Description
Plastics are increasingly recognized as a major threat to the marine environment with microplastics of special concern. Understanding spatial trends of microplastics is critical as studies have determined negative effects on organisms. This pilot study is the first to use mussels as a bionindicator to examine microplastics in Mission Bay, CA. Specifically, bioindicator effectiveness, spatial trends, and potential negative impacts of microplastics in mussels were assessed. Mussels from four sites around Mission Bay were collected, organic tissues were digested, and contents were filtered to examine ingested microplastics. Mussels were found to be an effective bioindicator of microplastics since microplastics were extracted from their tissues. A general trend of higher microplastics in the back of the bay than the mouth was observed. This trend was likely observed due to the back of the bay having more storm drains, higher freshwater input, and longer flushing intervals which can lead to higher contribution and longer retention of microplastics. Little color variation of microplastics was observed, indicating the microplastics were ubiquitous in the environment. With both these findings, there may be a more significant difference after a rain event that may input microplastics. No mussels with high microplastics reported a high condition, a measure of plumpness. Lower condition could be due to reduced filtering rates, stunted growth, and impaired energy allocation. The wide range of conditions with low microplastics may be due to another parameter, such as heavy metals. These findings exemplify the need for an expansion of biomonitoring efforts.
Mussels as a Bioindicator of Microplastic Pollution in Mission Bay
Plastics are increasingly recognized as a major threat to the marine environment with microplastics of special concern. Understanding spatial trends of microplastics is critical as studies have determined negative effects on organisms. This pilot study is the first to use mussels as a bionindicator to examine microplastics in Mission Bay, CA. Specifically, bioindicator effectiveness, spatial trends, and potential negative impacts of microplastics in mussels were assessed. Mussels from four sites around Mission Bay were collected, organic tissues were digested, and contents were filtered to examine ingested microplastics. Mussels were found to be an effective bioindicator of microplastics since microplastics were extracted from their tissues. A general trend of higher microplastics in the back of the bay than the mouth was observed. This trend was likely observed due to the back of the bay having more storm drains, higher freshwater input, and longer flushing intervals which can lead to higher contribution and longer retention of microplastics. Little color variation of microplastics was observed, indicating the microplastics were ubiquitous in the environment. With both these findings, there may be a more significant difference after a rain event that may input microplastics. No mussels with high microplastics reported a high condition, a measure of plumpness. Lower condition could be due to reduced filtering rates, stunted growth, and impaired energy allocation. The wide range of conditions with low microplastics may be due to another parameter, such as heavy metals. These findings exemplify the need for an expansion of biomonitoring efforts.