Metal concentrations in selected tissues and main prey species of the annulated sea snake (Hydrophis cyanocinctus) in the Hara Protected Area, northeastern coast of the Persian Gulf, Iran

Medically important snakes and snakebite envenoming in Iran

Snakebite is a common health condition in Iran with a diverse snake fauna, especially in tropical southern and mountainous western areas of the country with plethora of snake species. The list of medically important snakes, circumstances and effects of their bite, and necessary medical care require critical appraisal and should be updated regularly. This study aims to review and map the distributions of medically important snake species of Iran, re-evaluate their taxonomy, review their venomics, describe the clinical effects of envenoming, and discuss medical management and treatment, including the use of antivenom. Nearly 350 published articles and 26 textbooks with information on venomous and mildly venomous snake species and snakebites of Iran, were reviewed, many in Persian (Farsi) language, making them relatively inaccessible to an international readership. This has resulted in a revised updated list of Iran's medically important snake species, with taxonomic revisions of some, compilation of their morphological features, remapping of their geographical distributions, and description of species-specific clinical effects of envenoming. Moreover, the antivenom manufactured in Iran is discussed, together with treatment protocols that have been developed for the hospital management of envenomed patients.

Microlophus atacamensis as a biomonitor of coastal contamination in the Atacama Desert, Chile: An evaluation through a non-lethal technique

In this report, we investigated the accumulation of heavy metals in the lizard Microlophus atacamensis, in three coastal areas of the Atacama Desert, northern Chile. We captured reptiles in a non-intervened area (Parque Nacional Pan de Azúcar, PAZ), an area of mining impact (Caleta Palitos, PAL) and an active industrial zone (Puerto de Caldera, CAL). Our methods included a non-lethal sampling of reptiles' tails obtained by autotomy and a few sacrificed animals to perform a stomach contents analysis. The concentrations of lead, copper, nickel, zinc and cadmium were measured by atomic absorption spectrophotometry in both soil and prey and compared to those recorded in the lizards' tails. Data obtained from lizard tails captured in PAL showed significantly high concentrations of Pb, Cu, Ni, and Zn compared to the other two sites PAZ and CAL. We did not find statistically significant differences among PAZ, PAL and CAL soils, probably due to the similar geological composition of the sites. However, the regional background values for Pb indicate contamination or at least metal enrichment in soils of the three sites, for Cu the global background values indicate contamination for the three sites, and for Cd both the regional and global backgroud values show high values. The analysis of the stomach content showed differences in the food sources of the lizards among the sites studied. The concentration of heavy metal in lizard tissues versus prey delivered values of the Trophic Transfer Factor higher than one (1), suggesting that food may be a primary source of metals in the tissues of M. atacamensis. Calculations of the Bioaccumulation Factor (BAF) and the Ecological Risk (IR) resulted in values higher than one (1) indicating the relevance of this process in the sites studied. In this article, we report relationships between environmental contaminants, mainly putative preys, and concentrations found in lizard tails, which is more substantial in areas with historical heavy metal contamination such as PAL where the non-lethal technique developed in this research suggests a process of metal bioaccumulation in M. atacamensis.

High arsenic and low lead concentrations in fish and reptiles from Taim wetlands, a Ramsar site in southern Brazil

The pollution caused by heavy metals and metalloids represent an emerging threat to wetlands worldwide. Herein we examined the concentrations of arsenic (As) and lead (Pb) in fish and aquatic/semi-aquatic reptiles from Taim wetlands, a Ramsar site located at the southernmost Brazilian coastal plain. A total of 82 individuals from six fish and three reptile species from varied trophic levels were analysed through furnace graphite atomic absorption spectrophotometry. Mean As concentrations (μg·g^-1 dry weight) were markedly high, ranging from 13.06 ± 3.18 to 19.4 ± 4.04 in fish and 3.51 ± 2.36 to 19.00 ± 10.45 in reptiles. Mean Pb concentrations were low, ranging from 0.00067 ± 0.00060 to 0.0040 ± 0.00045 in fishes and 0.00103 ± 0.0011 to 0.0271 ± 0.0353 in reptiles. The highest As mean level was detected in the herbivore-insectivore fish Astyanax aff. fasciatus, a species of low trophic level among the analysed taxa. The highest Pb mean level was found in the broad-snouted caiman Caiman latirostris, the highest trophic level species analysed. The present study warns for the contamination of As especially in edible fish, which constitute a threat to the communities that use this resource in systems connected to Taim wetlands. As concentrations in reptiles were also higher than those reported in previous studies concerning the groups herein addressed. It is possible that the high As burdens found in the analysed species could be attributed to the use of fertilizers and pesticides in extensive irrigated rice areas located in Taim wetlands surroundings, but natural sources cannot be dismissed.

