Synergistic action of tropospheric ozone and carbon dioxide on yield and nutritional quality of Indian mustard (Brassica juncea (L.) Czern.)

Field experiments were conducted in open top chamber during rabi seasons of 2009–10 and 2010–11 at the research farm of the Indian Agricultural Research Institute, New Delhi to study the effect of tropospheric ozone (O₃) and carbon dioxide (CO₂) interaction on yield and nutritional quality of Indian mustard (Brassica juncea (L.) Czern.). Mustard plants were grown from emergence to maturity under different treatments: charcoal-filtered air (CF, 80–85 % less O₃ than ambient O₃ and ambient CO₂), nonfiltered air (NF, 5–10 % less O₃ than ambient O₃ and ambient CO₂ ), nonfiltered air with elevated carbon dioxide (NF?+?CO₂, NF air and 550?±?50 ppm CO₂), elevated ozone (EO, NF air and 25–35 ppb elevated O₃), elevated ozone along with elevated carbon dioxide (EO?+?CO₂, NF air, 25–35 ppb O₃ and 550?±?50 ppm CO₂), and ambient chamber less control (AC, ambient O₃ and CO₂). Elevated O₃ exposure led to reduced photosynthesis and leaf area index resulting in decreased seed yield of mustard. Elevated ozone significantly decreased the oil and micronutrient content in mustard. Thirteen to 17 ppm hour O₃ exposure (accumulated over threshold of 40 ppm, AOT 40) reduced the oil content by 18–20 %. Elevated CO₂ (500?±?50 ppm) along with EO was able to counter the decline in oil content in the seed, and it increased by 11 to 13 % over EO alone. Elevated CO₂, however, decreased protein, calcium, zinc, iron, magnesium, and sulfur content in seed as compared to the nonfiltered control, whereas removal of O₃ from air in the charcoal-filtered treatment resulted in a significant increase in the same.     

Indirect prediction of surface ozone concentration by plant growth responses in East Asia using mini-open top chambers

We developed small and mobile open top chambers (mini-OTC) measuring 0.6 m (W)?×?0.6 m (D)?×?1.2 m (H) with an air duct of 0.6 m (W)?×?0.23 m (D)?×?1.2 m (H). The air duct can be filled with activated charcoal to blow charcoal filtered air (CF) into the chamber, as opposed to non-filtered ambient air (NF). Ozone sensitive radish Raphanus sativus cv. Red Chime and rosette pakchoi Brassica campestris var. rosularis cv. ATU171 were exposed to NF and CF in mini-OTCs at different locations in East Asia. A total of 29 exposure experiments were conducted at nine locations, Shanghai, China, Ha Noi, Vietnam, Lampang, Phitsanulok and Pathumtani, Thailand, and Hiratsuka, Kisai, Abiko and Akagi, Japan. Although no significant relationships between the mean concentrations of ambient O₃ during the experimental period and the growth responses were observed for either species, multiple linear regression analysis suggested a good relationship between the biomass responses in each species and the O₃ concentration, temperature, and relative humidity. The cumulative daily mean O₃ (ppb/day) could be indirectly predicted by NF/CF based on the dry weight ratio of biomass, mean air temperature, and relative air humidity.     

Assessment of six Indian cultivars of mung bean against ozone by using foliar injury index and changes in carbon assimilation, gas exchange, chlorophyll fluorescence and photosynthetic pigments

Six Indian cultivars of Vigna radiata L. (HUM-1, HUM-2, HUM-6, HUM-23, HUM-24 and HUM-26) were exposed with ambient and elevated (ambient + 10 ppb ozone (O₃) for 6 h?day^?1) level of O₃ in open top chambers. Ozone sensitivity was assessed by recording the magnitude of foliar visible injury and changes in various physiological parameters. All the six cultivars showed visible foliar symptoms due to O₃, ranging 7.4 to 55.7 % injured leaf area. O₃ significantly depressed total chlorophyll, photosynthetic rate (Ps), quantum yield (F _v/F _m) and total biomass although the extent of variation was cultivar specific. Cultivar HUM-1 showed maximum reduction in Ps and stomatal conductance. The fluorescence parameters also indicated maximum damage to PSII reaction centres of HUM-1. Injury percentage, chlorophyll loss, Ps, F _v/F _m and total biomass reduced least in HUM-23 depicting highest O₃ resistance (R%).     

