Environmental Toxicology

In 1962, what was then a landmark novel ‘Silent Spring’ was published, the author was Rachel Carson. The novel highlighted the effects of man made chemicals on the environment and ecosystems. Carson describes in this novel, the powerful and detrimental effects that humans have on the natural world
This report will describe the harmful effects of environmental chemicals on man and ecosystems and attempts to assess whether these effects have lessened since the publication of Rachel Carson’s ‘Silent Spring’. Scientific evidence will be presented of the changing effects of environmental chemicals through time and on a global scale. Their methods of toxicity will be described

The Niagara Falls speak to us with great clarity about the evolution of the relationship between man and nature in Western culture. Here a shift can be recognized both in aesthetic and physical terms – from feelings of repulsion and anxiety to ones of enchantment and delight, from the fear of the overwhelming power of the falling waters to the illusion of man’s total control of them. Paradoxically, the Niagara region, a key node of the Great Lakes ecological and economic system, is a region that did not lack planning: the construction of the western end of the Erie Canal, the system of parks designed by Olmsted and Vaux in both Niagara Falls and Buffalo, and the large infrastructures Robert Moses and his Power Authority built in Niagara County, not to mention all of the utopian urban projects that were developed for Grand Island and Niagara Falls. Yet today Niagara is one of the poorest and most socially devastated counties in the state of New York. Its once booming industry has nearly completely evaporated, hiding a territory riddled with toxic landfills and decrepit neighbourhoods behind the touristy curtain of the falls. So what went wrong? How did the grandeur of the past get lost?

Recently, a novel approach to a highly sensitive and quantitative detection of rare earth element (REE) ions including La3+, Eu3+ and Tb3+, by the polymerase chain reaction (PCR) technique, has been reported. The detection of REE ions is based on the catalytic nature of REE ions targeting the deoxyribonucleic acid (DNA), thus monitoring of the ions can be achieved by reading the level of intact DNA by PCR. Despite of its high sensitivity (at ppb to ppt levels), the conventional PCR-based REE detection protocol requires certain length of time (1-2 hours). In the present study, we modified the PCR-based REE detection protocols by employing the high-speed PCR, and performed the automated and rapid detection of La3+ in small-sized aqueous samples within 5min.

Cadmium(Cd) is one of the most dangerous occupational and environmental toxins. The objective of the present
study is to examine the potential prophylactic effects of phytic acid (PA) on thyroid hormones of male rats
intoxicated with Cd. The male albino rats were divided into five groups: group I (control) was fed with the basal
diet, group II was intoxicated with Cd in drinking water, groups III, IV, and V were intoxicated with Cd in drinking
water and fed with the diet containing 3.5, 7, and 10 g of PA/kg, respectively. The results indicated that the serum
calcium, iron (Fe), and total Fe binding capacity levels and serum T3 and T4 in Cd-treated rats of group II were
decreased when compared with the control group, while PA-administered groups with Cd showed a significant
improvement when compared with the Cd-treated rats only. Serumthyroid stimulating hormone (TSH) level was
significantly increased in Cd-treated rats compared with the control group, while the addition of PA in diet
decreased the high levels of TSH. These results indicated a prophylactic effect of PA against Cd-induced toxicity
in rats.
Keywords
Cadmium, phytic acid, thyroid, T3, T4, TSH, toxicity

Perfluorooctanoic acid (PFOA) is a widespread contaminant in
the environment, that is, implicated in several toxicities. The
intestinal wall is first surface of interaction with any toxicant
after exposure through the oral route. Previous studies have
demonstrated: increased intestinal bioaccumulation of
PFOA in different experimental animals, PFOA-induced
changes in DNA methylation of several tissues, and alterations
in expression of tight junction (TJ) genes due to epigenetics
changes. Nevertheless, evidence on the toxicity of
PFOA on intestinal epigenetics and TJ genes is limited.
Thus, the present work investigates PFOA-induced changes
in expression of epigenetic genes of the colon in relation to
TJ genes alterations. CD-1 mice were orally dosed with 4
different concentrations of PFOA (1, 5, 10, or 20 mg/kg/d)
for 10 consecutive days, and its bioaccumulation and
induced changes in the expression of TJ and epigenetic
genes in the colon were investigated. The PFOA was accumulated
in very high concentrations in the colon tissue and
decreased the expression levels of DNA methyltransferase
genes (Dnmt3a and DNMT3b). However, no significant
alterations were observed in expression levels of 10-11
translocation (TET1 and TET2) genes. We also found a
significant reduction in the mRNA expression of TJ
protein-1 (TJP1) at the highest concentration of PFOA.
Furthermore, the mRNA expression levels were significantly
increased for occludin (OCLN) and Claudins
(CLDN2, CLDN3, CLDN8) genes at higher concentrations.
Therefore, our study demonstrates that PFOA initiates
DNA methylation alterations and changes the expression
of genes necessary for preserving the integrity of the colon
barrier.

