Cupit M, Larsson O, de Meeûs C, Eduljee G H, Hutton M
ERM, Eaton House, Oxford, UK.
Sci Total Environ. 2002 May 27;291(1-3):189-206. doi: 10.1016/s0048-9697(01)01099-3.
A preliminary, illustrative human health risk assessment of exposure to cadmium in phosphate fertilisers was performed using typical UK data and a protocol previously developed for application by individual Member States in the European Union. The risk assessment indicated that the for the most pessimistic population exposures characterised by both extreme (97th percentile) cereal and potato consumption and high susceptibility to cadmium uptake, the estimated dose was under the WHO Provisional Tolerable Weekly Intake (PTWI) for fertiliser cadmium concentrations ranging from 15 to 100 mg Cd/kg P2O5 applied over 100 years. However, the low margin of safety for high risk groups and the uncertainties inherent in the overall risk assessment suggested that a prudent risk management strategy would involve maintenance of low levels of cadmium in fertilisers and/or conditions that permitted low accumulation of cadmium in soils. On this basis, two main risk reduction measures were developed and assessed: (a) imposition of limits on cadmium concentration in fertilisers; and (b) imposition of charges on levels of cadmium in phosphate fertilisers. An assessment of the economic impact of these risk reduction measures indicated that, at all price elasticities, the most significant impact in terms of changes in demand and changes in consumer expenditure on phosphate fertilisers will be seen with cadmium charges where no thresholds are defined. The impact on the consumer (i.e. farmer) will be an increase in spending of approximately US $4000 per year, which is considered significant, accompanied by a decrease in demand above 20%. If a threshold is set at 60 mg Cd/kg P2O5, the impact is significantly reduced, but stays relatively high compared to the other options. The analysis also indicates that the use of low-cadmium rock is the low cost option. At a likely rock price increase of approximately 5% and assuming a likely price elasticity of -0.2, the yearly costs to farmers will be approximately US $82 which is considered a minimal impact. In the worst case scenario (elasticity of -0.6 and a 10% increase in rock prices), the increase in spending by farmers will be of 3.9% or US $221 which is also considered to represent a minimal impact. At similar price elasticities, the use of decadmation technologies is predicted to be more costly than the use of low-cadmium rock but this option can still be considered as having a minimal impact on the consumer (increase in expenditure of 1.9-13.3% or US $106-748).
利用英国的典型数据以及此前欧盟各成员国采用的一份方案，对磷肥中镉暴露进行了初步的、示例性的人体健康风险评估。风险评估表明，对于以极端（第97百分位数）谷物和马铃薯消费量以及对镉吸收的高易感性为特征的最悲观人群暴露情况而言，在100年期间施用的磷肥镉浓度为15至100毫克镉/千克五氧化二磷时，估计剂量低于世界卫生组织的暂定每周耐受摄入量（PTWI）。然而，高风险群体的安全边际较低以及总体风险评估中固有的不确定性表明，审慎的风险管理策略将包括维持肥料中镉的低含量和/或允许土壤中镉低积累的条件。在此基础上，制定并评估了两项主要的风险降低措施：（a）对肥料中的镉浓度设定限值；（b）对磷肥中的镉含量收取费用。对这些风险降低措施的经济影响评估表明，在所有价格弹性下，对于磷肥需求变化和消费者支出变化而言，在未定义阈值的情况下，镉收费产生的影响最为显著。对消费者（即农民）的影响将是每年支出增加约4000美元，这被认为是显著的，同时需求下降超过20%。如果将阈值设定为60毫克镉/千克五氧化二磷，影响将显著降低，但与其他选择相比仍相对较高。分析还表明，使用低镉岩石是低成本选择。在岩石价格可能上涨约5%且假设价格弹性为-0.2的情况下，农民每年的成本将约为82美元，这被认为影响极小。在最坏的情况（弹性为-0.6且岩石价格上涨10%）下，农民支出的增加将为3.9%或221美元，这也被认为影响极小。在类似的价格弹性下，预计使用除镉技术的成本高于使用低镉岩石，但该选择对消费者的影响仍可被视为极小（支出增加1.9 - 13.3%或106 - 748美元）。
