Uses of Probabilistic Exposure Models in Ecological Risk Assessments of Contaminated Sites

Food web models have two uses in assessments of environmental contaminants. First, they are used to determine whether remediation is needed by estimating exposure of end-point species and subsequent effects. Second, they are used to establish cleanup goals by estimating concentrations of contaminants in ambient media that will not cause significant effects. This paper demonstrates how achievement of these goals can be enhanced by the use of stochastic food web models. The models simulate the dynamics of PCBs and mercury in the food webs of mink and great blue herons. All parameters of the models are treated as having knowledge uncertainty, due to imperfect knowledge of the actual parameter values for the site, chemicals, and species of interest. This uncertainty is an indicator of the potential value of additional measurements. In addition, those parameters that are responsible for variance among individual organisms are assigned stochastic uncertainty. This uncertainty indicates the range of body burdens that are expected when the end-point species are monitored. These two types of uncertainty are separately accounted for in Monte Carlo simulations of the models. Preliminary monitoring results indicate that the models give reasonably good estimates of heron egg and nestling body burdens and of variance among individuals.     

家兔皮仿染水貂皮的研究

采用正交试验设计方法,研究用于仿染水貂皮的家兔坯皮质量要求、氧化染料配比以及染色工艺条件。研究结果表明,选用一级白色醛鞣冬季家兔坯皮,经脱脂、中和、媒染后用乌苏尔D0.20g/L,乌苏尔P0.25g/L,乌苏尔NZ1.00g/L,30％H_2O_31.4ml/L,25％NH_3·H_2O调PH值至8.0—8.5,温度36℃,浸染3h,取皮洗涤,干燥后,再提高浸染染料浓度3倍刷染一次,3h后、6h后提高为5倍浓度各刷染一次。经色度色差仪测定,仿貂兔皮与真貂反射系数曲线接近,仿染获得了成功。     

育成期水貂饲喂配合饲料试验报告

用总能在20kJ/kg、前期粗蛋白34%～40%、后期32%～38%;前期粗脂肪18%、后期16%;粗纤维2%～4%,粗灰粉6%～10%、钙1.5%～2.4%、磷1.0%～1.6%的配合饲料经160天饲喂育成期水貂,对水貂的生长发育及健康状况均无不良影响,效果与常规饲料无差异;毛皮质量较优,综合效益显著。每只水貂多收入6.84～8.14元。