Assessment of relative bioavailability of heavy metals in soil using in vivo mouse model and its implication for risk assessment compared with bioaccessibility using in vitro assay

There is limited study to simultaneously determine the relative bioavailability of heavy metals such as Cd, Pb, Cu, Cr(VI), and Ni in soil samples. In the present study, the bioaccessibility of heavy metals using in vitro assay was compared with the relative bioavailability of heavy metals using in vivo mouse model. The bioaccessibility of heavy metals ranged from 9.05 ± 0.97 % (Cr) to 42.8 ± 3.52 % (Cd). The uptake profile of heavy metals in soil and solution samples in mouse revealed that the uptake kinetics could be fitted to a two-compartment model. The relative bioavailability of heavy meals ranged from 34.8 ± 7.0 % (Ni) to 131 ± 20.3 % (Cu). Poor correlation between bioaccessibility and relative bioavailability of heavy metals was observed (r ² = 0.11, p > 0.05). The relative bioavailability of heavy metals was significantly higher than the bioaccessibility of heavy metals (p < 0.05). The present study indicated that the in vitro digestion method should be carefully employed in risk assessment.     

A simple and robust method for determination of neem (Azadirachta indica A. Juss) oil in neem oil coated urea

The production of neem oil coated urea (NOCU), a technology developed by the Indian Agricultural Research Institute, has been grown to over 2.0 million tons per year. The estimation of neem oil content in NOCU is important due to its significance in ensuring agronomic efficiency. Therefore, this study was taken up to develop a simple method for the determination of neem oil in NOCU. The procedure involves extraction of neem oil from NOCU; saponification of extracted oil; oxidation of released glycerol to formaldehyde, and subsequent conversion of formaldehyde to a dihydrolutidine derivative. Its concentration was determined spectrophotometrically. The recoveries of neem oil from NOCU with oil load of 500 and 1000?ppm were 87.6?±?3.0% and 90.0?±?4.8% respectively with direct method; and improved to 92.6?±?4.0% and 96.7?±?3.8% after including the in situ purification. A simple method based on the Hantzsch reaction was developed for the determination of neem oil in NOCU. This method is superior to earlier methods in terms of sensitivity, simplicity, and time required.     

栘依树抗氧化剂对香烟烟气自由基及人淋巴细胞姐妹染色单体交换率的影响

采用电子顺磁共振法研究了栘依树抗氧化剂对香烟烟气自由基含量的影响,并比较了不同自由基含量的香烟烟气冷凝物(CSC)对人淋巴细胞姐妹染色单体的损伤情况.在香烟滤嘴中注入50μL0.2%的栘依树抗氧化剂溶液后,香烟烟气中气相、粒相自由基含量分别降低40.2%和28.3%,平均降低39.6%;中高剂量的实验烟(添加栘依树),与对照烟(不加栘依树)相比,人淋巴细胞姐妹染色单体交换率显著降低(t＞t0．05),其中中剂量烟降低幅度更大；低剂量实验烟与对照烟相比,姐妹染色单体交换率也有降低趋势,但差异不显著(t相似文献   

葡多酚对口服乙醇小鼠肝细胞PCNA和Bcl-2表达的影响

为观察葡多酚(GPC)对小鼠乙醇性肝损伤的防护作用,将每天经口灌胃给予4 g·(kg·bw)-1乙醇的小鼠同时分别给予不同剂量的GPC,30 d后处死小鼠;取肝组织用MTT法检测各组小鼠肝细胞的增殖活性,用免疫组化法和图像分析方法检测PCNA和Bcl-2表达水平.结果显示:GPC高剂量组16 h的肝细胞增殖活性为0.4...     

Development of a complex-based flow injection spectrophotometric method for determination of the herbicide pinoxaden in environmental samples

A flow injection (FI) spectrophotometric method for the determination of the herbicide pinoxaden (PXD) has been proposed. PXD was converted in alkaline media with hydroxylamine hydrochloride to the hydroxamate salt. The salt was reacted with iron(III) chloride, and the absorbance of the red colored tris iron hydroxamate complex was measured at 500?nm using a FI system. The method was found to be linear between 0.5 and 40?mg?L^?1 with a molar absorptivity of 1.53?×?10^4?L?mol^?1?cm^?1. The limit of detection and limit of quantification were found to be 0.1?±?0.01?mg?L^?1 and 0.6?±?0.05?mg?L^?1, respectively. Any interference of fenoxaprop-p-ethyl (FE) was avoided by the separation of PXD by liquid chromatography with a mixture of dichloromethane and n-hexane (1?:?1) as eluent. The method was applied to the determination of PXD in soil, water, and wheat grains with percent recoveries of 98?±?2, 100?±?2, and 98?±?5, respectively. Sample throughput of 60 samples per hour was achieved under optimized conditions.     

