Degradation and Uptake of Benzene in Laboratory Phytoremediation Studies

In Whole-Plant Laboratory Studies, Hybrid Poplar Trees Were Shown to Impact a Variety of Fate and Transport Mechanisms for Benzene. Laboratory Experiments Investigated the Distribution of the Contaminant in the Plant Tissues, Degradation in the Soil Profile, and Volatilization from Both the Soil and Leaf Tissues. a New Testing System Was Developed that Allowed for Rapid Testing that is More Field-Representative Than Earlier Studies. Whole Plants Were Utilized in a Reactor Design that Included Both a Saturated and a Vadose Zone. the Continuous Feed Reactors Were Supplied with a Steady Influent Benzene Stream to Mimic Plume Conditions. the Presence of the Poplar Trees Enhanced the Degradation Rate of the Benzene, and Dramatically Decreased the Effluent Mass of Benzene. Benzene Was Also Volatilized from the Leaf Tissues, Providing Evidence to the Extent of Plant Enhanced Volatilization that Has Not Been Previously Documented. the Observed Degradation and Removal Pathways Were a Result of Active/live Trees. Reactors with Killed Controls Did Not Exhibit the Removal Seen in the Live Tree Replicates. the Soil Profile Maintained Higher Degradation Rates with the Trees Present. Causes for the Higher Degradation Rates Appeared to Be Larger Microbial Populations of Benzene Degraders and Preferable Redox Conditions in the Presence of the Poplars. These Results Combined with Previous Hydroponic and Related Field Scale Studies to Provide Evidence that Phytoremediation Has Potential for Effective, Efficient, and Environmentally Friendly Application at Benzene Contaminated Sites, and Potentially Other Contaminated Sites with Biodegradable Organics or VOCs

Benzene Toxicity and Removal in Laboratory Phytoremediation Studies

Hybrid Poplar Cuttings Were Shown to Impact the Fate and Transport of Subsurface Benzene, While Toxicity to the Poplars Was Not Observed. Laboratory Experiments Investigated the Toxicity Response of Poplar Cuttings to Benzene Exposure, Contaminant Distribution in Plant Tissues, Contaminant Degradation in the Soil Profile, and Contaminant Volatilization from the Soil and Plant Tissues. Two Separate Studies Were Conducted to Evaluate These Parameters. the First Study Examined the Toxicity of Benzene to Hybrid Poplar Cuttings in Batch Reactors. Poplar Cuttings Were Exposed to Various Concentrations of Benzene Contaminated Water in Two Different Types of Soil. Transpiration Rates Were Measured as an Indicator of Acute Toxicity. No Acute Toxicity Was Noted for Dose Concentrations Up to 1,000 Ppm. the Second Study Evaluated Benzene Fate and Transport. Live Poplar Cuttings and Excised Controls Were Planted in Flow-Through Reactors and Supplied with an Influent Benzene Stream to Mimic Plume Conditions. the Presence of Live Poplar Cuttings Enhanced Benzene Degradation and Decreased the Effluent Mass of Benzene. a Small Amount of Benzene Was Also Volatilized from the Plant Tissues, Providing Evidence of Plant-Enhanced Volatilization. Causes for the Higher Degradation Rates Appeared to Be Greater Microbial Populations of Benzene Degraders and a More Oxygenrich Environment. the Higher Redox Potential Observed May Be an Artifact of the Laboratory Reactor Design. the Results Obtained in This Research Combined with Previous Studies Provide Evidence that Phytoremediation Has the Potential for Effective, Efficient, and Environmentally Friendly Application at Sites Highly Contaminated with Benzene and Potentially for Other Sites Contaminated with Biodegradable Organics or Volatile Organic Compounds

Cost-Effectiveness of Newborn Screening for Phenylketonuria and Congenital Hypothyroidism

Objective To evaluate the long-term costs and health effects of the Swedish newborn screening program for classic phenylketonuria (PKU) alone and in combination with congenital hypothyroidism compared with no screening. Study design A decision-analytic model was developed to estimate and compare the long-term (80 years) costs and health effects of newborn screening for PKU and congenital hypothyroidism. Data were obtained from the liter-ature and translated to Swedish conditions. A societal perspective was taken, including costs falling on health care providers, municipal care and services, as well as production loss due to morbidity. Results Screening 100 000 newborns for PKU resulted in 73 gained quality-adjusted life-years (QALYs) compared with no screening. When adding congenital hypothyroidism, the number of gained QALYs was 232 compared with PKU alone, adding up to a total of 305 QALYs gained. Corresponding cost estimates were $80.8,$70.3, and $10.05 million USD for no screening, PKU screening, and PKU plus congenital hypothyroidism screening, respectively, indicating that screening for PKU plus congenital hypothyroidism was more effective and less costly compared with the other strategies. The majority of cost savings with PKU plus congenital hypothyroidism screening was due to reductions in productivity losses and municipal care and services costs. Conclusion The Swedish newborn screening program for PKU and congenital hypothyroidism saves substantial costs for society while generating additional QALYs, emphasizing the importance of public investments in early diagnosis and treatment. (J Pediatr 2023;256:38-43).Funding Agencies|Medical Diagnostics Karolinska</p