Exposure to particulate matter (PM) may alter lung homeostasis inducing changes in fluid balance and host defense. Bioavailability of soluble PM compounds like polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and transition metals has been shown to play a key role in lung injury. We have previously characterized the size, shape, and chemical components of urban air particles from Buenos Aires (UAP-BA) and their biological impact on lungs. Herein, we evaluate the possible toxic effect of UAP-BA-soluble fraction (UAP-BAsf) on pulmonary cells obtained from young (1-2 months old) and aged (9-12 months old) Wistar rats using phagocytosis, oxidant-antioxidant generation, and apoptosis as endpoints. UAP-BA were collected in downtown BA and residual oil fly ash (ROFA), employed as a positive control, was collected from Boston Edison Co., Mystic Power Plant, Mystic, CT, USA. Both particle-soluble fractions (sf) were employed at concentrations ranging from 0 to 100 m...

The clays consumed by geophagous individuals contain large quantities of aluminum, a known neurological and hematological toxin. This is the first study to evaluate the risk of aluminum poisoning in geophagous individuals. Blind determinations of plasma and urinary aluminum concentrations were carried out in 98 anemic geophagous pregnant women and 85 non-anemic non-geophagous pregnant women. Aluminum concentrations were significantly higher (P < 0.0001) in the geophagous anemic women than in the controls, with odds ratios of 6.83 (95% confidence interval [CI] = 2.72-19.31) for plasma concentrations (13.92 ± 14.09 μg/L versus 4.95 ± 7.11 μg/L) and 5.44 (95% CI = 2.17-14.8) for urinary concentrations (92.83 ± 251.21 μg/L versus 12.11 ± 23 μg/L). The ingested clay is the most likely source of this overexposure to aluminum. If confirmed, the clinical consequences of this absorption for pregnant women and their offspring should be explored.

This study was conducted for assessment of human health risks due to intake of heavy metal cont aminated vegetables through determination of the heavy metals' concentrations in soil and vegetables grown on it nearby Buriganga River, Dhaka, Bangladesh. Flame Atomi c Absorption Spectroscopy (AAS) was used to determine the concentrations of heavy metals. Moreover, Health Risk Index (HRI) of heavy metals was also calculated. The mean concentrations of heavy metals in soil were found in the decreasing order of Fe>Cr>Zn> Ni>Cu>Pb>Cd but in the case of roots and edible parts of vegetables, the mean concentrations of different heavy metals were as decreasing order of Fe>Cr>Zn>Pd>Ni>Cd>Cu and Fe>Cr>Zn>Pd>Ni>Cu>Cd respectively. In case of roots and edible parts of vegetables, except Cu and Ni all other heavy metal concentrations were higher than permissible limit. The HRI values of Cd, Cr, Fe, Pb and Zn were greater than 1 which indicated that contaminated vegetables were awfully detrimental to human health. Therefore, soil contamination as well as the heavy metal uptake into human body should be preven ted to avoid the health risk caused by heavy metal.