Study on concentration of ambient NH 3 and interactions with some other ambient trace gases

We present diurnal variation of ambient ammonia (NH₃) in relation with other trace gases (O₃, CO, NO, NO₂, and SO₂) and meteorological parameters at an urban site of Delhi during winter period. For the first time, ambient ammonia (NH₃) was monitored very precisely and continuously using ammonia analyzer, which operates on chemiluminescence method. NH₃ estimation efficiency of the chemiluminescence method (>90%) is much higher than the conventional chemical trapping method (reproducibility 4.5%). Ambient NH₃ concentration reaches its maxima (46.17 ppb) at night and minimum during midday. Result reveals that the ambient ammonia (NH₃) concentration is positively correlated with ambient NO (r ²?=?0.79) and NO₂ (r ²?=?0.91) mixing ratio and negatively correlated with ambient temperature (r ²?=???0.32). Wind direction and wind speed indicates that the nearby (~500 m NW) agricultural fields may be major source of ambient NH₃ at the observational site.     

The changes in different ozone metrics and their implications following precursor reductions over northern Taiwan from 1994 to 2007

The changes of different O₃ metrics such as O_{3_avg} (daily mean), O_X (NO₂ + O₃), O_{3_8h} (daily maximum 8-h moving average), O_{3_max} (daily maximum 1-h average), and exceedances of O_{3_8h} and O_{3_max} at 16 air quality monitoring stations over northern Taiwan from 1994 to 2007 are evaluated. The O_{3_avg} at the background site displays an increasing trend at 0.54 ±0.21 ppb (1.28 ±0.49%) per year. The O_X at urban sites shows a significant increase, indicating that even with the effect of reduced NO titration increasing photochemical production is evident. The exceedances of O_{3_8h} (>80 ppb) are about 14.9% higher than O_{3_max} (>120 ppb) with more exceedances at coastal or background sites, where the anthropogenic O₃ precursor emissions are lower. In addition to increasing background O₃ and reductions in NO titration, increasing O₃ production efficiency also plays a key role in the increase of moderate to high O₃ concentrations. The findings help explain the different trends in exceedances and levels of O_{3_8h} and O_{3_max} and are likewise important in the formation of O₃ control strategies.     

Change of air quality and its impact on atmospheric visibility in central-western Pearl River Delta

Ambient air quality data, including atmospheric visibility, of Foshan city, a highly polluted city in the Pearl River Delta (PRD), and data obtained by the On-line Air Pollutant Exhaust Monitoring Network (OAPEMN), recently established by the National Emission Monitoring and Control Network for major industrial enterprises, were analyzed and are reported here for the first time, revealing the change in air pollution patterns and its impact on visibility degradation in the last decade. Reduced visibility of less than 8 km (after elimination of rainy and foggy periods) was found 22% of the time from 1998 to 2008, accompanied by elevated levels of pollutants, especially SO₂ and PM₁₀, in comparison with that of other developed cities. However, PM₁₀ showed a steady decreasing trend (0.004 mg m^???3 year^???1) during 2001?C2008, in contrast to the noticeable increase in ambient NO₂ concentrations from ~0.020 mg m^???3 before 2005 to above 0.050 mg m^???3 afterward. Multiple regression analysis revealed that the percentage of reduced visibility strongly correlated with PM₁₀ concentration, suggesting that visibility degradation was directly proportional to the loading of particles. Moreover, the fairly significant correlation between reduced visibility and NO₂ concentration also implied that the impact of primary emissions of NO₂ and enhanced secondary pollutants, formed via photochemical processes in the atmosphere, could not be ignored. The decreased PM₁₀ levels were obviously the predominant factor for the improvement in visibility (5.0% per 0.01 mg m^???3) and were likely due to the implementation of stricter air pollution control measures for industrial exhaust, which also resulted in reduced SO₂ pollution levels in the recent 2 years. In particular, the OAPEMN records showed an overall enhanced SO₂ removal by 64% in major industrial sectors. The continuous increase in road traffic and lack of efficient NO _x control strategies in the PRD region, however, caused an increase in ambient NO₂ concentrations.     

