Joint toxicity of cadmium and fenpyroximate on two earthworms: Interspecific differences, subcellular partitioning and biomarker responses.

Cadmium (Cd) and fenpyroximate are common soil contaminants found together in the field, but their combined toxicity to terrestrial invertebrates has not been studied. Therefore, earthworms Aporrectodea jassyensis and Eisenia fetida were exposed into Cd (5, 10, 50 and 100 µg/g) and fenpyroximate (0.1, 0.5, 1, and 1.5 µg/g) and their mixture, and multiple biomarker responses (mortality, catalase (CAT), superoxide dismutase (SOD), total antioxidant activity (TAC), lipid peroxidation (MDA), protein content, weight loss and subcellular partitioning) were determined to estimate health status and mixture effect. MDA, SOD, TAC, and weight loss were significantly correlated with Cd in total internal and debris (p < 0.01). Fenpyroximate altered the subcellular distribution of Cd. It appears that maintaining Cd in a non-toxic form was the earthworms' primary Cd detoxification strategy. CAT activity was inhibited by Cd, fenpyroximate, and their combined presence. BRI values for all treatments indicated a major and severe alteration in earthworm's health. The combined toxicity of Cd and fenpyroximate was greater than the toxicity of either substance alone. According to EAI, all combined treatments exhibited a clear antagonistic effect. In general, the sensitivity of A. jassyensis was greater than that of E. fetida.

Trace element concentrations in water and Clupeonella cultriventris caspia in the Southern Caspian Sea and Assessment of Potential Risk to Human Health.

Despite the fishing pressure on common kilka (Clupeonella cultriventris caspia) and the importance of the Caspian Sea, there are little data on trace element levels in those. Therefore, the concentrations of 27 trace elements were measured in water (n=15) and C. cultriventris (n=1050) collected from the southern Caspian Sea. The concentrations of Cd, Hg, and Zn in the water exceeded permissible limits and posed potential ecological risks to the aquatic biota, especially in the southeastern region of the Caspian Sea. The estimated daily intakes of As, Cd, Co, Hg, Mn, Pb, Sb, and V from the consumption of C. cultriventris were higher than the acceptable daily intake recommended by the JECFA and USEPA. However, the target hazard quotients and hazard index values were lesser than one. It appears that C. cultriventris provides a small amount of essential element nutrition for consumers. In conclusion, this study revealed that consumers are exposed to As, Co, Hg, Mn, Mo, Sb, and, V through the consumption of C. cultriventris. Also, the concentrations of Cd, Hg, and Zn in water showed significant ecological risk.

Interspecific differences in toxicological response and subcellular partitioning of cadmium and lead in three earthworm species.

Earthworms are often used as test subjects in toxicological studies, due to their ubiquitousness and sensitivity to contaminant exposure. Such testing is typically conducted using Eisenia fetida as the test subject, but continued use of E. fetida (eco) toxicology is questionable. Therefore, in this study three earthworm species, Aporrectodea rosea, Aporrectodea trapezoides and E. fetida, were exposed to lethal and sublethal concentrations of cadmium (Cd) and lead (Pb) nitrate in artificial soil for 7, 14 and 28 days. A biomarker of genotoxicity (TUNEL assay), biochemical markers [malondialdehyde (MDA) and total antioxidant capacity (TAC)], weight loss, lethal toxicity (LC50) and subcellular partitioning were assessed. Cadmium and Pb caused significant inhibition in TAC and growth and significant increases in DNA damage and lipid peroxidation in the earthworms. Acute toxicity rank (14 days) for both Cd and Pb were E. fetida > A. trapezoides > A. rosea. Subcellular partitioning of Cd and Pb in the earthworms were cytosol > debris > granules and debris > granules > cytosol, respectively. Comparison of biomarker responses between study species showed that E. fetida proved to be less susceptible to Cd and Pb exposure than A. rosea and A. trapezoides. Therefore, this study confirms that A. rosea and A. trapezoides are more suitable as subjects than E. fetida for the soil toxicity tests, because of both their greater susceptibility to toxicants and in their abundance in the field.

Subcellular partitioning of cadmium and lead in Eisenia fetida and their effects to sperm count, morphology and apoptosis.

Earthworms and their biomarkers are considered good indicators for assessing the effects of toxic chemicals. Therefore, in this study, we exposed Eisenia fetida to lethal and sub-lethal concentrations of Cd and Pb nitrate in artificial soil for 14 and 28 days to evaluate the impact on subcellular partitioning, lethal toxicity (LC50), growth, sperm count, morphology and apoptosis (using TUNEL assay). The soluble internal pools of both metals were good predictors of the responses of biomarkers. We found sperm deformation, TUNEL positive sperms and weight loss positively and sperm count negatively correlated with the concentrations of Cd and Pb in the total internal and cytosolic fraction (p < 0.01) and to a lesser extent with Pb concentrations in the granular fraction (p < 0.05). Fourteen days LC50 for Cd and Pb were 2169 ±â€¯322 and 6387 ±â€¯904 µg/g, respectively. Cadmium and Pb caused a significant depression in sperm count after 14 (Cd: up to 46.9%; Pb: up to 36.24%) and 28 (Cd: up to 72.47%; Pb: up to 43.12%) days of exposure relative to the control (p < 0.05). Cadmium induced higher abnormality in sperm heads than Pb. For both metals, TUNEL positive sperms significantly increased after 14 (Cd: up to 14.17%; Pb: up to 16.33%) and 28 (Cd: up to 16.33%; Pb: up to 11.67%) days of exposure compared with the control (p < 0.05). The findings of this study, illustrate the importance of considering sperm parameters as a rapid, easy and sensitive biomarker for the evaluation of metal toxicity.

Metal Concentrations in Tissues of Gadwall and Common Teal from Miankaleh and Gomishan International Wetlands, Iran.

Miankaleh and Gomishan International Wetlands are important wintering areas for waterbirds in the Caspian Sea region. Previous studies revealed increased exposure to metals in some species of waterbirds using these wetlands. In this study, we examined concentrations of cadmium (Cd), chromium (Cr), iron (Fe), lead (Pb), and zinc (Zn) in kidneys, liver, and pectoral muscle of wintering Gadwall (Anas strepera) and Common Teal (Anas crecca) collected in 2012. In addition, we measured concentrations of these elements in water and sediments from the collection sites. The genders differed in only one element/tissue combination, i.e., concentrations of Fe were greater in the livers of males. Concentrations of elements observed in Gadwall were generally higher than in Common Teal; only renal Cr and muscle Zn did not differ between species. Mean Cd concentrations in Gadwall exceeded background levels, reaching 1.94 µg/g ww in kidneys and 1.09 µg/g ww in liver. Similarly, Pb concentrations in Gadwall were also elevated (4.14 µg/g ww in kidneys, 3.22 µg/g ww in liver). Concentrations of other metals were within ranges commonly found in waterfowl. Concentrations of elements in the environment were elevated above background and comparable with the data obtained for this region by other scientists. However, these levels were deemed to not be great enough to pose an acute health risk to waterfowl. Given increased concentrations of some metals in duck tissues, further inquiry into the source of the exposure is needed for this area.