The Alapahoochee watershed microgeographic structure and its potential influence on metal concentrations and genetic structure in the Florida cottonmouth, Agkistrodon piscivorus conanti, within the watershed

This study examines the microgeographic structure of the Alapahoochee watershed, part of the Suwannee River basin, south-central GA, USA, and relates it to variations in liver metal concentrations and genetic structure of the Florida cottonmouth, Agkistrodon piscivorus conanti. One objective was to determine if liver metal concentrations in A. piscivorus differ between Grand Bay and Mud creeks, which form the watershed's upper portion. Grand Bay Creek is relatively pristine, whereas Mud Creek is polluted with various metals. Genetic analyses were used to assess possible migration patterns between the creeks indicating whether the basin possesses a single population or two populations. Collections occurred in 2008 and 2009. Specimens were captured, euthanized, or collected as road kills, and liver metal concentrations were analyzed and DNA extracted. No differences in metal concentrations were detected between the creeks, except for nickel in females. Metal concentrations in A. piscivorus were not significantly different between males and females nor show a relationship to body size. Genetic analyses were limited to three primer sets, which amplified informative loci. Locus, CH4B, was highly divergent between the putative populations and particularly informative. Genetic structure indicates potential population isolation within the two creeks. Results suggest that two distinct A. piscivorus populations were present and those populations did not differ in their liver metal concentrations (exception being nickel), despite the differences in environmental metal concentrations in the areas. These findings provide new insight into metal accumulation and detoxification in these animals.

Industrial Melanism in the Seasnake Emydocephalus annulatus

Although classically associated with urban environments in invertebrates, melanism in terrestrial snakes is more often linked to occupancy of cool climates [1-3]. Thermal advantages to melanism do not apply in aquatic snakes [4], but although turtle-headed seasnakes (Emydocephalus annulatus) are banded or blotched across a wide geographic range [5], most individuals are melanic in polluted inshore bays of the Pacific island of New Caledonia [4]. Why has melanism evolved in these urban sites? Because trace elements bind to melanin, darker feathers enhance a bird's ability to shed pollutants [6]. Reptiles in polluted habitats also accumulate trace elements, which are expelled when the skin is sloughed [7-11]. Might melanism enable snakes to rid themselves of harmful pollutants? We measured trace elements in sloughed skins of seasnakes from urban-industrial versus other areas and in dark versus light skin. For the latter comparison, we used data from laticaudine seasnakes (sea kraits Laticauda spp.), in which each individual is dark and light banded, facilitating comparisons between dark and light skin. As predicted, concentrations of trace elements were higher in snakes from urban-industrial areas and higher in darker than paler skin (even within the same slough). The rate of excretion of trace elements is further enhanced by higher frequencies of sloughing in melanic than banded individuals, even within the same population, because of higher rates of algal settlement on darker skin. Thus, melanism of seasnakes in polluted sites may facilitate excretion of trace elements via sloughing. VIDEO ABSTRACT.

Arsenic, Cadmium, Chromium, Lead, Mercury and Selenium Concentrations in Pine Snakes (Pituophis melanoleucus) from the New Jersey Pine Barrens

Top trophic level predators are at risk from bioaccumulation of heavy metals from their prey. Using nondestructively collected tissues as a method of assessing metal concentrations in snakes is useful for populations that are threatened or declining. This paper reports concentrations of arsenic (As), cadmium (Cd), chromium (Cr), lead (Pb), mercury (Hg), and selenium (Se) in tissues of Northern pine snakes (Pituophis melanoleucus) from the New Jersey Pine Barrens, a relatively pristine, undisturbed habitat. We also determined if skin is an appropriate indicator of internal concentrations and identified the factors (tissue, year of collection, length, sex) that might explain variations in metal concentrations. Because they can grow to 2-m long and live for 25 years, we suggest that these snakes might accumulate heavy metals. Multiple regression models were significant, explaining 16% (lead) to 61% (mercury) of variation by tissue type. For mercury and chromium, size also was significant. The highest concentrations were in liver and kidney for all metals, except chromium and lead. Mercury concentrations in tissues were within the range reported for other snakes and were below effects concentrations in reptiles. The concentrations in skin were correlated with all internal tissues for mercury and for all internal tissues except heart for cadmium. These data show that shed skin can be used as an indicator of metals in pine snakes and that, at present, concentrations of heavy metals in this population are within the range of those found in other snake species from uncontaminated sites.