A New All Season Passive Sampling System for Monitoring Ozone in Air

A new all season passive sampling system for monitoring O₃ in the atmosphere has been developed in the laboratory and validated in the field. The unique features for this system include a newly designed passive sampler and a rain shelter, which allow the passive sampler to be installed in the field facing downwards. An equation associated with meteorological parameters is used to calculate the passive sampling rates. This system has been extensively tested in the lab (temperature from –18 to 20°C, relative humidity from 13 to 81%, and wind speed from 0.5 to 150 cm/s) and validated in the field in climates of all seasons. The accuracy of the ozone concentrations in the atmosphere obtained with the use of the new passive sampling system was higher than 85% compared to those obtained with continuous ozone analyzers. The new ozone passive sampling system can be used to measure ambient O₃ concentrations ranging from 3 ppb to 1000 ppb based on one-day exposure and 0.1 ppb to 140 ppb for a monthly exposure period. It is also reasonable to conclude that the new passive sampling system can be used for eight-hour exposure study because of the low field blanks and high sampling rates.     

Emissions of SO2, NO x and particulates from a pipe manufacturing plant and prediction of impact on air quality

Integrated pipe manufacturing industry is operation intensive and has significant air pollution potential especially when it is equipped with a captive power production facility. Emissions of SO₂, NO _x , and particulate matter (PM) were estimated from the stationary sources in a state-of-the-art pipe manufacturing plant in India. Major air polluting units like blast furnace, ductile iron spun pipe facility, and captive power production facility were selected for stack gas monitoring. Subsequently, ambient air quality modeling was undertaken to predict ground-level concentrations of the selected air pollutants using Industrial Source Complex (ISC 3) model. Emissions of SO₂, NO _x , and particulate matter from the stationary sources in selected facilities ranged from 0.02 to 16.5, 0.03 to 93.3, and 0.09 to 48.3 kg h^???1, respectively. Concentration of SO₂ and NO _x in stack gas of 1,180-kVA (1 KW = 1.25 kVA) diesel generator exceeded the upper safe limits prescribed by the State Pollution Control Board, while concentrations of the same from all other units were within the prescribed limits. Particulate emission was highest from the barrel grinding operation, where grinding of the manufactured pipes is undertaken for giving the final shape. Particulate emission was also high from dedusting operation where coal dust is handled. Air quality modeling indicated that maximum possible ground-level concentration of PM, SO₂, and NO _x were to the tune of 13, 3, and 18 μg/m³, respectively, which are within the prescribed limits for ambient air given by the Central Pollution Control Board.     

Evaluation of applicability of the Sartorius Airport MD8 sampler for detection of Bacillus endospores in indoor air

This study was designed to evaluate the measuring range and lowest limit of detection of Bacillus endospores in the ambient room air when the Sartorius MD8 sampler, and two different culture methods for bacterial enumeration were used. Different concentrations of bioaerosol were generated inside the test chamber filled with either the high-efficiency particulate air (HEPA)-filtered air or with the ambient room air. The detection of endospores in the HEPA-filtered air was achievable: (1) when they were aerosolized at a concentration above 7.56?×?10³ CFU/m³ and analyzed with spread plate method, and (2) when they were aerosolized at a concentration above 4.00?×?10² CFU/m³ and analyzed with pour plate method. The detection of endospores in the ambient room air was possible: (1) when they were aerosolized at a concentration above 9.1?×?10³ CFU/m³ and analyzed with spread plate method, and (2) when they were aerosolized at a concentration above 5.6?×?10² CFU/m³ and analyzed with pour plate method. The microorganisms present in the ambient room air interfere with precise quantification of Bacillus endospores when their concentration is relatively low. The results of this study may be helpful in critical assessment of the results obtained from monitoring the air for bacterial endospores.     

基于不同时间尺度综合指数贡献率的攀枝花市大气污染特征分析

选取2016—2022年攀枝花市环境空气质量监测数据，基于年度、季度、月度、小时时间尺度评价环境空气质量综合指数贡献率。结果表明，攀枝花市污染类型已由传统的单一工业型污染转变为复合型污染，且污染物在不同时间尺度下的分布特征明显。从季度尺度来看，第一季度细颗粒物(PM_2.5)综合指数贡献率较大，第二和第三季度臭氧(O₃)综合指数贡献率较大，第四季度二氧化氮(NO₂)及PM_2.5综合指数贡献率较大。从月度尺度来看，O₃在3—8月的贡献较大，PM_2.5、NO₂、可吸入颗粒物(PM₁₀)、一氧化碳(CO)、二氧化硫(SO₂)在1—2月及11—12月的贡献较大。从小时尺度来看，O₃在13—19点贡献较大，PM₁₀、PM_2.5、CO在8—13点贡献较大，SO₂在9—13点贡献较大，NO₂在8—1...     

