How Much Mercury Is in Crab?

Mercury is an extremely dangerous toxic metal, known to harm children and babies’ brains, as well as cross the placenta to harm fetuses. Eating two servings of low-contaminant fish each week may reduce your exposure risk of mercury.

Crab Grapsus grapsus from both urban and protected sites across Galapagos was collected for analysis to measure mercury levels in their leg muscles, with barnacles and oysters from those locations also collected as comparison samples.

Methylmercury

Mercury is a heavy metal that can be harmful to human health when consumed in high concentrations, especially as methylmercury. Methylmercury exposure poses particular concerns to developing fetuses and young children. Exposed early in development to methylmercury can result in cognitive issues, vision difficulties and numbness in fingers and toes, interfering with coordination, speech and hearing skills as well as hampering coordination, speech and hearing capabilities. Long-term exposure to high concentrations of mercury may result in neurological effects, including memory loss. Most individuals carry some level of mercury in their systems at safe levels that do not pose health issues. Mercury levels found in seafood, particularly fish, can be hazardous. Large predatory species like sharks and tuna can contain levels up to 10 million times higher than what exists naturally in their surrounding environments, so eating such fish could be potentially deadly.

Mercury is a naturally-occurring element that can enter our bodies through food sources like seafood and air pollution, becoming toxic once inside. Once inside, methylmercury enters our digestive tracts and bloodstream, where it accumulates to dangerous levels. To mitigate its toxicity, selenium-rich foods may help the body dispose of it more easily by binding to it and helping the body flush it out naturally.

Researchers studied methylmercury levels in crabs (Grapsus grapsus) from five sites in Galapagos Islands. They observed that uninhabited areas contained lower levels than inhabited ones due to contamination from sources like pollution or fishing discards scavenged by local populations.

Grapsus grapsus from Santa Cruz Island’s Academy Bay site was found to contain the highest mercury concentration, located near Puerto Ayora’s main jetty and ferry terminal. Crabs from this urban site were nearly four times more likely to contain methylmercury than their counterparts from a protected site several kilometers away.

Bioaccumulation

Mercury can bioaccumulate through food chains, beginning with phytoplankton (microscopic marine algae) being consumed by zooplankton before being eaten by small fish and aquatic animals that feed off these organisms, eventually being consumed by larger creatures that consume them again – this process of biomagnification occurs. As persistent pollutants tend to bioaccumulate at higher trophic levels, food chains play an integral part in mitigating exposure to toxic contaminants.

Researchers recently conducted a comprehensive examination of mercury concentration levels in crabs (Grapsus grapsus) from five sites within the Galapagos archipelago. Leg muscle values varied significantly among sites, from 0.06 at Isabella National Park in protected location to 2.04 on San Cristobal island – with both G grapsus and sea lions, Zalophus wollebaeki inhabiting San Cristobal where G grapsus crabs known to feed on bird carcasses and placentas before feeding on them both.

Results also demonstrate that sediment organic matter is an important source of mercury for lower trophic level organisms, with both total mercury and methylmercury (MeHg) concentrations positively correlating with normalized sediment TOC content; MeHg was more readily taken up than Hg. This suggests it might be more rapidly absorbed from sediments.

Crabs can bioaccumulate mercury through eating prey with high mercury content or passive absorption. Once consumed, mercury travels throughout the body and collects in organs like the brain and kidneys – this could have serious repercussions for pregnant women and children, though prevention is possible through restricting seafood consumption.

Mercury levels found in G grapsus legs at South Plaza and Academy Bay locations exceeded government agency thresholds set out as being harmful for pregnant women, those trying to become pregnant, and children. These findings illustrate the importance of monitoring mercury levels in local island foods.

Health risks

Mercury is a toxic heavy metal that accumulates in human bodies, posing a potential health risk to both adults and children alike. Mercury levels found in seafood we consume can vary considerably depending on factors like its type, size and source; those eating more types or species with higher mercury concentrations could face higher health risks from eating that fish species. Beyond human exposure, mercury also poses dangers to marine organisms whose food chains it contaminates as it bioaccumulates through them.

Mercury pollution can be particularly problematic in coastal environments, particularly estuaries and intertidal habitats. Studies have demonstrated that benthic invertebrates play an integral part in transporting mercury to higher trophic levels – this is especially evident among ephemeral aquatic species such as sea urchins, oysters and crabs that are consumed by larger predatory fish and ultimately end up in humans’ diets. Mercury bioaccumulates up marine food chains causing health risks to pregnant women and young children

Dietary exposure of human population living in Galapagos archipelago to mercury via blue crabs may be one of the primary sources for local human exposure to it. Given their remote location and lack of human pollution sources, high mercury concentrations were somewhat unexpected given their large G. graspsus muscles found here – moreover these levels correlated directly with carapace width, suggesting Hg bioaccumulation rather than simple ingestion from sediments.

Researchers employed multivariate regression models to better understand what factors affect G. grapsus mercury concentration levels. The models considered factors like tissue type, river habitat and width of crab muscle and carapace width. A final model best explained the relationship between BSAF(Hg) and sediment total Hg and MeHg and accounted for 54% of variance among them respectively; furthermore it also considered significant spatial variation in how organic matter reduces mercury bioavailability to both crabs and prey alike.

Pregnancy

Pregnant women should opt for seafood that’s low in mercury to ensure that their fetuses receive adequate amounts of proteins and omega-3 fatty acids essential to baby brain development. To achieve optimal outcomes during gestation, pregnant women should try eating varieties such as swordfish, king mackerel and tilefish that contain high mercury levels as these also contain lead and cadmium heavy metals that could potentially harm fetal development.

Seafood provides essential nutrients, including omega-3 fatty acids, protein, vitamin B12, iodine and zinc that are crucial to fetal development and reduced the risk of birth defects. If you’re allergic to shellfish it’s wise to stay away from crabs and other seafoods; additionally, if you have mercury fillings it’s wise to talk with your dentist about replacing them with safer options.

While most types of seafood are safe for pregnant women to consume, it’s wise to make wise selections when it comes to crab. Some species, like blue or Dungeness crabs are high in mercury content and should be avoided during pregnancy; instead opt for King crab, one of the safest options.

Another risk associated with eating crabs is the possibility of food-borne illness, but this can be mitigated by making sure they’re cooked thoroughly to destroy any bacteria or parasites present. Furthermore, fresh seafood should always be thoroughly washed prior to being prepared in the oven, and raw fruit and vegetables must always be peeled prior to consumption.

Recent research from Avon Longitudinal Study of Parents and Children (ALSPAC) looked into whether maternal prenatal mercury exposure affected children’s reading, spelling, phoneme awareness, or math skills after birth. No correlation could be drawn between prenatal mercury exposure and their academic achievements in reading, spelling, phoneme awareness or math; and subsequent academic achievements at school age. Unfortunately this evidence does not support this claim.

The FDA advises pregnant and breastfeeding women to consume up to 12 ounces per week of mercury-low fish such as crab, shrimp, canned light tuna, salmon, pollock and crab in order to limit mercury exposure; cooking or grilling the fish instead of frying is best in order to limit its impact on health; when choosing farm-raised varieties over wild ones is preferable as these typically have lower mercury levels than wild varieties.