Oxidative stress biomarkers, cholinesterase activity and biotransformation enzymes in the liver of dice snake (Natrix tessellata Laurenti) during pre-hibernation and post-hibernation: A possible correlation with heavy metals in the environment

We investigated in the liver of dice snakes during pre- and post-hibernation changes in the following antioxidant parameters: total, manganese and copper zinc containing superoxide dismutases (Tot SOD, MnSOD, CuZn SOD, respectively), catalase (CAT), glutathione peroxidase (GSH-Px), glutathione reductase (GR) and the concentrations of total glutathione (GSH) and sulfhydryl groups (-SH). In addition, we examined the expression of phase I biotransformation enzyme cytochrome P₄₅₀1A (CYP1A) and the activity of phase II biotransformation enzyme glutathioneS-transferase (GST), the level of lipid peroxidation (by measuring the thiobarbituric acid-reactive substances (TBARS)), cholinesterase activity (ChE) and metallothionein expression (MT). We also measured the concentrations of heavy metals, including Al, Cd, As, Co, Cr, Cu, Fe, Mn, Mo, Ni, Pb and Zn in the water and snake liver during both periods. During the post-hibernation period, the activities of Tot SOD, CuZn SOD and GST and the concentration of GSH were significantly decreased, while GSH-Px and GR activities, the concentrations of -SH groups and TBARS were significantly increased. The activities of Mn SOD, CAT and ChE, and the relative amounts of CYP1A and MT did not significantly change during the investigated periods. The observed differences in the examined parameters probably represent adaptive physiological responses to sudden changes in tissue oxygenation during arousal from hibernation. Our findings also indicate that the accumulated metals modulated the responses of the examined parameters during the investigated periods.

Sea snakes (Elapidae, Hydrophiinae) in their westernmost extent: an updated and illustrated checklist and key to the species in the Persian Gulf and Gulf of Oman

The Persian Gulf is known as the westernmost distribution limit for sea snakes, except for Hydrophis platurus (Linnaeus, 1766) that reaches southeastern Africa. Previous identification guides for sea snakes of the Persian Gulf and its adjacent waters in the Gulf of Oman were based on old data and confined mostly to written descriptions. Therefore, a series of field surveys were carried out in 2013 and 2014 through Iranian coastal waters of both gulfs to provide a comprehensive sampling of sea snakes in the area. This paper presents an illustrated and updated checklist and identification tool for sea snakes in the Persian Gulf and Gulf of Oman, which are based on new material and a review of the literature. This checklist includes ten species of marine hydrophiines, of which one, Microcephalophis cantoris (Günther, 1864), is a new record for the area. All specimens examined herein are deposited and available at the Zoological Museum of Shahid Bahonar University of Kerman, Kerman province, Iran.

Concentrations of trace elements in the kidney, liver, muscle, and skin of short sea snake (Lapemis curtus) from the Strait of Hormuz Persian Gulf

To our knowledge, this is the first report into trace elements accumulation in tissues of the short sea snake (Lapemis curtus). Lead (Pb), cadmium (Cd), copper (Cu), vanadium (V), nickel (Ni), and zinc (Zn) were determined in the kidney, liver, skin, and muscle tissues of short sea snake, L. curtus, from the Strait of Hormuz during October 2011. Skins generally displayed the lowest trace element burdens. Kidneys displayed the highest Pb, Cd, V, Ni, and Cu mean concentrations (0.89, 0.04, 1.66, 6.22, and 20.23 μg g(-1) dry weight, respectively), while muscle exhibited the highest Zn levels (493.32 μg g(-1) dry weight). Concentration ranges of the selected trace elements were compared with those reported in other studies. Data presented here may be considered as a baseline for further ecotoxicological studies in sea snakes.