黑龙江省环境空气污染物和气象要素的典型相关分析

通过对黑龙江省4个自然年(2016年1月1日—2019年12月31日)环境空气污染物和气象要素的分析,揭示了黑龙江省气象条件对空气污染物浓度的影响规律与特征。对PM_(2.5)、PM_(10)、SO_2、NO_2、CO和O_3等6项污染物的描述性统计和简单的相关分析显示:黑龙江省环境空气质量呈现逐年变好的趋势,非采暖期环境空气质量好于采暖期,6项污染物中除O_3呈现夏季偏高以外,其余污染物采暖期浓度均高于非采暖期。运用典型相关分析法探究环境空气污染物与温度、降水量、相对湿度、风速和气压5项气象要素之间的关系,并进行统计学检验,结果表明:环境空气污染物与气象要素之间存在显著相关,温度、风速和相对湿度对污染物具有显著影响。非采暖期大气相对湿度对PM_(10)和O_3-8h的影响显著;而在采暖期,风速对PM_(10)和PM_(2.5)的影响显著。     

Human health damage caused by particulate matter PM10 and ozone in urban environments: the case of Athens, Greece

Studies conducted over the past decades have provided substantial evidence that both the long- and the short-term exposures to ozone and particulate matter are responsible for mortality and cardiopulmonary morbidity. This paper examines the relationship between exposure to ambient concentrations of ozone (O₃) and particulate matter with aerodynamic diameter of less than 10 μm (PM₁₀) and public health and provides the quantification of the burden of disease from PM₁₀ and O₃-related mortality and morbidity through a Life Cycle Impact Assessment focused on the greater area of Athens, Greece. Thus, characterizations factors (CFs) for human health damage are calculated in 17 sites in Athens, in terms of the annual marginal change in the disability-adjusted life years (DALYs) due to a marginal increase in the ambient concentrations. It is found that the PM₁₀ intake factors range between 1.25?×?10^?6 and 2.78?×?10^?6, suggesting that 1.25–2.78 μg of PM₁₀ are inhaled by the Athenian population per kg of PM₁₀ in the urban atmosphere. Mortality due to chronic exposure to PM₁₀ has a dominant contribution to years of life lost with values ranging between 6.2?×?10^?5 and 1.1?×?10^?4. On the other hand, the mortality caused by short-term exposure to O₃ is weaker with the CFs ranging between 1.58?×?10^?7?years of life lost in the urban/traffic areas and 4.71?×?10^?7?years in the suburbs. Finally, it is found that 9,000 DALYs are lost on average in Athens, corresponding to 0.0018 DALYs per person. This is equal to 0.135 DALYs per person over a lifetime of approximately 75 years, assuming constant emission rates for the whole period.     

Effect of elevated CO2 on degradation of azoxystrobin and soil microbial activity in rice soil

An experiment was conducted in open-top chambers (OTC) to study the effect of elevated CO₂ (580?±?20 μmol mol^?1) on azoxystrobin degradation and soil microbial activities. Results indicated that elevated CO₂ did not have any significant effect on the persistence of azoxystrobin in rice-planted soil. The half-life values for the azoxystrobin in rice soils were 20.3 days in control (rice grown at ambient CO₂ outdoors), 19.3 days in rice grown under ambient CO₂ atmosphere in OTC, and 17.5 days in rice grown under elevated CO₂ atmosphere in OTC. Azoxystrobin acid was recovered as the only metabolite of azoxystrobin, but it did not accumulate in the soil/water and was further metabolized. Elevated CO₂ enhanced soil microbial biomass (MBC) and alkaline phosphatase activity of soil. Compared with rice grown at ambient CO₂ (both outdoors and in OTC), the soil MBC at elevated CO₂ increased by twofold. Elevated CO₂ did not affect dehydrogenase, fluorescein diacetate, and acid phosphatase activity. Azoxystrobin application to soils, both ambient and elevated CO₂, inhibited alkaline phosphates activity, while no effect was observed on other enzymes. Slight increase (1.8–2 °C) in temperature inside OTC did not affect microbial parameters, as similar activities were recorded in rice grown outdoors and in OTC at ambient CO₂. Higher MBC in soil at elevated CO₂ could be attributed to increased carbon availability in the rhizosphere via plant metabolism and root secretion; however, it did not significantly increase azoxystrobin degradation, suggesting that pesticide degradation was not the result of soil MBC alone. Study suggested that increased CO₂ levels following global warming might not adversely affect azoxystrobin degradation. However, global warming is a continuous and cumulative process, therefore, long-term studies are necessary to get more realistic assessment of global warming on fate of pesticide.     

