What are the environmental risks of mycotoxins present in freshwater ecosystems within UK agricultural landscapes?

真菌毒素是生长在各种谷类作物上的真菌如曲霉属和镰刀菌属的有毒次级代谢产物。近年来，由于采用了最少耕作做法，减少了作物轮作和气候变化，作物中的真菌感染有所增加。摄入、吸入或皮肤接触霉菌毒素会对人类和野生动物的健康产生不利影响。美国政府的科学家最近报告说，在牲畜使用的溪流或作为人类饮用水源的溪流中，霉菌毒素的浓度高得令人担忧。2014年美国研究的结果表明，扩散（例如从真菌感染的作物释放）和点源（例如食品加工厂）都是真菌毒素进入淡水生态系统的重要途径。因此，真菌毒素是一类重要的新出现的污染物，但显然缺乏关于其对水生生物健康影响的科学数据。真菌毒素具有广泛的物理化学特性（辛醇/水分配系数对数值为<1 to >7），而且往往不易生物降解。真菌毒素的主要类群包括黄曲霉毒素、白僵菌素、青霉烯和玉米赤霉烯酮。真菌毒素的某些代谢物会导致哺乳动物的内分泌紊乱（例如α-玉米赤霉醇（a-ZOL）和β-玉米赤霉醇（b-ZOL）具有与甾体雌激素相似的雌激素活性，a-ZOL在北美通常用于促进牛的生长）。然而，缺乏关于大多数真菌毒素对鱼类和其他水生生物的发育和生殖影响的数据。在未来，合成杀真菌剂的抗病性问题的增加可能会导致真菌毒素暴露的增加和随之而来的健康风险。最近的欧洲法规也可能导致可持续农业和园艺的杀真菌剂供应量大幅减少，除非科学可用于对真菌毒素和杀真菌剂进行比较风险评估。必须填补这一关键的知识空白，以支持可持续的作物生产，并就真菌毒素与合成杀真菌剂对野生动物的风险做出基于证据的决定。这个学生奖学金将解决的假设，有在英国农业景观内的淡水和生物群中的霉菌毒素的有害水平。拟议的工作将（a）量化地表沃茨和无脊椎动物中的霉菌毒素浓度，（B）进行实验室研究，调查其对鱼类和水生无脊椎动物的生态毒理学影响。现场和实验室数据将被整合，以解决第一次在英国地表沃茨检测到的真菌毒素所带来的相对风险。

Mycotoxins are toxic secondary metabolites of fungi such as Aspergillus sp. and Fusarium sp. that grow on a wide variety of cereal crops. Fungal infestations in crops have increased in recent years due to the adoption of minimal tillage practices, decreased crop rotations and climate change. Exposure to mycotoxins has adverse impacts on the health of humans and wildlife following ingestion, inhalation or skin contact. United States government scientists very recently reported worryingly high concentrations of mycotoxins in streams used by livestock or as sources of human drinking water. Results of the 2014 US study suggest that both diffuse (e.g. release from fungi infected crops) and point (e.g. food processing plants) sources are important pathways for mycotoxin transport into freshwater ecosystems. Mycotoxins are therefore an important class of emerging contaminants and yet there is a clear lack of scientific data on their health impacts in aquatic organisms. Mycotoxins display a wide range of physico-chemical properties (with log Kow values from <1 to >7) and are often resistant to biodegradation. The main groups of mycotoxins including aflatoxins, beauvericin, trichothecenes and zearalenone. Some metabolites of mycotoxins cause endocrine disruption in mammals (for instance alpha-zearalanol (a-ZOL) and beta-zearalanol (b-ZOL) have oestrogenic activity similar to that of steroidal oestrogens and a-ZOL is commonly used in North America for growth promotion in cattle). However, there is a lack of data on the developmental and reproductive effects of most mycotoxins to fish and other aquatic organisms. In the future the increase in disease resistance problems with synthetic fungicides will likely lead to increased mycotoxin exposure and consequent health risks. Recent European regulation may also lead to significant reductions in fungicide availability for sustainable agriculture and horticulture unless the science is available to undertake a comparative risk assessment of mycotoxins and fungicides. It is essential to fill this critical knowledge gap in order to support sustainable crop production and make evidence-based decisions on the risks to wildlife of mycotoxin versus synthetic fungicides. This studentship will address the hypothesis that there are harmful levels of mycotoxins in freshwaters and biota within UK agricultural landscapes. The proposed work will (a) quantify mycotoxin concentrations in surface waters and invertebrates and (b) conduct laboratory studies to investigate their ecotoxicological impacts in fish and aquatic invertebrates. The field and laboratory data will be integrated to address for the first time the relative risks posed by mycotoxins detected in UK surface waters.