Determination of mercury and vanadium concentration in Johnius belangerii (C) fish in Musa estuary in Persian Gulf

The main aim of this study was to determine the concentrations of mercury and vanadium in Johnius belangerii (C) fish in the Musa estuary. A total of 67 fishes were caught from the Musa estuary during five intervals of 15days in the summer of 2013. After biometric measurements were conducted, the concentrations of mercury and vanadium were measured in the muscle tissue of fish using a direct method analyzer (DMA) and a graphite furnace atomic absorption spectrophotometer, respectively. The mean concentration of mercury and vanadium in the muscle tissue of fish was 3.154±1.981 and 2.921±0.873mg/kg w.w, respectively. The generalized linear model (GLM) analysis showed a significantly positive relationship among mercury concentration, length, and weight (P=0.000). In addition, there was a significantly negative relationship between vanadium concentration and fish length (P=0.000). A reverse association was found between concentrations of mercury and vanadium. Mercury concentration exceeded the allowable standards of the Environmental Protection Agency (EPA), the World Health Organization (WHO), and the Food and Drug Administration (FDA) in J. belangerii (C).

Polycyclic aromatic hydrocarbons (PAHs) and n-alkanes in beaked sea snake Enhydrina schistose (Daudin, 1803) from the Mandovi estuary, Goa

An ecotoxicological study were conducted to evaluate the concentrations of PAHs and n-alkanes, in gut, liver and kidney tissues of two individuals of Enhydrina schistose (Daudin, 1803), using gas chromatography/mass spectrometry. The concentrations of PAHs (0.10 µg/g) and n-alkanes (8.12 µg/g) were elevated in the gut, and liver (PAHs 0.05 µg/g tissue, n-alkanes 29.16 µg/g tissue). In kidney of both specimen-A and B the PAHs (0.01 and 0.1 µg/g) and n-alkanes (0.22 and 2.06 µg/g) concentration was detected. This was an initial survey (n = 2) and the main goal was to know accumulation and distribution of PAHs and n-alkanes in the sea snakes. This study indicates high accumulation of petroleum hydrocarbon in gut, liver and kidney of sea snake. Since, this species also act as pray for sea eagles and some predatory fishes such as tiger shark, there is high possibilities of PAHs being circulated in marine food chain.

Distribution patterns of PAHs in different tissues of annulated sea snake (Hydrophis cyanocinctus) and short sea snake (Lapemis curtus) from the Hara Protected Area on the North Coast of the Persian Gulf, Iran

The levels of 22 polycyclic aromatic hydrocarbons (PAHs) were determined in the skin, liver, kidney and muscle tissues of annulated sea snake (Hydrophis cyanocinctus), and short sea snake (Lapemis curtus) collected from the Hara Protected Area, Persian Gulf during October 2010. Low molecular weight (≤3-rings) had the highest levels in skin, while high molecular weight (≥4-rings) was highest in the kidney. The lowest levels of analyzed PAHs were found in muscle in the both species. H. cyanocinctus (59.37 ng g(-1) dw) revealed to be significantly more contaminated than L. curtus (50.51 ng g(-1) dw). Naphtalene was the PAH most frequently detected and at the highest level in the different tissues both species. Di- and tri-cyclic PAHs were predominant in both species suggesting petrogenic origin rather than pyrogenic sources of PAHs. The present study represents the first data of contamination by PAHs in sea snake from the Persian Gulf.

Anguilliform fish reveal large scale contamination by mine trace elements in the coral reefs of New Caledonia

Due to intensive mining activity, increasing urbanization and industrialization, vast amounts of contaminants are discharged into the lagoon of New Caledonia, one of the largest continuous coral reef systems and a major biodiversity hotspot. The levels of 11 trace element concentrations were examined in the muscles of predator fish in the south-western lagoon (moray eels and congers). These species are sedentary, widespread, abundant, and they are easily collected using a sea snake sampling technique. We found the highest mean and maximal concentrations of different trace elements ever found in coral fish, notably regarding trace elements typical from mining activity (e.g., mean values for Cr and Ni, respectively: 5.53 ± 6.99 μg g(-1) [max, 35.7 μg g(-1)] and 2.84 ± 3.38 μg g(-1) [max, 18.0 μg g(-1)]). Results show that important trace element contamination extends throughout the lagoon to the barrier reef, following a concentration gradient from the oldest nickel factory (Nouméa).