Development of baseline (air quality) data in Pakistan

During 2003–2004, SUPARCO, the Pakistan Space and Upper Atmosphere Research Commission has conducted a year long baseline air quality study in country’s major urban areas (Karachi, Lahore, Quetta, Rawalpindi, Islamabad and Peshawar). The objective of this study was to establish baseline levels and behavior of airborne pollutants in urban centers with temporal and spatial parameters. This study reveals that the highest concentrations of CO were observed at Quetta (14 ppm) while other pollutants like SO₂ (52.5 ppb), NO _x (60.75 ppb) and O₃ (50 ppb) were higher at Lahore compared to other urban centers like Karachi, Peshawar etc. The maximum particulate (TSP) and PM10 levels were observed at Lahore (996 ug/m³ and 368 ug/m³ respectively), Quetta (778 ug/m³, 298 ug/m³) and in Karachi (410 ug/m³, 302 ug/m³). In all major cities the highest levels were recorded at major intersections and variations were directly correlated with traffic density. These pollutants showed highest levels in summer and spring while lowest were observed in winter and monsoon. A data bank has been generated for future planning and air pollution impact studies.     

Ozone and/or Water Stresses Could have Influenced the Betula ermanii Cham. Forest Decline Observed at Oku-Nikko, Japan

A serious forest decline of Betula ermanii Cham. has been observed at Mt. Mae-Shirane, Oku-Nikko, Japan, where high ozone (O₃) concentration and severe water deficiency have been measured. In order to consider the possibility whether O₃ and/or water stresses could have been the causes of the forest decline of B. ermanii, plant growth experiments were conducted in environment-controlled growth cabinets. Two-year-old seedlings of B. ermanii were exposed to either charcoal-filtered air (O₃ concentration <5 ppb) or 50 ppb O₃ (daily average, ranging between 20–100 ppb) for 123 days at 20.0/12.5 ± 1.0°C (day/night) and 70/80 ± 7% relative humidity (day/night). Simultaneously, seedlings were treated with three watering regime: 1.0 < pF < 1.8 (no water stress), 1.8 < pF < 2.5 (mild water stress) or 2.5 < pF < 3.0 (severe water stress). O₃ exposure significantly reduced the dry weights of leaf, root and the whole plant, while water stress significantly reduced the dry weights of each organ and the whole plant. Significant reductions of net photosynthesis, transpiration and stomatal conductance were also observed under O₃ and/or water deficiency treatments, while contents of RuBP carboxylase/oxygenase (Rubisco), chlorophyll _a+b and some essential nutrient elements (N, P, K, Mg and Ca) were not markedly changed. It was suggested that the decrease in net photosynthetic rate induced mainly by stomatal closure was the major cause of the growth reduction under O₃ and/or water stresses. No significant interactions between O₃ and water stresses were observed in terms of the depression of dry matter production, which suggested that simultaneous stress treatments of O₃ exposure and water deficiency could affect the tree growth of B. ermanii additively.     

Why Should We Calculate Complex Indices of Ozone Exposure? Results from Mediterranean Background Sites

While moving towards a flux-based approach, exposure-based ozone metrics are still a practical measure for summarising ambient air quality. Ozone hourly concentrations for the period 2000–2004 from sites in the Mediterranean Italy (≤600 m a.s.l.) were examined to define the O₃ summary statistic in the area, and to determine how O₃ exposure indices correlate to each other. Thirty-four of the most common O₃ exposure metrics were calculated. The results show that background O₃ pollution in Italy exceeds the European and North American standards. The exceedances of the target value, information and alert thresholds set by the 2002/3/CE Directive should encourage Italy to take the appropriate measures to reduce the risk. All the O₃ exposure indices, except the maximum permissible ozone concentration (MPOC) for forests, point to the potential for negative effects on vegetation and human health across Italy. As indices evaluated significantly correlated with each other, we suggest use of the most biologically meaningful metric when summarizing air quality information.     

