Our project aims to take up two hazardous substances from the environment: cadmium and sulphate. As part of the project we looked at the impact each of these has on their surroundings and weighed the prose and cons of using synthetic biology to solve this problem. For the full report, see the link below

Cadmium in the Water...

Cadmium in natural waters exists as either free/aquated cation (Cd²⁺/CdOH⁺)^[1] this is due to the competition of organic binding resulting in aluminium causing the almost complete displacement of cadmium.

A large amount of cadmium pollution in water ways is due to either industrial waste or fertilizers produced from phosphate ores. In unpolluted natural waters the cadmium concentrations are usually below 1μg/l^[2] however the maximum level ever recorded was in Rio Rimao in Peru at 100μg/l^[3]. The WHO have set the guideline level of cadmium in global drinking waters as 3μg/l^[4] In 2007 UNEP stated these would be the parameters set for water quality as a global index^[5].

References

1. Posselt, H. S., Weber, W. J., (1974) Environmental chemistry of Cd in aqueous systems. In. Rubin, A. J. (ed) Aqueous environmental chemistry of metals. Ann Arbor Science Publ. Inc., Ann Arbor, Michigan, p 255-289
2. Friberg L, Nordberg GF, Vouk VB, eds. (1986) Handbook of the toxicology of metals.Vol. II. Amsterdam, Elsevier, pp. 130–184.
3. WHO/UNEP (1989) GEMS — Global fresh water quality Published on behalf of the World Health Organization/United Nations Environment Programme. Oxford, Blackwell Reference.
4. WHO. (2004.) Guidelines for Drinking-water Quality. Third Edition Volume 1:Recommendations. World Health Organisation, Geneva
5. United nations environment programme global environment monitoring system (GEMS)/ water programme (2007) Global drinking water quality index development and sensitivity analysis report. Burlington p 7.

...and Cadmium in People

The main issues with cadmium getting into waterways and food supplies are the affects that it will have on the people who ingest it. The effects of cadmium poisoning can be devastating as it is a known carcinogen and can consequently lead to death if ingested in large quantities. The other l effects of cadmium ingestion include:

• Gastrointestinal effects such as nausea, vomiting, salivation, abdominal pain, cramps and diarrhea^[1]

• Anemia due to the cadmium resulting in a lower level of iron intake in the gastrointestinal region, this is especially problematic if the affected individual already has low levels of iron intake in their diet^[2]

• Kidney damage is a common symptom of cadmium toxicity which further leads to a decrease in production of vitamin D^[3]

• Osteomalacia and osteoporosis both of which lead sufferers to have increased chance of bone fractures and lower bone density ^[4]. This may be as a result of the kidney damage giving way to decreased levels of vitamin D. ^[5]

References

1. Buckler, H. M., Smith, W. D., Rees, W. D. (1986) Self poisoning with oral cadmium chloride. Br Med J. 292(6535), 1559–1560.
2. Kagamimiori, S., Watanabe, M., Nakagawa, H., Okumura, Y. (1986) Case- control study on cardiovascular function in females with a history of heavy exposure to cadmium. Bull Environ Contam Toxicol. 36 (4), 484-490.
3. Arisawa, K., Nakano, A., Saito, H. et al. (2001) Mortality and cancer incidence among a population previously exposed to environmental cadmium. Int Arch Occup Environ Health. 74, 255-262.
4. Shigematsu, I. (1984) The epidemiological approach to cadmium pollution in Japan. Ann Acad Med Singapore. 13, 231-236.
5. Kido, T., Nogawa, K., Yamada, Y., et al (1989) Osteopenia in inhabitants with renal dysfunction induced by exposure to environmental cadmium. Int Arch Occup Environ Health. 61, 271-276.