A novel extraction method for analysing available sulfamethoxazole in soil

A novel extraction method was established to determine the water-extractable (available) content of sulfamethoxazole (SMX) in soil. The SMX imprinted polymers (MIPs) were synthesised and the performance was evaluated by Fourier transform infrared spectroscopy, scanning electron microscopy and binding experiments. Results showed that the MIPs exhibited good selectivity for SMX, so the MIPs were applied as a sorbent. SMX in soil was extracted by water, sorbed from the extract to MIPs and analysed with a high performance liquid chromatography (HPLC) after its desorption from MIPs. Meanwhile, the classic organic solvent extraction was employed to measure the total SMX content in soil. Results showed that when SMX level in spiked soils varying from 1.0–500?μg?kg^?1, the observed recoveries of available SMX contents ranged from 63.27?±?3.11% to 82.11?±?2.77% (n?=?3), while the total SMX varied between 89.59?±?1.65% and 97.64?±?3.92% (n?=?3). The detection limit of the developed method for SMX in soils was 0.05?μg?kg^?1. Available SMX contents in five field soil samples ranged from 0.13 to 4.14?μg?kg^?1, which were only 0.35–25.40% of the respective total SMX contents. Results from this study manifest the importance of the extents of SMX immobilisation with different soils for assessing SMX's ecological and human health risks.     

Application of ecosystem health cost-effect analysis in eco-planning in Guangzhou City, China

Ecosystem health has been a focal point and research frontier of applied ecology in recent years, increasingly used in urban ecological studies. To quantify the effect of ecological improvement from eco-planning, an ecosystem health assessment method is used in eco-planning evaluation and decision support in the urban eco-planning research of Guangzhou City of China. Based on features of an urban ecosystem, five factors such as vigor, organizational structure, resilience, ability to maintain ecosystem service, and influence on people’s health were selected to develop the assessment indicator system. Then, to evaluate the validity of planning measures, a cost-effect analysis of the different scenarios on eco-planning was made, taking investment of the planned projects as the cost and ecosystem health state after implementing the scenarios as the effect. To establish priority of all the proposed planning schemes or countermeasures, variation of the ecosystem health state was evaluated when the investment of eco-environmental construction projects changes by ±10%, ±20% and ±50%, respectively. Thus, the order of importance of eco-environment construction projects to the urban ecosystem health state can be worked out, providing a reference for prioritizing the implementation of such urban eco-environmental projects. The study proved the trial value of an ecosystem health evaluation method in urban eco-planning research.     

Vertical distribution and mortality of <Emphasis Type="Italic">Calanus finmarchicus</Emphasis> during overwintering in oceanic waters southwest of Iceland

The seasonal vertical distribution and the predatory regime encountered by Calanus finmarchicus were studied along a transect across the Reykjanes Ridge in the oceanic area southwest of Iceland from data collected during four cruises between November 1996 and June 1997. The mortality for the overwintering period was estimated using linear regressions of density estimates from November 1996 to April 1997. In addition, we also estimated the mortality of the oldest population stages (C4 and older) in April and June by applying the vertical table method. During winter (November/December–January/February), the animals mainly resided at a depth of ∼300–1,500 m in the water of Atlantic origin. Ascent to upper layers took place mainly during March and April, and continued until May. During all cruises, continuous deep-scattering layers were observed, mainly within the range of 400–500 m to 700–800 m depth. Based on sampling with a Harstad pelagic trawl in April, the scattering was mainly ascribed to jellyfish (mainly Periphylla periphylla), small mesopelagic oceanic fishes (several species but Benthosema glaciale and Maurolicus muelleri were most abundant), euphausiids (mainly Meganyctiphanes norvegica) and shrimps (mainly Sergestes arcticus). These species may represent a predatory threat to overwintering C. finmarchicus. From November to April, daily per capita mortality rates were estimated to be (mean ± 95% CL) 0.004 ± 0.0028 for the total data set, and 0.004 ± 0.0033 and 0.004 ± 0.0023 (day^-1) for the Iceland Basin and Irminger Basin, respectively. Mortality rates were higher later in life (mean ± 95% CL) for C5/females (0.13 ± 0.044) and C5/males (0.19 ± 0.051) than for C4/C5 (0.00 ± 0.035) when averaged over all samples taken in April and June 1997. We discuss how the observed distribution and mortality rates of overwintering C. finmarchicus might be related to predatory regime.     

