Modelling and measurement of Cd exposure and pathology in human volunteers living in proximity to a smelter source

人（和环境物种）接触空气、水、土壤和食物中的重金属（如镉、铅、汞、铜）污染可造成一系列健康问题。世界上许多地方都有与接触金属污染有关的疾病的例子，包括日本因食用受污染的鱼而导致汞中毒，以及孟加拉国和印度成千上万人饮用受污染水井的水而导致类金属元素砷中毒。在离家更近的英国，铅被广泛认为与生活在繁忙道路附近的儿童的一系列发育障碍有关，这些儿童经常受到使用老式含铅汽油的汽车排放的烟雾的影响。由于镉在摄入后不能很好地从体内排出，常见的环境污染物镉是一种金属，它被认为是生活在工业污染源附近的人群中造成人类健康问题的原因之一。事实上，这种金属倾向于在肾脏中积累，这使得这个器官对镉中毒特别敏感。在这个探索性项目中，我们汇集了环境科学、医学、流行病学和基础生物化学方面的专业知识，研究接触镉是否以及在多大程度上导致肾脏疾病。这项研究的重点是布里斯托尔附近塞文河口的埃文茅斯镇周围地区，直到最近，这里还是世界上最大的镉/铅/锌冶炼厂之一的所在地。在该厂运行期间（1928-2003年），大量镉和其他金属（包括铅、汞和锌）被释放出来，污染了环境，并使当地居民（约5万人居住在冶炼厂5公里范围内）暴露在污染中。众所周知，冶炼厂周围的农村受到这些金属的严重污染，对它们对植物和动物的影响的研究表明，在距离工厂许多公里的地方也存在有毒影响。然而，令人惊讶的是，有毒金属对人类的影响还没有得到很好的了解。为了解决这个问题，本研究将提供有关埃文茅斯金属污染对当地居民影响的信息。收集到的信息将有助于评估英国许多地区（特别是城市地区）仍在发生的镉污染对人们健康和福祉的更广泛影响。我们评估受冶炼厂污染地区对人们潜在毒性影响的方法是：-测量空气尘埃、土壤和家庭种植蔬菜中的镉含量，这些是人类接触镉的主要途径；-将这些镉浓度测量作为监管机构用于预测污染地点镉暴露的现有人类环境暴露评估方法的输入，并通过将暴露预测与从Avonmouth已知邮政编码地点收集的200名人类志愿者的尿液中测量的镉浓度（在现有项目中）进行比较来验证这些评估；-测量从200名志愿者收集的人体尿液样本中正常代谢产生的小分子（如氨基酸、糖、DNA和RNA成分）的浓度，并将这些结果与现有的肾脏毒性信息进行比较，以确定镉暴露如何影响生活在埃文茅斯地区的人的肾脏健康，这些地区的空气、水、土壤和自制食物中镉含量分别为高、中、低水平。通过资助这一项目，NERC将对研究进行成本投资，以解决环境和人类健康研究中的基本问题（环境中污染物的数量、进入人体的数量和最终毒性影响之间的联系），并将产生关于人体样本的新数据，与实际地点现有的毒性和地理污染物数据交叉参考。

Exposure of people (and environmental species) to heavy metal (e.g. cadmium, lead, mercury, copper) pollution in air, water, soil and food can cause a range of health problems. Examples of diseases associated with exposure to metal pollution are known from many parts of the world, including mercury poisoning through eating contaminated fish in Japan and poisoning by the metalloid element arsenic of many thousands of people that drank waters from contaminated wells in Bangladesh and India. Closer to home in the UK, lead was widely implicated in a range of developmental impairments occurring in children living close to busy roads who were regularly subjected to exhaust smoke from cars using the old type of leaded petrol. Because it is not well excreted from the body after ingestion, the common environmental pollutant cadmium is one metal that has been implicated in as causing of human health problems in populations living close to industrial sources. The fact that this metal tends to accumulate in the kidney makes this organ particularly sensitive to cadmium toxicity. In this exploratory project, we bring together expertise from environmental science, medicine and epidemiology and fundamental biochemistry to investigate whether and to what extent exposure to cadmium causes kidney disease. The study is focused on the area around the town of Avonmouth on the Severn Estuary near Bristol which was until recently home to one of the world's largest cadmium/lead/zinc smelters. During the active life of the plant (1928-2003), significant quantities of cadmium and other metals (including Pb, Hg and Zn) were released, contaminating the environment and exposing local residents (~50,000 people live within 5 km of the smelter). The countryside around the smelter is known to be badly contaminated with these metals and studies of their impacts on plants and animal have revealed toxic effects at locations many kilometers from the factory. Surprisingly, however, the impacts on the toxic metals on the human population are not well understood. To address this, this study will provide information on the effects of metal pollution at Avonmouth on local residents. The information gathered will be beneficial for assessing the wider effects of the cadmium pollution that is still occurring in many parts of the UK (particularly urban areas) on people's health and wellbeing. Our approach to assessing the potential for toxic effects on people in the area polluted by the smelter are to: - measure the amount of cadmium in aerial dust, soil and home grown vegetables that represent the main routes of human exposure; - use these measurements of cadmium concentration as input to existing human environmental exposure assessment methods that are used by regulatory agencies to predict cadmium exposure at contaminated sites and validate these assessments by comparing exposure predictions to measured cadmium concentrations in urine collected (in an existing project) from 200 human volunteers from known postcode locations at Avonmouth; - measuring the concentrations of the small molecules produced by normal metabolism that are present in human urine (e.g. amino acid, sugars, components of DNA and RNA) samples collected from the 200 volunteers and comparing these results to existing information on renal toxicity to establish how cadmium exposure affects kidney health for persons living in postcodes in the Avonmouth area with high, moderate and low levels of cadmium present in air, water, soil and home grown food. By funding this project, NERC would be making a cost investment in research that addresses fundamental issue in environment and human health research (the link between the amount of a pollutant in the environment, the amount entering the human body and the ultimate toxic effect) and would generate novel data, on human samples, cross-referenced to existing toxicity and geographical pollutant data at a real site.