MICROBIAL MOBILIZATION FROM URBAN SOILS TO LAKES AND PONDS: EXAMPLES FROM NEW YORK CITY

Anthropogenic activities cause an increase of organic materials and nutrients and this poses a serious threat in urban environments. The densities of fecal indicator bacteria (FIBs) in the urban area exhibit a clear land-use dependency in the natural water and are often linked with nutrient inputs. Data from preliminary investigation indicated elevated FIBs in soil and water of a New York City (NYC) lake even in the winter. Very few studies on mobilization of FIBs in natural water from surrounding soils were reported in NYC area In an attempt to study temporal and spatial bio-geochemical dynamics of both fresh water environment, the study was performed in two fresh water lakes including Corona Meadow Lake (N 40^o 44′ 19″, W 73^o 50′ 46″) and Oakland Lake (N 40° 45' 31", W -73° 45' 33") and in two fresh water ponds representing Baisley Pond (N 40^o 40′ 58″, W 73^o 47′ 10”) and Bowne Pond (N 40° 46' 14", W 73° 48' 25"). These water bodies vary in terms of recreational activities and different environmental settings. This study focused on environmental research to improve understanding of FIBs transport processes in the environmental system which is a critical aspect of decision-making in risk assessment, and remediation strategies. Results from Meadow Lake were found to dramatically exceed the EPA permissible limit for FIBs with the concentration of 1011200, 501350 and 230700 MPN/100mL for total coliform, E. coli and Enterococci respectively. Microbial sediment counts were at a very wide range of 800 to 80,200 counts/Kg wet sample for total coliform. No E. coli was detected and for Enterococci there was a range of where in some places, no microbes were detected. The physical water parameters are somewhat similar for temperature (4.2-5.3 degree C), conductivity (6850-7890 µS/cm), and different for salinity (3.6-4.4 ppt). Salinity concentration may be due to surface melt water runoff charged with salt solution during the winter. The study will be continued to identify the primary sources of this contamination and its variation, if there are any.