Toxicological assessment of various media using several biological markers: Case study results using an integrated approach

Assessments of toxicological impacts in water and soil media are becoming increasingly important as planning and monitoring tools in the environment. Estimation of the environmental risk of industrial and recreational sites has primarily been based on physico-chemical analyses. The developments of new innovative technologies rely on integrated chemical and biological analyses to determine its potential toxicological hazard to the environment. Monitoring of existing resources may depend on the use of "indicator" organisms that are used to detect the presence of contaminants. In an integrated approach to toxicity assessment this research not only looks at chemical constituents, but at the effects on biological systems.; In two case studies, surrogate species were used to predict the possibility of hazardous conditions in surface waters and soils. The first study focuses on the assessment of surface water quality in the Houston-Galveston Bay watershed using several bacteria as indicators. The second study looks at the effects of a new remediation technology and its effects on terrestrial plants in the soil via seed germination and root length tests. The biological analyses complements the physico-chemical analyses and thus provides a more comprehensive toxicity assessment.; While the first case study results show variability in the type of indicators used, there is evidence to support using one alternative method to measure the traditional indicator of microbial contamination. Eight out of ten experimental sites violated the suggested criteria for Enterococcus, 5 out of 10 had violations for E. coli, while only 3 violations occurred with fecal coliform group. There seemed to be an excellent correlation between the IDEXX laboratory results and the membrane filtration method results for fecal coliform method. In the second case study, the challenge to develop a risk based protocol is addressed. Using a combination of established toxicity tests, the data clearly demonstrated that there is low risk in toxic exposure to the surrounding environment. It is suggested that the concentration ratio of surfactant weight to soil weight be kept below 10%. This is an added advantage since the remediation agent also significantly removed contaminant in soil systems.; In any case, the risk evaluation is strengthened by not only observing physico-chemical factors, but by observing its effects on biological systems. The IDEXX system provides a quick, efficient, and reliable method to measure contamination in comparison to traditional methods. To determine the potential toxicity of a new chemical, several tests were used to draw risk conclusions based on a risk assessment model. Further, the remediation chemical was used on a small pilot area to look at its effectiveness and its effects on the ecology around it. This research shows that there were no adverse effects from the use of the remediation chemical.