土壤中六六六在消化道中生物可给性的体外测定

采用体外消化实验模拟了4种有机质含量不同的土壤中六六六在胃和小肠中的释放,重点验证了消化释放出来的六六六在固态消化残渣上的吸着现象以及该现象对测定消化率的影响的研究假设.结果表明,固相吸着对测定消化率有非常显著的影响,这在有机质含量偏高的土壤中尤其明显.吸着影响可以用不同液固比实验设计配合非线性拟合方法加以校正.对有机碳含量分别为0.63%、1.08%、1.60%和2.87%的4种土壤,未经校正的总六六六消化率的均值与标准差分别为(16.7±2.8)%、(11.6±2.0)%、6.9%和(26.4±1.3)%,校正后则分别达到16.7%、16.5%、16.5%和59.7%.显然,除有机质含量很低的样品,未经校正的测定结果显著低估了消化道吸收风险.     

Effects of molecular weight and concentration of carboxymethyl cellulose on morphology of hydroxyapatite nanoparticles as prepared with one-step wet chemical method

Nano-sized apatite particles (nAP) synthesized with carboxymethyl cellulose (CMC) have shown great application potentials in in situ heavy metal remediation. However, differences in CMC’s properties effects on the size of nAP produced are not well understood. In this paper, two types of CMC, with respective molecular weights (MW) of ～120000 and ～240000 Dalton or respective polymerization degrees of 500 (CMC-500) and 1050 (CMC-1050), were studied in a concentration range of 0.05%–0.5% (w/w) for nAP synthesis. Morphology of the particles was characterized with transmission electron microscopy (TEM). Results showed that 0.05% CMC-500 solution gave an average particle size of 148.7±134.9 nm, 0.25% CMC-500 solution produced particles of 21.8±20.4 nm, and, 0.5% CMC-500 solution contained particles of 15.8±7.7 nm. In comparison, 0.05% CMC-1050 solution produced nanoparticles of 6.8±3.2 nm, 0.25% CMC-1050 produced smaller nAP of 4.3±3.2 nm, and 0.5% CMC-1050 synthesized the smallest nanoparticles in this study, with an average diameter of 3.0±2.1 nm. Chemical composition of the products was identified with X-ray diffraction (XRD) as pure hydroxyapatite. Interactions between nAP and CMC were discussed with help of attenuated total reflection Fourier transform infrared (ATRFTIR) spectroscopic data. This study showed that CMC at higher concentration as well as higher MW facilitated to produce finer nanoparticles, showing that nAP size could be manipulated by selecting appropriate CMC MW and/or applying appropriate CMC concentration.     

Electro-remediation of tailings from a multi-metal sulphide mine: comparing removal efficiencies of Pb,Zn, Cu and Cd

Sulphidic mine tailings characterised by high concentrations of heavy metals (Pb 3532?±?97?mg/kg, Zn 8450?±?154?mg/kg, Cu 239?±?18?mg/kg and Cd 14.1?±?0.3?mg/kg) and abundant carbonate (17%) were subjected to eight lab-scale electrodialytic remediation (EDR) experiments to investigate the influence of current density, treatment time and particle size on removal efficiency. Pb and Cu removal improved when increasing current density, while Zn and Cd removal did not. In contrast Zn and Cd removal improved by grinding the tailings, while Pb and Cu removal did not. At the highest current density (1.2?mA/cm²), 94%, 75%, 71% and 67% removal of Pb, Zn, Cu and Cd could be achieved, respectively, on grinded tailings in 28 days. Sequential chemical extraction made before and after EDR revealed larger oxidisable fractions of Zn, Cu and Cd, representing large fractions of sulphides, which was likely to be the main barrier to be removed as efficiently as Pb. This was in accordance with acid/base extraction tests in which Pb showed high solubility at both high and low pH (up to 65% and 86% of extraction, respectively), while considerable extraction of Zn (55%) happened only at low pH; and very limited extraction (<20%) of Cu and Cd occurred at any pH.     

