Evolutionary Stress Ecology and Ecotoxicology, University of Leuven, Charles Deberiotstraat 32, B-3000, Leuven, Belgium.
Evolutionary Stress Ecology and Ecotoxicology, University of Leuven, Charles Deberiotstraat 32, B-3000, Leuven, Belgium.
Environ Pollut. 2019 May;248:209-218. doi: 10.1016/j.envpol.2019.02.022. Epub 2019 Feb 11.
There is increasing concern that climate change may make organisms more sensitive to chemical pollution. Many pesticides are indeed more toxic at higher mean temperatures. Yet, we know next to nothing about the effect of another key component of climate change, the increase of daily temperature fluctuations (DTFs), on pesticide toxicity. Therefore, we tested the effect of the pesticide chlorpyrifos under different levels of DTF (constant = 0 °C, low = 5 °C (current maximum level) and high = 10 °C (predicted maximum level under global warming)) around the same mean temperature on key life history and physiological traits of Ischnura elegans damselfly larvae in a common-garden experiment. At all levels of DTF, chlorpyrifos exposure was stressful: it reduced energy storage (fat content) and the activity of its target enzyme acetylcholinesterase, while it increased the activity of the detoxification enzyme cytochrome P450 monooxygenase. Notably, chlorpyrifos did not cause mortality or reduced growth rate at the constant temperature (0 °C DTF), yet increased mortality 6x and reduced growth rate with ca. 115% in the presence of DTF. This indicates that daily short-term exposures to higher temperatures can increase pesticide toxicity. Our data suggest that when 5 °C DTF will become more common in the studied high-latitude populations, this will increase the toxicity of CPF, and that a further increase from 5° DTF to 10 °C DTF may not result in a further increase of pesticide toxicity. Our results highlight the biological importance of including daily temperature fluctuations in ecological risk assessment of pesticides and as an extra dimension in the climate-induced toxicant sensitivity concept.
人们越来越担心气候变化可能使生物对化学污染物更加敏感。许多杀虫剂在较高的平均温度下确实毒性更大。然而，我们对气候变化的另一个关键组成部分——日温度波动（DTF）的增加对杀虫剂毒性的影响几乎一无所知。因此，我们在相同的平均温度下，在不同的 DTF 水平（恒定= 0°C，低= 5°C（当前的最高水平）和高= 10°C（全球变暖下的预测最高水平））下，测试了杀虫剂毒死蜱对伊蚊幼虫关键生活史和生理特征的影响，这是一个普通花园实验。在所有 DTF 水平下，毒死蜱暴露都有压力：它降低了能量储存（脂肪含量）和其靶酶乙酰胆碱酯酶的活性，同时增加了解毒酶细胞色素 P450 单加氧酶的活性。值得注意的是，在恒温（0°C DTF）下，毒死蜱不会导致死亡率或生长速度降低，但在 DTF 存在的情况下，死亡率增加了 6 倍，生长速度降低了约 115%。这表明，每日短期暴露于较高温度会增加杀虫剂毒性。我们的数据表明，当 5°C DTF 在研究的高纬度种群中变得更加普遍时，这将增加 CPF 的毒性，而从 5°C DTF 进一步增加到 10°C DTF 可能不会导致杀虫剂毒性进一步增加。我们的结果强调了在生态风险评估中包含日温度波动以及在气候诱导的毒性敏感性概念中作为额外维度的生物学重要性。
