Contents and mass balances of some potentially toxic elements in the wastewater-fed fish pond : a case study of Hoang Mai District, Hanoi, Vietnam | |
| Author | Le Thai Ha |
| Call Number | AIT Thesis no.EV-09-10 |
| Subject(s) | Water reuse--Vietnam--Hanoi Cadmium |
| Note | A thesis report submitted in partial fulfillment of the requirements for the degree of Master of Science |
| Publisher | Asian Institute of Technology |
| Abstract | The objectives of this study were to evaluate the contents of Cd and As in the water, sediment, water spinach (Ipoemoea aquatica), Common carp (Cyprinus carpio) and Tilapia (Orechromis niloticus) and their mass balances in a wastewater fed-fish pond in Hoangmai district, Hanoi, Vietnam. Samples were collected, prepared and analyzed by Graphite Furnace Atomic Absorption Spectrometry (GF/AAS). The total Cd concentrations in the water samples were lower than the Vietnamese standards for fresh water quality gudelines for protection of aquatic life, while the As concentrations in the inlet and outlet points of 45.86 and 23.22 μg/L, respectively, were higher than and may be toxic to the fish living in the pond and the surrounding vegetable farms because the outlet water was reused as irrigation water. About 63% of Cd entered the fish pond was in the suspended particular matter (SPM) form, while only 14% of As entered the fish pond was in the SPM form. The lower Cd and As concentrations in the outlet water than the inlet water showed that there were some removal processes of these two elements in the fish pond. The water spinach and fish in this wastewater fed-fish pond were considered safe for human consumption with respect of Cd and As because the concentration of two these compounds were below the International Maximum Limits and Vietnamese Maximum Limit. The mass balances analysis showed that 70% of total Cd and 12% of total As were accumulated in SPM which could have effects in the food chain and pose some health risks in the long term because SPM including plankton is main food for fish living in the pond.15% of Cd and 40 % of As accumulated in the pond sediment also could have effects if the sediment was dredged and applied to the surrounding agricultural fields. Further study is needed to determine the Cd and As removal mechanisms and the speciation fractions in the fish pond to properly assess their potential risks. |
| Year | 2009 |
| Type | Thesis |
| School | School of Environment, Resources, and Development (SERD) |
| Department | Department of Energy and Climate Change (Former title: Department of Energy, Environment, and Climate Change (DEECC)) |
| Academic Program/FoS | Environmental Engineering (EV) |
| Chairperson(s) | Chongrak Polprasert; |
| Examination Committee(s) | Shipin, Oleg V.;Thammarat Koottatep;Holm, Peter E.; |
| Scholarship Donor(s) | DANIDA Metsafe project (Vietnam); |
| Degree | Thesis (M.Sc.) - Asian Institute of Technology, 2009 |