Acute and sublethal toxicity of Bronopol and Detarox®AP were assessed in S. woodiana. • 96 h LC 50 of Bronopol is higher than Detarox® AP. • Both biocides exert weak oxidative pressure in digestive gland and gills. • Environmental risk assessment shows a more muted risk for Detarox® AP than Bronopol. • A greater eco-sustainability of Detarox® AP compared to Bronopol is suggested.

The acute toxicity of carbosulfan and chlorpyrifos in formulated pesticides to glochidia (larvae) of the freshwater mussel (Hyriopsis bialata Simpson, 1900) was evaluated under static conditions in moderately hard dechlorinated tap water. Measured pesticide concentrations were 26 to 34% lower than nominal concentrations; therefore, all results are expressed in terms of measured active ingredient. Carbosulfan was relatively non-toxic to the mussel larvae with median effective concentrations (EC) of carbosulfan at 24 and 48 h greater than 0.10 mg/L. The ECs of chlorpyrifos at 24 and 48 h were 0.083 and 0.078 mg/L, respectively (measured concentrations). The 48-h EC of a combined exposure to a mixture of chlorpyrifos and carbosulfan at a constant ratio of 2.9:1 was 0.0142:0.049 mg CP:CB/L. In a separate experiment, the effect of water hardness on carbosulfan, chlorpyrifos, or a combined exposure was assessed using glochidia exposed to either soft, moderately hard, or hard reconstituted water. There was no effect of water hardness on the survival of glochidia after 24- or 48-h exposure to carbosulfan. The chlorpyrifos 48-h ECs in soft water, moderately hard water, and hard water were 0.18, 0.11, and 0.16 mg/L, respectively. The data indicate that the lowest water hardness resulted in the highest survival of glochidia, whereas an increase to moderate water hardness resulted in significantly decreased survival of glochidia (F = 15.5, P < 0.05). The ECs of a combined exposure at 48 h in soft water, moderately hard water, and hard water were 0.124:0.044, 0.132:0.047, and 0.064:0.022 mg CP:CB/L, respectively. The data indicate that the combined toxicity was lowest at low and moderate water hardness, whereas an increase to high water hardness resulted in a significantly decreased survival of glochidia. After 48 h, the toxicity of the combined chlorpyrifos and carbosulfan exposure in soft and hard water was greater than that of chlorpyrifos alone.

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A new species of the genus Pinctada is described from samples collected from the east coast of Phuket Island, Thailand in the Andaman Sea. Pinctada phuketensissp. nov. is distinguished from other species on both molecular and morphological data. Morphologically, the valves of P. phuketensis are characterized by a slightly developed to undeveloped posterior auricle, a small, narrow slit-like byssal notch, the absence of hinge teeth, and a pale to transparent non-nacreous border, with a few dark brown or red blotches. This new species resembles P. fucata but differs by its smaller size and the absence of hinge teeth. Phylogenetic analyses based on both mitochondrial (COI) and nuclear (18S rDNA, ITS1 and ITS2) genes and species delimitation using COI data strongly support that P. phuketensis is a distinct species, which is closely related to Pinctada albina and Pinctada nigra.