Classic and temporal mixture synergism in terrestrial ecosystems: Prevalence, mechanisms and impacts

陆地生态系统中的经典和时间混合协同作用：普遍性、机制和影响

• 批准号: NE/S000224/1
• 负责人: David Spurgeon
• 金额: $ 133.77万
• 依托单位: NERC CEH (Up to 30.11.2019)
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2018
• 资助国家: 英国
• 起止时间: 2018 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FS000224%2F1
• 关键词: Classic; temporal; mixture; synergism; terrestrial

Invertebrate species living above and below ground are central to terrestrial food webs and key contributors to carbon cycling, soil fertility and pest control. Many of these important species are highly vulnerable to chemical pollution. The range of chemicals these species are regularly exposed to is becoming increasingly complex. For example, farmers now use 50% more types of pesticide on arable crops than they did 15 years ago and an ever-increasing diversity of chemicals enter ecosystems from our domestic and industrial wastes. A challenge for chemical producers, users and regulators is to find ways to maximise the benefits of chemical use, while minimising any negative effects. Scientific research to support better 'ecological risk assessment' of chemicals is central to meeting this challenge. Many of the chemicals we use today come from new, less well studied, compound classes that can affect biological processes, in diverse ways, in different species. Our current lack of knowledge about these chemicals makes their ecological effects difficult to assess. Things become more complicated when we realise that pollutants almost always occur as mixtures. If we want to properly to address and avoid unwanted chemical impacts, we need to better understand and take account of chemical mixtures. The most commonly used way to predict the likely effects of pollutant mixtures on invertebrates and ecosystems assumes that chemicals do not interact with each other and that, therefore, their toxicities can be added together. This relatively simple 'additive' approach has been shown to work most of the time. However, for a substantial proportion of mixtures (up to 20% depending on chemical classes included), the observed effects are worse than expected based on addition. Where such 'synergy' occurs, environmental protection policies for mixtures based on additivity will underestimate actual effects (see Fig. 1, Case for Support). Clearly this is a problem. To address it, we need to identify interactive chemical mixtures and predict the most likely causes of synergy. In turn, this requires us to understand how the mechanisms of toxicity of different chemicals in a mixture interplay with the different biochemical, physiological and ecological traits of exposed species to cause synergy. The main aim of this project is to gain and apply this knowledge. Our own research has identified some chemical mixtures that are more likely to show synergy, with higher levels of toxicity to exposed invertebrates. For example, where: (a) a chemical affects the way that another is detoxified or activated; or (b) a chemical increases the biological uptake of another chemical; or (c) prior exposure to a chemical changes the biological toxicity of another chemical, depending on the timing of exposure. However, we are very far from understanding all cases. Thus, this project aims to transform our ability to identify, quantify and predict the potential for synergy in common terrestrial pollution scenarios (agrochemical use, waste inputs). Working with partner agencies, we will identify potentially synergistic chemical pollutant mixtures, relevant to terrestrial ecosystems, and conduct experiments to test their effects on a range of invertebrate species. When we observe synergy in one species, other species will be tested to discover if this is a general effect. Biochemical and genetic methods will be used to identify mechanisms of toxicity and species traits associated with synergism, integrating this information to develop models and new predictive tools. To ensure the effects we see in the laboratory are relevant to the field, we will conduct studies in outdoor systems to test for the presence of synergism in natural communities. Ultimately, we will use our findings to produce a POSTnote 'White paper' detailing how future risk assessment policies can explicitly consider synergism to support environmental protection.

居住在地面上和下方的无脊椎动物物种对陆地食物网是核心循环，土壤生育能力和害虫控制的关键因素。这些重要物种中的许多高度容易受到化学污染。这些物种经常暴露的化学物质范围变得越来越复杂。例如，与15年前相比，农民在可耕作作物上使用50％的农药类型，而多样化的化学物质不断增加，从我们的家庭和工业废物中进入生态系统。对于化学生产者，用户和调节器面临的挑战是找到最大化化学使用益处的方法，同时最大程度地减少任何负面影响。支持更好的化学物质“生态风险评估”的科学研究对于应对这一挑战至关重要。我们今天使用的许多化学物质来自新的，较少的化合物类别，可以以不同的方式影响生物学过程。我们目前对这些化学物质缺乏知识使他们的生态影响难以评估。当我们意识到污染物几乎总是作为混合物而发生时，事情变得更加复杂。如果我们想适当地解决并避免不需要的化学作用，我们需要更好地理解和考虑化学混合物。预测污染物混合物对无脊椎动物和生态系统的可能影响的最常用方法是，化学物质不会相互相互作用，因此，可以将其毒性加在一起。这种相对简单的“添加剂”方法已显示出大多数情况下起作用。但是，对于相当一部分混合物（根据包括化学类别的不同，最高20％），根据加法，观察到的效果比预期的要差。在发生这种“协同作用”的地方，基于添加性的混合物的环境保护政策将低估实际效果（请参见图1，支持案例）。显然这是一个问题。为了解决它，我们需要确定交互式化学混合物并预测协同作用的最可能原因。反过来，这要求我们了解混合物中不同化学物质的毒性机制如何与暴露物种的不同生化，生理和生态特征相互作用引起协同作用。该项目的主要目的是获取和应用此知识。我们自己的研究已经确定了一些化学混合物，这些化学混合物更可能表现出协同作用，并且对暴露无脊椎动物的毒性较高。例如，其中：（a）化学物质会影响他人被解毒或激活的方式；或（b）一种化学物质增加了另一种化学物质的生物学摄取；或（c）事先暴露于化学物质会改变另一种化学物质的生物毒性，具体取决于暴露的时间。但是，我们远非了解所有情况。因此，该项目旨在改变我们识别，量化和预测常见陆地污染情景中协同作用的能力（农业化学使用，废物输入）。与合作伙伴机构合作，我们将确定与陆地生态系统相关的潜在协同化学污染物混合物，并进行实验以测试其对一系列无脊椎动物物种的影响。当我们观察到一个物种的协同作用时，将测试其他物种以发现这是否是一般效果。生化和遗传方法将用于识别毒性和与协同作用相关的物种特征的机制，将这些信息整合到开发模型和新的预测工具。为了确保我们在实验室中看到的影响与该领域相关，我们将在室外系统进行研究，以测试自然社区中的协同作用。最终，我们将使用我们的发现来制作一份注释“白皮书”，详细说明未来的风险评估政策如何明确考虑协同作用以支持环境保护。