Dispersant and salinity effects on weathering and acute toxicity of South Louisiana crude oil.

Chemical dispersants are an important technology in the remediation of oil spills in the aquatic environment, facilitating degradation of crude oil and salinity is an important factor in dispersant effectiveness. The aim of the present study was to explore the role of salinity on the degradation chemistry of crude oil polycyclic aromatic hydrocarbons (PAHs) and acute toxicity of the water accommodated fraction (WAF) of the dispersant COREXIT 9500A and chemically dispersed crude oil on a common estuarine fish. Laboratory microcosms were designed at salinities of 4 parts per thousand (ppt), 12 ppt, or 18 ppt and spiked with crude oil, COREXIT 9500A, or a combined exposure to crude oil and COREXIT and allowed to biodegrade for 1 wk, 4 wk, and 16 wk. The WAF was harvested for analytical PAH analysis and acute toxicity testing in juvenile Fundulus grandis. Compared with undispersed oil, COREXIT exponentially increased the PAH concentrations in the WAF for up to 16 wk; hopane-normalized concentrations indicated that biodegradation was slowed for the first 4 wk. Dispersed crude oil and COREXIT were acutely toxic following 1 wk of biodegradation with no correlation between PAH concentrations and crude oil WAF mortality. Both dispersant and dispersant oil mixtures remained toxic for at least 4 wk at the lowest salinity tested, suggesting increased sensitivity or reduced biodegradation of toxic components in low-saline environments. At the lowest salinity, oil dispersed with COREXIT was more toxic than either the COREXIT alone or oil alone, even after 16 wk of biodegradation.

Prognostic factors for acute and late skin reactions in radiotherapy patients.

PURPOSE: Patients treated with identical radiotherapy schedules show a substantial variation in the degree of acute and late normal tissue reactions. To identify any possible contributing factors to this phenomenon, we have analyzed the treatments of 402 breast cancer patients. METHODS AND MATERIALS: The patients received adjuvant postoperative radiotherapy between 1972 and 1985 and have been followed up since then. Multivariate analyses were performed with peak reflectance erythema and peak acute reaction score as endpoints for the acute reactions, and with progression rate of telangiectasia as well as telangiectasia score as endpoints for the late reactions. Twenty patient- and treatment-related factors were tested such as age, menopausal status, hemoglobin level, serum calcium, smoking habits, hypothyroidism, diabetes, hypertension, blood pressure, cardiovascular and autoimmune disease, the influence of hormone therapy and chemotherapy, pretreatment reflectance value, acute skin reactions, radiation quality, individual dose, bilateral fields, and the total effect (TE) for the dose schedule applied. RESULTS: The TE was a strong prognostic factor for all endpoints. In addition to TE, blood pressure was prognostic for the peak erythema measured by reflectance spectrophotometry, and the pretreatment reflectance value was prognostic for the acute score. The only independent prognostic factors found for the progression of skin telangiectasia and telangiectasia score except for TE were the individual dose and the acute skin reactions. CONCLUSIONS: These factors explained at most about 30% of the variance describing the total patient-to-patient variability for each endpoint. The remaining variability is still unexplained but may be related to individual differences in cellular radiosensitivity, partly determined by genetic variations and partly by unknown epigenetic factors.