Nonionic surfactants are amphilic chemicals that enhance desorption and bioavailability by increasing solubility and dispersion of poorly soluble hydrocarbons and oils. This study was conducted to determine the toxicity of commercial nonionic surfactants by using the Microtox ® Acute Toxicity test which is a rapid, simple test for toxicity. The test uses the luminescent bacterium V. fischeri as the test organism. Five common commercial nonionic surfactants Tergitol NP-10, Triton X-100, Igepal 630, Brij 35 and Tween 40 were used in the study. Light readings were taken initially as well as at 0 minutes, 5 minutes and 10 minutes to see how the toxicity of each surfactant changed with time. Experiments were conducted to determine the five-minute EC 50 values. EC 50 is the effective concentration that causes a 50% decrease in light output in a 5-minute exposure period. A higher effective concentration is interpreted as a lower toxicity. The critical toxic concentration (CTC) was also determined. Toxicity of the surfactants varied according to their difference in chemical structures and branching. EC 50 values were less than the CTC and CMC values of all select surfactants. Higher toxicity was shown by surfactant solutions that contained a benzene ring in comparison to the others.

Bangladesh is currently the subject of the world's largest mass arsenic poisoning in history. Groundwater throughout Bangladesh and West Bengal is contaminated with naturally occurring arsenic from the alluvial and deltaic sediments that form the region's aquifers. It has been estimated that 75 million people are at risk of developing health effects associated with the ingestion of arsenic. This project focuses on the use of microorganisms such as bacteria and algae to remove arsenic from water. Arsenic in the arsenite form was used in the studies. Experiments were conducted with a common alga and wastewater bacteria. A common green algae Scenedesmus abundans was used for determining arsenic uptake in batch experiments. Results of the experiments indicated that the algae biosorption could be modeled by the conventional Langmuir isotherm model. Algae morphology studies indicated that the algae cells were impacted due to the presence of arsenic as evidenced by clumping or loss of cell clusters. The wastewater bacteria also were capable of high percent of arsenic removal. Results indicate that microbial uptake of arsenic may be a viable method of pretreatment of arsenic contaminated water. However algae and sludge disposal would pose a problem and will have to be dealt with accordingly.

Increased nitrogen levels has been shown to be a problem in Southern New Jersey lakes, with anthropogenic loadings being the most serious concern (Aber, 1992). It has been suggested that biomass, diversity, and community structure of periphytic algae are good biotic indicators for monitoring water quality and nutrient enrichment in fresh water lakes. (Biggs, 1989). Since, for algae and many other aquatic organisms, nitrogen is one of the most important factors for growth, a good correlation it is expected between nitrogen loading and algal growth. In this bench‐scale microcosm study the periphytic community was analyzed using chlorophyll a, dry‐ash weight biomass and cell counts, as well as the diversity and community structure for a six‐month period, in three tanks with different nitrogen levels (control=non‐detectable; low and high). Physical (T/DO/pH) and chemical (nutrients) parameters were measured monthly. Biological parameters were compared with the different nitrogen loading using correlation analysis to show whether nitrogen is a factor in the over‐enrichment of New Jersey lakes. To compare the bench‐scale microcosm study with the natural settings periphytic algae from two Southern New Jersey lakes, Oswego Lake (no nitrogen) and Oakford Lake (high nitrogen), were also collected during fall of 2002 to summer of 2003.

No abstract

The application of engineering skills to address the needs of non-engineers are always desired by industry, and working on these applications is critical to the success of our students. Starting in spring 2005, a group of Rowan undergraduate students from Mechanical Engineering, Electrical and Computer Engineering, and Biology have been working together to develop a mobile aqua sensor under the guidance of faculty from each of these departments. Within one year's time, the group has designed and built three generations of prototypes, conducted several experiments, and modified our design with inputs from all parties and from empirical results.