Rate of occurrence of failures based on a nonhomogeneous Poisson process: an ozone analyzer case study

Atmospheric pollutant monitoring constitutes a primordial activity in public policies concerning air quality. In São Paulo State, Brazil, the São Paulo State Environment Company (CETESB) maintains an automatic network which continuously monitors CO, SO₂, NO _x , O₃, and particulate matter concentrations in the air. The monitoring process accuracy is a fundamental condition for the actions to be taken by CETESB. As one of the support systems, a preventive maintenance program for the different analyzers used is part of the data quality strategy. Knowledge of the behavior of analyzer failure times could help optimize the program. To achieve this goal, the failure times of an ozone analyzer—considered a repairable system—were modeled by means of the nonhomogeneous Poisson process. The rate of occurrence of failures (ROCOF) was estimated for the intervals 0–70,800 h and 0–88,320 h, in which six and seven failures were observed, respectively. The results showed that the ROCOF estimate is influenced by the choice of the observation period, t ₀?=?70,800 h and t ₇?=?88,320 h in the cases analyzed. Identification of preventive maintenance actions, mainly when parts replacement occurs in the last interval of observation, is highlighted, justifying the alteration in the behavior of the inter-arrival times. The performance of a follow-up on each analyzer is recommended in order to record the impact of the performed preventive maintenance program on the enhancement of its useful life.     

The relationship between typhoons' peripheral circulation and ground-level ozone concentrations in central Taiwan

Surface data of meteorological parameters (wind speed, wind direction, and mixing height) and air pollutant concentrations (O₃, NO, and NO₂) were collected for a 92-day period associated with typhoon formation in 2005. The influence of typhoons on O₃ concentration were defined by azimuth and distance from Taiwan, and Types A, B, and C correspond to typhoons less than 1,500 km from Taiwan and located between azimuths 45° and 135°, 135° and 225°, and 225° and 45°, respectively. Type D corresponds to typhoons more than 1,500 km from Taiwan. Titration reactions were conducted at three temporal phases: 2000–0700, 0800–1100, and 1200–1400 LST (Local Standard Time). The air pollution model (TAPM) was used to simulate wind fields and trajectories of air masses. It was determined that typhoon position affected O₃ concentration, temporal and spatial patterns of O₃ titration and vertical meteorological characteristics, which were not all at the statistically significant level.     

西藏自治区“十二五”和“十三五”环境空气质量变化特征

"十二五"以来中国先后颁布了一系列大气污染防治政策并实施相应的大气污染治理措施以提高环境空气质量。为研究西藏自治区"十二五"(2011-2015年)和"十三五"(2016 -2020年)时期环境空气质量变化状况,评估大气污染防治措施实施效果,笔者对2011-2020年西藏自治区7个城市(地区)主要大气污染物浓度和优良天数比例变化进行分析。结果表明:随着一系列大气污染防治措施的实施,西藏自治区环境空气质量显著提升,与"十二五"时期相比,"十三五"时期西藏自治区年平均优良天数比例由97.5%±2.0%提升至99.3%±0.4%,SO₂、 NO₂、 PM₁₀、 PM_2.5浓度年均值和CO 浓度第95百分位数均呈下降趋势,其中CO、PM₁₀和PM_2.5浓度下降幅度较大,O₃日最大8h滑动平均值第90百分位数略有上升。西藏自治区环境空气质量与人口、经济发展程度呈负相关关系。受污染源排放、气象条件和区域传输等因素影响,西藏自治区O₃浓度春、夏季较高,而其余污染物浓度冬季较高。     

Effects of selected metal oxide nanoparticles on Artemia salina larvae: evaluation of mortality and behavioural and biochemical responses

The aim was to investigate the toxicity of selected metal oxide nanoparticles (MO-NPs) on the brine shrimp Artemia salina, by evaluating mortality and behavioural and biochemical responses. Larvae were exposed to tin(IV) oxide (stannic oxide (SnO₂)), cerium(IV) oxide (CeO₂) and iron(II, III) oxide (Fe₃O₄) NPs for 48 h in seawater, with MO-NP suspensions from 0.01 to 1.0 mg/mL. Mortality and behavioural responses (swimming speed alteration) and enzymatic activities of cholinesterase, glutathione-S-transferase and catalase were evaluated. Although the MO-NPs did not induce any mortality of the larvae, they caused changes in behavioural and biochemical responses. Swimming speed significantly decreased in larvae exposed to CeO₂ NPs. Cholinesterase and glutathione-S-transferase activities were significantly inhibited in larvae exposed to SnO₂ NPs, whereas cholinesterase activity significantly increased after CeO₂ NP and Fe₃O₄ NP exposure. Catalase activity significantly increased in larvae exposed to Fe₃O₄ NPs. In conclusion, swimming alteration and cholinesterase activity represent valid endpoints for MO-NP exposure, while glutathione-S-transferase and catalase activities appear to be NP-specific.