Clam Ruditapes philippinarum recovery from short-term exposure to the combined effect of salinity shifts and Arsenic contamination

• Arsenic exposure and salinity shifts caused biochemical alterations in Ruditapes philippinarum.
• When As and salinity act in combination, clams experienced stronger biochemical alterations.
• Clams re-established their biochemical status after a 28 days recovery period.
• Clams decreased their As concentration after recovery.

The current study assessed the biochemical alterations induced in the clam species Ruditapes philippinarum after exposure to salinity shifts (14, 28 and 42) and arsenic (As) contamination (0 and 2 mg/L). The capacity of this species to recover (96 h and 28 days) after exposure (96 h) to both stressors, acting alone and in combination, was also evaluated. After exposure, regardless of the salinity tested, clams contaminated with As showed higher concentrations than non-contaminated specimens. After recovery, As concentration in clams decreased, with contaminated and non-contaminated specimens presenting similar values. The results obtained further demonstrated that exposure to As (2 mg/L) at different salinities (salinities 14, 28 and 42) and salinity 42 (As 0 mg/L) lead to an increase of lipid peroxidation and detoxification mechanisms in clams, compared with non-contaminated clams at salinities of 14 and 28. After recovery, at salinities 14 and 28, clams previously exposed to As were capable to decrease their oxidative stress to levels found in non-contaminated clams. Nevertheless, at salinity 42 both contaminated and non-contaminated clams did not survive. Overall results of measured energy-related parameters, indicators of oxidative stress, antioxidant and biotransformation enzymes indicated that As exposure and salinity shifts caused biochemical alterations in R. philippinarum, with stronger impacts when both stressors were acting in combination.