coastal waters. In this case, the study found that high levels of zinc ions does have a negative effect on immune and regenerative responses. However, the effect seems to be reversible and these particular invertibrates do not necessary store the toxins lifelong (Canicatti and Grasso, 1988).

Literature Review - One significant waste product in modern mining and factory run-off is zinc. In the mid-1970s, these levels were measured from the mine-waste in North Wales and a population study was made on the resident macro-invertebrate communities approximately 60 meters downstream from the input. Results shows a significant decrease in population levels in comparison with like areas, and those species that remained showed signs of stress and disease (Willis, 1985).

Zinc is also a predominant component in batteries of all types, and although a number of strides have occurred that lessen the potential for environmental contamination, the unfortunate chemical action of zinc actually allows it to disperse in a wider pattern when mixed with water, particularly salt water (Laws, 2000, 409). Because the natural environment is unpolluted by zinc, however, it is easy to measure contamination and levels that move towards toxicity. Zinc in the soil also leeches into the aquifer, and thus has the potential for a lengthy and long environmental detriment (Nriagu, 1980, 380-2).

Minute traces of zinc are, in fact, essential for human health, although excessive zinc may be helpful in that it suprpresses copper and iron absorption (Fosmire, 1990). Levels of zinc in excess of 500 ppm in soil likewise interfere with a plant's ability to absorb essential minerals and thus take on symptoms much like anemia (Emsley, 2001, 499-505). In the waterm, invertebrates are often the first and easiest to examine for zinc toxicity as their bodies seem to absorb the metal quicker and with quicker, as well as longer lasting, effects. This is true in fresh and well as salt wate, zinc seems to spread more rapidly in sea water, even affecting higher animals (Taban, Cathiene and Burkard, 1982).

Research Project - The term scientific method refers to a way of investigation or the acquisition of knowledge through the testing of a theory or hypothesis, then working through measurements (observation and empirical notes) to come up with a result, which should prove or disprove the original theory. Thus, the basic method consists of a) formulating a question or hypothesis, b) designing an experiment or means of collecting data, c) observation or experimentation, d) analyzing the results and considering the proof or disproof of the hypotheses, and e) suggestions for future research (Cary, 2003).

In this case, and because invertebrates are relatively easy to access regarding zinc the following is a simple introductory examination on the topic:

Freshwater crayfish, particularly the species of marbled Procambarus Marmorkrebs, are easily accessible through the aquarium hobby industry. They are also the only known crayfish to clone itself and their patterns of behavior and reproduction have been well documented.