Microplastics are widespread in the marine environment, whereby the uptake of these tiny particles by organisms, can cause adverse biological responses. Plastic debris also act as a vector of many contaminants, herein depending on type, size, shape and chemical properties, possibly intensifying their effects on marine organisms. This study aimed to assess the accumulation and potential toxicity of different sizes of microplastics with and without adsorbed perfluorooctane sulfonic acid (PFOS) in the clam Scrobicularia plana. Clams were exposed to low-density polyethylene microplastics (1 mg L^-1) of two different sizes (4-6 and 20-25 μm) virgin and contaminated with PFOS (55.7±5.3 and 46.1±2.9 μg g⁻¹ respectively) over 14 days. Microplastic ingestion, PFOS accumulation and filtration rate were determined along with a multi biomarker approach to assess the biological effects of microplastics ingestion. Biomarkers include oxidative stress (superoxide dismutase, catalase, glutathione peroxidases), biotransformation enzymes (glutathione-S-transferases activity), neurotoxicity (acetylcholinesterase activity), oxidative damage and apoptosis. Microplastics ingestion and PFOS accumulation was microplastic size dependent but not PFOS dependent and filtration rate was reduced at the end of the exposure. Reactive oxygen species in gills and digestive gland were generated as a result of exposure to both types of microplastics, confirming the disturbance of the antioxidant system. Larger virgin microparticles lead to stronger impacts, when compared to smaller ones which was also supported by the Integrated Biomarker Responses index calculated for both tissues. An anti-apoptotic response was detected in digestive glands under exposure to any of the MPs treatments.

微塑料广泛存在于海洋环境中，因此生物对这些细小颗粒的吸收会引起不利的生物学反应。塑料碎片还充当许多污染物的媒介，在此取决于类型，大小，形状和化学性质，可能会增强其对海洋生物的影响。这项研究的目的是评估平面大小蛤with中有和没有吸附全氟辛烷磺酸（PFOS）的不同大小的微塑料的积累和潜在毒性。将蛤暴露于两种不同尺寸（4-6和20-25μm）的低密度聚乙烯微塑料（1 mg L ^-1）并被PFOS（55.7±5.3和46.1±2.9μgg ^-1）污染分别）超过14天。确定了微塑性摄入，全氟辛烷磺酸的积累和过滤速率，以及用于评估微塑性摄入生物效应的多生物标志物方法。生物标志物包括氧化应激（超氧化物歧化酶，过氧化氢酶，谷胱甘肽过氧化物酶），生物转化酶（谷胱甘肽-S-转移酶活性），神经毒性（乙酰胆碱酯酶活性），氧化损伤和细胞凋亡。微塑料的摄入和全氟辛烷磺酸的积累与微塑料的大小有关，而与全氟辛烷磺酸无关，并且在暴露结束时过滤率降低。暴露于两种类型的微塑料中的结果是产生了腮和消化腺中的活性氧，这证实了抗氧化剂系统的干扰。较大的原始微粒会产生更大的影响，与较小的相比，这也得到了针对两种组织计算的综合生物标志物反应指数的支持。暴露于任何MPs处理的消化腺中均检测到抗凋亡反应。