A variety of chemicals including foaming agents are used to aid in the protection of forest resources from the wild land fires. The fire-fighting foams (FFFs) are formulations composed principally of surfactants. As a part of Japanese national project, environmentally inert FFFs have been developed. There is an emerging need for testing the impacts of these FFFs on the living organisms composing the typical landscapes or ecosystems in Japan. In the present report, we aimed to describe our latest attempt for assessing both the short-tem and long-term impacts of FFFs in aquatic (fresh water) and semi-aquatic (wetland) ecosystems , by employing the laboratory-sized model assays (preliminary studies) and the biotope-based observation, respectively. In the biotope assays which was based on the observation in compact biotopes mimicking the fresh water environments and wetland, both the acute and long-term eco-toxic impacts of two FFFs (soap-based and synthetic detergent-based) were assessed. Spraying of synthetic detergent-based foam formula was shown to be more toxic compared to soap-based formula and mock water treatment.

In the study, first-time personal exposure level of polycyclic aromatic hydrocarbons (PAHs) was measured during cooking hours in participants of three different types of kitchen both in the particulate and gaseous phase using traditional and improved cookstoves. Along with that, indoor particulate matter (PM) concentration was also estimated during the cooking hours to examine the impact of intervention in different kitchens. The results of the study clearly revealed that the kitchen characteristics and type of cookstove technology have a significant impact on PM 2.5 , PM 1 and PAHs concentration. Cookstoves intervention has resulted in maximum reduction of PM 1 i.e. 75% in an enclosed kitchen followed by semi-enclosed and open kitchen having 71% and 52%, respectively. In addition, correlation analysis of PM 2.5 and PM 1 with PAHs showed a strong association (r 2 = 0.9), showing the affinity of PAHs to bind to fine range of particles. Health risk assessment was also carried out to assess the PM daily dose and carcinogenic and non-carcinogenic risk due to inhalation of PAHs. The study confirmed the personal concentration of PAHs compounds was significantly high (p < 0.05) during use of traditional cook-stove compared to improved cookstove among all the three kitchens. Furthermore, to measure the toxicity levels, PAHs concentrations have been converted to benzo[a]pyrene equivalence for calculating cancer and non-cancer effects using toxicity equivalency factors. The overall lifetime carcinogenic risk was the highest 2.5E-03, 6.4E-04 among women who prepared meals in the enclosed kitchen compared to 8.4E-04, 1.3E-04 in semi-enclosed and 2.2E-04, 4.6E-05 in the open kitchen during use of traditional and improved cookstoves, respectively, which exceeded the US EPA standard i.e. 1 × 10 −6. The study underlined the importance of personal monitoring for exposure, and risks-based studies along with the time-activity of user to measure the actual inhalation risk for the participants. These findings indicated that women are exposed to hazardous smoke in the indoor kitchen and are at greater risk of developing cancer, especially in rural areas.

For many years organophosphate pesticides considered the main option for a lot of people in many countries to
manage different pests. It's more than 70 years now and OPs still use with certain purposes in gardens, fields and greenhouses as crop protection agents, or even at houses as public health agents. Thus, year after year and with the repeating usage of organophosphate agents many problems were appeared as a result to excessive use of pesticides. The adverse effects of
pesticides usage represented in the effects on human health, environment, pesticides residue in crops and soil & water
contaminated by these pesticides. Therefore, it was necessary to throw a light on the risks that generated by irresponsible usage  of organophosphate pesticides.

Quand l’Homme a commencé à faire de l’agriculture, il a d’abord appris à combiner les plantes, de façon à ce qu’elles se protègent naturellement. Depuis l’Antiquité, l’Homme a commencé à utiliser des pesticides, comme le souffre ou l’arsenic, en quantités juste suffisantes pour l’aider à protéger ses champs.
Apres la deuxième guerre mondiale, le taux de la famine ne cessa d’augmenter , le nombres des terres cultivées augmentes mais le résultats n’est pas suffisants , donc place aux produits miracles « les pesticides  » le rendement augmente la famine diminue mais  cette solution deviens un problème aujourd’hui  l’utilisation démesurée des pesticides est remise en cause, des chercheurs ont prouvé que  les pesticides peuvent avoir des effets négatifs sur l’environnement et sur la santé humaine

Acute toxicity tests of five metals (aluminum, cadmium, iron, lead, zinc) were performed to determine LC50 values in two
species of freshwater rotifers: Asplanchna brigthwellii and its prey Brachionus calyciflorus. We conducted the tests
using neonates less than 24 hr-old, each test consisted of five replicates, negative control and five metal concentrations
(Al, Cd, Fe, Pb, Zn). We found that the prey rotifer B. calyciflorus was more sensitive to Al, Cd, Pb and Fe than the
predator rotifer A. brightwellii. For both rotifers Cd was the most toxic of the five metals. Our B. calyciflorus strain is
sensitive when compared with other B. calyciflorus strains and other species and genera of the family Brachionidae. In
the other hand, LC50 values of A. brigthwellii are compared with rotifer and copepod predators.