明日叶查尔酮对小鼠H22肝癌细胞增殖活性的抑制作用

为研究明日叶查尔酮(AC)对小鼠H22+肝癌细胞增殖的抑制作用,采用如下方法进行实验:1)将50只荷H22肝癌小鼠随机分为5组,每组10只.低、中、高剂量组每日分别灌胃给予5、20和40 mg·kg-1明日叶查尔酮,肿瘤对照组给予生理盐水,环磷酰胺(CTX)组隔天腹腔注射20 mg· kg-1的CTX.饲养10 d后处...     

Recycle of buried macroalgal detritus in sediments: use of dual-labelling experiments in the field

In intertidal sediments, burial and decomposition of macroalgal detritus can fuel the sediment of carbon (C) and nitrogen (N), which can be either promptly mineralised or assimilated to enter the food web. This study investigates the transfer of algal-derived C and N to the sediment and to the infauna feeding primarily on benthic diatoms. Thalli of Ulva spp. were ¹³C- and ¹⁵N-labelled in the mesocosm and frozen to create detritus. Thawed macroalgae were, then, buried in the sediment of an intertidal sand-flat forming a mosaic of small patches (50 × 50 cm²) enriched with the macroalgae interspersed with bare sediment. The area was dominated by Corophium volutator and Hydrobia ulvae. The uptake of ¹³C and ¹⁵N was measured in the residual macroalgae, in the sediment and in those animals. Decomposition of detritus was rapid and after 4 weeks the residual biomass was 3% the amount added. Algal-derived ¹³C and ¹⁵N were moved to the sediment. The total amount of ¹³C and ¹⁵N retained in the sediment after completing the decomposition was 3.4 ± 0.5% ¹³C and 2.7 ± 0.6% ¹⁵N the amount decomposed. During the first 2 weeks more N than C was assimilated (1.7% ¹³C and 13.5% ¹⁵N). During the remaining two weeks, N was released from the sediment, while there was little accumulation of C (+6.4 ± 2.0 % ¹³C and −7.7 ± 3.8% ¹⁵N). At the end of the decomposition, animals were ¹⁵N- and ¹³C-labelled. Considering the total accumulation of label in the sediment, they accounted for 3.5 ± 1.8% ¹³C and 25.8 ± 12.9 % ¹⁵N. Similarly, considering the mass of the heavy isotopes gained (¹³C) or lost (¹⁵N) during the remaining 2 weeks, the animals accounted for 4.7 ± 2.1% of the ¹³C in excess and for 18.6 ± 9.1% of the ¹⁵N loss. The transfer of C and N to the sediment and to the surface deposit-feeders can be a relevant mechanism to remove the excess of detritus from the sediment.     

Assessment of radon concentration and heavy metal contamination in groundwater of Udhampur district,Jammu &amp; Kashmir,India

Radon concentration was measured in water samples of 41 different locations from Udhampur district of Jammu & Kashmir, India, by using RAD7 and Smart RnDuo monitor. The variation of radon concentration in water ranged from 1.44 ± 0.31 to 63.64 ± 2.88 Bq L^?1, with a mean value of 28.73 Bq L^?1 using RAD7 and 0.64 ± 0.28 to 52.65 ± 2.50 Bq L^?1, with a mean value of 20.30 Bq L^?1 using Smart RnDuo monitor, respectively. About 17.07% of the studied water samples recorded to display elevated radon concentration above the reference range suggested by United Nation Scientific Committee on the Effects of Atomic Radiations (UNSCEAR). The mean annual effective dose of these samples was determined, and 78.95% samples were found to be within the safe limits set by World Health Organisation (WHO) and European Council (EU). The study revealed good agreement between the values obtained with two methods. Heavy metals (Zn, Cd, Fe, Cu, Ni, As, Hg, Co, Pb and Cr) were determined in water samples by microwave plasma atomic emission spectrometer, and their correlation with radon content was also analysed.     

