No abstract

Safe potable water is a luxury that is generally unavailable to the majority of rural and suburban populations of developing, underdeveloped, and often developed countries. Important considerations in the development and maintenance of safe water supplies is the availability and use of efficient, inexpensive, and appropriate technology for removing microbial hazards, parasites, and toxicants. The Manz intermittent slow sand filter was known to be user friendly, small enough to fit into the smallest kitchen, and could remove up to 97% of the fecal coliforms present in the raw water before treatment by the Manz filter. This filter was evaluated for its ability to remove parasitic cysts and toxicants as well as bacteria. Using two different filters and two different water supplies our results indicated that the intermittent slow sand filter could remove 83+% total heterotrophic bacterial populations, 100% of Giardia cysts, 99.98% of Cryptosporidium oocysts, and 50–90% of organic and inorganic toxicants when administered in concentrations varying from 10–>100× environmental pollution levels. Methodology details are provided in the paper. ©1999 John Wiley & Sons, Inc. Environ Toxicol 14: 217–225, 1999

Highway runoff is a significant source of contaminants entering many freshwater systems. To provide information on effects of highway runoff on aquatic biota, runoff samples were collected from three sites representing different classes of highways with low, intermediate and high traffic intensities.Samples were analysed for chloride, trace metals and polycyclic aromatic hydrocarbons (PAHs).Runoff from a major multilane divided highway, with the highest traffic intensity, contained the highest levels of chloride (45- A companion paper discusses spatial and temporal aspects of contaminant-associated toxicity of highway runoff.

In trying to establish the extent and degree of impact of point and nonpoint source contaminants on riverine systems, it is important to know the implications of the data obtained from various sampling points in a riverine system. Spatial variability between water and/or sediment samples collected in close approximation at the same sites was assessed by the battery of tests approach. In these samples there appeared to be no consistent relationship between sediment structure, microbial population, and toxicant concentrations. Furthermore the ATP‐TOX System and Mutatox tests were the most responsive tests in all types of samples. Since sediments with their bound contaminants may be an important factor in this data interpretation, different methods for releasing and concentrating the sediment bound contaminants were evaluated. The results and implications of these results are described.

Highway runoff is a significant source of contaminants entering many freshwater systems. A battery of bioassays was used to assess the degree of runoff toxicity. The toxicity results are described in the spatial and temporal context and are linked to the runoff chemistry. Runoff samples from three sites, representing different classes of highways (high, intermediate and low traffic intensity), were used to assess the degree of runoff toxicity. Runoff from the major multilane divided highway, with the highest traffic intensity (92,000 vehicles/24 h), had the highest levels of contaminants and displayed the greatest toxicity. Variations in toxic responses were observed both seasonally and throughout runoff events. The runoff samples containing high concentrations of road salts from winter maintenance were acutely toxic to Daphnia magna. In general, a sharp decline in runoff toxicity over time showed that the 'first flush' was the most toxic. Road solids present in runoff showed moderate to severe toxicity using a nematode bioassay. Consistently, a significant mixed function oxidase (MFO) induction was observed in rainbow trout exposed to runoff with high concentrations of polycyclic aromatic hydrocarbons (PAHs). The data show that vehicular operation, road maintenance and metal highway structures were significant contributors to contaminant-associated toxicity in road runoff.