Risk Assessment Of Metal Leaching Into Groundwater From Phosphate And Thermal Treated Sediments
Date
2009Author
Axe2, Lisa
Ndiba, Peter K.
Type
Technical ReportLanguage
enMetadata
Show full item recordAbstract
Beneficial reuse as an alternative to disposal is increasingly being considered in management of contaminated sediments dredged from harbors. The risk of metal leaching into groundwater in reuse of phosphate and thermal treated sediments was assessed with sequential extraction, synthetic precipitation leaching procedure (SPLP), and leaching as a function of pH and liquid to solid ratio (L/S). Sequential extraction revealed that phosphate addition at 5% by dry weight, followed by calcination at 700°C reduced metal association with exchangeable/carbonate and organic phases and increased that with sparingly soluble residuals. Over the pH range 4 to 9, metal leachability varied by two to four orders of magnitude while varying L/S over 5 to 100 showed little difference. The SPLP revealed that risk to groundwater criteria based on applying a dilution attenuation factor (DAF) of 13 (New Jersey) to groundwater quality levels were achieved. Risk criteria based on a DAF of 1 (Florida and Wisconsin) were exceeded for Pb, Cd, and Mn; thermodynamic analysis demonstrates that the criteria cannot be satisfied should dissolution control pore water concentrations.
Read More: http://ascelibrary.org/doi/abs/10.1061/(ASCE)EE.1943-7870.0000164
URI
http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29EE.1943-7870.0000164http://hdl.handle.net/11295/28580
Citation
Ndiba, P. and Axe, L. (2010). ”Risk Assessment of Metal Leaching into Groundwater from Phosphate and Thermal Treated Sediments.” J. Environ. Eng., 136(4), 427–434. TECHNICAL PAPERSPublisher
American Society of Civil Engineers Civil Engineering, University of Nairobi Civil and Environmental Engineering, New Jersey Institute of Technology (NJIT), University Heights, Newark,