真鲷去毒相关基因cDNA序列的克隆与肝脏组成型表达分析

赤潮发生时产生的一些海洋生物毒素对人类和海洋动物的安全形成潜在的威胁甚至导致死亡.为从分子水平探讨鱼类中海洋藻毒素的去毒分子机理,采用RT-PCR法克隆了真鲷(Pagrus major)肝脏芳香烃受体核转位蛋白(ARNT)和I时相异生素代谢酶细胞色素P4501A(CYP1A)基因cDNA核心序列,同时,应用半定量RT-PCR方法,以β-肌动蛋白作为外参照,在其指数期增长的范围内研究了芳香烃受体(AHR)、ARNT、CYP1A、II时相异生素代谢酶alpha型谷胱甘肽S-转移酶(GSTA1、GSTA2)、rho型谷胱甘肽S-转移酶(GSTR)、热休克蛋白70(HSP70)基因组成型表达水平.结果发现,真鲷ARNT、CYP1A基因cDNA核心序列片段分别长438bp和908bp,分别编码146和302个氨基酸.序列同源性分析发现,真鲷与门齿鲷(Stenotomus chrysops)、石首鱼(Micropogon undulatus)ARNT基因氨基酸序列同源性高达97.2%、95.2%,与斑马鱼(Brachydanio rerio)、人、大鼠、小鼠ARNT同源性较低(77.2%～79.3%).真鲷与门齿鲷、金头鲷(Sparus auratus)、欧洲川鲽(Rhombus maximus)、欧洲海鲈(Dicentrachus labrax)CYP1A基因氨基酸序列同源性较高,为84.8%～94.0%,与斑马鱼、人、小鼠CYP1A同源性较低,为59.6%～77.8%.真鲷肝脏AHR、ARNT、CYP1A、GSTA1、GSTA2、GSTR和HSP70基因组成型表达水平分别为(25.32±6.56)%、(26.22±4.24)%、(146.5±16.06)%、(55.42±3.75)%、(48.82±10.89)%、(79.47±3.13)%、(107.42±14.34)%.     

Elemental composition of particulate matters around Urmia Lake,Iran

Atmospheric particulate matters and their elements were concurrently measured at two sites located in the north and southeast parts of Urmia Lake from January to September 2013. At both sampling sites, average concentrations of total suspended particulate, particles with the aerodynamic diameter of smaller than 10 µm, smaller than 2.5 µm, and smaller than 1 µm were 260 ± 106, 180 ± 73, 30 ± 8, and 25 ± 7 µg m^?3, respectively. The analyzed water soluble ions accounted for approximately 11%–13% mass concentrations of total suspended particulate and 8%–9% of particles smaller than 10 µm, and the sum of the concentrations of the analyzed elements associated with both ranged from 9 to 41 µg m^?3 (6.5%–9.6% in mass) and 7 to 26 µg m^?3 (5.5%–11.3% in mass), respectively. Thus, particulate matter was composed of a complex mixture of minerals such as halite, quartz, gypsum, hexahydrite, and Bassanite.     

Extracellular polymeric substances (EPS) from cyanobacterial mats: characterisation and isolation method optimisation

Extracellular polymeric substances (EPS) play an important role in bacterial mat formation and sediment stabilisation of coastal zones. The analysis of these secretion products on a molecular level is a prerequisite to understand their formation mechanisms and ecological function in microbial consortia. The present study focuses on the optimisation of EPS isolation and characterisation from cohesive cyanobacterial mats. Extracted EPS were analysed for quantity, content of total organic carbon and nitrogen, and bulk contents of neutral sugars, uronic acids, and proteins. These criteria are strongly influenced by the extraction conditions applied and therefore, the effects of different extraction media (NaCl or artificial seawater), addition of EDTA, centrifugal force, and purification via repeated ethanol precipitation on extraction success were determined. From this an optimised extraction procedure for EPS resulted. When using fresh mat samples, the yield of EPS amounted to 3.3 ± 0.8 mg g⁻¹ mat (dw). The isolated EPS were composed of nearly equal amounts of proteins and uronic acids (12.7 ± 1.5 and 11.8 ± 1.1%, respectively) and the bulk content of neutral sugars was 30.5 ± 2.6%. High contents of TOC and TN indicated relatively pure EPS and only a low contribution of inorganic compounds. Furthermore, low contents of 2-keto-3-deoxyoctonate and the small protein/polysaccharide-ratio in the EPS extracted by our method, signified low contaminations by intracellular polymers and hence a low rupture of cells. Our method provides an useful tool to evaluate further investigations of the composition, characteristics and properties of EPS on a sound basis.     

Metallothionein induction in mice by CCL4: Hepatic Zn‐status and distribution of administered Cd∗

Induction of metallothionein (MT), Zn status and the subcellular distribution of administered Cd were studied in liver after single administration of CC1₄ to mice. Hepatic MT was increased up to 153±16 μMT/g liver 18 h after injection of 2ml CCl₄/kg body weight. The observed decrease in Zn bound to cytosolic high molecular weight proteins from 25.5 ± 0.6 to 19.8±1.1 resp. 19.0 ± 1.7 μgZn/g and the increase in MT bound Zn from 4.0±0.5 to 9.5 ± 1.1 resp. 10.9±1.1 μgZn/g compensate each other.

