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Quantification of Heavy Metals and Other Inorganic Contaminants on the Productivity of Microalgae
Published on: July 10, 2015
Size-specific mediation of the physiological responses and degradation ability of microalgae to sulfamerazine by
Xinlei Wang1, Min Lv2, Jin Liu1
1School of Environmental and Material Engineering, Yantai University, Yantai 264005, China.
Abstract:
Antibiotics and microplastics (MPs) are two classes of emerging contaminants that are commonly found in various water environments. However, how different sized MPs affect the toxicity and biodegradation of antibiotics remains poorly understood. We investigated the effects of polystyrene (PS) MPs with different particle sizes (100 nm and 30 μm) on the physiological responses and degradation behavior of Phaeodactylum tricornutum to sulfamerazine (SMR). Results showed that microalgae growth was inhibited by SMR, and MPs especially those of smaller size exacerbated the inhibitory effects of SMR on microalgae, including decreasing the content of chlorophyll a, carotenoids, malondiadehyde and superoxide dismutase activity. MPs exhibited low adsorption towards SMR, and MPs especially 30 μm MPs strengthened SMR photodegradation through leaching more organic chemicals. In comparison, 100 nm MPs obstructed the light, resulting in insignificant effects on photodegradation. Apart from photodegradation, SMR could be bioaccumulated and biodegraded by microalgae, and biodegradation was the main removal mechanism. The overall influence of MPs on SMR degradation by microalgae was a balance of the promotion on photodegradation and negative effects on microalgae growth, with the degradation efficiency and rate of SMR significantly lower in treatment of 100 nm MPs (0.0128 ± 0.0012 day-1, 30.13 ± 0.36 %) than treatments without MPs (0.0155 ± 0.0011 day-1, 32.90 ± 3.11 %) or with 30 μm MPs (0.0165 ± 0.0013 day-1, 34.46 ± 2.52 %). Overall, this study reveals the size-specific effects of MPs on the toxicity and degradation behavior of SMR, providing novel insights into the combined effects of SMR and MPs.
Insights
Microplastics (MPs) and sulfamerazine (SMR) co-contaminate water. Smaller MPs worsen SMR toxicity to microalgae, while larger MPs enhance SMR photodegradation, impacting overall SMR removal.
Area of Science:
- Environmental Science
- Environmental Chemistry
- Ecotoxicology
Background:
- Antibiotics and microplastics (MPs) are prevalent emerging contaminants in aquatic environments.
- The combined effects of different sized MPs on antibiotic toxicity and biodegradation are poorly understood.
- Investigating the interaction between MPs and antibiotics is crucial for assessing environmental risks.
Purpose of the Study:
- To investigate the effects of different sized polystyrene (PS) MPs (100 nm and 30 μm) on the toxicity and degradation of sulfamerazine (SMR) by the microalga Phaeodactylum tricornutum.
- To elucidate the role of MP size in the physiological responses and SMR removal mechanisms.
- To understand the interplay between MPs, antibiotics, and microalgae in aquatic ecosystems.
Main Methods:
- Exposure of Phaeodactylum tricornutum to SMR and PS MPs of varying sizes (100 nm and 30 μm).
- Assessment of microalgal physiological responses: chlorophyll a, carotenoids, malondiadehyde (MDA), and superoxide dismutase (SOD) activity.
- Evaluation of SMR adsorption by MPs and photodegradation kinetics, alongside bioaccumulation and biodegradation by microalgae.
Main Results:
- SMR inhibited microalgal growth; smaller MPs (100 nm) exacerbated these inhibitory effects.
- Larger MPs (30 μm) enhanced SMR photodegradation by leaching organic chemicals, while smaller MPs hindered it by blocking light.
- Biodegradation was the primary SMR removal mechanism, but overall SMR degradation efficiency was reduced by 100 nm MPs compared to controls or 30 μm MPs.
Conclusions:
- Microplastic particle size significantly influences the toxicity and degradation of sulfamerazine in aquatic environments.
- Smaller MPs amplify antibiotic toxicity to microalgae, whereas larger MPs can promote photodegradation but may negatively impact overall removal efficiency.
- This study highlights the size-dependent effects of MPs on antibiotic fate and provides critical insights into the combined risks of these emerging contaminants.
