Microplastics in commercial seafood: Pleoticus muelleri as a case study in an estuarine environment highly affected by human pressure (Southwestern Atlantic).

Plastic pollution in seafood has become a worldwide safety concern due to its possible harm to humans. This is the first study which has investigated the length-weight relationship, growth patterns and condition factor, together with the concentrations of microplastics (MPs) and mesoplastics (MesoPs) in Pleoticus muelleri from the Bahia Blanca Estuary (BBE), Argentina. Forty-nine individuals were collected from three sampling stations in the BBE, and each abdominal muscle with the gastrointestinal tract was analyzed. P. muelleri showed an isometric growth pattern (b = 3.0054) with values of K similar among the individuals collected (ranged between 0.80 and 0.91), considering them in good condition compared to other crustacean species around the world. 96% of shrimp presented transparent or black synthetic fibers as prevalent types, with an abundance average of (3.0 ± 2.90) MPs/g w. w. And (0.053 ± 0.16) MesoPs/g w. w. as well as a dominant size range of 0.5-1.5 mm, in accordance with recent studies in the same area. The linear regression analysis showed that K was independent of the concentration of MPs ingested by P. muelleri, with R2 ranging between 0.024 and 0.194 indicating that MPs contamination does not affect the nutritional condition of shrimp. SEM/EDX detected the presence of elements like C, O, K, and Mg, tissue residues and fractures on the surface of the analyzed fibers. FTIR confirmed different types of polymers in shrimp related to textile fabrics probably from untreated sewage discharges from nearby cities. The results of this research provide useful information for a better understanding of MPs contamination in seafood, suggesting P. muelleri as a suitable species for monitoring MPs in estuarine ecosystems. Likewise, more research is required to know the effects of MPs on food safety in humans.

Heavy metals concentrations in zooplankton and suspended particulate matter in a southwestern Atlantic temperate estuary (Argentina).

The present work includes part of the first studies of metals concentrations in the zooplankton from a heavily industrialized estuary of Argentina, the Bahía Blanca estuary. Cd, Cu, and Pb concentrations in the zooplankton (macro- and mesozooplankton) and the suspended particulate matter were measured at stations with different degree of pollution. Physicochemical variables and zooplankton composition and abundance were also analyzed. Thus, the aim of the present work was to analyze the spatial and temporal distribution of heavy metals in these two different fractions, and the possible relation among them due to their importance in the biogeochemical cycles of marine environments. Samplings were carried out during a year, from March 2005 to April 2006, every 2 months, at stations located near chemical and petrochemical industries, stations far from these points and one station in an intermediate location. In the mesozooplankton, the mean concentrations of Cd, Cu, and Pb were 3.63 ± 1.46, 34.46 ± 5.40, and 11.54 ± 3.04 µg g(-1) dry weight (d.w.) respectively, while in the macrozooplankton, 3.20 ± 2.28, 21.86 ± 4.79, and 8.36 ± 1.85 µg g(-1) d.w. On the other hand, particulate Cd, Cu, and Pb presented a mean concentration of 3.33 ± 1.22, 12.75 ± 2.67, and 12.53 ± 3.20 µg g(-1) d.w., respectively. Metals' levels in both the SPM and zooplankton fluctuated throughout the study time and were relatively high in the particulate phase especially for Cu and Pb. Moreover, zooplankton accumulated important concentrations of the three metals. The sources of them are probably the discharges of the industries and domestic sewages located near the estuary.

Lead concentrations in zooplankton, water, and particulate matter of a southwestern Atlantic temperate estuary (Argentina).

This study presents for the first time valuable results of lead (Pb) accumulation in zooplankton from a southwestern Atlantic temperate estuary, the Bahía Blanca estuary, one of the most important and industrialized coastal environments of Argentina. It considers Pb concentrations in zooplankton organisms as well as in the dissolved and particulate phases. These fractions were analyzed on account of their important role in the biogeochemical cycles of trace elements in estuarine environments. In addition, the major physicochemical variables, i.e., nutrients, and pigment concentrations, and zooplankton composition and abundance, were also considered to understand Pb levels in the above-mentioned fractions. Samplings were performed from March to December 2005 with a bimonthly frequency and comprised a study area with stations located near industrial settlements and other stations a few kilometers far from these points. The results of the physicochemical variables and nutrients and pigments agreed with historic values for the estuary and did not present any evidence of abnormalities. Dissolved Pb presented a mean concentration of 2.15 ± 0.46 µg L(-1), whereas particulate Pb presented a mean concentration of 13.52 ± 3.07 µg g(-1) dry weight (dw). In the mesozooplankton, represented by copepods, the mean concentration was similar to the particulate fraction (13.38 ± 4.41 µg g(-1) dw), whereas in the macrozooplankton, represented by mysids, it was lower (9.81 ± 1.89 µg g(-1) dw). Thus, Pb concentrations were relatively high in the dissolved and particulate phases. Moreover, zooplankton accumulated important concentrations of this metal, which was mainly incorporated through suspended particulate matter (SPM). The source of Pb in all of these fractions is related to the industry discharges as well domestic sewage located near the sampling stations. Finally, through these results, it was possible to show the importance of zooplankton and SPM in the biogeochemical cycle of Pb as well as the interaction between these fractions in an estuarine and anthropogenic environment, such as the Bahía Blanca estuary.