On-site wastewater treatment systems (OWTS) can contribute nitrogen (N) to coastal waters. In coastal areas with shallow groundwater, OWTS are likely affected by meteorological events. However, the meteorological influences on temporal variability of N exports from OWTS are not well documented. Hydrogeological characterization and seasonal monitoring of wastewater and groundwater quality were conducted at a residence adjacent to the Pamlico River Estuary, North Carolina, during a 2-yr field study (October 2009-2011). Rainfall was elevated during the first study year, relative to the annual mean. In the second year, drought was followed by extreme precipitation from Hurricane Irene. Recent meteorological conditions influenced N speciation and concentrations in groundwater. Groundwater total dissolved nitrogen (TDN) beneath the OWTS drainfield was dominated by nitrate during the drought; during wetter periods, ammonium and organic N were common. Effective precipitation (precipitation [P] minus evapotranspiration [ET]) affected OWTS TDN exports because of its influence on groundwater recharge and discharge. Groundwater nitrate-N concentrations beneath the drainfield were typically higher than 10 mg/L when total biweekly precipitation was less than evapotranspiration (precipitation deficit: P < ET). Overall, groundwater TDN concentrations were elevated above background concentrations at distances > 15 m downgradient of the drainfield. Although OWTS nitrate inputs caused elevated groundwater nitrate concentrations between the drainfield and the estuary, the majority of nitrate was attenuated via denitrification between the OWTS and 48 m to the estuary. However, DON originating from the OWTS was mobile and contributed to elevated TDN concentrations along the groundwater flowpath to the estuary.

In July 2008, clusters of laboratory-confirmed cryptosporidiosis cases and reports of gastrointestinal illness in persons who visited a lake were reported to Tarrant County Public Health. In response, epidemiologic, laboratory, and environmental health investigations were initiated. A matched case-control study determined that swallowing the lake water was associated with illness (adjusted odds ratio = 16.3; 95% confidence interval: 2.5-infinity). The environmental health investigation narrowed down the potential sources of contamination. Laboratory testing detected Cryptosporidium hominis in case-patient stool specimens and Cryptosporidium species in lake water. It was only through the joint effort that epidemiologic, laboratory, and environmental health investigators could determine that >1 human diarrheal fecal incidents in the lake likely led to contamination of the water. This same collaborative effort will be needed to develop and maintain an effective national Model Aquatic Health Code.

A multistate Escherichia coli O157:H7 outbreak in August and September 2006 was found to be associated with consumption of fresh bagged spinach traced to California. The California Food Emergency Response Team (CALFERT), consisting of personnel from the California Department of Public Health Food and Drug Branch (FDB) and the U.S. Food and Drug Administration (FDA) undertook an environmental investigation to determine how and why the spinach became contaminated. At the invitation of FDA and FDB, the Centers for Disease Control and Prevention (CDC) also participated in the environmental investigation. This paper presents findings from the portion of the environmental investigation focusing on environmental factors related to irrigation water that may have contributed to contamination of the spinach and hence to the outbreak. Analysis of the available data suggests that depths to groundwater and groundwater-surface water interactions may pose risks to ready-to-eat crops. These risks should be further evaluated and quantified to understand and identify the factors that contributed to this and similar outbreaks. One implication of this analysis is the need to continue to conceptually broaden the scope of produce-related outbreak investigations. Where feasible, investigation strategies should integrate possible contamination sources beyond those actually found on the farms that are identified as sources of produce involved in outbreaks.

In 2007, approximately 20% of U.S. | households—60 to 65 million Americans— | were served by some type of onsite | wastewater (OWW) system (American | Housing Survey, 2008). We expect these | systems to safely disperse treated household | wastewater into the soil and help to recharge | aquifers. But these systems have been associated with groundwater contamination and | are possibly a threat to public health. Our | knowledge of the performance of OWW | systems remains inadequate. Thus, we need | to enhance the public health perspective | on OWW systems by better understanding | their performance through | developing monitoring methodologies, | and | conducting epidemiologic studies to determine their impact on human health. | Most OWW systems in the United States | are conventional systems (see Figure 1). | Data on performance of these systems and | their components are limited. Hoover, Rubin, & Humenik (1998) reported that OWW | systems result in desirable levels of treatment. Only a few researchers, however, have | reported on the quality of wastewater entering or leaving septic tanks without assessing | performance of these systems (Valiela et al., | 1992; Viraraghavan & Hashem, 1986). Levels of solids, organic matter, nutrients, microorganisms, and other constituents of raw | wastewaters and effluents are unknown for | conventional and alternative OWW systems, | making it difficult to determine the overall | performance of these systems.