MICROBIAL MOBILIZATION FROM URBAN SOILS TO LAKES AND PONDS

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 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 done in two fresh water lakes (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 (Baisley Pond; N 40^o 40′ 58″, W 73^o 47′ 10” and Bowne Pond; N 40° 46' 14", W 73° 48' 25") that vary in terms of recreational activities and different environmental settings. Soon we would also like to expand this study into the brackish water environment by going to Jamaica Bay in Jamaica, Queens. 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 counts of 1.01 x 10⁸ , 5.01 x 10⁵, and 2.30 x 10⁵ MPN/100mL for total coliform, E. coli and Enterococci respectively. Microbial counts in soils were at a very wide range from non-detectable to 4.04 x 10⁵, counts/Kg wet sample for total coliform. E. coli was detected at a range of non-detectable to 1.44 x 10⁵, and for Enterococci there was a range of non-detectable to1.7 x 10⁴. The physical properties of water including temperature, conductivity, salinity and pH varied in the lakes/ponds with a wide range of (21-31^oC), (101-4500 µS/cm), (0.04-5.7ppt) and (6.50-8.51) for temperature, conductivity, salinity and pH respectively. The study will be continued to identify the primary sources of this contamination and its variation, if there are any. The fate of microbes in the surrounding soils will be studied in the context of seasonal variation in water and soils of the fresh and brackish water environment.