Formaldehyde (FHO) is a multipurpose chemical that is an eye, nose, throat and skin irritant, sensitizer and allergen, as well as a class 1 human carcinogen. Brazilian hair treatments, containing high levels of FHO (up to 11%), have become regularly used that have the potential to expose clients to toxic levels in excess of current regulatory standards. We report on a patient who underwent a single hair treatment and subsequently developed an autoimmune disease. We review the relevant literature on autoimmune disease and formaldehyde exposure. Our case adds to existing knowledge and suggests that physicians ask their patients about commercial products that contain formaldehyde when diagnosing autoimmune conditions.

The present study was planned aiming to investigate the effects of atrazine
herbicide exposure on stress biomarkers acetylcholinesterase activity (AchE) and
cortisol, oxidative stress responses and the histopathological changes in liver of
female Clarias gariepinus and the ameliorative effect of vitamin E supplementation
(240mg/kg diet) on the degree of atrazine sublethal toxicity (1.37mg/l) for 6 weeks.
Chronic exposure to atrazine revealed a marked inhibition in the activity of AchE.
But, significant increase of serum cortisol level was recorded. Moreover, atrazine
exposure was associated with a marked induction of oxidative damage in liver tissue
as evidenced by increased level of lipid peroxidation (LPO) and reduced glutathione
(GSH) content. Atrazine exposure also led to a significant increase in the activities of
catalase (CAT) and superoxide dismutase (SOD).Furthermore, histopathological
examination of the liver of exposed fish showed dilatation and congestion of blood
vessels, fatty degeneration, necrosis and pyknotic nuclei of hepatocytes. However,
fish fed diet supplemented with vitamin E exhibited protective effect by minimizing
the atrazine-induced toxicity, through measured values more or less similar to the
control group fish.
Key words: Atrazine, Clarias gariepinus, Cortisol, Oxidative stress, Histopathology

Nitrite is a compound with a high toxicity to aquatic animals. Several anthropogenic pollution sources are increasing the concentrations of this component of the nitrogen cycle. Despite this toxicity, there is little available literature on its effects on freshwater invertebrates. Laboratory bioassays were performed to obtain data on the lethal effects of nitrite to three species of freshwater invertebrates: the planarian Polycelis felina and the amphipods Echinogammarus echinosetosus and Eulimnogammarus toletanus. The LC50, LC10, and LC0.01 values (mg/L NO2N) at 24, 48, 72, and 96 h were calculated for each species. E. toletanus and E. echinosetosus were the most sensitive species, with 96 h LC50 values of 2.09 and 2.59 mg/L NO2N, respectively. In contrast, the planarian P. felina showed a higher tolerance to nitrite, with a 96 h LC50 value of 60.0 mg/L NO2N. The obtained results were compared with the reported nitrite data for other freshwater invertebrates. This study may contribute to a more appropriate assessment of the ecological risk of this compound in freshwater ecosystems. © 2006 Wiley Periodicals, Inc. Environ Toxicol 21: 90–94, 2006.

High level of heavy metal contaminants in air is known to cause serious health problems if remained unchecked for a long period of time. Anthropogenic activities such as vehicular emissions and number of industries are responsible for increasing the level of heavy metals. The aim of the present study was to biologically monitor the level of heavy metal contamination by spider webs. These sites were selected based on variable traffic volume and number of industries. Atomic absorption spectrometry (AAS) was used for the analysis of metal pollution content. The study determined that the level of heavy metals at the selected sampling sites were several folds higher than that at the control site and in previously reported literature. Pb was determined to be the most abundant heavy metal, while Thokar Niaz Baig was reported as the most contaminated site. These elevated levels of metal contaminants are associated with heavy traffic flow, number of industries and constructional activities in the respective areas.