Zn content of whole liver and hepatic cytosol remained unchanged. Hepatic subcellular distribution of 4 mg Cd/kg body weight, administered 2 h prior termination was also influenced by CC1₄. Cd bound to high molecular weight proteins decreased from 10.0±1.0 to 7.2±1.6 resp. 3.7 ± 2.6 μg Cd/g and Cd bound to MT increased from 12.5 ± 1.4 to 18.0 ± 3.8 resp. 23.1± 6.4 μgCd/g. Cd content of both, whole liver and cytosol was not significantly different from control. The induction of MT has been suggested to be beneficial due to its role in the sequestration of toxic metals. The depletion of Zn from cytosolic high molecular weight proteins however might adversively influence essential physiological processes.     

Spore inhibition-based enzyme substrate assay for monitoring of aflatoxin M1 in milk

A spore germination-based concept and its transformation into a field level prototype for monitoring aflatoxin M₁ (AFM₁) in milk was developed. Initially, 15 strains of Bacillus spp. procured from different culture collection were screened for AFM₁ sensitivity using spot assay and marker strain showing inhibition at 0.5 ppb was selected based upon maximum zone of inhibition. The selected strain B. megaterium 2949 was further screened for different enzymes activities and subsequently its spores were produced to an extent of 73.13% ± 3.197% in newly developed sporulation medium containing beef extract (0.0075% ± 0.0004%), yeast extract (0.015% ± 0.001%), peptone (0.0375% ± 0.0016%), and sodium chloride (0.0375% ± 0.0018%). A spore germination-based concept/ assay was optimized by immobilizing spores in eppendorf with pretreated milk (80°C/15 min) containing germinant and chromogenic substrate followed by incubation at 37°C. The appearance of sky blue color within real time of 45 min indicated spores germination and release of specific marker enzyme such as acetyl esterase and its specific action on chromogenic substrate which demonstrates absence of AFM₁ in milk. However, if there was no color change, presence of AFM₁ at 0.5 ppb MRL was denoted by Codex. The developed concept on AFM₁ detection was validated and a correlation of 0.97 was established with AOAC approved Charm 6602 and ELISA at Codex MRL with minimal false positive and negative results. The cost effective test has potential application in dairy farms, manufacturing, and R&D units for routine monitoring of AFM₁ in milk.     

Broad-band versus narrow-band irradiance for estimating latitude by archival tags

The relative effectiveness of different bands of irradiance to estimate the latitude of archival tags was evaluated. These tags are placed on fishes in order to describe their movements during long distance migrations. Measurements were recorded of broad-band irradiance with and without a cosine collector and narrow-band irradiance of seven narrow bands with 50% attenuation 30 nm on either side of their central wavelength of 400 (violet), 450 (blue), 500 (blue–green), 550 (green), 600 (yellow), 650 (orange), and 700 nm (red). A holographic, cosine collector was used to reduce the vertical transmission of irradiance to the sensor and to increase horizontal transmission of irradiance so the sensor detected more of the diffuse irradiance penetrating the water at dawn and dusk. Daily measurements were made during seven periods of 1–2 days each, beginning 28 June (after 21 June solstice) and ending on 6 October 1999 (after September 23 equinox) of submarine irradiance at 15-s intervals at a fixed depth (10 m) and location (38.31°N; 123.08°W) in Horseshoe Cove, California. Irradiance transmission at this site is intermediate between the clearest offshore waters, where blue irradiance (450 nm) penetrates farther with depth than green irradiance (550 nm) and most oceanic and coastal waters, where green penetrates farther than blue irradiance. Two algorithms were used to estimate latitude, the maximum slope method and the maximum logarithmic difference method. The broad-band, cosine-corrected light, excluding those deployments near the equinox when error is highest, produced an estimate of latitude of 38.30° for both methods and a latitudinal error of ±34.4 km for the former and ±27.2 km for the latter. The mean latitudinal error for non-cosine-collected, broad-band irradiance was ±190.9 km, using the slope algorithm and ±184.8 km using the difference algorithm. The blue band of irradiance, which attenuates least with increasing depth in clear, oceanic water, also produced a comparatively high-latitudinal error of ±163.8 km error for the former algorithm and ±170.4 km for the latter algorithm. Tag designers should consider using cosine-collectors over the irradiance sensors on their archival tags to increase the accuracy of position estimates.